Transcript Intro to Animals

Bio II
Rupp
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VERTEBRATE—ANY ANIMAL
WITH A BACKBONE
INVERTEBRATE—ANY ANIMAL
WITHOUT A BACKBONE
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 50
trillion cells in the
human body
 Cells need eachother
and specialize
 Cell junctions—
connections between
cells—allow tissue
formation and
communication
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 Ingestion
of food
 Breakdown of food to
release molecules
essential to life
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 Diploid
zygote—first
cell of a new
individual (ploidy
number)
 Differentiation
 Specialization
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 Ability
to move
comes from the
unique relationship of
two tissue types
• Muscle
• Nerve (neurons)
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 First
animals
probably arose from
the sea
 Loosely connected
flagellated protists
 Division in labor
allowed
multicellularity
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 Oparin’s
theory on
Early Earth
 Miller-Urey
Experiment
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 Symmetry—a
consistent overall pattern
of structure
 Simple organisms lack symmetry
 Patterns of symmetry
• Nonsymmetrical
• Radial symmetry
• Bilateral symmetry
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 Cephalization
 Germ
layers—
fundamental tissue
types found in
embryos of animals
except sponges
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 Similarities
in structure allow biologists
to classify—morphology
• Multicellular, limited cell specialization =
sponges
• Tissues in two layers = cnidarians and
ctenophores
• Tissues in three layers and bilaterally
symmetrical = all other phyla from figure 34-5
page 672
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 Invertebrates
 Chordates
• Notochord
• Postanal tail
• Pharyngeal gill pouches or slits
• Dorsal, hollow nerve cord
 Vertebrates
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Invertebrates
Vertebrates
Symmetry
Radial or bilateral
--
Integument
--
Usually to hold water in;
specific functions
Segmentation
Repeating subunits
Ribs and vertebrae
Support of the body
Exoskeleton
Endoskeleton
Respiratory
Gills
Lungs
Circulatory
Open
Closed
Digestive/Excretory
Gut or digestive tract
Gut or digestive tract as well
as filters like kidneys
Nervous
Extraordinary diversity
Highly organized brains and
nervous systems
Reproduction/Development
Sexual and asexual,
hermaphroditic, indirect
development
Eggs released to water, eggs
held internally, development
internal or external,
typically direct development
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SPERM




Small
Motile
Head contains
chromosomes
Tail is a flagellum
EGG OR OVUM



Large
Cytoplasm and yolk
Yolk size depends on
development length; longer
development = big yolk
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 Sperm
membrane
joins with egg
membrane and
sperm nucleus enters
the egg cytoplasm
 Sperm entry causes
an electrical reaction
to block more sperm
from entering
 Nuclei
of sperm and
egg merge to form a
diploid zygote
 DNA replication and
mitotic division
begins
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PREFORMATION



Organisms were preformed
inside the egg or sperm
The organism in the egg or
sperm needed only to
unfold
Some claimed to see the
organisms in sperm
EPIGENESIS




Kasper Friedrich Wolff
Said eggs do not contain
preformed organisms only
the raw material to form
organisms
Materials need to be
activated
Basis for how things
actually work
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 Restores
diploid
number
 Activates egg to
develop
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Cleavage—divisions of
the zygote
 Exponential increase
 Cells get smaller with
each division
 As division occurs the
cells form a hollow ball
called a blastula
 Empty space in the
blastula is the
blastocoel

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 Stage
of development
that follows blastula
 Blastula indents or
invaginates and the
region becomes
known as the
blastopore
 Invagination leads to
a multilayered
embryo
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 Archenteron
• Deep cavity of the gastrula
• Becomes the gut
• Throat, gills, lungs , liver, pancreas
 Ectoderm
• Outer layer
• Skin, hair, nails, nervous system
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 Endoderm
• Inner layer
• Epithelial lining of gut
 Mesoderm
• Middle layer
• Skeleton, muscles, circulatory system
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 Coelom—a
body cavity lined with a
mesoderm
 Development can be based upon how the
coelom forms, aka, patterns of cleavage
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PROTOSTOMES




Blastopore forms the mouth
Mouth forms first
Anus forms second
Spiral cleavage
DEUTEROSTOMES




Blastopore forms anus
Anus forms first
Mouth forms second
Radial cleavage
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DETERMINATE CLEAVAGE



The fate of the cells is
determined at an early
developmental stage
Separation of the zygote at
the 4-cell stage results in
cell death
The future of each cell is
determined
INDETERMINATE CLEAVAGE



The fate of each cell is not
determined at an early
developmental stage
Cells can be separated and
survive (cloning)
The future of each cell is
not determined
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SCHIZOCOELY



Split body cavity
Endoderm/ectoderm
junction cells divide to
form mesoderm
Mesoderm is separated by
the blastopore
ENTEROCOELY



Gut body cavity
Cells that form the
archenteron begin to
divided to form the
mesoderm
“Mickey Mouse Ears”
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 Acoelomate
• No body cavity
• Ectoderm and endoderm are connected by
mesoderm
 Pseudocoelomate
• False body cavity
• Mesoderm lines the ectoderm
• Gut is suspended in body fluid
 Coelomate
• True body cavity
• Mesoderm provides support to ectoderm and
endodermic gut
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Gamete
Formation
Fertilization
Cleavage
Gastrulation
Organogenesis
Growth
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