Transcript 1 ANIMALS Characteristics

The Kingdom ANIMALS
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Eukaryotic cells
Multicellular
Heterotrophic by ingestion
Classification Tools for Animals
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1. Body Symmetry
2. Level of Body Organization
3. Body Cavities:Presence of a Coelom
4. Embryological Development: Protostome vs
Deterostome
5. Segmentation / Cephalization
6. Presence of a Notochord
7. Presence of a Vertebral Column
1. Body Symmetry
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A. Asymmetry
B. Radial Symmetry
C. Bilateral Symmetry
D. (Pentaradial symmetry – Echninoderms)
a. Asymmetry –No symmetry at all!
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Example: Porifera
Sea Sponges and Corals
Porifera
Radial Symmetry
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Example: Cnidaria
Cnidaria and Radial Symmetry
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Cnidaria actually go
through a
developmental
stage of bilateral
symmetry before
they develop their
radial symmetry as
an adult.
Sea
Anemone
Crown Jellyfish
Soft Coral Polyps
Bilateral Symmetry
– Candy striped Annelid
Blue Spotted Sting Ray
Marine Flatworm
African Elephants
2. Levels of Organization
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A. Cellular – no true tissues
B. Tissues
C. Organ
a. Cellular Level of Organization
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Porifera are
really just an
assemblage of
different
specialized
cells. They
have no tissues
or organs
b. Tissue Level of Organization
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Cnidaria have two tissue layers surrounding it’s sac
body plan. They do not have any organs or organ
systems
c. Organ Level of Organization
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Platyhelminthes
(flatworms) are the first
animals on the
phylogenetic tree that
have simple organs.
They have very primitive
“brains” in their “heads”called cephalization
Platyhelminthes (flatworms)- have
simple organs and exhibit simple
cephalization
Organ System Level of
Organization
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As we move up
the evolutionary
tree, organ
systems become
increasingly more
complicated
Body Cavities
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A. Sac body plan
B. tube-within-a-tube body plan
- Acoelomates
- Pseudocoelomates
- Coelomates
a. Sac Body Plan – only one opening for
food to enter and wastes to exit
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Porifera (sponges)
Cnidaria (jellyfish)
Platyhelminthes
(flatworms)
b. Tube-Within-A-Tube Body Plan
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Implies that there is an entrance (mouth) for
nutrients and an exit (anus) for wastes
Most primitive animal with this plan:
Nematodes
Acoelomates, Pseudocoelomates,
and Coelomates
Acoelomates:
Animals without a Coelom
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There is no internal body cavity aside from the
digestive cavity
Pseudocoelomates: Animals with an
internal body cavity that is partially lined with
mesoderm
Coelomates:
Animals with a true Coelom
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A true coelom is an
internal body cavity that
is completely lined with
mesoderm
4. Embryo
Development:
Protostome vs.
Deuterostome
5. Segmentation – Annelids, Arthropods
and Chordates
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Repetition of body parts along the length of the
body
Leads to specialization of parts because
various segments can become differentiated
for specific purposes
Segmentation
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- easily seen in
the Arthropods
6. Presence of a Notochord
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A notochord is a supporting rod that runs down
the dorsal surface, just below the nerve cord.
Animals that have a notochord are called
chordates.
Vertebrate vs
Invertebrate.
External
Fertilization
vs
Internal
Fertilization
a. Invertebrate Chordates:
Tunicates
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most animals that have
notochords also have
vertebrate. However,
there are 2 groups that
do not.
Those animals that do
not have vertebrate are
called the
INVERTEBRATE
CHORDATES
a. Invertebrate Chordates:
Lancelets
Vertebrates –
Chordates with a backbone