Chapter 22

Chapter 22 - NOTES FOR BIOLOGY 1002 SECTIONS 001 and 002...

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NOTES FOR BIOLOGY 1002 SECTIONS 001 and 002 Spring 2008 DR. STEVEN POMARICO Outline 2A CHAPTER 22 Animal Diversity I: Invertebrates The main distinguishing features of the Kingdom Animalia are -Eukaryotic -Multicellular -Heterotrophic - Ingestive method of digestion -Sexual reproduction - No cell wall -Rapid response to stimuli (nerves and muscles) In addition to these characteristics, as animals evolved from the animal-like protists, they developed more complex and organized bodies. Some of these increases in complexity and organization are: -cellular specialization -body plan - cephalization -body cavity - segmentation -digestive system
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Cephalization is the concentration of nervous tissue (including a “brain” and sensory organs) into a defined region (head) of the body. Segmentation is a body design in which similar repeating units are present. These and other characteristics are used to define the groups within the Kingdom Animalia. ( See table 22-1 ). Cellular specialization leads to the development of tissues, which then can lead to the combination of tissues into an organ . Organs may then become arranged into organ systems . Tissues are specialized cells with a common structure and function that are grouped together. Organs are centers of bodily function, which are usually made up of different tissues. Organ systems are groups of two or more organs that function together to perform a common task (e.g., digestion, gas exchange, reproduction) The presence or absence of tissues in an organism defines the first separation of a group from the rest of the animals. Sponges - Phylum Porifera (see fig 22-5) Characteristic of sponges - Sessile - non-moving -Filter feeders -May reproduce sexually or asexually by budding -Most species have an asymmetric body plan designed for water filtration - Lack tissue structure but have specialized cells (see fig 22-4)
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Three types of specialized cells are found in the sponge phylum Epithelial cells -outer covering layer (like a skin) Make up and regulate the pores Collar cells - Inner layer which pumps water through the sponge using flagella and filters out the food Amoeboid cells - mobile cells between the two layers that ingest the collected food -Responsible for reproduction -Secretion of skeletal structure of spicules . The lack of tissues in sponges also result in the asymmetric body plan. All other animal phyla have both defined tissues and body plan or symmetry . Symmetry
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This note was uploaded on 04/17/2008 for the course BIOL 1002 taught by Professor Pomarico during the Spring '08 term at LSU.

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Chapter 22 - NOTES FOR BIOLOGY 1002 SECTIONS 001 and 002...

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