Biology 28 & 29

1. Describe the different types of symmetry.

 Asymmetry: no particular pattern to body shape

Radial symmetry: Body organized circularly; similar to a wheel

Bilateral symmetry: Definite right and left halves; humans have bilateral symmetry

2. What are the differences between protostomes and deuterostomes?

 Protostomes: Blastopore becomes mouth; ventral nerve cord ; spinal cleavage

Deuterostomes: Blastopore becomes anus; dorsal nerve cord; radial cleavage

3. What animals are in each of the following phyla?  What characteristics are unique to each phyla?

  A. porifera: sponges; no symmetry; no tissue; filter food particles from water

  B. cnidaria: Jellyfish, corals, sea anemones; radial symmetry; tissues; stinging tentacles; olyp has mouth directed upward; Medusa has mouth directed downward

  C. mollusca: Snails, clams, oysters, squid, octopus; all have a mantle, a visceral mass, and a foot

  D. annelida: segmented worms; earthworms, leeches; body segments repeated along length of body

  E. platyhelminthes: Flatworms; planaria, tapeworms; flat body; no body cavity

  F. nematoda: Roundworms; non-segmented body; some are parasites

  G. arthropoda: Exoskeleton; jointed appendages; segmented body; crustaceans; crabs, shrimp, lobsters, crayfish

  H. Echinodermata: Starfish; deuterostomes, water vascular system; radial symmetry in adult; bilateral symmetry in larva

1. Define endothermic and ectothermic.  Which vertebrates are endothermic?  Which vertebrates are ectothermic?

 Ectothermic: Body temperature stays relatively the same as the environment; Amphibians, reptiles, fish

Endothermic: Internal way to control body temperature; Birds, mammals

2. Define monotreme and marsupial.

 Monotreme: Mammals that lay eggs; includes duck-billed platypus and spiny anteater

Marsupial: Mammals with pouches; young born very immature; complete development in mothers pouch, where mammary glands are located; includes kangaroos, koalas, and opossums 

3. List the characteristics of all chordates.

Deuterostomes; postnatal tail; notochord; dorsal tubular nerve cord; pharyngeal pouches