Comparative Vertebrate Anatomy Unit Two Objectives One & Two

Comparative Vertebrate AnatomyUnit Two

Objectives One & Two

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Vertebrate Skeletal FunctionsVertebrate Skeletal Functions

Gives the body shapeGives the body shape

Supports the body weightSupports the body weight

Acts as levers for movementActs as levers for movement

Provides surface for muscle Provides surface for muscle attachment (origins & attachment (origins & insertions)insertions)

Vertebrate Skeletal FunctionsVertebrate Skeletal Functions

Protects soft tissues and Protects soft tissues and internal organsinternal organs

Mineral storageMineral storage

Blood cell productionBlood cell production

Vertebrate Skeletal Vertebrate Skeletal ComponentsComponents

Exoskeleton - superficial or Exoskeleton - superficial or integumentalintegumental * arises from the dermis or * arises from the dermis or keratinized epidermiskeratinized epidermis * provides protection for body * provides protection for body surface & external supportsurface & external support * dermal bone may sink and * dermal bone may sink and associate with deep bone to associate with deep bone to form a composite boneform a composite bone


Endoskeleton – deep boneEndoskeleton – deep bone * arises from the mesoderm* arises from the mesoderm * includes bones and * includes bones and associated associated cartilages & ligamentscartilages & ligaments * supports and protects the * supports and protects the body, body, provides surface for muscle provides surface for muscle attachment, produces blood attachment, produces blood cells and stores mineralscells and stores minerals


The vertebrate skeleton can be The vertebrate skeleton can be divided into two regions:divided into two regions: * cranial skeleton (skull)* cranial skeleton (skull) > splanchnocranium> splanchnocranium > chondrocranium> chondrocranium > dermatocranium> dermatocranium * functions to support and * functions to support and protect the brain and sense protect the brain and sense organsorgans


The vertebrate skeleton can be The vertebrate skeleton can be divided into two regions:divided into two regions: * postcranial skeleton* postcranial skeleton > axial skeleton> axial skeleton > forms the longitudinal > forms the longitudinal axisaxis > appendicular skeleton> appendicular skeleton > pectoral & pelvic girdles> pectoral & pelvic girdles


Splanchnocranium Splanchnocranium * arises from the ectodermal * arises from the ectodermal neural crest cellsneural crest cells * forms the branchial arches* forms the branchial arches * comprised of up to five * comprised of up to five articulated elements/sidearticulated elements/side > pharyngobranchial, > pharyngobranchial, epibranchial, epibranchial, ceratobranchial, ceratobranchial, hypobranchial, hypobranchial, basibranchialbasibranchial


Splanchnocranium functions: Splanchnocranium functions: * supports gills* supports gills * surface for attachment of * surface for attachment of respiratory musclesrespiratory muscles * contributes to jaw (arch I)* contributes to jaw (arch I) * contributes to hyoid arch * contributes to hyoid arch (arch II)(arch II)

SplanchnocraniSplanchnocraniumum

Vertebrate Skeletal Vertebrate Skeletal ComponentsComponentsChondrocranium Chondrocranium

* arises from the ectodermal * arises from the ectodermal neural crest cells and the neural crest cells and the mesenchymal cells of the mesenchymal cells of the mesodermmesoderm * the ectodermal elements * the ectodermal elements form form the nasal capsule and part the nasal capsule and part of of the otic capsule and the otic capsule and trabeculaetrabeculae * the mesodermal elements * the mesodermal elements form form the rest of the the rest of the chondrocraniumchondrocranium


Chondrocranium functions: Chondrocranium functions: * forms the braincase of * forms the braincase of elasmobranchs (no elasmobranchs (no ossification)ossification) * forms the scaffolding of the * forms the scaffolding of the brain in other vertebratesbrain in other vertebrates (partial to total ossification)(partial to total ossification)

ChondrocraniuChondrocraniumm


Dermatocranium Dermatocranium * arises from ectodermal and * arises from ectodermal and mesodermal tissues of the mesodermal tissues of the dermisdermis * made up of dermal bones * made up of dermal bones that that are produced by are produced by intramembranous intramembranous ossificationossification * comprises most of the skull * comprises most of the skull in in amniotesamniotes


Dermatocranium functions: Dermatocranium functions: * forms the roof and lateral * forms the roof and lateral elements of the skull, elements of the skull, completing a bony completing a bony encasement encasement for the brainfor the brain * contributes to the jaw * contributes to the jaw casementcasement

DermatocraniDermatocraniumum


Dermatocranium can by groups Dermatocranium can by groups in “series” according to their in “series” according to their locationlocationFacial series are the bones that Facial series are the bones that encircle the external nares and encircle the external nares and form the snoutform the snout > premaxilla> premaxilla > maxilla> maxilla > nasal> nasal > septomaxilla (may be > septomaxilla (may be absent) absent)


Dermatocranium can by groups Dermatocranium can by groups in “series” according to their in “series” according to their locationlocationOrbital series are the bones Orbital series are the bones that encircle the eyethat encircle the eye > lacrimal> lacrimal > prefrontal & postfrontal> prefrontal & postfrontal > postorbital> postorbital > jugal > jugal

Vertebrate Skeletal Vertebrate Skeletal ComponentsComponentsDermatocranium can by groups Dermatocranium can by groups

in “series” according to their in “series” according to their locationlocationTemporal series are the bones Temporal series are the bones that lie behind the orbit & that lie behind the orbit & complete the posterior wall of complete the posterior wall of the braincasethe braincase > intertemporal & > intertemporal & supratemporalsupratemporal (absent in amniotes)(absent in amniotes) > tabular (absent in > tabular (absent in amniotes)amniotes) > squamosal> squamosal > quadratojugal > quadratojugal


Dermatocranium can by groups Dermatocranium can by groups in “series” according to their in “series” according to their locationlocationVault series are the bones that Vault series are the bones that form a roof over the brainform a roof over the brain > frontal> frontal > postparietal (interparietal)> postparietal (interparietal) > parietal > parietal


in “series” according to their in “series” according to their locationlocationPalatal series are the bones Palatal series are the bones that form the roof of the mouth that form the roof of the mouth (may bear teeth)(may bear teeth) > pterygoid> pterygoid > vomer> vomer > palatine> palatine > ectopterygoid> ectopterygoid > parasphenoid > parasphenoid


in “series” according to their in “series” according to their locationlocationMandibular series are the Mandibular series are the bones that form the jawbones that form the jaw > dentary> dentary > splenials> splenials > angular> angular > surangular> surangular > prearticular> prearticular > coronoids > coronoids


Objective Three




Vertebrate Jaw FormationVertebrate Jaw Formation

The jaw first formed in The jaw first formed in acanthodians and acanthodians and placodermsplacoderms

Opened up an enormous Opened up an enormous variety of new food variety of new food sources, first as a capture sources, first as a capture trap and then as a trap and then as a crushing, chewing crushing, chewing structurestructure

These fish were no longer These fish were no longer confined to ciliary/mucus confined to ciliary/mucus feedingfeeding

Vertebrate Jaw FormationVertebrate Jaw FormationThe serial theory of jaw The serial theory of jaw originorigin ~ T. H. Huxley~ T. H. Huxley ~ jaws developed from ~ jaws developed from the first the first two pair of gill archestwo pair of gill arches ~ arch I gave rise to the ~ arch I gave rise to the mandibular arch, while mandibular arch, while arch II arch II gave rise to the hyoid gave rise to the hyoid archarch ~ posterior arches ~ posterior arches became became gnathostome branchial gnathostome branchial archesarches


The composite theory of jaw The composite theory of jaw originorigin ~ Erik Jarvik~ Erik Jarvik ~ hypothesizes ten ~ hypothesizes ten original original branchial archesbranchial arches ~ arch I ~ arch I »» terminal arch terminal arch ~ arch II ~ arch II » » premandibular premandibular archarch ~ arch III ~ arch III » » mandibular mandibular archarch ~ arch II ~ arch II » » hyoid archhyoid arch


The composite theory of jaw The composite theory of jaw originorigin ~ states that several ~ states that several elements of elements of several arches came several arches came together to together to form one composite form one composite mandiblemandible

VertebrVertebrate Jaw ate Jaw FormatiFormati

onon

Vertebrate Jaw AttachmentVertebrate Jaw Attachment

Jaw attachment types are Jaw attachment types are based on their based on their suspensorium (how the suspensorium (how the mandible is attached)mandible is attached)Currently six recognized Currently six recognized types of jaw attachmenttypes of jaw attachment


Euautostylic - Euautostylic - mandibular mandibular arch arch suspended by suspended by itselfitselfPaleostylic - Paleostylic - no arches no arches attached to attached to the skull the skull


Amphistylic - jaw attached Amphistylic - jaw attached by two articulationsby two articulations > anteriorly by a ligament > anteriorly by a ligament to the to the palatoquadratepalatoquadrate > posteriorly to the > posteriorly to the hyomandibulahyomandibula


AmphistyAmphistyliclic


Metautostylic Metautostylic – jaw attaches – jaw attaches directly directly through the through the quadrate bonequadrate boneHyostylic – Hyostylic – mandibular mandibular arch attaches arch attaches through the through the hyomandibulahyomandibula

Vertebrate Jaw AttachmentVertebrate Jaw AttachmentCraniostylic - lower jaw Craniostylic - lower jaw (dentary) is suspended from (dentary) is suspended from the squamosal the squamosal > the upper jaw is a part of > the upper jaw is a part of the the braincasebraincase > no jaw contribution from > no jaw contribution from the the splanchnocraniumsplanchnocranium > palatoquadrate & > palatoquadrate & Meckels Meckels cartilage become the cartilage become the incus & incus & malleusmalleus

VertebraVertebrate Jaw te Jaw

AttachmAttachmentent

CraniostyCraniostyliclic


Objective Four




The movement between the The movement between the upper jaw and the braincaseupper jaw and the braincase

