Introduction to Animals Chapter 27 Page

Characteristics of Animals Heterotrophy-cannot make own food Mobility-can perform rapid complex movements Multicellularity- many celled organism Diploidy-adults have two copies of each chromosome Sexual Reproduction-most animals have this type Absence of a Cell Wall-only type of Multi has no Bastula Formation-from zygote Tissue-group of cells with common function

Origin of Animal Tissues and Organs Primary tissue layerGives rise to EctodermOuter layer of the skin, nervous system, sense organs EndothermLining of digestive tract, respiratory system, etc MesodermSkeleton, Muscles, Circulatory, Sex organs

Body Symmetry Asymmetrical-simplest body plan Radial-have body parts arranged around a central axis Bilateral- a body design in which there are distinct right and left halves.

Internal Body Cavity Coelom-a fluid filled space between the body wall and digestive tract Acoelomates-with no body cavity just tissues Pseudocolomates-have a body cavity located between the nesoderm and endoderm Coelomates-body cavity within mesoderm

Body Segmentation Segments-a series of repeating similar units Somites-repeating blocks of tissue Modification of segments-allows for greater flexibility and special parts

Kinds of Animals 35 Phylums- divided by many different characteristics Based on 9 evolutionary milestones: A. Multicellular B. Tissues C. Bilateral symmetry D. Body cavity

Animal body Systems 1. Digestion 2. Respiration 3.Circulation A. Open circulatory system-fluid goes into body cavity B. Closed circulatory system- blood goes through blood vessels

Animal body Systems 4. Conduction of Nerve Impulses 5. Support 6. Execretion

Kinds of animals(cont) E. Coelom F. Segmentation G. Jointed appendages H. Deuterosomes I. Notochord