¿ What anatomical/physiological features distinguish vertebrates?

¿ What anatomical/physiological features distinguish vertebrates? ¿ Who are

vertebrates related to, and how are

they related to each other ?

¿ What are the roles of vertebrates in aquatic and terrestrial

ecosystems ?

¿ How many different kinds or species of vertebrates are there ?

¿ In what ecosystems do vertebrates occur ?

There are over 57,000 living vertebrate species

For every extant species there were ~100 that are now extinct

Vertebrates are found in almost all environments on earth, from ocean depth to highest mountains and from pole to pole

Vertebrates range in size from tiny fish, amphibians and reptiles small enough to fit on a coin, to blue whales who are so huge their heart is a big a small car

Vertebrate lifestyle is energetically expensive… obtain energy as both carnivores and herbivores with many specializations in between

The vertebrate story…

Two major groups of vertebrates

1) Non-amniotes:A-gnathans (Myxinoidea & Petromyzontoidea ) (~100 species)

Chondr-ichthians (~1,000 species)

Osteichthians (~27,000 species)

Amphibians (~6,400 species)



Two major groups of vertebrates…

2) Amniotes , which also has two major groups:Sauropsids - Testudinians (~300 species)

Lepido-saurians (~8,000 species)

Crocodilians (~25 species)

Avians (~9,700 species)

Synapsids –Mammalians (~4,800 species)


New species…

¿How many species are there on planet Earth?

Estimates vary by an order of magnitude!

Thousands of species described annually

Most are small and of “other” kingdoms… still some vertebrates being described.

Examples…

AgnathaExtinct: Ostracoderms

*Covered by bony armor

*Mostly small fish 2cm (some up to 2m)

*Small mouth openings

*4 openings on dorsal surface of head

*Extinct after abundance of jawed fishes on the scene

http://universe-review.ca/I10-27-jawlessfish.jpg

AgnathaExtant: “Cyclostomes”Hagfish and Lamprey

*Are not as closely related as might appear

*Hagfish are scavengers that lack the rasping denticles of lamprey

*Most Lamprey are parasitic

http://www.exploretheabyss.com/photo/gallery/gallery/ds_trawl/images/HagfishLR.jpg

http://www.nwrc.usgs.gov/world/images/lamprey.jpg

http://www.glaucus.org.uk/sea-lamprey-sucker-RL.jpg

Extant Jawless fishes…

Agnathans are a Polyphyletic group!

Super class Agnatha (oldest craniates in fossil record) Cambrian or earlier

Most abundant in Silurian and lower Devonian

Fossil fish small <15cm (although some up to 2m)

Sucking or scooping feeding mechanism

Conodonts resemble hagfish (Cambrian to Triassic)

All gill tissue is endodermal in origin

Gill structures, arteries, nerves etc. internal to branchial skeleton

http://tolweb.org/Vertebrata


Hagfish (Myxinoidea) …Class - MyxiniOrder – MyxiniformesFamily – MyxinidaeGenera – 6 from mostly temperate waters

Species - > 40 with Pacific and Atlantic Hagfish most well known.

At least one fossil representative from Carboniferous that resembles modern species.

Only occur in marine habitats

Live on soft bottoms of mud, silt or clay usually from 25 – 600m deep.

http://www.bio.uio.no/akv/english/research/mzk/benthos_pictures.html

http://www.youtube.com/watch?v=g8pONkTyk2c http://www.youtube.com/watch?v=NYRr_MrjebA&NR=1

http://www.youtube.com/watch?v=g8pONkTyk2c

http://www.youtube.com/watch?v=NYRr_MrjebA&NR=1


Hagfish (Myxinoidea) …They burrow and perhaps feed on soft-bodied worms etc. they encounter.

Also scavenge and prey on fishApparently good sense of smell,as they quickly find netted fish.

Unique “knotting” technique allows them to pull meat from carcass.

