chapter34-deuterostomeAnimals[1] - BLY 122 Chapter 32...

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Deuterostome Animals 1 BLY 122 A. Hunter from C. S. Major Chapter 32 Deuterostome Animals I. Why Do Biologists Study Deuterostome Animals? A. Because Humans Are Deuterostomes 1. We identify with other vertebrates because they are like us. 2. Other mammals affect our lives since we interact with them as livestock and pets. B. Deuterostomes play important roles in our ecological community and our human economy. 1. Most large deuterostomes dominate the upper food chains in most ecosystems. a. Fish and echinoderms are important herbivores and predators in marine environments. b. Reptiles and mammals are important herbivores and predators in terrestrial environments. 2. Humans depend on vertebrates for food and power. a. Fish and livestock are key sources of protein in many cultures. b. Many cultures still depend on horsepower and oxpower for transportation and agriculture. II. How Do Biologists Study Deuterostomes? A. Biologists investigate three central issues while studying deuterostomes. 1. Understanding the diversity of body plans in the three deuterostome phyla, echinoderms, hemichordates, and chordates 2. Exploring how vertebrates evolved from vertebrates 3. Grasping how vertebrates made the transition from water to land B. Analyzing Morphological Traits 1. What do all deuterostomes have in common? a. They are triploblastic and have a coelom. b. They have similar patterns of embryonic development. c. They differ in that echinoderms reverted to radial symmetry. (1) Their ancestors are bilaterally symmetrical. (2) Adults have five-sided radial symmetry. (3) Larvae are bilaterally symmetrical 2. The water vascular system of echinoderms; body organization without a head and tail a. Echinoderms consist of a body with a number of fluid-filled tubes and chambers called the water vascular system. (1) One of the tubes is open to the exterior so seawater can flow into and out of the system. (2) These tubes and chambers form a sophisticated hydrostatic skeleton. b. One part of the fluid-filled structure is called the tube foot. (1) Podia are sections to the tube feet that extend outside the body and contact substrate. (2) Podia extend and shorten via muscle contractions that move water within the tube feet. (3) These podia movements allow the animal to alternately grab and release the substrate, thus moving along it. c. Echinoderms have a hard, supportive endoskeleton inside the body. (1) During development, internal cells release calcium carbonate in plate form inside the skin. (2) The plates may remain separate, resulting in a flexible body; or they may fuse, resulting in a rigid body. 3. The origin of chordates illustrates the evolution of several unique traits.
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This note was uploaded on 11/11/2009 for the course BLY 459 taught by Professor Obrien,j during the Spring '08 term at S. Alabama.

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chapter34-deuterostomeAnimals[1] - BLY 122 Chapter 32...

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