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THE ANIMAL KINGDOMMulticellular heterotrophs with tissues

Porifera – sponges

Cnidaria-- jellyfish, hydras, anemones, etc.

Platyhelminthes-- flatworms

Nematoda– roundworms

Annelida-- segmented worms and leeches

Mollusca-- clams, snails, octopuses, squid

Arthropoda-- insects, crustaceans, arachnids

Echinodermata-- starfish, brittlestars, sand dollars

Chordata– vertebrates: fish, amphibians, reptiles, birds, mammals

Animal CharacteristicsMulticellular heterotrophs that:

have a body cavity

do not have cell walls (unlike plants, fungi, and

bacteria)

have tissues-- groups of cells that work together/recognize each other

have tissues arranged into organs.

Animals are sometimes classified according to their symmetry(complex animals have more sophisticated symmetry)

Asymmetry—no apparent symmetry (many sponges)Spherical symmetry—no top, bottom, left, right, front, or back (embryological stages-- morula, etc.)Radial symmetry—have top and bottom (starfish, jellyfish, et.al.)Bilateral symmetry—have front, back, right, left, top, bottom (worms, humans, dogs)

Directions on a bilaterally-symmetrical animal

DORSAL

ANTERIOR POSTERIOR

VENTRAL LATERAL: toward the side

Animals are sometimes classified by degree of cephalization

Cephalization: anterior brain and sensory organs

Allows for more efficient concentration of effort in one region rather than having the entire body fulfill that function. Can therefore identify threats, or opportunities, more quickly.

Animals are sometimes classified as:Invertebrates—no backbone

Vertebrates—have backbone /dorsal nerve cord

Animals are sometimes classified by their body cavity:(coelom = body cavity)

Acoelomates—no body cavity (some sponges have b.c.)Pseudocoelomates—have fold that functions as b.c.Coelomates—have a true body cavity for organs