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D.N.A
Objective: SWBAT explain the origin and
diversity of animals
 What do you believe are the
characteristics that separate animals
from the other groups of living things?
AP Biology
HOMEWORK
 Cladogram practice and discussion
question posted on wikispace
 Due Friday by 11:59 pm
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Kingdom: Animals
Domain Eukarya
Domain
Bacteria
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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

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Variety of organisms
Early embryonic stages
 Zygote (fertilization of egg and sperm)

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 gastrula…
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“BODY PLAN”
 Biologists categorize the diversity of
animals by body structure
 Helped to infer the phylogenetic
relationship between animal groups
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SYMMETRY
 Some animals have radial symmetry

(a)
Like in a flower pot
Radial symmetry. The parts of a
radial animal, such as a sea anemone
(phylum Cnidaria), radiate from the
center. Any imaginary slice through
the central axis divides the animal
into mirror images.
Figure 32.7a
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 Some animals exhibit bilateral symmetry

(b)
Or two-sided symmetry
Bilateral symmetry. A bilateral
animal, such as a lobster (phylum
Arthropoda), has a left side and a
right side. Only one imaginary cut
divides the animal into mirror-image
halves.
Figure 32.7b
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 Bilaterally symmetrical animals have
A dorsal (top) side and a ventral (bottom)
side
 A right and left side
 Anterior (head) and posterior (tail) ends

 Cephalization - the development of a head
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ORGANIZATION OF TISSUE
 Animal body plans

Also vary according to the organization of
the animal’s tissues
 Tissues

Are collections of specialized cells isolated
from other tissues by membranous layers
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Gastrulation (creation of gastrula
(early multicellular embryo)
 zygote  blastula  gastrula

rearranges the blastula to form
3-layered embryo with a primitive gut
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Body Cavities
 In triploblastic (3 tissue layers) animals

A body cavity may be present or absent

Body Cavity - Fluid-filled space between the
digestive tract and body wall
 cushions the internal organs
 enables growth and movement
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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
 A true body cavity

Is called a coelom and is derived from
mesoderm
Coelom
Coelomate. Coelomates such as
(a) annelids have a true coelom, a body
cavity completely lined by tissue
derived from mesoderm.
Tissue layer
lining coelom
and suspending
internal organs
(from mesoderm)
Digestive tract
(from endoderm)
Figure 32.8a
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Body covering
(from ectoderm)
 A pseudocoelom (false body cavity)

Is a body cavity partially lined by tissue from
the mesoderm
Body covering
(from ectoderm)
(b)
Pseudocoelomate. Pseudocoelomates
such as nematodes have a body cavity only
partially lined by tissue derived from
mesoderm.
Pseudocoelom
Digestive tract
(from ectoderm)
Figure 32.8b
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Muscle layer
(from
mesoderm)
Acoelomates
 Organisms without body cavities
Body covering
(from ectoderm)
(c)
Acoelomate. Acoelomates such as
flatworms lack a body cavity between
the digestive tract and outer body wall.
Digestive tract
(from endoderm)
Figure 32.8c
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Tissuefilled region
(from
mesoderm)
Protostome and Deuterostome
Development
 Based on certain features seen in early
development

Many animals can be categorized as having
one of two developmental modes:
protostome development or deuterostome
development
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Basic body plan
 Protostomes (stoma – mouth)



“1st mouth”
blastopore = mouth
Invertebrates
 Deuterostomes



“2nd mouth”
blastopore = anus
echinoderms & vertebrates
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2004-
Mini Poster Project
 Each group will focus on a specific
animal group
Name
 Picture/Examples
 Body plan

 Symmetry?
 Coelom
 Cephalization
 Anything special about the animal group
that distinguishes it from the rest
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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
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
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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
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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 + 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?
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
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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
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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
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
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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
 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
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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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That’s
the buzz!
Any
Questions?
AP Biology
2007-2008
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