Eversion and retraction of teeth on each side of mouth pull off/in food

http://bakkouz.net/pix/Hagfish.jpg

http://sophont.blogspot.com/2004_02_01_archive.html


Hagfish (Myxinoidea) …Eyes degenerate and covered by skin

Large tentacles surround nasal opening and mouth

Probably lack a larval stage

http://www.uoregon.edu/~joet/Pictures-Pages/Image5.html

http://a.abcnews.com/Technology/AmazingAnimals/popup?id=4958186&contentIndex=1&page=6&start=false

http://www.gma.org/fogm/myxine_glutinosa.htm


Hagfish (Myxinoidea) … 5 to 15 pairs of gills (depending on species)

Some species have branchial ducts that exit via a single tube and external opening Broad-gilled Hagfish

http://www.austmus.gov.au/fishes/fishfacts/fish/ecirrhatus5.htm

http://www.austmus.gov.au/fishes/fishfacts/fish/ecirrhatus6.htm

Broad-gilled Hagfish


Hagfish (Myxinoidea) …Cartilaginous skeleton not well developed…* No vertebrae* Only a membranous roof of the skull

1 semicircular canal on each side of head (Lamprey have 2 and other vertebrates have 3)

In addition to primitive heart… they also have contractile vascular regions in:* Tail* Cardinal vein* Portal vein

Have red blood cells like other vertebrates… but only one type of WBC.


Hagfish (Myxinoidea) …Females outnumber males 100 to 1

Thought at first to be hemaphroditic

Almost nothing known of their reproductive biology!

Recent studies have verified the presence of neural crest cells.


Hagfish (Myxinoidea) …Well known for a defensive mechanism… SLIME!

Abundant mucous glands secreting mucus and coiled proteins

Proteins straighten in water and trap mucus close to hagfishes body

After danger has left, hagfish ties a knot in tail and pulls it towards its head “squeegie-ing” off the slime.


Hagfish (Myxinoidea) …Some commercial use in Asia as source for leather and meat.

Can cause some Economic loss to commercial fisheries when able to access fish caught in gill netsand/or long lines

“Human exploitationOf natural resources,such as fisheries, typically depletesstocks because no attention is givento the biology of the resource and itsrenewable, sustainable characteristics.For example, we do not know how longHagfish live; how old they are when they first begin to reproduce; exactly how, when or where they breed; where the youngest juveniles live; what are the diets and energy requirements of free-living hagfishes; or virtually any of the other information needed for good management. As a result, eel-skin wallets will probably become as rare as items made of whalebone , tortoise shell and ivory. “(Pough et al . 2009, pg. 59)

http://www.daylife.com/photo/0g1T92TaxK623

http://www.daylife.com/photo/0e9DdRDaeV8qa


Lamprey (Petromyzontoidea) …Class – CephalaspidomorphiOrder – Petromyzontiformes / (Hyperoartia)Family – PetromyzontidaeGenera – 10Species - ~ 40 with Petromyzon sp. and Lampetra sp. most well known.

Superficially resemble Hagfish, but differ in several important ways including vertebrae

Unique in having a nasal opening (single) that leads to the pituitary gland.

http://www.gma.org/fogm/Petromyzon_marinus.htm


Lamprey (Petromyzontoidea) …

Petromyzon marinus Sea Lamprey


Lampreys (Petromyzontoidea) …Most species areparasitic

Use hornified “teeth”on the surface of theoral hood and tongue

Can have a negativeImpact on gameand commercialfisheries

http://www.gma.org/fogm/Petromyzon_marinus.htm

http://en.wikipedia.org/wiki/File:Boca_de_lamprea.1_-_Aquarium_Finisterrae.JPG

http://www.biology.duke.edu/bio217/2005/ncy/sea%20lamprey.html

http://upload.wikimedia.org/wikipedia/commons/d/d0/Boca_de_lamprea.1_-_Aquarium_Finisterrae.JPG

http://upload.wikimedia.org/wikipedia/commons/d/d0/Boca_de_lamprea.1_-_Aquarium_Finisterrae.JPG


Lampreys (Petromyzontoidea) … Lampreys have 7 pairs of gill pouches

Do not typically use flow-through ventilation

Rather, they use tidal ventilation

http://www.rsc.org/chemistryworld/News/2005/September/03100501.asp


Lampreys (Petromyzontoidea) … Nearly all species are anadromous

Anadromous species that grow in adult form in the sea are the largest (up to 1m)

A small parasitic species (Lampetra minima) was full grown at less than 10 cm (now extinct)

Spawn in streams

Lay 100,000s of eggs

http://oregonstate.edu/dept/ODFW/NativeFish/Lamprey.htm


Lampreys (Petromyzontoidea) …Larval lamprey are called ammocoetes

Live in gravel beds filtering plankton and organic debris for 3-7 years

Metamorphose and then begin journey to sea or other major water basin where they will grow and mature.

Usually live as adults for less than 2 years.

