Animal Diversity Flashcards

Flashcards covering key vocabulary and concepts from an animal diversity lecture.

Animals

Eukaryotic, multicellular, heterotrophic organisms that obtain nutrients by eating without cell walls.

Egg and sperm

The entirety of the haploid phase of the animal life cycle.

O2 increase

Increase in oxygen in the atmosphere that allowed for more animal life.

Hypothetical common ancestor of animals

A flagellated protist resembling feeding cells of sponges.

Cambrian Explosion

535-525 MYA; time when numerous fossils give us an idea of what early animals might have been like.

Animal Phylogeny is

Based on general body structure

Radial Symmetry

Axis is in the center, any slice to the center creates mirror images.

Bilateral Symmetry

Only one slice divides the animal into clear left/right mirror images with a defined head.

Gastrulation

Developmental process where cells rearrange

Three Germ Layers

Ectoderm, Mesoderm, and Endoderm.

Acoelomate

No body cavity

Coelomate

Complete coelom surrounded by mesoderm

Pseudocoelomate

Partial coelom

Larvae

Immature animals that look different from adults.

Metamorphosis

Dramatic change in body form.

Invertebrates

Animals without backbones; 95% of the animal kingdom.

Phylum Porifera (Sponges)

Stationary animals with no nerves or muscles that are aquatic feeders.

Suspension feeders

Collect particles from H2O (water).

Sponges

Filter 10,000x their volume in a day

Choanocytes

Flagellated feeding cells in sponges.

Phylum Cnidaria (jellies, sea anemone, corals)

Have tissues, are radially symmetrical, mostly marine, and have only endo- and ectoderm.

Polyp

Stationary body form of cnidarians.

Medusa

Floating body form of cnidarians.

Cnidocytes

Function in defense and prey capture in cnidarians.

Phylum Mollusca (snails, slugs, oysters, clams, etc.)

Soft-bodied invertebrates, but often protected by shells, feed with a radula, and have a similar body plan.

The 'HAM'

Hypothetical ancestral mollusc's body plan

Mollusks display many similar groups like

Visceral mass , Mantle, and Muscular foot

Gastropods

Developmental twist which lowers the center of gravity. Head can retreat quickly into shell during attacks.

Bivalves

Clams, scallops, oysters, mussels: foot acts as a digging tool; no radula - filter feeding; head reduced or nonexistent.

Cephalopods

Nautilus, squid, octopus: highly modified body & tentacles and 'head' both derived from foot; very active, mobile, agile; intelligent, good vision, highly predatory.

Phylum Platyhelminthes (flatworms, planaria

Simple, bilaterally symmetrical acoelomates

Hermaphroditic

Often has both male and female sex organs

Tapeworms - major type of flatworm

Parasites of vertebrates; no gut - absorbs nutrients from host; head modified as a holding organ.

Phylum Nematoda

Roundworms that are parasitic and cause disease in plants and animals and important decomposers.

Phylum Annelida (earthworms, leeches, etc.)

Segmented coelomates with a complete digestive tract and internal structures are repeated