The majority of gnathostomes The majority of gnathostomes exhibit cranial kinesisexhibit cranial kinesis

This characteristic has its This characteristic has its advantages and advantages and disadvantages disadvantages

Advantages: Advantages: ~ mouth configuration & size ~ mouth configuration & size can be can be rapidly changed to rapidly changed to accommodate accommodate prey size and feeding prey size and feeding strategystrategy ~ the moveable upper jaw ~ the moveable upper jaw bearing bearing teeth can be positioned for teeth can be positioned for the the most effective chewing or most effective chewing or bitingbiting

Disadvantages: Disadvantages: ~ the loosely articulated ~ the loosely articulated bones have bones have less supportless support ~ the weaker support results ~ the weaker support results in less in less strength for biting and strength for biting and chewingchewing

The lack of movement The lack of movement between the upper jaw and between the upper jaw and the braincase (fused)the braincase (fused)Characteristic of amphibians, Characteristic of amphibians, turtles, crocodilians & turtles, crocodilians & mammalsmammalsThis condition has its This condition has its advantages and advantages and disadvantages disadvantages

Advantages: Advantages: ~ provides strong support for ~ provides strong support for the the tooth bearing upper jaw, tooth bearing upper jaw, leading leading to a firmer, more powerful to a firmer, more powerful biting biting and chewing mechanismand chewing mechanism ~ enables young mammals to ~ enables young mammals to sucklesuckle

Disadvantages: Disadvantages: ~ the ability to protract the ~ the ability to protract the jaw is jaw is extremely limitedextremely limited ~ the limited protractability ~ the limited protractability means means akinetic skulls cannot akinetic skulls cannot perform the perform the actions of the kinetic skull actions of the kinetic skull


Objective Five




Vertebrate Skull Vertebrate Skull PhylogenyPhylogenyThe vertebrate skull is a The vertebrate skull is a composite of the composite of the splanchnocranium, splanchnocranium, chondrocranium & chondrocranium & dermatocranium, with each dermatocranium, with each coming from a separate coming from a separate phylogenetic sourcephylogenetic sourceSkull evolution and variation Skull evolution and variation are reflections of cephalization are reflections of cephalization & feeding styles& feeding styles

Vertebrate Skull Vertebrate Skull PhylogenyPhylogeny

The evolution of the The evolution of the gnathostome skull represents a gnathostome skull represents a shift in diet and a more active shift in diet and a more active lifestylelifestyleSome skull components are Some skull components are derived from the bony shields of derived from the bony shields of early gnathostomes such as early gnathostomes such as placoderms & acanthoidiansplacoderms & acanthoidians


Chondrichthyes Chondrichthyes (sharks, skates & rays)(sharks, skates & rays) ▪ ▪ skeleton is almost entirely skeleton is almost entirely cartilage, with very few cartilage, with very few bones bones present present ▪ ▪ the chondrocranium forms the chondrocranium forms the the entire braincase, while the entire braincase, while the dermatocraium is absentdermatocraium is absent


Chondrichthyes Chondrichthyes (sharks, skates & rays)(sharks, skates & rays) ▪ ▪ exhibit a modified hypostylic exhibit a modified hypostylic skull, allowing extensive skull, allowing extensive protraction/retraction of the protraction/retraction of the jawjaw



Actinopterygii Actinopterygii (modern ray finned bony fish)(modern ray finned bony fish) ▪ ▪ skeleton is almost entirely skeleton is almost entirely bone, with an increase in the bone, with an increase in the number of skull bonesnumber of skull bones ▪ ▪ many elements of the skulls many elements of the skulls have have been liberated (kinesis), been liberated (kinesis), assisting in the procurement assisting in the procurement of of foodfood


Actinopterygii Actinopterygii (modern ray finned bony fish)(modern ray finned bony fish) ▪ ▪ opercular bone present, opercular bone present, covering the gills and covering the gills and contributing to opercular contributing to opercular pumpingpumping ▪ ▪ due to the increase in prey due to the increase in prey size, size, the buccal cavity is more the buccal cavity is more muscularized for better muscularized for better chewingchewing


Actinopterygii Actinopterygii (modern ray finned bony fish)(modern ray finned bony fish) ▪ ▪ exhibit a hyostylic exhibit a hyostylic suspensorium suspensorium that often has a symplectic that often has a symplectic bone bone to support kinesisto support kinesis


VertebraVertebrate Skull te Skull

PhylogenPhylogenyy


Sarcopterygii Sarcopterygii (lobe finned bony fish)(lobe finned bony fish) ▪ ▪ most exhibit akinesis, most exhibit akinesis, indicating indicating hard prey itemshard prey items ▪ ▪ the crossopterygians do the crossopterygians do exhibit exhibit kinesis and have kinesis and have labyrinthodont labyrinthodont teeth (coelocanth)teeth (coelocanth)


AmphibiaAmphibia(modern amphibians)(modern amphibians) ▪ ▪ exhibit a major reduction in exhibit a major reduction in dermal skull bonesdermal skull bones ▪ ▪ the splanchnocranium is the splanchnocranium is reduced with the loss of the reduced with the loss of the hyomandibula as a jaw bone hyomandibula as a jaw bone (becomes the columella) and (becomes the columella) and loss of the opercular seriesloss of the opercular series


AmphibiaAmphibia(modern amphibians)(modern amphibians) ▪ ▪ pectoral girdle is detached pectoral girdle is detached from from the skullthe skull ▪ ▪ jaw articulates between the jaw articulates between the articular (Meckels cartilage) articular (Meckels cartilage) and and quadrate bonesquadrate bones ▪ ▪ well developed hyoid well developed hyoid apparatusapparatus ▪ ▪ otic notch present for otic notch present for tympanumtympanum


AmphibiaAmphibia(modern amphibians)(modern amphibians)


ReptiliaReptilia(parareptilia & eureptilia)(parareptilia & eureptilia) ▪ ▪ exhibits diversity in the exhibits diversity in the dermatocranium (temporal dermatocranium (temporal fenestrae)fenestrae) ▪ ▪ turtles - anapsid, have no turtles - anapsid, have no teeth teeth or prostrusible tongue & or prostrusible tongue & exhibit exhibit the articular/quadrate jaw the articular/quadrate jaw articulation (hyomandibula articulation (hyomandibula becomes the columella)becomes the columella)


ReptiliaReptilia(parareptilia & eureptilia)(parareptilia & eureptilia) ▪ ▪ all other modern reptiles all other modern reptiles (excluding crocodilians) are (excluding crocodilians) are diapsid and exhibit increased diapsid and exhibit increased motility of the tongue motility of the tongue (lingual (lingual feeding) and extensive feeding) and extensive cranial cranial kinesiskinesis


ReptiliaReptilia(parareptilia & eureptilia)(parareptilia & eureptilia) ▪ ▪ skull kinesis increases in skull kinesis increases in snakes snakes and lizards due to the and lizards due to the transcranial jointtranscranial joint


ReptiliaReptilia(parareptilia & eureptilia)(parareptilia & eureptilia) ~ metakinesis - hinges at back ~ metakinesis - hinges at back of of the skullthe skull ~ mesokinesis - hinges at back ~ mesokinesis - hinges at back of the eyeof the eye ~ prokinesis - hinges in front ~ prokinesis - hinges in front of of orbitsorbits


ReptiliaReptilia(parareptilia & eureptilia)(parareptilia & eureptilia) ▪ ▪ crocodilians exhibit crocodilians exhibit akinesis, akinesis, thecodont dentition and the thecodont dentition and the development of a secondary development of a secondary palatepalate


ReptiliaReptilia(parareptilia & eureptilia)(parareptilia & eureptilia)


AvesAves(birds)(birds) ▪ ▪ diapsid skull with smaller diapsid skull with smaller size size and large reduction in and large reduction in number of number of bones (adaptation for flight)bones (adaptation for flight) ▪ ▪ the braincase is completely the braincase is completely ossified and expandedossified and expanded


AvesAves(birds)(birds) ▪ ▪ prokinetic jaw is formed into prokinetic jaw is formed into toothless beak with toothless beak with keratinized keratinized sheath along a nasal-frontal sheath along a nasal-frontal hingehinge ▪ ▪ have a quadrate-articular have a quadrate-articular jaw jaw articulationarticulation

VertebrVertebrate ate

Skull Skull PhylogePhyloge

nyny


MammaliaMammalia(mammals)(mammals) ▪ ▪ synapsi skull with extensive synapsi skull with extensive loss loss of or fusion of dermal boneof or fusion of dermal bone ▪ ▪ exhibit a zygomatic arch exhibit a zygomatic arch (processes of the squamosal (processes of the squamosal & & jugal)jugal) ▪ ▪ occipitals are fusedoccipitals are fused


MammaliaMammalia(mammals)(mammals) ▪ ▪ auditory bulla are enlarged auditory bulla are enlarged to to house the ossicles of the house the ossicles of the middle middle earear ▪ ▪ occiptal condyle is bilobed, occiptal condyle is bilobed, articulating with the atlasarticulating with the atlas ▪ ▪ have thin, scroll like bones have thin, scroll like bones in in the nasal capsule the nasal capsule (turbinates)(turbinates)


MammaliaMammalia(mammals)(mammals) ▪ ▪ formation of a nuchal crest formation of a nuchal crest across the occipital regionacross the occipital region ▪ ▪ dentary-squamosal dentary-squamosal articulation articulation of the jaw of the jaw ▪ ▪ quadrate & articular bones quadrate & articular bones move move from the jaw joint to become from the jaw joint to become the the malleus & incus (middle ear malleus & incus (middle ear ossicles)ossicles)


MammaliaMammalia(mammals)(mammals) ▪ ▪ secondary palate comprised secondary palate comprised of a of a hard and soft palatehard and soft palate ▪ ▪ exhibit diphodonty exhibit diphodonty

