Kingdom: Animals
Domain Eukarya
Domain
Bacteria
Domain
Archaea
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Common ancestor
Domain
Eukarya
Animal Characteristics
 Heterotrophs

must ingest others for nutrients
 Multicellular

complex bodies
 No cell walls

allows active movement
 Sexual reproduction
no alternation of generations
 no haploid gametophyte

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Animal Evolution
Cnidaria
Porifera
sponges
jellyfish
Nematoda
Platyhelminthes
Annelida
Mollusca
Echinoderm
Arthropoda
flatworms roundworms mollusks segmented
worms
insects
spiders
Chordata
starfish
vertebrates
backbone
segmentation
endoskeleton
coelom
body cavity
bilateral symmetry
tissues
multicellularity
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Ancestral Protist
Body Cavity
How much is
the digestive
tract separated
from the rest
of the body?
ectoderm
mesoderm
endoderm
acoelomate
ectoderm
mesoderm
endoderm
pseudocoelomate
pseudocoel
 3 body layers
ectoderm
 mesoderm
 endoderm

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ectoderm
mesoderm
coelom cavity
coelomate
endoderm
Invertebrate: Porifera
 Sponges

no distinct tissues or organs
 do have specialized cells
no symmetry
 sessile (as adults)

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food taken into each
cell by endocytosis
Invertebrate: 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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Stinging cells of Cnidarians
mouth
tentacles
sensory
cell
stinging
cell
hydra
trigger
stinging cell
with nematocyst
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discharged
nematocyst
undischarged
nematocyst
Invertebrate: Platyhelminthes
 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!
ectoderm
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mesoderm
endoderm
Invertebrate: Nematoda
 Roundworms
bilaterally symmetrical
 have both mouth & anus

 well-developed digestive system

many are parasitic
 hookworm
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C. elegans
Invertebrate: Mollusca
 Mollusks
clams, snails, squid
 bilaterally symmetrical (with exceptions)
 soft bodies, mostly protected by hard shells
 true coelem

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Invertebrate: Annelida
 Segmented worms
earthworms, leeches
 segments are not specialized
 bilaterally symmetrical
 true coelem
fan worm

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leech
Invertebrate: Arthropoda
 Spiders, insects, crustaceans
most successful animal phylum
 bilaterally symmetrical
 segmented

 allows jointed appendages

exoskeleton
 chitin + protein
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Arthropod groups
arachnids
8 legs, 2 body parts
spiders, ticks, scorpions
crustaceans
gills, 2 pairs antennae
crab, lobster, barnacles,
shrimp
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insects
6 legs, 3 body parts
Invertebrate: Echinodermata
 Starfish, sea urchins, sea cucumber
radially symmetrical
 spiny exoskeleton

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Invertebrate quick check…
Invertebrates: Porifera, Cnidaria, Platyhelminthes, Nematoda,
Annelida, Mollusca, Arthropoda, Echinodermata
 Which group includes snails, clams, and squid?
 Which group is the sponges?
 Which are the flatworms?
…segmented worms?
…roundworms?
 Which group has jointed appendages & an
exoskeleton?
 Which two groups are radially symmetrical?
 Which group has no symmetry?
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Chordata
 Vertebrates
fish, amphibians, reptiles, birds, mammals
hollow dorsal
nerve cord
 internal bony skeleton

 backbone encasing
becomes brain
& spinal cord
spinal column
 skull-encased brain
becomes gills or
Eustachian tube
pharyngeal
pouches
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postanal
becomes tail tail
or tailbone
becomes
vertebrae
notochord
450 mya
salmon, trout, sharks
Vertebrates: Fish
 Characteristics

gills
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
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aquatic egg
body
Transition to Land
Evolution of tetrapods
Humerus
Femur
Pelvis
Tibia
Ulna
Shoulder
Radius
Lobe-finned fish
Fibula
Pelvis
Femur
Humerus
Tibia
Fibula
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Early amphibian
Ulna
Shoulder
Radius
350 mya
frogs
salamanders
toads
Vertebrates: Amphibian
 Characteristics

lung
body structure
 legs (tetrapods)
 moist skin

buccal
cavity
glottis
closed
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)
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250 mya
Vertebrates: Reptiles
 Characteristics

dinosaurs, turtles
lizards, snakes
alligators, crocodile
body structure
 dry skin, scales, armor

body function





lungs for gas exchange
thoracic breathing; negative pressure
three-chambered heart
ectotherms
leathery
reproduction
shell
embryo
amnion
 internal fertilization
 external development in
amniotic egg
chorion
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allantois
yolk sac
150 mya
finches, hawk
ostrich, turkey
Vertebrates: 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
 Everybody Loves Eggs!
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trachea
lung
anterior
air sacs
posterior
air sacs
220 mya / 65 mya
Vertebrates: Mammals
 Characteristics

body structure
 hair
 specialized teeth

mice, ferret
elephants, bats
whales, humans
body function
muscles
contract
 lungs, diaphragm; negative pressure
 four-chambered heart
diaphragm
 endotherms
contracts

reproduction
 internal fertilization
 internal development in uterus
 nourishment through placenta
 birth live young
 mammary glands make milk
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Vertebrates: Mammals
 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 subgroups of mammals?
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Any
Questions?
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