Transcript AP Biology
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?
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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
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acoelomate
ectoderm
mesoderm
endoderm
pseudocoelomate
ectoderm
mesoderm
endoderm
pseudocoel
coelomate
ectoderm
mesoderm
coelom cavity
endoderm
protostome vs. deuterostome