Transcript Animals 26-1PPT - holyoke

Kingdom Animalia
 Animals
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are:
Multicellular, with tissues and organ systems that
perform specialized functions
Eukaryotic, with no cell walls
Heterotrophic
Mobile at some point in their life-cycle
Animal Groups
Animals are placed into one of two informal
groups for classification purposes:
1. Invertebrates- 95% of animal species are
invertebrates, animals that do not have a
backbone. Everything from insects to squid.
2. Vertebrates- 5% of animals species, including
mammals, birds, reptiles, amphibians and fish.
What Animals Do
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Eat: Animals find and eat their food. They can
be carnivorous, herbivorous, omnivorous (both)
or parasitic. Animals can also be filter-feeders
and detrivores (eat dead things.)
Respiration: Animals take in oxygen and breathe
out carbon dioxide.
Circulation: Most animals have a circulatory
system to move materials within their bodies.
What Animals Do
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Excretion: Most animals have systems to get
waste products like ammonia out of their bodies.
Response: Nervous systems within animals allow
them to respond to events in their environment.
Movement: Most animals are motile, and have
muscles that contract, allowing them to move.
Reproduction: Most reproduction is sexual with
the fusion of haploid gametes, although asexual
reproduction occurs in many invertebrates.
Animal Development (p. 661)
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All reproduce sexually, some also reproduce asexually.
All animal cells originally come from a zygote.
The first cell divisions of the zygote are called
cleavages.
Several cleavages result in the production of a small,
hollow ball of cells called a blastula
As the cells continue to divide, they push into the
interior
The developing organism becomes a gastrula
Development cont…
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The gastrula has an opening called the
blastopore
Because each cleavage results in smaller and
smaller cells, the gastrula is usually about the
same size as the original zygote.
During later development of the gastrula, the
cells undergo differentiation.
Protostome vs. Deuterosome
Protostome – mouth formed from blastopore
*Mostly invertebrates
Deuterostome – anus is formed from the
blastopore and the mouth is formed second.
*Echinoderms & all vertebrates
Body Cavities
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Coelom – lies between the digestive tract and
the body wall
Important because it provides space in which
internal organs can be suspended
Provide room for internal organs (growth)
Some cavities have fluids that are involved in
circulation, feeding & excretion.
Body Symmetry
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The bodies of most animals show some kind of
symmetry
Organisms that lack symmetry are called
asymmetrical
Spatial Relationships of Bilateral
Symmetry
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Front of an animal = anterior
Opposite of the head, or hind end = posterior
Underside = ventral
Opposite of the ventral surface (or back) =
dorsal
Medial = toward the midline
Lateral = away from the midline (sides)
Cephalization
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Most animals with bilateral symmetry
It is a concentration of sense organs and
nerve cells at the front of the body.
Allows animals to respond to stimuli in a more
advanced way than simple animals
WRAP UP!
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Video (14 mins)…and video quiz
Guided Reading Packet 26-1