Vertebrate Vertebrate Skull Skull

PhylogenyPhylogeny



Objective Six





Objectives Seven




History of the Articular, History of the Articular, Quadrate & Hyomandibula Quadrate & Hyomandibula

BonesBones Taxon Articular Quadrate Hyomandibula

Sharks Meckel’s Palatoquadrate

Yes

Bony fish Yes Yes Yes

Amphibians Yes Yes Columella

Reptiles Yes Yes Columella

Birds Yes Yes Columella

Mammals Malleus Incus Stapes

History of the Articular, History of the Articular, Quadrate & Hyomandibula Quadrate & Hyomandibula

BonesBones


Objectives Eight




Vertebrate PalatesVertebrate Palates

Primary palatePrimary palate » the floor of the skull (roof » the floor of the skull (roof of mouth) of mouth) » comprised of the following » comprised of the following and their and their derivatives (at least in derivatives (at least in part)part) ~ vomer~ vomer ~ palatine~ palatine ~ pterygoid~ pterygoid ~ ectopterygoid~ ectopterygoid ~ paraspheniod~ paraspheniod

Vertebrate PalatesVertebrate Palates

Secondary palateSecondary palate » forms ventrally to the » forms ventrally to the primary palate primary palate » formed from extensions of » formed from extensions of the the followingfollowing ~ maxilla~ maxilla ~ palatine~ palatine ~ premaxilla~ premaxilla » separates the respiratory » separates the respiratory passage passage from the mouthfrom the mouth

Vertebrate Vertebrate PalatesPalates

Secondary Secondary palatepalate » found in » found in crocodilians crocodilians and and mammals mammals » contributes » contributes to to akinesisakinesis


Objective Nine




Composite SkullComposite Skull

The composite skull is The composite skull is composed of modified portions composed of modified portions of the dermatocranium, of the dermatocranium, chondrocranium & chondrocranium & splanchnocraniumsplanchnocranium

Composite SkullComposite Skull

Armadillo Armadillo embryoembryo

Adult frogAdult frog

Composite BonesComposite Bones

Composite bones are those Composite bones are those which are composed of portions which are composed of portions of the dermatocranium, of the dermatocranium, chondrocranium & chondrocranium & splanchnocraniumsplanchnocraniumExamples include the temporal, Examples include the temporal, occipital & sphenoid bones occipital & sphenoid bones

Composite Composite BonesBones

Composite Skulls & BonesComposite Skulls & Bones

Composite skulls & bones Composite skulls & bones significantly reduce the overall significantly reduce the overall weight of the skull and increase weight of the skull and increase the strength of the bonesthe strength of the bones

Formation is caused by fusion, Formation is caused by fusion, loss of bones and movement of loss of bones and movement of bones to other areas bones to other areas

Comparative Vertebrate Anatomy

Unit TwoObjectives Ten, Eleven &

Twelve




Vertebral Column Vertebral Column (Vertebrae) Functions(Vertebrae) Functions

Protects the spinal cord & blood Protects the spinal cord & blood vesselsvesselsProvides surface area for muscle Provides surface area for muscle attachment attachment

Assists in suspension of the Assists in suspension of the body body Contributes to locomotion Contributes to locomotion

Distributes weight Distributes weight

Vertebrae ComponentsVertebrae Components

Dorsal arches Dorsal arches ◦ ◦ neural & interneural neural & interneural componentscomponents ◦ ◦ protects the neural tubeprotects the neural tubeVentral archesVentral arches ◦ ◦ hemal & interhemal hemal & interhemal componentscomponents ◦ ◦ protects blood vessels protects blood vessels


The dorsal pleurocentrum and The dorsal pleurocentrum and ventral intercentrum are ventral intercentrum are expansions of the bases of the expansions of the bases of the ventral arches that support and ventral arches that support and anchor the archesanchor the arches

These arches sit on the These arches sit on the notochord in early vertebrates notochord in early vertebrates



Primitive vertebral segments Primitive vertebral segments contain a maximum of each of contain a maximum of each of the following: the following: > two dorsal arches > two dorsal arches (neural & interneural)(neural & interneural) > two ventral arches> two ventral arches (hemal & interhemal)(hemal & interhemal) > two centra > two centra (pleural or hemal)(pleural or hemal)



Modification of these Modification of these components led to enlargement components led to enlargement of some and reduction of othersof some and reduction of others

Eventually the vertebrae Eventually the vertebrae replaced the notochord as the replaced the notochord as the primary mechanical axis primary mechanical axis

Over time vertebral segments Over time vertebral segments differentiated regionally within differentiated regionally within the column the column

Vertebrae DifferentiationVertebrae Differentiation

In fish the vertebrae In fish the vertebrae differentiate into a trunk region differentiate into a trunk region and a caudal region and a caudal region

In some tetrapods there is only In some tetrapods there is only cervical (anterior) and sacral cervical (anterior) and sacral (posterior) regions, while others (posterior) regions, while others have more differentiation have more differentiation


Cervical region - neck Cervical region - neck (anterior) (anterior) Thoracic region - chest Thoracic region - chest

Lumbar region - abdominal Lumbar region - abdominal (between thoracic & sacral)(between thoracic & sacral)

Sacral region - hips (posterior)Sacral region - hips (posterior)Caudal region - tailCaudal region - tail


This differentiation has This differentiation has occurred due to modification occurred due to modification and variation of the vertebrae and variation of the vertebrae componentscomponents

Centra and VariationsCentra and Variations

A centrum is the main body of a A centrum is the main body of a vertebraevertebrae

Variations among the taxa Variations among the taxa include the extent of include the extent of ossification, relative importance ossification, relative importance of the pleurocentrum & of the pleurocentrum & intercentrum, and the degree in intercentrum, and the degree in which the centra replace or which the centra replace or assist the notochord in supportassist the notochord in support

Centrum TypesCentrum Types

Aspondyly - no centrum Aspondyly - no centrum

Monospondyly - one centrum Monospondyly - one centrum per per segmentsegmentDispondyly - two centra per Dispondyly - two centra per segmentsegment - some exhibit - some exhibit bothboth types in types in different different regionsregions

Centrum TypesCentrum Types

Polyspondyly - five or six centra Polyspondyly - five or six centra per per segment segment - Holocephalii- Holocephalii

Centra and Neural ArchesCentra and Neural Arches

In tetrapods there are two In tetrapods there are two conditions relative to the centra conditions relative to the centra and neural archesand neural arches

Aspiospondyly - the Aspiospondyly - the intercentrum, pleurocentrum & intercentrum, pleurocentrum & neural arches are separate neural arches are separate ossified componentsossified components


In tetrapods there are two In tetrapods there are two conditions relative to the centra conditions relative to the centra and neural archesand neural arches ~ aspidospondyly - separate ~ aspidospondyly - separate componentscomponents ~ holospondyly - fused ~ holospondyly - fused componentscomponents


In amniote tetrapods the In amniote tetrapods the pleurocentrum dominates the pleurocentrum dominates the centrum and the intercentrum centrum and the intercentrum contributes to the intervertebral contributes to the intervertebral discdisc


Vertebral Column Vertebral Column ArticulationsArticulations

Individual vertebrae articulate Individual vertebrae articulate with each other to form the with each other to form the axial columnaxial columnArticulations of the vertebrae Articulations of the vertebrae are between their centraare between their centra

The articulating surfaces of the The articulating surfaces of the centra affect the column by centra affect the column by determining the distribution of determining the distribution of forces forces

Acoelous Acoelous * flat faced centra* flat faced centra * withstands compression, but * withstands compression, but with poor flexibility with poor flexibility * found in mammals* found in mammals


Amphicoelous Amphicoelous * both ends concave* both ends concave * limited movement in all * limited movement in all directionsdirections * common in fish * common in fish & apodans& apodans


Procoelous Procoelous * anterior concave, posterior * anterior concave, posterior convexconvex * great mobility * great mobility (ball & socket)(ball & socket) * many amniotes* many amniotes


Opisthocoelous Opisthocoelous * anterior convex, posterior * anterior convex, posterior concaveconcave * great mobility * great mobility (ball & socket)(ball & socket) * many amniotes* many amniotes


Heterocoelous Heterocoelous * both ends saddle shaped* both ends saddle shaped * allows lateral & vertical * allows lateral & vertical flexionflexion * prevents twisting* prevents twisting & wringing& wringing * cervicals of * cervicals of turtles & birdsturtles & birds


Apophyses are processes that Apophyses are processes that extend from the centra and extend from the centra and arches that articulate with the arches that articulate with the ribs and other vertebraeribs and other vertebrae


There are three types that There are three types that articulate with the ribs and one articulate with the ribs and one that interlock with adjacent that interlock with adjacent vertebraevertebrae


Intervertebral disc - pad of Intervertebral disc - pad of fibrocartilage between the fibrocartilage between the centra centra of mammals of mammals


Nucleus pulposus - gel like core Nucleus pulposus - gel like core of the intervertebral disc of the intervertebral disc derived from the notochordderived from the notochord


Intervertebral cartilage - Intervertebral cartilage - cartilage pad found between the cartilage pad found between the centra of non-mammalscentra of non-mammals

Intervertebral ligaments - Intervertebral ligaments - fibrous ligaments that hold fibrous ligaments that hold vertebrae to vertebrae vertebrae to vertebrae


Objective Thirteen




Rib Structure & Rib Structure & FunctionFunction

Ribs (costa) are bones Ribs (costa) are bones that act as struts, that act as struts, interconnecting the vertebrae interconnecting the vertebrae and sternumand sternum

They are formed by They are formed by endochondral ossificationendochondral ossification


Most vertebrates have one Most vertebrates have one dorsal set, but some have dorsal set, but some have ventral ribs (fish), while others ventral ribs (fish), while others can have two setscan have two sets


