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Kingdom: Animals
Domain Eukarya
Domain
Bacteria
AP Biology
Domain
Archaea
Domain
Eukarya
2007-2008
Common ancestor
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
Echinodermata
Arthropoda
flatworms roundworms mollusks segmented
worms
redundancy,
segmentation
specialization,  mobility
insects
spiders
starfish
Chordata
vertebrates
 body & brain
backbone
size,  mobility
 body size endoskeleton
coelom  digestive sys
radial
body cavity  body complexity
 digestive & repro sys
bilateral symmetry
tissues
multicellularity
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Ancestral Protist
distinct body plan; cephalization
specialized structure & function,
muscle & nerve tissue
specialization &  body complexity
bilateral
Body Cavity
 Space for organ
system development

increase digestive &
reproductive systems
 increase food
capacity & digestion
 increase gamete
production
 Coelem


mesoderm &
endoderm interact
during development
allows complex
structures to develop
in digestive system
 ex. Stomach
 CLICK FOR VIDEO
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acoelomate
ectoderm
mesoderm
endoderm
pseudocoelomate
ectoderm
mesoderm
endoderm
pseudocoel
coelomate
ectoderm
mesoderm
coelom cavity
endoderm
protostome vs. deuterostome
What’s the most complex
problem in biology?
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2004-2005
The most complex problem
How to get from here to there
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2004-
Egg   zygote   morula
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2004-
Egg   morula   blastula
 Blastula formation

successive divisions
result in a blastula
 hollow single-layered
sphere enclosing a
space = blastocoel
AP Biology
2004-
AP Biology
2004-
Early embryonic stages
 Morula

solid ball stage
 Blastula

hollow fluid-filled ball stage
 by time human embryo reaches uterus
 Gastrula

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development of primitive digestive tract
(gut) & tissue layers
2004-
Gastrulation
 zygote  blastula  gastrula
How you looked
as a blastula…
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2004-
Gastrulation
 zygote  blastula  gastrula

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rearranges the blastula to form
3-layered embryo with a primitive gut
2004-
Gastrulation
archenteron:
forms endoderm
embryonic gut
blastopore:
forms at sperm
penetration point
mesoderm
dorsal lip: organizing center
for development
tissue formation
AP Biology
2004-
Primary tissue or “germ” layers
 ectoderm

external surfaces: skin
 epidermis (skin); nails, hair & glands; tooth enamel;
eye lens; epithelial lining of nose, mouth & rectum;
nervous system
 endoderm

internal lining
 epithelial lining of digestive tract & respiratory
systems; reproductive system & urinary tract;
digestive organs
 mesoderm

middle tissues: muscle, blood & bone
 notochord; skeletal, muscular, circulatory, lymphatic,
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excretory & reproductive systems; lining of body
cavity
2004-
Basic body plan
 Archenteron becomes
embryonic gut


mouth at one end
anus at the other
 Protostomes



“1st mouth”
blastopore = mouth
invertebrates
 Deuterostomes



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“2nd mouth”
blastopore = anus
echinoderms &
vertebrates
2004-
Invertebrate: Porifera
 Sponges

no distinct tissues or organs
 do have specialized cells
no symmetry
 sessile (as adults)

AP Biology
food taken into each
cell by endocytosis
Invertebrate: Cnidaria
 Jellyfish, hydra, sea anemone, coral
tissues, but no organs
polyp
 two cell layers
 radial symmetry
 predators

 tentacles surround
gut opening
 extracellular
digestion
 release enzymes
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into gut cavity
 absorption by cells
lining gut
medusa
Stinging cells of Cnidarians
mouth
tentacles
sensory
cell
stinging
cell
hydra
trigger
stinging cell
with nematocyst
AP Biology
discharged
nematocyst
undischarged
nematocyst
Invertebrate: Platyhelminthes
 Flatworms



tapeworm, planaria
mostly parasitic
bilaterally symmetrical
 have right & left & then have
head (anterior) end & posterior end
Animals now
 cephalization = development of brain
face the world
 concentration of sense organs in head
head on!
 increase specialization in body plan
ectoderm
AP Biology
acoelomate
mesoderm
endoderm
Invertebrate: Nematoda
 Roundworms


bilaterally symmetrical
body cavity
C. elegans
 pseudocoelom = simple body cavity
 digestive system
 tube running through length of body (mouth to anus)

many are parasitic
 hookworm
AP Biology
Invertebrate: Mollusca
 Mollusks




slugs, snails, clams, squid
bilaterally symmetrical (with exceptions)
soft bodies, mostly protected by hard shells
true coelem
 increases complexity & specialization of internal organs
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Invertebrate: Annelida
 Segmented worms


earthworms, leeches
segments
 increase mobility
 redundancy in body sections


AP Biology
bilaterally symmetrical
true coelem
fan worm
leech
Invertebrate: Arthropoda
 Spiders, insects, crustaceans



most successful animal phylum
bilaterally symmetrical
segmented
 specialized segments
 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



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radially symmetrical as adults
spiny endoskeleton
loss of bilateral symmetry?
deuterostome
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 have radial symmetry?
 What is the adaptive advantage of bilateral
symmetry?
AP Biology
 Which group has no symmetry?
 Which group includes snails, clams, and squid? Mollusks
 Which group is the sponges? Porifera
 Which are the flatworms? Platyhelminthes




…segmented worms? Annelids
…roundworms? Nematodes
Which group has jointed appendages & an exoskeleton?
Arthropods
Which two groups have radial symmetry? Cnidaria,
Echinoderm
What is the adaptive advantage of bilateral symmetry?
cephalization
Which group has no symmetry? Profiera
AP Biology
Chordata
 Vertebrates
fish, amphibians,
reptiles, birds,
mammals
 internal bony
becomes gills or
skeleton
Eustachian tube

 backbone encasing
spinal column
 skull-encased brain

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deuterostome
hollow
dorsal
nerve cord
becomes brai
& spinal cord
pharyngeal
pouches
postanal
becomes tail tail
or tailbone
becomes
vertebrae
notochord
450 mya
salmon, trout, sharks
Vertebrates: Fish
 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
AP Biology
aquatic egg
body
gills
Transition to Land
Evolution of tetrapods
Humerus
Femur
Pelvis
Tibia
Ulna
Shoulder
Radius
Lobe-finned fish
Fibula
Pelvis
Femur
Humerus
Tibia
Fibula
AP Biology
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)
AP Biology
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
AP Biology
allantois
yolk sac
150 mya
Vertebrates: Birds (Aves)
finches, hawk
ostrich, turkey
 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
AP Biology
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
AP Biology
Vertebrates: Mammals
 Sub-groups

monotremes
 egg-laying mammals
 lack placenta & true nipples
 duckbilled platypus, echidna

marsupials
 pouched mammals
 offspring feed from nipples in pouch
 short-lived placenta
 koala, kangaroo, opossum

placental
 true placenta
 nutrient & waste filter
 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?
AP Biology
That’s
the buzz!
Any
Questions?
AP Biology
2007-2008