They migrate back up to their hatching grounds (now spawning grounds)

Mate and then die!


Lampreys (Petromyzontoidea) …







Gnathostomes3 groups appeared in the Paleozoic:

1) Placoderms (ex. Arthrodires) had large boney plates and paired fins

http://www.noaca.org/earlgeo.gif

http://www.cnrs.fr/cw/dossiers/dosevol/imgArt/dioram/PaleozoDevon/Zimg/dicksonosteus.jpg


2) Chondrichthyans (cartilagenous fishes)*Includes sharks, rays, skates, and ratfish

*Cartilaginous skeletons

*Many with placoids

*No bony operculum

http://www.lifeglobe.com/images/product/Sharks/sharks04_r2_c2.jpg

http://www.pangaeadesigns.com/_graphics/page/fish/large/ratfish.jpg


3) Teleostomes (spiny and bony fishes)

*Acanthodians are (spiny fishes) are extinct

*Had skeleton of bone and cartilage

*Had an operculum

http://sps.k12.ar.us/massengale/images/R-acanthodians.gif

OsteichthyansShared ancestors with tetrapods

Have an air sac

Dermal bone

Paired fins… either ray finned (actinopterygii) or fleshy finned (sarcopterygii)

http://www.paleodirect.org/fg009.htm

ActinopterygiiBasal groups include Sturgeon and Paddlefish

http://www.hellscanyonsportfishing.com/images/sturgeon%20pictures/Kevin%20&%20Sturgeon%202.jpg

http://www.digimorph.org/specimens/Polypterus_senegalus/whole/specimen.jpg

ActinopterygiiAdvanced groups include Gars, Bowfins and Teleosts (most other bony fish)

http://www.sdafs.org/laafs/Amazing%20Fish%20Pictures/Big%20Alligator%20Gar%2009-03.JPG

SarcopterygiiHave fleshy lobed fins, internal nares and a bony operculum

2 major clades:

Actinistians, extinct except “coelocanths”

Rhipidistians (and dipnoi)“lungfish”

http://kentsimmons.uwinnipeg.ca/16cm05/1116/34-14-Coelocanth.jpg

http://www.bertsgeschiedenissite.nl/geschiedenis%20aarde/lungfish.jpg

Amphibia*Paraphyletic group… omitting amniote descendants

*Extinct groups include Labrynthodonts (Ichthyostega)

*Extant group (Lissamphibia) includes:

Apoda (caecilians)

Urodela (salamanders)

Anura (frogs)

http://news.siu.edu/news/May05/images/salamander.jpg

http://www.yesnet.yk.ca/schools/wes/webquests_themes/frogs_theme/frogs_K/frog_species/barred/images/

barred_leaf_frog_jpg.jpg

http://www.bbc.co.uk/radio4/science/media/Btaitanus-PC1b.jpg

AmniotesGroup includes Reptiles and Synapsids

Reptilia (paraphyletic)

Chelonia (testudinea) “turtles”

Rhynchocephalians “tuatara”

Squamates “lizards, snakes etc.”

Crocodylians “crocodiles” etc.

Aves “birds”

SynapsidsAmniotes with synapsid skull, hair, mammary glands & nipples (most)

Mammalia

Monotremata

Mammalia

Marsupialia

Mammalia

Insectivora

Mammalia

Xenarthra

Mammalia

Tubulidentata

Mammalia

Pholidota

Mammalia

Chiroptera

Mammalia

Primates

Mammalia

Lagomorpha

Mammalia

Rodentia

Mammalia

Carnivora

Mammalia

Pinnipedia

Mammalia

Perissodactyla

Mammalia

Atriodactyla

Mammalia

Hyracoidea

Mammalia

Proboscidea

Mammalia

Sirenia

Mammalia

Cetacea

• Cloaca/Eggs

• No front teeth (or no teeth at all)

• Opposable thumbs

• Peg-like teeth (African)

• Pouch

• Scaly

• Smooth cerebral cortex/sharp teeth

• Two pairs of incisors (only central growing)

• Wings

• Aquatic ungulates without hind-

limbs

• Aquatic with nostrils on top of

head

• Canine with fins/terrestrial birth

• Growing incisors/hoof-like nails

• Incisors form tusks

• Single pair of growing incisors

• Ungulates with even #

toes/paraxonic foot

• Ungulates with odd # toes

(usually)/mesaxonic foot

• Well developed canines

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¿ What anatomical/physiological features distinguish vertebrates?