Invertebrate Classification

Question 1

Cell number

Answer 1

Unicellular versus multicellular.

Choanoflagellates form colonies; gave rise to sponges (choanocytes).

Question 2

General body form

Answer 2

Radial symmetry versus bilateral symmetry

Question 3

Germ layers

Answer 3

Diploblastic versus triploblastic.

Give rise to tissues and organs systems and body

Question 4

Body cavity

Answer 4

Acoelomate = no body cavity

Pseudocoelomate = body cavity partially surrounded by mesoderm

Coelomate = body cavity completely surrounded by mesoderm

Question 5

Embryonic pattern

Answer 5

Protostome = mouth first formed then anus

Deuterostome = anus first formed in mouth

Question 6

Evolutionary relationship

Answer 6

Kingdom, phylum, class, order, family, genus, species

Question 7

Taxon

Answer 7

Group of distinguishable things

Question 8

Monophyletic

Answer 8

One; come from a single ancestor and includes all members

Question 9

Paraphyletic

Answer 9

Not all descendants are included in the grouping from common ancestor

Question 10

Habitat and lifestyle

Answer 10

Terrestrial, Marine, freshwater.
Littoral, open ocean. Mobile, sessile, sedentary.
Pelagic = swim around, benthic = at bottom.
Plankton = drift, nekton = swim. Herbivores, carnivores.
Suspension feeders, deposit feeders. Predator, symbiotic associations (Mutual, commensal, parasitic).