Rib functions are varied:Rib functions are varied: > body suspension> body suspension > protect internal > protect internal organs organs > provides surface > provides surface area for muscle area for muscle attachmentattachment > aids in pulmonary > aids in pulmonary ventilationventilation


Ribs (costa) are bones Ribs (costa) are bones that act as struts, that act as struts, interconnecting the vertebrae interconnecting the vertebrae and sternumand sternum

They are formed by They are formed by endochondral ossificationendochondral ossification


Primitive tetrapods have a Primitive tetrapods have a bicipital (two head) bicipital (two head) arrangement of rib articulationarrangement of rib articulation

The tuberculum is the dorsal The tuberculum is the dorsal head that articulates with the head that articulates with the diapophysesdiapophyses


The capitulum is the ventral The capitulum is the ventral head that articulates with the head that articulates with the parapophysesparapophyses

A facet is a small concavity A facet is a small concavity that persists when the that persists when the processes fail to develop processes fail to develop



Ribs are classified by their Ribs are classified by their articulation with the sternumarticulation with the sternum

True ribs articulate True ribs articulate ventrally with the sternum ventrally with the sternum and consist of two joined and consist of two joined segmentssegments


The vertebral (costal) rib is The vertebral (costal) rib is the segment that articulates the segment that articulates with the vertebraewith the vertebrae

The sternal rib is usually The sternal rib is usually cartilagenous and is the cartilagenous and is the segment that articulates with segment that articulates with the sternumthe sternum


The vertebral (costal) rib is The vertebral (costal) rib is the segment that articulates the segment that articulates with the vertebraewith the vertebrae

The sternal rib is usually The sternal rib is usually cartilagenous and is the cartilagenous and is the segment that articulates with segment that articulates with the sternumthe sternum


False ribs are those that False ribs are those that articulate with each other, but articulate with each other, but not the sternumnot the sternum

Floating ribs are those that Floating ribs are those that have no ventral articulation at have no ventral articulation at allall


Sternum Structure Sternum Structure & Function& Function

The sternum is a mid-ventral The sternum is a mid-ventral structure of endochondral structure of endochondral origin that secures the ventral origin that secures the ventral tips of the ribs to form the rib tips of the ribs to form the rib cagecage


It is usually flattened, It is usually flattened, providing a surface for muscle providing a surface for muscle attachmentattachment

The articulation of the ribs The articulation of the ribs with the sternum forms the rib with the sternum forms the rib cagecage


The rib cage protects the The rib cage protects the thoracic viscera and functions thoracic viscera and functions in pulmonary ventilation by in pulmonary ventilation by expanding and compressing expanding and compressing the thoracic cavitythe thoracic cavity


The sternum is lacking in fish, The sternum is lacking in fish, turtles, snakes and limbless turtles, snakes and limbless lizardslizards

In some groups it is composed In some groups it is composed of a single bone, the sternal of a single bone, the sternal plateplate


In birds, the sternum has a In birds, the sternum has a large keel called the carina for large keel called the carina for flight muscle attachmentflight muscle attachment


In mammals it is composed of In mammals it is composed of three elementsthree elements - manubrium- manubrium - sternebrae- sternebrae - xiphisternum- xiphisternum



Objective Fourteen




Appendicular Appendicular SkeletonSkeleton

Includes paired fins, paired Includes paired fins, paired limbs and their associated limbs and their associated girdlesgirdlesAppendages function in Appendages function in locomotion, support, locomotion, support, protection, feeding & protection, feeding & reproductionreproduction


Paired fins are webbed Paired fins are webbed processes that are supported processes that are supported internally by fin rays found on internally by fin rays found on the distal end of the finthe distal end of the fin

They form at the interface They form at the interface between the dermis & between the dermis & epidermis, then sink into the epidermis, then sink into the dermisdermis


Fin ray types & modificationsFin ray types & modifications+ ceratotrichia - keratinized + ceratotrichia - keratinized rays rays found in chondrichthiansfound in chondrichthians+ lepidotrichia - chondrified or + lepidotrichia - chondrified or ossified rays found in ossified rays found in osteichthiansosteichthians+ actinotrichia - modified, + actinotrichia - modified, keratinized tip found in keratinized tip found in actinopterygiansactinopterygians



Pterygiophores are proximal Pterygiophores are proximal fin elements that consist of fin elements that consist of two types two types + basals - elements that + basals - elements that articulate articulate with the girdlewith the girdle + radials - elements found in + radials - elements found in the the middle of the fin, middle of the fin, between basals & between basals & fin fin raysrays



Limbs (chiridium) are Limbs (chiridium) are muscular appendages that are muscular appendages that are supported internally by bones supported internally by bones that articulate with well that articulate with well defined joints, bearing digits defined joints, bearing digits on the distal endon the distal endLimbs consists of three basic Limbs consists of three basic partsparts



Stylopodium - proximal Stylopodium - proximal segment containing single bonesegment containing single bone > humerus (forelimb) > humerus (forelimb) articulates at the glenoid articulates at the glenoid fossafossa > femur (hindlimb) > femur (hindlimb) articulates articulates at the acetabulumat the acetabulum


Zeugopodium - middle segment Zeugopodium - middle segment containing two bones containing two bones articulating between the articulating between the stylopodium & autopodiumstylopodium & autopodium > radius & ulna (forelimb) > radius & ulna (forelimb) > fibula & tibia (hindlimb)> fibula & tibia (hindlimb)


Autopodium - distal segment Autopodium - distal segment containing articulating bones containing articulating bones and the digits (phalanges)and the digits (phalanges) > manus (forelimb carpels & > manus (forelimb carpels & metacarpels) metacarpels) > pes (hindlimb tarsals & > pes (hindlimb tarsals & metatarsals)metatarsals)


Girdles are internal bilaterally Girdles are internal bilaterally symmetrical structures that symmetrical structures that are directly or indirectly are directly or indirectly connected with the axial connected with the axial skeleton by way of modified skeleton by way of modified vertebraevertebraeThere are two girdlesThere are two girdles ~ pectoral - attaches ~ pectoral - attaches forelimbsforelimbs ~ pelvic - attaches hindlimbs~ pelvic - attaches hindlimbs


In fish the pectoral girdle In fish the pectoral girdle articulates with the skull (no articulates with the skull (no neck, more stability)neck, more stability)

Tetrapods have lost the Tetrapods have lost the articulation, increasing cranial articulation, increasing cranial mobility (neck)mobility (neck)


Tetrapod girdles are ossified Tetrapod girdles are ossified and more robost, indicating and more robost, indicating increasing exploitation of increasing exploitation of terrestrial environmentsterrestrial environments


Girdles are articulation sites Girdles are articulation sites between the axial skeleton and between the axial skeleton and the limbsthe limbs

They also serve as support & They also serve as support & foundation regions for the foundation regions for the body and limbsbody and limbs


Objective Fifteen




Fin OriginsFin Origins

Fins indicate the phylogenetic Fins indicate the phylogenetic stock of ensuing appendagesstock of ensuing appendages

There are two theories of fin There are two theories of fin originsorigins * Gill Arch Theory* Gill Arch Theory * Fin Fold Theory* Fin Fold Theory


The Gill Arch Theory stated The Gill Arch Theory stated that paired fins arose from gill that paired fins arose from gill archesarchesThis theory has been shown to This theory has been shown to be invalidbe invalid


The Fin Fold Theory was The Fin Fold Theory was proposed independently by proposed independently by F.M. Balfour & J.K. ThacherF.M. Balfour & J.K. Thacher

This theory states that fins This theory states that fins arose from paired, continuous arose from paired, continuous ventrolateral folds in the body ventrolateral folds in the body wallwall


Eventually these folds would Eventually these folds would have been strengthened have been strengthened internally by endoskeletal internally by endoskeletal pterygiophorespterygiophoresOne of the advantages of One of the advantages of paired fins is stabilization of paired fins is stabilization of the movements of a the movements of a streamlined body in waterstreamlined body in water





The metpterygial stem is the The metpterygial stem is the most constant part of fins and most constant part of fins and is recognized in gnathostome is recognized in gnathostome fish & tetrapod limbsfish & tetrapod limbs

Embryological studies indicate Embryological studies indicate a common developmental a common developmental pattern in tetrapod forelimbs pattern in tetrapod forelimbs & hindlimbs& hindlimbs




Unit TwoObjective Sixteen




Pectoral GirdlesPectoral Girdles

Cambrian agnathans support Cambrian agnathans support the Fin Fold Theory due to the the Fin Fold Theory due to the presence of ventrolateral folds presence of ventrolateral folds without paired finswithout paired fins

The lack of paired fins would The lack of paired fins would also mean the lack of a pelvic also mean the lack of a pelvic girdlegirdle


Pectoral girdles appear with Pectoral girdles appear with the development of paired fins the development of paired fins in the gnathostomesin the gnathostomes

The Silurian placoderms The Silurian placoderms enjoyed a wide radiation, enjoyed a wide radiation, possessing paired fins with possessing paired fins with pectoral girdlespectoral girdles


Chondrichthyans use their Chondrichthyans use their paired fins as stabilizers and paired fins as stabilizers and for lift (a primitive condition) for lift (a primitive condition)

The pectoral girdle of modern The pectoral girdle of modern chondrichthyans is a fused U chondrichthyans is a fused U shaped endochondral shaped endochondral structure called the structure called the scapulocoracoid barscapulocoracoid bar



The pectoral girdle of The pectoral girdle of actinopterygians is comprised actinopterygians is comprised mainly of dermal elements and mainly of dermal elements and some endochondral elements some endochondral elements Actinopterygian fins are not Actinopterygian fins are not used for lift, but instead as used for lift, but instead as directional, guiding devices directional, guiding devices


The actinopterygian pectoral The actinopterygian pectoral girdle is comprised of five girdle is comprised of five partsparts † † cleithrumcleithrum † † scapulocoracoid scapulocoracoid † † clavicleclavicle † † supracleithrumsupracleithrum † † posttemporalposttemporal



