Transcript The Animal Kingdom

The Animal Kingdom
Welcome to your kingdom!
Where we’ve been…and where we’re headed….
What is an animal?
• Multicellular, eukaryotic heterotrophs
• They lack cell walls: their bodies are held
together by other proteins like collagen and
cell junctions that hold the cells together to
provide an animal strength in form
• Some animals also have a skeleton:
– Exoskeletons (on the outside) made of chitin
(these will need to be shed in order for the animal to
grow) ex. Shells of insects, crabs, spiders
– Endoskeletons (on the inside) made of bone
– Hydrostatic skeletons: water or another fluid provides
pressure pushing out from the inside of the animal to
provide support (like a water balloon)
• Animals are capable of moving from one
place to another
– This is made possible by the coordination of
two “new” types of tissue: nerve and muscle
Of course there are some exceptions: sedentary
(or sessile) animals have no movement; they
remain fixed in one location
• Most biologists agree that the animal kingdom can
be traced back to one common ancestor about 700
million years ago
This ancestor was most likely a protozoan.
One hypothesis suggests that this flagellated
protist formed a single layer, hollow ball of cells.
Eventually, some of these cells began to specialize
creating two or more layers of cells
The opening to
the digestive
cavity (the
blastopore)
becomes the
mouth
Animal embryos form layers
• Ectoderm: forms the outer covering and nervous
system
• Mesoderm: forms all of the other stuff in between
• Endoderm: lines the digestive tract and makes the
accessory organs
If an animal has all three layers:
Triploblastic (3 layers)
Only two layers:
Diploblastic (2 layers)
Animal Symmetry
1. Some animals lack
symmetry all together
(they are asymmetrical)
Animal Symmetry
2. Others have radial
symmetry (like a
flower pot)
No matter how you
would cut the animal
vertically through the
body, all of the wedges
would appear the same
Animal Symmetry
3. While others have
bilateral symmetry
(two-sided symmetry)
Terms associated with bilateral
symmetry
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Dorsal
Ventral
Anterior
Posteror
Phylum Porifera
The Sponges
Basic body plan of sponges
Only one cell layer; no true tissues
Almost everything is accomplished by
diffusion
Glenn and Martha Vargas
© 2004 California Academy of Sciences
Vase sponge
Eugene Weber
© 2001 California Academy of Sciences
The Glass Sponge
This is the skeleton
only; all of the other
cells have
disintegrated.
Phylum Cnidaria
(The Cnidarians)
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Sea Anemones
Hydra
Coral
Jellyfish
Basic Body Plan
• *Two body forms: polyp
and medusa
• *Stinging tentacles
surround the mouth
• Only two cell layers:
epidermis and
gastrodermis
• First animals to have a
mouth
• Members can reproduce
sexually as well as
asexually (budding)
Jellyfish Life Cycle
• Note the change
between polyp and
medusa
Gerald and Buff Corsi
© 1999 California Academy of Sciences
Gerald and Buff Corsi
© 2002 California Academy of Sciences
Gerald and Buff Corsi
© 2002 California Academy of Sciences
© 2003 Dr. Peter Weish
Glenn and Martha Vargas
© 2004 California Academy of Sciences
“Artic Jelly” washed up on shore
Artic Jelly…up close and personal…
E. Eugenia Patten
© 2001 California Academy of Sciences
Dr. Robert Thomas and Margaret Orr
© 2004 California Academy of Sciences
Gerald and Buff Corsi
© 1999 California Academy of Sciences
Gerald and Buff Corsi
© 1999 California Academy of
Sciences
Coral Polyps
Eugene Weber
© 2001 California Academy of Sciences
Glenn and Martha Vargas
© 2004 California Academy of Sciences
Beatrice F. Howitt
© 2002 California Academy of Sciences
Portuguese Man-of-War; a colonial cnidarian
Gerald and Buff Corsi
© 1999 California Academy of Sciences
Phylum Ctenphora: (“Comb jellies”)
Beroe species
Phylum Platyhelminthes
(the flatworms)
• Tapeworms
• Flukes
• Planaria
Phylum Platyhelminthes: the flatworms
Planaria
Planaria splitting…
General Characteristics
of the flatworms
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bilateral symmetry
three cell layers
possess a ganglia (forerunner of a brain)
sensory receptors
pharynx that leads to digestive cavity (but
still no anus)
• flame cells help excrete metabolic wastes
(their version of urine)
Planaria body plan
The Flame Cell
Tapeworms…..
Tapeworm scolex showing hooks and suckers
Scolex of a rat tapeworm
Proglottids
Pork Tapeworm Life Cycle
Fish Tapeworm Life Cycle
Dog tape worm
Marine flatworm
Nothing beyond this point on the
final!!!!
Phylum Nematoda
(the roundworms)
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Tube-within-a tube body plan
WOW!!! An anus!!!
They have a hydrostatic skeleton
Reproduce only sexually
Many are parasites
Phylum Arthropoda
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Bilateral symmetry
Breath by using gills
Well developed nervous system
Most have shells
All have a mantle: a fleshy fold of tissue
that surrounds the internal organs
• Most have a shell
Class Gastropoda
(the gastropods-snails, slugs)
• Name means “stomach foot”
• Most have one shell (like snails)
• Feed with a radula