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Learn about the characteristics, development stages, and symmetry of animals, including feeding, respiration, and reproduction. Understand how animals are grouped based on their body layers and cavity types.
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Characteristics of animals • Feeding- Must consume food. Does not produce it’s own food. Heterotrophic • Respiration- Takes in oxygen and gives off CO2 • Circulation-Has a means to distribute O2 • Excretion- Means to eliminate waste • Response –Respond to environment using specialized cells • Movement-Able to move from one place to another. Mobile • Reproduction- Able to reproduce sexually • Eukaryotic- Cell with cell membrane and true nuclei.
Development of animals • Fertilization- sperm and egg join together (1n+1n=2n) • Mitosis of 2n cell = 2 cells, 4 cells, 8 cells,.16…32……. • Now get a hollow ball of cells called a BLASTULA that is filled with fluid • One side of blastula pinches inward to form GASTRULA • Hole that forms is called BLASTOPORE
BLASTULA GASTRULA
Animals Grouped by Fate of Blastopore • Depending on what becomes of blastopore animals are divided into 2 groups • 1. blastopore becomes mouth- PROTOSTOME(then second opening becomes anus) • 2. blastopore becomes anus –DEUTEROSTOME(then second opening is mouth) • Cells then differentiate for animal to reach adulthood.
Gastulation is what forms an inside and an outside of the organism. • Inside layer called ENDODERM-becomes lining of the gut • Outside layer of cells called ECTODERM-becomes skin and nervous system • Some animals have a 3rd middle layer called MESODERM-becomes the circulatory system, muscle system, and excretory system
Symmetry • Animals can be divided into groups by their symmetry.
Asymmetry • No symmetry • Asymmetrical • sponges
Radial symmetry • Organism can be divided along any plane • Jellyfish
Bilateral Symmetry • Organism has left and right • Anterior and posterior • Front and Back • Ventral and Dorsal
Animals with 3 body layers • Animals with 3 body layers(Ectoderm,Endoderm, and Mesoderm) can be divided into 3 groups depending on how much of their body cavity is covered by mesoderm. • Body cavity is called COELOME
Acoelomate • No body cavity. • Digestive tract runs length of body • Flatworms • Solid all the way through
Pseudocoelomate(false cavity) • Space between endoderm and mesoderm is filled with fluid • Coelome not compltely covered by mesoderm, just partially • 1 way digestive tract • Round worm
Coelomate(true body cavity) • True body cavity all surrounded by mesoderm • Fluid filled • Contains specialized organs • Humans, Earthworm