What is an Animal? A multicellular organism of the kingdom Animalia that uses locomotion, metabolism, pronounced response to stimuli, and fixed bodily structure

Characteristics of Animals All animals have several characteristics in common. What are the four common characteristics of animals? – Eukaryotic – Multicellular – Heterotrophic – No cell wall

What Do Animals Do to Survive? Feed Respire Circulate Excrete Respond Move Reproduce

Trends in Animal Evolution Your survey of the animal kingdom will begin with simple forms and move through more complicated ones.

Phylogenetic relationships: Trends in Animal Evolution

Cell Specialization and Levels of Organization Groups of specialized cells that work together form tissues. Tissues join together to form organs. Group of organs work together to form organ systems – EX: Circulatory system

Cephalization Concentration of sense organs and nerve cells at the front end or head of the body.

Flatworm Range in size from.2 inches to 50 feet!

Animal Body Plans What is symmetry? Arrangement of body parts on opposite sides of a plane or line Asymmetry Radial Symmetry Bilateral Symmetry

What type of symmetry? Radial

What type of symmetry? Bilateral

What type of symmetry? Asymmetrical

What type of symmetry? Radial

Animal Body Plans Acoelom – Without a body cavity

Animal Body Plans Pseudocoelom – Fluid-filled internal space that is in direct contact with the wall of the digestive tract.

Animal Body Plans Coelom – Fluid-filled body cavity completely lined by a layer of mesoderm cells and suspending internal organs

Animal Body Plans

How do these body plans develop?

Early Development

Development of Animal Body Plans Cell Division – The zygote divides by mitosis and cell division to form two cells in a process called cleavage. – How important is this first cell division? Problems can lead to defects in embryo Zygote

Development of Animals: Gastrulation (a process of forming cell layers) The zygote undergoes a series of divisions to form a blastula, which is a hollow ball of cells. DemoPhylums Porifera and Cnidaria only have two layers

Protostome vs. deuterostome Mouth is formed from the blastoporeAnus is formed from the blastopore

Formation of a Coelom (body cavity): Neurulation Body cavity – a fluid-filled space that lies between the digestive tract and the body wall. Gastrula Embryo Development