ANIMAL CHARACTERISTICS

TRUE OF ANIMALS• They move• They reproduce• They have cell membranes & organelles• They are multicellular• They eat other organisms= Heterotrophic

BODY SYMMETRY

• Radial– Body parts arranged around a central axis– Similar to the spokes around a bicycle tire– Example: sea urchin, starfish

BODY SYMMETRY• Bilateral

– Divide down middle: have 2 mirror images– There is a dorsal, ventral, anterior, and

posterior surfaces– Cephalization: development of sense organs

on anterior end (become active and mobile)

BODY SYMMETRY• Bilateral

– Examples: mammals, reptiles, amphibians, worms, etc

BODY SYMMETRY

• Asymmetrical– Irregular depending on body growth– Example: sponge

BODY POSITIONS• Ventral : bottom / underneath surface• Posterior: to the back / dorsal • Anterior: front end• Sagittal: a side view

Pa nthe ra le o

BODY POSITIONS

• Frontal: facing the front, dividing the body equally in anterior & posterior portions

• Transverse: dividing horizontally• Superior: above• Inferior: below

Skeletons

• Hydrostatic: water in a closed cavity– Moves like a water balloon– Examples: soft invertebrates - hydra,

earthworms

Skeletons

• Exoskeleton: muscles attached to the inside– Better protection for internal organs– A problem when they grow– Examples: insects, clams, crabs

Skeletons • Endoskeleton

– Bones on the inside– Allows for easier and more complete movement– Examples: mammals

COELOMS

• Coelom (SEE LUHM)• A fluid filled sac between the outer wall and

the organs• Space completely inside of mesoderm,

filled with body fluids• Coelomates: Have true coelom

COELOMS

• Acoelomates: space completely filled with tissues

• Pseudocoelomates: only one lining of mesoderm created this space

DIGESTIVE SYSTEM

• Gastrovascular Cavity: every cell is exposed to food digestion, no specialization– Digestive cavity with one opening– Example: hydra, flatworm

DIGESTIVE SYSTEM

• Digestive tract: specialized organs digest food– Digestive cavity with two openings– Has a mouth and anus– Most animals: mammals, reptiles, fish,

amphibians, birds

CIRCULATORY SYSTEM

• Open system – Vessels pump fluid into body cavity &

over body tissues• Closed system

– heart pumps blood through vessels into body cells and then back to heart

NERVOUS SYSTEM

• Nerve Net: covers tissues, yet there is no coordination of information. A simple stimulus response system

• Ganglia: A group of nerves that act as a center to interpret stimulus and response to situation. Can be light sensitive, or touch

• Brain & Sensory organs: Complex system of information gathering