ANIMALS Ch 28-36

Write down some things they all share and then some differences Write down some things they all share and then some differences

General Characteristics  Multicellular  Heterotrophic  Eukaryotic  Move (some stay in place – sessile)  No cell walls  Internal digestion  Symmetry

Symmetry  Asymmetry (no equal halves)  Radial (Spin on vertical axis and always equal halves)  Bilateral (only one possibility along vertical axis to get two equal halves)  Anterior: Head  Posterior: Rear  Dorsal: Back  Ventral: Belly

Hydra

 Budding Hydra

Carolina Anole

Barred Tiger Salamander

Animal Development 1.Fertilization – forms zygote 2.Cleavage (splits) to make 2 celled zygote 3.Keeps going until blastula is formed (fluid-filled ball of cells) 4.Blastula indents to make gastrula (initially 2, later 3 cell layers: endo- (inside) and ectoderm (outside), then mesoderm (middle layer) 5.Differentiation takes place. Cells of each -derm form certain body systems 1.Ecto: Integumentary (skin), nervous 2.Meso: muscular, reproductive, circulatory, skeletal, connective, kidneys 3.Endo: digestive lining, major organs

Types of Animals according to Body Cavities  Acoelomates: digestive tract but no body cavity (flatworm)  Pseudocoelomates: have fluid-filled cavity partially lined with mesoderm (roundworm)  Coelomates: have true cavity completely surrounded by mesoderm (human)

Phylum Porifera  Sponges  Filter feeders  Asymmetrical/ radial  (A)sexual (budding or internal/external)  Can regenerate parts

Phylum Cnideria  Jellyfish, Hydrozoans (Hydra Portugese Man of war, Corals)  Have nematocysts (sting prey)  Simple digestive system  Polyp and medusa stages in life cycle  Often form colonies  Oxygen diffuses right into cells

Phylum Platyhelminthes  All flatworms: tapeworms, flukes, planarians  1 mm to several meters  Bilateral symmetry  Free-living or parasitic  scolex: knob-shaped head of tapeworm  Proglottids: detachable section of tapeworm with male/female reproductive systems, muscle, nerve cells

Female – 3.5 mm

Phylum Nematoda  Roundworms: Ascaris, hookworm, pinworm, Trichinella  Free-living and parasitic ones  Smaller than faltworms, tapered at both ends  Pseudocoelom, mouth and anus

Phylum Mollusca  100,000 species of slugs, sbails, shelled animals  3 classes: bivalves, gastropods, cephalopods  Have mantle: membrane that surrounds internal organs of mollusk  Radula: tongue-like organ with rows of teeth to “rasp” off and break through things  Siphon: organ through which water is pushed for jet-propulsion.

Phylum Annelida  Includes bristle worms, earthworms and leeches  Bodies appear to be divided into segments  Everywhere other than deserts and Arctic  Have gizzard: sac with hard walls, grinds food before it enters intestines