The crossopterygian The crossopterygian Sarcopterygii possess features Sarcopterygii possess features and limb patterns that are and limb patterns that are very similar to early tetrapods very similar to early tetrapods

Their fins were for crawling Their fins were for crawling through shallow water, but not through shallow water, but not for terrestrial locomotion for terrestrial locomotion



The tetrapod pectoral girdle is The tetrapod pectoral girdle is consists of less bones, consists of less bones, providing more strength and providing more strength and stability stability These changes correlate with These changes correlate with the demands of locomotion on the demands of locomotion on land land


The tetrapod pectoral girdle The tetrapod pectoral girdle loses its articulation with the loses its articulation with the skull, increasing cranial skull, increasing cranial mobility and reducing shock mobility and reducing shock on the skullon the skull

The girdle consists of dermal The girdle consists of dermal and endochondral elements and endochondral elements


Tetrapod pectoral girdles Tetrapod pectoral girdles consist of the followingconsist of the following →→ scapulascapula - - pairedpaired → → procoracoid - paired procoracoid - paired anterior elements (not anterior elements (not found found in mammals)in mammals) → → coracoid – paired posteriorcoracoid – paired posterior elements (found only in elements (found only in mammals)mammals)


Tetrapod pectoral girdles Tetrapod pectoral girdles consist of the followingconsist of the following →→ clavicle - paired (lost in clavicle - paired (lost in some)some) → → interclavicle - unpaired interclavicle - unpaired (lost (lost in some)in some) → → cleithrum - found only in cleithrum - found only in some amphibianssome amphibians

PectorPectoral al

GirdlesGirdles


Unit TwoObjective Sixteen

Pelvic GirdlesPelvic Girdles

Pelvic girdles are Pelvic girdles are endochondral in origin and endochondral in origin and are of one element in fish are of one element in fish and early tetrapodsand early tetrapodsFirst appeared in First appeared in placodermsplacoderms In chondrichthyans it In chondrichthyans it consists of a single U shape consists of a single U shape structure called the structure called the pubioischiac barpubioischiac bar



The crossopterygian The crossopterygian Sarcopterygii possess Sarcopterygii possess features and limb patterns features and limb patterns that are very similar to that are very similar to early tetrapodsearly tetrapodsTheir fins were for crawling Their fins were for crawling through shallow water, but through shallow water, but not for terrestrial not for terrestrial locomotionlocomotion


Pelvic GirdlesPelvic GirdlesIn tetrapods the pelvic In tetrapods the pelvic girdle consists of three girdle consists of three elements - ilium, ischium & elements - ilium, ischium & pubispubisThere are various There are various modifications of the three modifications of the three and some groups are and some groups are defined by their defined by their arrangementarrangementIn avians there is a In avians there is a complete fusion of the complete fusion of the three called the innominate three called the innominate bonebone

Pelvic Pelvic GirdlesGirdles


Objective Eighteen




Tetrapod Tetrapod AppendagesAppendages


The autopodium consists of the The autopodium consists of the distal phalanges, the median distal phalanges, the median metapodials and the proximal metapodials and the proximal podials podials

The manus is the autopodium The manus is the autopodium of the forelimbs, consisting of of the forelimbs, consisting of proximal carpals, median proximal carpals, median metacarpals & distal phalangesmetacarpals & distal phalanges


The pes is the autopodium of The pes is the autopodium of the hindlimbs, consisting of the hindlimbs, consisting of proximal tarsals, median proximal tarsals, median metatarsals & distal phalanges metatarsals & distal phalanges

Tetrapod Tetrapod AppendaAppenda

gesges


Pentadactyly is the most Pentadactyly is the most common condition among common condition among tetrapodstetrapodsPolydactyly is an ancient Polydactyly is an ancient condition still found in some condition still found in some groupsgroupsUngulates exhibit a reversal of Ungulates exhibit a reversal of these trends by reducing the these trends by reducing the number of digitsnumber of digits


Polyphalangy is a trend in Polyphalangy is a trend in which there is an increase in which there is an increase in the number of phalanges, such the number of phalanges, such as in aquatic mammals as in aquatic mammals


Articulation between the Articulation between the forelimb autopodium and forelimb autopodium and zeugopodium involves the zeugopodium involves the followingfollowing + radiale+ radiale + ulnare+ ulnare + intermedium+ intermedium + centrale+ centrale + sesamoid bones+ sesamoid bones



Articulation between the Articulation between the hindlimb autopodium and hindlimb autopodium and zeugopodium in many cases zeugopodium in many cases involves the fusion of or loss of involves the fusion of or loss of bones bones Many cursorial mammals have Many cursorial mammals have lost lateral digits and the lost lateral digits and the medial metatarsals have fused medial metatarsals have fused into a single cannon bone into a single cannon bone


Avians have a fusion of tarsals Avians have a fusion of tarsals & metatarsals into a single & metatarsals into a single tarsometatarsus tarsometatarsus

The fusion of the tibiale & The fusion of the tibiale & intermedium form the intermedium form the astragalus which articulates astragalus which articulates with the tibia with the tibia


The calcaneum (fibulare) The calcaneum (fibulare) articulates with the fibula articulates with the fibula

The centrale and sesamoid The centrale and sesamoid bones are also present in many bones are also present in many groups groups


Tetrapod Tetrapod LocomotionLocomotion

Saltatorial (ricochetal) - Saltatorial (ricochetal) - hopping hopping - frogs - frogs Arboreal - tree dwelling & Arboreal - tree dwelling & climbingclimbing - brachiation - brachiation - primates- primatesScansorial - tree dwelling & Scansorial - tree dwelling & climbingclimbing - clawed - clawed - squirrels- squirrels


Unguligrade - cursorial Unguligrade - cursorial ~ walking on digit tips~ walking on digit tips ~ increases the stride length ~ increases the stride length ~ deer, horses, etc. ~ deer, horses, etc.

Plantigrade - cursorialPlantigrade - cursorial ~ entire sole of foot on ~ entire sole of foot on groundground ~ decreases stride length~ decreases stride length ~ humans ~ humans


Digitigrade - cursorial Digitigrade - cursorial ~ walking on digits~ walking on digits ~ some increase of the stride ~ some increase of the stride length length ~ dogs, cats, etc. ~ dogs, cats, etc.



Foot falls are the patterns of Foot falls are the patterns of contact with the ground by the contact with the ground by the manus & pes manus & pes



Evolution of the Evolution of the Appendicular Appendicular

SkeletonSkeletonCrossopterygians would have Crossopterygians would have used their fins to drag along used their fins to drag along the shallows and pivot their the shallows and pivot their bodiesbodiesThey may have begun to move They may have begun to move onto land due to predators, onto land due to predators, exploiting new food sources or exploiting new food sources or habitat disappearance habitat disappearance


SkeletonSkeletonWith movement onto land, With movement onto land, limbs would replace body limbs would replace body musculature as the main musculature as the main structures for locomotionstructures for locomotionThe tetrapod axial skeleton is The tetrapod axial skeleton is slung from the pectoral girdle slung from the pectoral girdle and directly connected to the and directly connected to the pelvic girdle pelvic girdle


SkeletonSkeleton


SkeletonSkeleton


SkeletonSkeletonThis design causes the This design causes the propulsive forces from the propulsive forces from the hindlimbs to be transferred hindlimbs to be transferred directly to the axial skeletondirectly to the axial skeleton


SkeletonSkeleton


SkeletonSkeleton


SkeletonSkeleton


SkeletonSkeletonAirfoil – an object that produces Airfoil – an object that produces a useful reaction when placed a useful reaction when placed in a moving stream of airin a moving stream of air


SkeletonSkeleton

Drag – the component of the lift Drag – the component of the lift force acting opposite to the force acting opposite to the direction of traveldirection of travel

Lift – the force produced by an Lift – the force produced by an airfoil perpendicular to its airfoil perpendicular to its surfacesurface


SkeletonSkeleton


Objective Twenty




Muscle CharacteristicsMuscle Characteristics

The ability to contractThe ability to contract

Contraction results in Contraction results in movementmovementContraction occurs due to Contraction occurs due to sliding filamentssliding filaments

Muscles contract due to nerve Muscles contract due to nerve activityactivityMuscles can be under Muscles can be under voluntary or involuntary voluntary or involuntary controlcontrol

Muscle ActionsMuscle Actions

Propulsion of materials Propulsion of materials through tubesthrough tubes

Animate the skeletonAnimate the skeleton

Control entry & exit of Control entry & exit of materialsmaterials


Control hair or feathers for Control hair or feathers for insulationinsulation

ThermogenesisThermogenesis

Create low voltage electrical Create low voltage electrical fieldsfields

Muscle ClassificationMuscle Classification

Red muscle & white muscleRed muscle & white muscle

Somatic & visceral locationsSomatic & visceral locations

Voluntary & involuntary Voluntary & involuntary controlcontrolThree histological typesThree histological types > skeletal> skeletal > cardiac> cardiac > smooth> smooth

Skeletal Muscle Skeletal Muscle CharacteristicsCharacteristics

Striated & multinucleatedStriated & multinucleated

Somatic muscle under Somatic muscle under voluntary controlvoluntary controlQuick response time due to Quick response time due to nerve stimulation of nerve stimulation of independently contracting independently contracting muscle fibersmuscle fibersResults in body movement, Results in body movement, posture and balanceposture and balance

Smooth Muscle Smooth Muscle CharacteristicsCharacteristics

Non-striated & Non-striated & mononucleatedmononucleatedUnder involuntary controlUnder involuntary control

Relatively slow response time Relatively slow response time due to stimulation produced due to stimulation produced by pacemaker potentials & by pacemaker potentials & hormoneshormonesResults in internal organ Results in internal organ movements and glandular movements and glandular secretionssecretions

