Transcript AP Biology 2007-2008

Kingdom: Animals
Domain Eukarya
Invertebrates
Domain
Eubacteria
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
The Gut
 Region where food is digested and then


absorbed
Saclike gut
 One opening for taking in food and
expelling waste
Complete digestive system
 Opening at both ends; mouth and anus
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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
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acoelomate
ectoderm
mesoderm
endoderm
pseudocoelomate
ectoderm
mesoderm
endoderm
pseudocoel
coelomate
ectoderm
mesoderm
coelom cavity
endoderm
protostome vs. deuterostome
 The difference between protostomes and deuterostomes can first be
analyzed within embryonic development. During development, an
opening on the surface of the embryo will eventually connect to the
the developing gut, which is called the archenteron, to the outside
environment. The opening on the surface of the embryo is called the
blastopore. Later on, a second opening at the opposite end of the
embryo turns the pouch-like gut into a digestive tube. In protosomes,
the blastopore develops into the mouth and the second opening
forms the anus. In deuterostomes, the blastopore develops into the
anus and the second opening forms the mouth
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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
Sponge Structure
water out
glasslike
structural
elements
amoeboid
cell
pore
semifluid
matrix
central
cavity
flattened
surface
cells
water in
flagellum
microvilli
nucleus
Figure 25.7a
Page 419
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
Phylum Cnidaria


Have stinging
cells inside of
nematocysts
On tentacles
capsule’s lid
at free surface
of epidermal
cell
trigger
barbed
thread
inside
capsule
nematocyst
Figure 25.8
Page 420
Stinging cells of Cnidarians
mouth
tentacles
sensory
cell
stinging
cell
hydra
trigger
stinging cell
with nematocyst
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discharged
nematocyst
undischarged
nematocyst
Obelia Life Cycle (Hydrozoan)
reproductive
polyp
male medusa
female medusa
ovum
sperm
zygote
feeding
polyp
polyp
forming
planula
Figure 25.10
Page 421
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
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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
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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


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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 (carbohydrate)
+ 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?
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 Which group has no symmetry?