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study guide bio 3 - Biology Exam 3 Study Guide Chapter 33...

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Biology Exam 3 Study Guide Chapter 33 I. Cniderians are grouped into four classes 1. Hydrozoa (hydroids) 2. Scyphozoa (jellyfish) 3. Cubozoa (sea wasps and box jellyfish) 4. Anthozoa (anemones and sea coral) Class Hydrozoa: the hydroids 1. Both polyp and medusa stages in their life cycle 2. Some are bioluminescent 3. Hydra is exceptional in having no medusa stage and existing as a solitary polyp 4. Each polyp sits on a basal disk, which the hydra can use to glide around, aided by mucous secretions Class Scyphozoa: the jellyfish (sea jellies) 1. In all, medusa stage is dominant a. Bell-shaped with hanging tentacles around their margins 2. Polyp stage is small, inconspicuous, and simple in structure 3. Outer layer (epithelium) contains a number of specialized cells a. each can contradict individually b. together, the cells form a muscular ring around the margin of the bell that pulses rhythmically and propels the animal through the water 4. separate male and female individuals a. polyps can reproduce asexually Class Cubozoa: The box jellyfish (box jellies)
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1. box shaped medusa 2. polyp stage is inconspicuous, and, in many cases, not known 3. the stings of some species can be fatal to humans Class Anthozoa: The sea anemones and coral 1. largest class of cnidarians 2. fertilized eggs develop into planulae that settle as polyps 3. no medusa are formed 4. true corals secrete exoskeletons of calcium carbonate II. The Comb Jellies, phylum Ctenophora, use cilia for movement 1. They have anal pores so that water and other substances pass completely through the animal 2. Two long retractable tentacles used to capture prey a. Colloblast- on contact with zooplankton, this special type of cell bursts and discharges a strong adhesive material 3. Largest animals that use cilia for locomotion 4. Bioluminescent 5. Considered diploblasts with radial symmetry 6. True muscle cells derived from the mesoderm, making them triploblasts 7. Three main axes of symmetry, so not strictly radial The Bilaterian Acoelomates 1. Bilateral symmetry 2. Bilaterians classified by three conditions a. Acoelomates b. Psuedocoelomates
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c. Coelomates 3. Three embryonic germ layers formed during development a. Ectoderm b. Endoderm c. Mesoderm I. The flatworms, phylum Platyhelminthes, have an incomplete gut or none at all 1. Considered the simplest of bilaterally symmetrical animals with a definite head at the anterior end and certain complex structures like their reproductive apparatus 2. Compact bodies a. The only internal space consists of an incomplete (blind) digestive cavity 3. Many species are parasitic, occurring within the bodies of other animals, but others are free living in a variety of marine and freshwater habitats 4. Movement based on ciliated epithelial cells, which are particular concentrated on their ventral surface 5. Well developed musculature Digestion in flatworms 1. Incomplete gut= one with only one opening 2. Gut is branched and extends throughout the body, functioning in both the
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This note was uploaded on 07/15/2008 for the course BI 102 taught by Professor Peabody during the Spring '08 term at Stonehill.

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study guide bio 3 - Biology Exam 3 Study Guide Chapter 33...

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