Cardiac Muscle Cardiac Muscle CharacteristicsCharacteristics

Striated, branched & Striated, branched & mononucleatedmononucleated

Under involuntary controlUnder involuntary control

Quick response time due to Quick response time due to pacemaker produced action pacemaker produced action potentialspotentials

Cardiac Muscle Cardiac Muscle CharacteristicsCharacteristics

Intercalated discs connecting Intercalated discs connecting fibers produce simultaneous fibers produce simultaneous contractioncontractionResults in heart beats and the Results in heart beats and the movement of bloodmovement of blood

Muscle ClassificationMuscle Classification

Red muscle & white muscleRed muscle & white muscle

Somatic & visceral locationsSomatic & visceral locations

Voluntary & involuntary Voluntary & involuntary controlcontrolThree histological typesThree histological types > skeletal> skeletal > cardiac> cardiac > smooth> smooth

Muscle Muscle AnatomAnatom

yy

Muscle AnatomyMuscle Anatomy


OriginOriginHeadHead

GasteGaster r (belly)(belly)

SlipSlip


Tendons are fibrous Tendons are fibrous connective tissues that are connective tissues that are continuous with the continuous with the periosteum of the boneperiosteum of the boneTendons connect muscle to Tendons connect muscle to bone, cartilage or other bone, cartilage or other connective tissuesconnective tissues


Aponeuroses are thin, flat Aponeuroses are thin, flat sheet like tendonssheet like tendons

Facia are sheets of Facia are sheets of connective tissues that connective tissues that encapsulate and bind body encapsulate and bind body parts togetherparts together

MotorMotor UnitUnit


Objective Twenty One

Muscle OriginsMuscle Origins

Mesenchyme - a loose Mesenchyme - a loose conferderation of embryonic conferderation of embryonic cells give rise to smooth cells give rise to smooth muscle in the blood vessels & muscle in the blood vessels & some viscerasome viscera

All muscle originates from the All muscle originates from the mesodermal germ layermesodermal germ layer


Hypomere - paired Hypomere - paired outpocketings of the body outpocketings of the body mesoderm that embrace the mesoderm that embrace the gut and produce the smooth gut and produce the smooth muscle of the alimentary canal muscle of the alimentary canal & its derivatives & its derivatives


Paraxial mesoderm - mesoderm Paraxial mesoderm - mesoderm that forms next to the neural that forms next to the neural tube along the axis of the tube along the axis of the body, giving rise to the body, giving rise to the skeletal muscles skeletal muscles



Objective Twenty Two


Objective Twenty Three


Objective Twenty Four


Since muscles can only Since muscles can only contract, there is an opposite contract, there is an opposite reaction to pull them back to reaction to pull them back to their original positiontheir original positionIn most cases, especially with In most cases, especially with skeletal muscle, this opposite skeletal muscle, this opposite reaction is brought about by reaction is brought about by opposing muscles or muscle opposing muscles or muscle groupsgroups


Synergists are muscles or Synergists are muscles or muscle groups that perform muscle groups that perform the same or similar actions on the same or similar actions on the same bone(s) or body the same bone(s) or body regionregion - tensor facia latae, gluteus- tensor facia latae, gluteus


Antagonists are muscles or Antagonists are muscles or muscle groups that perform muscle groups that perform opposite actions on the same opposite actions on the same bone or body regionbone or body region - tensor fascia latae, adductor - tensor fascia latae, adductor longuslongusFixators are muscles that act Fixators are muscles that act to hold a body part rigid to hold a body part rigid


Flexors are muscles which Flexors are muscles which decrease the angle between decrease the angle between articulating bones articulating bones - biceps brachii, rectus - biceps brachii, rectus abdominisabdominisExtensors are muscles which Extensors are muscles which increase the angle between increase the angle between articulating bonesarticulating bones - triceps brachii, quadriceps - triceps brachii, quadriceps


Adductors are muscles which Adductors are muscles which move the limbs toward the move the limbs toward the body midline body midline - pectoralis major- pectoralis majorAbductors are muscles which Abductors are muscles which move the limbs away from the move the limbs away from the body midlinebody midline - deltoid- deltoid


Levators are muscles Levators are muscles associated with the jaw or associated with the jaw or scapula which close or elevate scapula which close or elevate their associated bone their associated bone - digastric, masseter- digastric, masseterDepressors are muscles Depressors are muscles associated with the jaw that associated with the jaw that open or depress the jawopen or depress the jaw - lateral pterygoid- lateral pterygoid


Protractors are muscles that Protractors are muscles that cause the projection of a part cause the projection of a part - lateral pterygoid- lateral pterygoid

Retractors are muscles that Retractors are muscles that return a part from a protracted return a part from a protracted positionposition - masseter- masseter


Rotators are muscles that Rotators are muscles that cause a limb to move 360cause a limb to move 360oo about its axisabout its axisSupinators are rotators that Supinators are rotators that move the palm or sole upwardsmove the palm or sole upwards - supinator- supinatorPronators are rotators that Pronators are rotators that move the palm or sole move the palm or sole downwardsdownwards - pronator teres- pronator teres


Sphincters are muscles that Sphincters are muscles that constrict to close an openingconstrict to close an opening - cardiac sphincter, anal - cardiac sphincter, anal sphinctersphincterDilators are muscles that Dilators are muscles that constrict to widen an opening constrict to widen an opening or orificeor orifice - ciliary muscles- ciliary muscles



Objective Twenty Five

Vertebrate Digestive Vertebrate Digestive SystemsSystems

The function of a digestive system The function of a digestive system is to physically & chemically is to physically & chemically breakdown food so that energy breakdown food so that energy can be released and nutrients can be released and nutrients obtainedobtainedThe function of a digestive system The function of a digestive system is to physically & chemically is to physically & chemically breakdown food so that energy breakdown food so that energy can be released and nutrients can be released and nutrients obtainedobtained


Physical digestion breaks the food Physical digestion breaks the food into smaller particles, while into smaller particles, while chemical digestion breaks chemical digestion breaks macromolecules into monomersmacromolecules into monomers

The monomers will then be The monomers will then be absorbed into the bloodstream absorbed into the bloodstream where they will be distributed to where they will be distributed to body cells for energy needs and body cells for energy needs and building materialsbuilding materials


It is a tubular passage that It is a tubular passage that extends from the lips of the extends from the lips of the mouth, through the body, and mouth, through the body, and terminates with a cloacal opening terminates with a cloacal opening or anusor anusThis system can be divided into This system can be divided into three regions based on the types three regions based on the types of glands present of glands present + buccal cavity+ buccal cavity + pharynx+ pharynx + alimentary canal+ alimentary canal


The alimentary canal can be The alimentary canal can be further divided into four segmentsfurther divided into four segments + esophagus+ esophagus + stomach+ stomach + small intestine+ small intestine + large intestine+ large intestine


Associated with the system are Associated with the system are four glands/organs that are four glands/organs that are located outside the tube, but located outside the tube, but secrete fluids into the system to secrete fluids into the system to aid in digestionaid in digestion + salivary glands+ salivary glands + liver+ liver + gall bladder+ gall bladder + pancreas+ pancreas


Embryology of Digestive Embryology of Digestive SystemsSystems

The gut is a tube derived from the The gut is a tube derived from the endoderm endoderm

It gives rise to the pharynx, It gives rise to the pharynx, alimentary canal & associated alimentary canal & associated accessory glandsaccessory glands

The stomodeum is an anterior The stomodeum is an anterior invagination of the ectoderm that invagination of the ectoderm that meets the foregut via the meets the foregut via the buccopharyngeal membranebuccopharyngeal membrane


The stomodeum gives rise to the The stomodeum gives rise to the buccal cavity buccal cavity

The proctodeum is a posterior The proctodeum is a posterior invagination of the ectoderm that invagination of the ectoderm that meets the hindgut via the cloacal meets the hindgut via the cloacal membranemembrane

The proctodeum gives rise to the The proctodeum gives rise to the adult cloacaadult cloaca


The visceral peritoneum is the The visceral peritoneum is the membrane that covers the membrane that covers the digestive organs and is derived digestive organs and is derived from the mesoderm from the mesoderm


Unit TwoObjectives Twenty Six-

Twenty Nine

Components of Digestive Components of Digestive SystemsSystems

The buccal cavity begins The buccal cavity begins mechanical & chemical digestion mechanical & chemical digestion and can act as a temporary and can act as a temporary storage area storage area

Lips are structures that follow the Lips are structures that follow the tooth line, defining the anterior tooth line, defining the anterior margin of the mouth and are many margin of the mouth and are many time pliable and muscular time pliable and muscular

Lips may be pliable and muscular Lips may be pliable and muscular


Cheeks are structures that form Cheeks are structures that form the sides of the buccal cavity and the sides of the buccal cavity and keep food from falling out of the keep food from falling out of the mouth mouth They are most developed in They are most developed in mammals, aiding in suckling and mammals, aiding in suckling and mechanical digestion mechanical digestion

Many mammals have cheek Many mammals have cheek pouches, extending storage pouches, extending storage abilitiesabilities


The palatoglossal arch marks the The palatoglossal arch marks the posterior margin of the mouth posterior margin of the mouth

The palate is the bony roof of the The palate is the bony roof of the mouth mouth

All vertebrates have a primary All vertebrates have a primary palate, separating the buccal palate, separating the buccal cavity from the cranial cavitycavity from the cranial cavity


In fish the primary palate is low In fish the primary palate is low arching and does not have arching and does not have openingsopenings

In tetrapods, nasal passages reach In tetrapods, nasal passages reach the mouth through internal nares the mouth through internal nares (choanae) in the primary palate (choanae) in the primary palate


A secondary palate that separates A secondary palate that separates the nasal passages from the the nasal passages from the mouth is found in crocodilians and mouth is found in crocodilians and mammals mammals

The anterior portion is the bony The anterior portion is the bony hard palate and the posterior is hard palate and the posterior is the soft palate that terminates the soft palate that terminates with the uvulawith the uvula



