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What is an Animal?. 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?. Feeding Respiration Circulation Excretion
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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? • Feeding • Respiration • Circulation • Excretion • Response • Movement • Reproduction
Trends in Animal Evolution • Your survey of the animal kingdom will begin with simple forms and move through more complicated ones.
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.
Animal Body Plans • What is symmetry? Arrangement of body parts on opposite sides of a plane or line Asymmetry Bilateral Symmetry Radial Symmetry
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
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 led 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. Demo PhylumsPorifera and Cnidaria only have two layers
Protostome vs. deuterostome Mouth is formed from the blastopore Anus 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