Organisms and the Environment - Invertebrates (protostomes)

Exam 2 - Unit 2

Profiera

• parazoa - simplest multicellular animal

• has tiny pores - water currents bring in food and O2

• specialized cells - no tissues

• simple skeleton

• no movement

• EX: sponges

cnidaria

• radial symmetry, diploblast

• 2 forms: polyps and medusae

• specialized tissues

• gastrovascular cavity (one simple opening)

• cnidocytes (stinging cells)

• EX: jellyfish

Lophotrochozoa

• ½ protostome class

• live in water

• use cilia or body wall contractions to move

platyhelminthes (flatworms)

• ciliated soft bodied animals

• gastrovascular cavity (one opening)

• bilateral symmetry

• have tissues and organs

• acoelomate

mollusca

• trocophore larvare

• complex organ systems

• complete gut (mouth and anus)

• varying degrees of cephalization

• muscular foot for movement

• second in diversity to arthropods

annelida

• well developed head

• trochophore larvae

• segmentation, divided by septa

• more complex, specialized systems (digestion)

• complete gut (mouth and anus)

ecdysozoa

• contains animals that molt

• exoskeleton - hard cuticle that molts

nematoda (round worm)

• pseudocoelomate

• complete gut (mouth and anus)

• simple systems (digestive, nervous)

• thick, flexible cuticle molts as animal grows

arthropoda

• the most diverse

• more specialized segments

• appendages: jointed

• hard cuticular exoskeleton that molts

• more cephalization

  • complex behavior

  • complex sensory organs