Teeth are probably derivatives of Teeth are probably derivatives of dermal plating from early fishdermal plating from early fish

In most vertebrates they are used In most vertebrates they are used to capture and hold prey, and may to capture and hold prey, and may be used to crush the preybe used to crush the prey

They are composed of calcium They are composed of calcium salts and are almost always salts and are almost always covered in enamelcovered in enamel


In mammals and a few other In mammals and a few other groups teeth are also used to groups teeth are also used to masticatemasticate

They not only reduce the size of They not only reduce the size of the food, but also mix it with the food, but also mix it with saliva to form a bolussaliva to form a bolus

Teeth are the major factor in Teeth are the major factor in mechanical digestion in the buccal mechanical digestion in the buccal cavitycavity


The mechanical digestion of the The mechanical digestion of the teeth greatly increase the surface teeth greatly increase the surface area for chemical digestionarea for chemical digestion

The puncturing of the teeth may The puncturing of the teeth may also inject digestive enzymes into also inject digestive enzymes into the foodthe food



Vertebrates with homodont Vertebrates with homodont dentition exhibit teeth of the same dentition exhibit teeth of the same shape and general appearance, shape and general appearance, although size may differalthough size may differ

This type of dentition is usually This type of dentition is usually found in fish, amphibians & found in fish, amphibians & reptilesreptiles


Vertebrates with heterodont Vertebrates with heterodont dentition exhibit teeth that differ dentition exhibit teeth that differ in shape, size, occlusal surface & in shape, size, occlusal surface & function that are segregated in function that are segregated in regionsregions

This type of dentition is found This type of dentition is found almost exclusively in mammalsalmost exclusively in mammals


Vertebrates with polyphyodont Vertebrates with polyphyodont dentition exhibit continual, dentition exhibit continual, lifetime replacement of worn, lifetime replacement of worn, broken or lost teethbroken or lost teeth

This replacement pattern of This replacement pattern of dentition is usually found in fish, dentition is usually found in fish, amphibians & reptilesamphibians & reptiles


Vertebrates with diphyodont Vertebrates with diphyodont dentition exhibit the growth of just dentition exhibit the growth of just two sets of teeth – deciduous two sets of teeth – deciduous (milk) & permanent (adult)(milk) & permanent (adult)

This replacement pattern of This replacement pattern of dentition is typical of the dentition is typical of the mammalsmammals


Deciduous teeth include incisors, Deciduous teeth include incisors, canines & premolarscanines & premolars

Permanent teeth also include a Permanent teeth also include a second set of incisors, canines & second set of incisors, canines & premolars, as well as molarspremolars, as well as molars

Components Components of Digestive of Digestive

SystemsSystems


The tongue is a soft tissue The tongue is a soft tissue component that is composed component that is composed mainly of muscle that is attached mainly of muscle that is attached to the hyoid boneto the hyoid bone

A true tongue is usually lacking in A true tongue is usually lacking in gnathostome fish and first appears gnathostome fish and first appears in tetrapods in tetrapods


Vertebrate tongues can have Vertebrate tongues can have several functions:several functions: > mechanical digestion> mechanical digestion > prey capture (lingual feeding)> prey capture (lingual feeding) > chemoreception (taste buds)> chemoreception (taste buds) > chemoreception (scent > chemoreception (scent gathering gathering using the vomeronasal organ)using the vomeronasal organ) > aids in the production of > aids in the production of soundssounds


The pharynx is a passageway for The pharynx is a passageway for food to the esophagus in all food to the esophagus in all vertebrates and for air in vertebrates and for air in pulmonatespulmonates

It is responsible for deglutition It is responsible for deglutition (swallowing) (swallowing)


In pulmonates the pharynx In pulmonates the pharynx terminates in the esophageal terminates in the esophageal opening and the glottisopening and the glottis

Most vertebrates bolt food, so the Most vertebrates bolt food, so the esophagus will expand to esophagus will expand to accommodate the size accommodate the size

The epiglottis covers the glottis The epiglottis covers the glottis during deglutition during deglutition


The pharynx or pharyngeal The pharynx or pharyngeal pouches have many derivatives:pouches have many derivatives: > eustachian tube> eustachian tube > thyroid & parathyroid glands> thyroid & parathyroid glands > thymus gland> thymus gland > pharyngeal, lingual & palatine > pharyngeal, lingual & palatine tonsilstonsils > the tongue (in part)> the tongue (in part) > lung pirmordium> lung pirmordium


The alimentary canal is designed The alimentary canal is designed to suit the diet of the organismto suit the diet of the organism

Histologically it is a four layered Histologically it is a four layered structure made up of the mucosa, structure made up of the mucosa, submucosa, muscularis & submucosa, muscularis & adventitia (serosa) adventitia (serosa)


The mucosa is the innermost layer The mucosa is the innermost layer comprised of epithelium, comprised of epithelium, muscularis mucosae & loose muscularis mucosae & loose connective tissueconnective tissueThe submucosa is the second layer The submucosa is the second layer and is made up of loose connective and is made up of loose connective tissue, nerves & blood and lymph tissue, nerves & blood and lymph supply supply


The muscularis is the third layer The muscularis is the third layer comprised of an inner layer of comprised of an inner layer of circular smooth muscle and an circular smooth muscle and an outer layer of longitudinal smooth outer layer of longitudinal smooth musclemuscle


The adventitia is the outermost The adventitia is the outermost layer made up of fibrous layer made up of fibrous connective tissue covered by connective tissue covered by epithelial membrane epithelial membrane

The adventitia is referred to as the The adventitia is referred to as the serosa if mesenteries are present serosa if mesenteries are present



The esophagus is an expandable The esophagus is an expandable tube that connects the pharynx to tube that connects the pharynx to the stomach the stomach

It has little or no digestive It has little or no digestive function, but in some it is modified function, but in some it is modified for storagefor storage


The stomach is an expanded The stomach is an expanded structure that functions in structure that functions in mechanical and chemical digestion mechanical and chemical digestion and as temporary storage in and as temporary storage in irregularly feeding animals irregularly feeding animals It is an extremely acidic (pH of 2) It is an extremely acidic (pH of 2) environment due to the production environment due to the production of HCl of HCl


Processes of the stomach include:Processes of the stomach include: > mechanical digestion through > mechanical digestion through churningchurning > chemical digestion of proteins> chemical digestion of proteins > production of mucus for > production of mucus for protection protection > absorption of vitamins, water, > absorption of vitamins, water, salts & alchoholsalts & alchohol


The stomach produces HCl, The stomach produces HCl, enzymes and mucus from glands enzymes and mucus from glands found in gastric pits found in gastric pits

After a period of time the churning After a period of time the churning produces a slurry mixture of food, produces a slurry mixture of food, HCl, enzymes & mucus called HCl, enzymes & mucus called chymechyme


The inner lining has large folds The inner lining has large folds called rugae which increases called rugae which increases surface area and allows for surface area and allows for expansion expansion


The stomach is divided into three The stomach is divided into three regions:regions: > cardiac> cardiac > fundus> fundus > pyloric > pyloric

It is separated from the rest of the It is separated from the rest of the alimentary by two sphincters – the alimentary by two sphincters – the cardiac & pyloric cardiac & pyloric


SystemsSystems


The small intestine is a long, The small intestine is a long, tubular structure that is modified tubular structure that is modified for chemical digestion and for chemical digestion and absorption absorption It is divided into three regions:It is divided into three regions: > duodenum> duodenum > jejunum> jejunum > ileum > ileum


The mucosa is folded into The mucosa is folded into microscopic finger-like projections microscopic finger-like projections called villi, greatly increasing the called villi, greatly increasing the surface areasurface area

Each villus is covered with folded Each villus is covered with folded epithelial cell surfaces referred to epithelial cell surfaces referred to as microvilli, further increasing as microvilli, further increasing surface areasurface area


SystemsSystems



The duodenum receives chyme The duodenum receives chyme from the stomach, bile from the from the stomach, bile from the liver and pancreatic fluids from the liver and pancreatic fluids from the pancreaspancreas

The duodenal mucosa also The duodenal mucosa also produces enzymes for the produces enzymes for the catabolism of lipids, carbohydrates catabolism of lipids, carbohydrates & proteins& proteins


The duodenum functions at an The duodenum functions at an optimum pH of 8-9optimum pH of 8-9

The jejunum and ileum are The jejunum and ileum are primarily absorptive regionsprimarily absorptive regions

The small intestine terminates The small intestine terminates with the ileocelcal valve located with the ileocelcal valve located between it and the large intestine between it and the large intestine


The large intestine begins at the The large intestine begins at the ileocecal valve and terminates in a ileocecal valve and terminates in a cloaca or anuscloaca or anus

It functions primarily to handle It functions primarily to handle undigested food, but will absorb undigested food, but will absorb some minerals and vitamins, as some minerals and vitamins, as well as waterwell as water

It is a straighter tube, lacking villi, It is a straighter tube, lacking villi, that may have a rectum that may have a rectum



Specializations of Digestive Specializations of Digestive SystemsSystems

Fishes have distinct digestive Fishes have distinct digestive regions with the alimentary canal regions with the alimentary canal ending in a cloaca in all but the ending in a cloaca in all but the bony fish (anus)bony fish (anus)

The spiral valve is found in the The spiral valve is found in the intestine of elasmobranchs and intestine of elasmobranchs and primitive bony fish, increasing primitive bony fish, increasing surface area and the time food surface area and the time food spends in the intestine spends in the intestine

Specializations Specializations of Digestive of Digestive

SystemsSystems

Elasmobranchs Elasmobranchs have a rectal have a rectal gland to gland to eliminate excess eliminate excess saltsalt


Herbivores have increased Herbivores have increased intestinal length due to the fact intestinal length due to the fact that plant material is very difficult that plant material is very difficult to digestto digest

