2007-2008 AP Biology

Invertebrate and Vertebrate Evolution and Diversity

AP Biology

Porifera

Cnidaria

Platyhelminthes

sponges jellyfish flatworms roundworms

Nematoda

Mollusca Arthropoda Chordata

Annelida Echinoderm

mollusks

multicellularity

Ancestral Protist

tissues

bilateral symmetry

body cavity

segmentation

Animal Evolution

coelom

starfish vertebrates

endoskeleton

segmentedworms

insectsspiders

backbone

AP Biology

Phylum Porifera Sponges

no distinct tissues or organs do have specialized cells

no symmetry sessile (as adults)

food taken into each cell by endocytosis

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Phylum Cnidaria Jellyfish, hydra, sea anemone, coral

tissues, but no organs two cell layers radial symmetry predators

tentacles surround gut opening

extracellular digestion

release enzymes into gut cavity

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hydra

stinging cellwith nematocyst

trigger

dischargednematocyst

undischargednematocyst

tentacles

mouth

sensorycell

stingingcell

Stinging cells of Cnidarians

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Phylum Platyhelminthes

ectoderm

mesoderm

endoderm

Flatworms tapeworm, planaria mostly parasitic bilaterally symmetrical

allows high level of specialization within parts of the body

now have a mouth at one end & an anus at the other!

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Phylum Nematoda Roundworms

bilaterally symmetrical have both mouth & anus

well-developed digestive system many are parasitic

hookworm

C. elegans

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Phylum Mollusca Mollusks

clams, snails, squid bilaterally symmetrical (with exceptions)

soft bodies, mostly protected by hard shells true coelem

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Phylum Annelida Segmented worms

earthworms, leeches segments are not specialized bilaterally symmetrical true coelem fan worm leech

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Phylum Arthropoda Spiders, insects, crustaceans

most successful animal phylum bilaterally symmetrical segmented

allows jointed appendages exoskeleton

chitin + protein

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Arthropod groups

insects6 legs, 3 body parts

crustaceansgills, 2 pairs antennaecrab, lobster, barnacles, shrmp

arachnids8 legs, 2 body partsspiders, ticks, scorpions

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Phylum Echinodermata Starfish, sea urchins, sea cucumber

Water vascular system (hydraulic canals) Locomotion, feeding, gas exchange

radially symmetrical spiny exoskeleton

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Two subphyla of invertebrate animals… And the subphylum Vertebrata

fish, amphibians, reptiles, birds, mammals internal bony skeleton

backbone encasing spinal column

skull-encased brain

postanaltail notochord

hollow dorsalnerve cord

pharyngealpouches

Phylum Chordata

becomes brain & spinal cord

becomes vertebrae

becomes gills or Eustachian tube

becomes tail or tailbone

Oh, look…your first

baby picture!

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Vertebrates: Fishsalmon, trout, sharks

450 mya450 mya

Characteristics body structure

bony & cartilaginous skeleton jaws & paired appendages (fins) scales

body function gills for gas exchange two-chambered heart;

single loop blood circulation ectotherms

reproduction external fertilization external development in

aquatic egg

gills

body

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Transition to LandEvolution of tetrapods

Tibia

Femur

Fibula

Humerus Shoulder

RadiusUlna

Tibia

FemurPelvis

Fibula Lobe-finned fish

Humerus

Shoulder

Radius

Ulna

Pelvis

Early amphibian

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lung

buccalcavity

glottisclosed

Class Amphibia Characteristics

body structure legs (tetrapods) moist skin

body function lungs (positive pressure) &

diffusion through skin for gas exchange three-chambered heart;

veins from lungs back to heart ectotherms

reproduction external fertilization external development in aquatic egg metamorphosis (tadpole to adult)

frogssalamanders toads

350 mya350 mya

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Class Reptilia Characteristics

body structure dry skin, scales, armor

body function lungs for gas exchange thoracic breathing; negative pressure three-chambered heart ectotherms

reproduction internal fertilization external development in

amniotic egg

250 mya250 myadinosaurs, turtles lizards, snakesalligators, crocodile

embryoleatheryshell

chorion

allantoisyolk sac

amnion

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Class Aves (Birds) Characteristics

body structure feathers & wings thin, hollow bone;

flight skeleton body function

very efficient lungs & air sacs four-chambered heart endotherms

reproduction internal fertilization external development in

amniotic egg

150 mya150 myafinches, hawk ostrich, turkey

trachea

anteriorair sacs

lung

posteriorair sacs

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Class Mammalia Characteristics

body structure hair specialized teeth

body function lungs, diaphragm; negative pressure four-chambered heart endotherms

reproduction internal fertilization internal development in uterus

nourishment through placenta birth live young mammary glands make milk

220 mya / 65 mya220 mya / 65 myamice, ferret elephants, batswhales, humans

musclescontract

diaphragmcontracts

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Class Mammalia Sub-groups

monotremes egg-laying mammals duckbilled platypus, echidna

marsupials pouched mammals short-lived placenta koala, kangaroo, opossum

placental true placenta shrews, bats, whales, humans

AP Biology

Vertebrate quick check… Which vertebrates lay eggs with shells? Which vertebrates are covered with scales? What adaptations do birds have for flying? What kind of symmetry do all vertebrates have? Which vertebrates are ectothermic and which

are endothermic Why must amphibians live near water? What reproductive adaptations made mammals

very successful? What characteristics distinguish the 3 sub-

groups of mammals?