 Heterotrophs  Kingdom animalia  Multicellular  Eukaryotic  Cells lack cell walls

Animals contain tissues -> group of cells that perform a similar function  Epithelial – cover body structures (skin, lining of lungs)  Muscular – moving parts of animals’ bodies  Connective – support an animal’s body & connect its parts (bone, blood)  Nervous – carry information throughout body

Invertebrates:  Do not have a backbone or vertebral column  95 % of animals  Include sea stars, worms, jellyfishes, insects Vertebrates:  Do have a backbone or vertebral column  5 % of animals  Include fishes, amphibians, reptiles, birds and mammals

Physiology – study of functions of organisms Anatomy – structure of organisms allows animals to carry out physiological processes Homeostasis – maintenance of stable internal environments  feedback inhibition – product or result of process stops or limits process

 Feeding – most animals ingest (eat) food Herbivores, carnivores, filter feeders, symbiosis  Respiration – all animals take in oxygen and give off carbon dioxide  Circulation – movement of materials around within their bodies (diffusion in small animals, circulatory systems in larger animals)

 Excretion – removal of metabolic wastes (primary waste -> ammonia)  Response – nervous system -> responds to stimuli & processes information for response  Movement – muscles allow animals to move (motile) and also to function even if sessile  Reproduction – sexual (two organisms, haploid gametes) & asexual (one organism, genetically identical)

Complex organisms tend to have:  High levels of cell specialization -> cells carry out different (specialized)functions Due to chemical makeup & structure of cells  Levels of Organization Groups of specialized cells form tissues -> tissues form organs -> organs make up organ systems

 Early Development Animals that reproduce sexually begin life as a zygote (fertilized egg) -> zygote undergoes a series of divisions to form blastula (hollow ball of cells)

 The blastula folds in on itself, forming a single opening called a blastopore.  The blastopore leads into a central tube that runs the length of the developing embryo. This tube becomes the digestive tract and is formed in one of two ways.

 Protostome - animal whose mouth is formed from the blastopore. (most invertebrates)  Deuterostome - animal whose anus (opening through which waste leaves digestive tract) is formed from the blastopore.

 During early development, the cells of most animal embryos differentiate into three layers called germ layers.  Endoderm - innermost germ layer, develops into linings of the digestive tract and much of the respiratory system.  Mesoderm - middle layer, develops into muscles and much of the circulatory, reproductive, and excretory organ systems  Ectoderm - outermost layer, develops into the sense organs, nerves, and the outer layer of the skin.

 Body Symmetry – all animals exhibit body symmetry in structure (except sponges) Radial Symmetry - any number of imaginary planes can be drawn through the center, each dividing the body into equal halves. bilateral symmetry - only one imaginary plane can divide the body into two equal halves—left and right.

 Sea anemones  Sea stars  Jellyfish

 Anterior – front end  Posterior – back end  Dorsal – upper side  Ventral – lower side

 Bilateral symmetry allows for segmentation, in which the body is constructed of many repeated and similar parts, or segments.  The combination of bilateral symmetry and segmentation is found in two successful animal groups—arthropods and vertebrates.

 Cephalization – concentration of sense organs and nerve cells at the front end of the body  Animals with bilateral symmetry usually move with the anterior end forward, so this end comes in contact with new parts of the environment first.  As sense organs have evolved, they have tended to gather at the anterior end, as have nerve cells that process information and “decide” what the animal should do.

 Body Cavity Formation  Most animals have a body cavity, a fluid- filled space between the digestive tract and body wall.  A body cavity provides a space in which internal organs can be suspended so that they are not pressed on by muscles or twisted out of shape by body movements.