Some vertebrates have extensions Some vertebrates have extensions of the alimentary canal:of the alimentary canal: > crop (temporary storage)> crop (temporary storage) > caecum (fermentation)> caecum (fermentation) > appendix> appendix


Gizzards are muscular stomach Gizzards are muscular stomach regions that are used to grind food regions that are used to grind food



Unit TwoObjective Thirty


Ruminants are mammals that have Ruminants are mammals that have a multichambered esophagus & a multichambered esophagus & stomach that make them foregut stomach that make them foregut fermenters fermenters


SpecializationSpecializations of Digestive s of Digestive

SystemsSystems


Hindgut fermenters have a Hindgut fermenters have a monogastric systemmonogastric system

The plant material is masticated, The plant material is masticated, passed to the stomach, then passed to the stomach, then quickly moved to the small quickly moved to the small intestineintestineSmall pieces pass into a caecum Small pieces pass into a caecum for fermentationfor fermentation


SpecializationSpecializations of Digestive s of Digestive

SystemsSystems



Coprophagy is a strategy in which Coprophagy is a strategy in which the cecal feces are re-ingested so the cecal feces are re-ingested so that undigested material can pass that undigested material can pass through againthrough again


Unit TwoObjective Thirty One

Oral glands are any that secrete Oral glands are any that secrete mucus and/or seral fluid in the mucus and/or seral fluid in the mouthmouth

These are most common in These are most common in tetrapodstetrapods

Accessory Organs of Accessory Organs of Digestive SystemsDigestive Systems

Salivary glands are oral glands Salivary glands are oral glands that secrete seral fluids containing that secrete seral fluids containing a high concentration of amylasesa high concentration of amylases

They are found in pairs:They are found in pairs: > sublingual> sublingual > mandibular> mandibular > parotid (mammals)> parotid (mammals) > others found in herps> others found in herps


Salivary gland functions:Salivary gland functions: > moisten & stick together food> moisten & stick together food > initiate chemical digestion> initiate chemical digestion > sanitize the oral cavity> sanitize the oral cavity


The liver is a multifunctional organ The liver is a multifunctional organ that produces bile for the that produces bile for the emulsification of fatsemulsification of fats

The bile is drained from the liver The bile is drained from the liver through of series of hepatic ducts through of series of hepatic ducts that converge to form a common that converge to form a common hepatic ducthepatic duct


The bile backflows through the The bile backflows through the cystic duct to be stored and cystic duct to be stored and concentrated in the gall bladderconcentrated in the gall bladder

The cystic duct and common The cystic duct and common hepatic duct merge to form the hepatic duct merge to form the common bile ductcommon bile duct


The pancreas is a multifunctional The pancreas is a multifunctional organ that functions as an organ that functions as an endocrine and exocrine glandendocrine and exocrine gland

For digestion, it secretes a For digestion, it secretes a pancreatic fluid that is rich in pancreatic fluid that is rich in enzymes for the catabolism of enzymes for the catabolism of lipids, carbohydrates & proteinslipids, carbohydrates & proteins


Another major component of Another major component of pancreatic fluid is sodium pancreatic fluid is sodium bicarbonate, a strong base to bicarbonate, a strong base to counteract the acidic chymecounteract the acidic chyme

The pancreatic fluid is drained The pancreatic fluid is drained from the pancreas by the from the pancreas by the pancreatic ductpancreatic duct


The pancreatic duct merges with The pancreatic duct merges with the common bile duct to form the the common bile duct to form the hepaticopancreatic duct, which hepaticopancreatic duct, which then dumps into the duodenumthen dumps into the duodenum


Science dealing with Science dealing with vertebrate structurevertebrate structureEncompasses extinct and Encompasses extinct and extant organismsextant organisms

Originated in the 16Originated in the 16thth Century Century when global exploration beganwhen global exploration began

Comparative VertebrateComparative Vertebrate Anatomy Anatomy

Homology – similar structures found in Homology – similar structures found in related groups due to a common related groups due to a common ancestorancestor

Homoplasy – structures that have Homoplasy – structures that have similar appearance, but may or may similar appearance, but may or may not have common ancestry or similar not have common ancestry or similar functionfunction

Analogy – similar structures with the Analogy – similar structures with the same function, but no common same function, but no common ancestryancestry

Anatomical TermsAnatomical Terms

Symmetry – the balanced Symmetry – the balanced arrangement of body partsarrangement of body parts

Bilateral symmetry – the Bilateral symmetry – the arrangement of body parts arrangement of body parts such that a single plane such that a single plane passing dorsoventrally passing dorsoventrally through the sagittal line through the sagittal line divides the animal into right divides the animal into right and left mirror imagesand left mirror images

Contributors to CVA

• John Ray (1627-1705)– Argued that diversity

of organisms was proof of God’s almighty power

– Stimulated active collecting, cataloging, classification, and analysis

Time Horizons and Time Horizons and Radiometric DatingRadiometric Dating

Time horizonsTime horizons– Layers of rock containing organisms Layers of rock containing organisms

from one “slice” of timefrom one “slice” of time– Can be used to sequence organisms Can be used to sequence organisms

from oldest to most recentfrom oldest to most recent• Relative agesRelative ages

– No absolute age (i.e. in years old)No absolute age (i.e. in years old)– Can be used to determine evolutionary Can be used to determine evolutionary

orderorder

Chordate Chordate CharacteristicsCharacteristics

Chordates appeared 5.5 x 10Chordates appeared 5.5 x 1088 years agoyears ago

Eucoelomates – body cavity Eucoelomates – body cavity encased encased entirely in entirely in mesodermmesodermDeuterostome developmentDeuterostome development

Vertebrate Vertebrate CharacteristicsCharacteristics

Vertebrates appeared in the Vertebrates appeared in the late Cambrian period (5.0 x 10late Cambrian period (5.0 x 1088 ya)ya)First vertebrates were First vertebrates were ostracoderm fishostracoderm fish

The notochord was replaced The notochord was replaced by a vertebral column in mostby a vertebral column in most

Apply the characteristics and Apply the characteristics and structures discussed in structures discussed in Objective Five to a given Objective Five to a given vertebrate representativevertebrate representative

Go for it!!!Go for it!!!

Comparative VertebrateComparative Vertebrate Anatomy Anatomy

Vertebrate Class Vertebrate Class CharacteristicsCharacteristics

Class Myxini (the hagfishes)Class Myxini (the hagfishes)

The most primitive of the The most primitive of the vertebrates, jawless, vertebrates, jawless, ectotherms, with eel-like bodies ectotherms, with eel-like bodies and no paired fins, and lacking and no paired fins, and lacking bones or scalesbones or scalesOcean bottom dwellers with no Ocean bottom dwellers with no eyes and are primarily eyes and are primarily scavengersscavengers


Class Placodermi (all extinct)Class Placodermi (all extinct)

Fish similar to the Fish similar to the ostracoderms, but with a jaw ostracoderms, but with a jaw and two pairs of paired fins andand two pairs of paired fins and

Notochord surrounded by Notochord surrounded by ossified neural and hemal ossified neural and hemal arches, indicating the origins of arches, indicating the origins of a vertebral columna vertebral column


Class Amphibia (first tetrapods)Class Amphibia (first tetrapods)

Originated 360mya during the Originated 360mya during the Devonian period from Devonian period from labyrithodont sarcopterygianslabyrithodont sarcopterygians

Body covered in a thin, gland Body covered in a thin, gland rich skinrich skin


Class Reptilia (first amniotes)Class Reptilia (first amniotes)

Originated 340mya during the Originated 340mya during the Carboniferous period from Carboniferous period from cotylosaurs (stem reptiles)cotylosaurs (stem reptiles)

Body covered in a scaled, dry, Body covered in a scaled, dry, leathery skinleathery skin


Class Aves (modern birds)Class Aves (modern birds)

Bird ancestors are found in the Bird ancestors are found in the Infraclass ArchosauromorphaInfraclass Archosauromorpha - Archosauria - Archosauria → Saurischia → → Saurischia → TherpodsTherpods

Originated in the late Permian Originated in the late Permian periodperiod


Class MammaliaClass Mammalia

Originated from the therapsids Originated from the therapsids during the Triassic period and during the Triassic period and then radiated extensively then radiated extensively during the Tertiary period during the Tertiary period (synapsid skull)(synapsid skull)Hair a derivative of the Hair a derivative of the integument and mammary integument and mammary glands to produce milkglands to produce milk

Vertebrate Growth Vertebrate Growth RatesRates

Allometry – the relative Allometry – the relative change in change in shape in shape in correlation correlation with a with a change in sizechange in size

Allometry is caused by two Allometry is caused by two rates of growth at the same rates of growth at the same timetime - arithmetic (addition)- arithmetic (addition) - exponential (multiplication)- exponential (multiplication)

Biological DesignBiological Design

Size – the mass of an organism Size – the mass of an organism - length & height - length & height (sometimes)(sometimes)

Small organisms ruled by Small organisms ruled by surface tension, large ones by surface tension, large ones by gravitygravity

A composite organ that A composite organ that originates from two different originates from two different embryological layersembryological layers

It is divided into three layersIt is divided into three layers epidermis (ectoderm)epidermis (ectoderm) dermis (mesoderm)dermis (mesoderm) hypodermis (mesoderm)hypodermis (mesoderm)

Vertebrate IntegumentVertebrate Integument

Features of the Features of the IntegumentIntegument

Fish Fish integument is integument is mucus mucus secreting, secreting, nonkeratinizenonkeratinized, with all d, with all layers made layers made up of living up of living cellscells

Specializations of the Specializations of the IntegumentIntegument

Nails, claws & hooves (unguis)Nails, claws & hooves (unguis)

Grow from a bed of matrix cells Grow from a bed of matrix cells and a layer of subunguisand a layer of subunguis

Documents

Comparative Vertebrate Anatomy Unit Two Objectives One & Two