Biology_2007_Virtual_Lab_Answer_Key-1

6 suppose you coated the leaves of a plant with

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6. Suppose you coated the leaves of a plant with petroleum jelly. How would the plants’ rate of transpiration be affected? The plant would not transpire at all because the petroleum jelly would cover the stomata on the plant leaves, trapping water inside the leaves and preventing its release into the environment. 7. Of what value to a plant is the ability to lose water through transpiration? Transpiration allows plants, which cannot move, to respond to changes in the environment. Lab 20: Earthworm Dissection Analysis The answers are intended only as samples. Answers also depend on how students completed the lab and on the random data generated by the computer. 1. What part of the digestive system would you see in a cross section anterior to the gizzard?
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One would see the crop, a thin walled sac that holds soil (food) before it is passed to the gizzard. 2. What structure in the earthworm has a similar function as the human heart? Explain your answer. The muscular dorsal blood vessel and the contracting aortic arches that pump blood through the animal have a similar function. 3. What do two earthworms exchange during mating? Explain your answer. The two worms exchange sperm. Earthworms are hermaphrodites which means that an individual animal produces both sperm and eggs. 4. Describe the difference between a closed and an open circulatory system. Earthworms have a closed circulatory system. The blood carrying oxygen to and carbon dioxide from body cells flows through vessels to reach all parts of the body. In an open circulatory system the blood moves through vessels and into open spaces around the body organs. 5. Do earthworms have a front and a back end? Explain your answer. Yes, they do. Their basic body plan is a tube within a tube. Food is taken in by the mouth, an opening at the anterior end of the worm, and wastes are released through the anus, an opening at the posterior end. The worm crawls by first stretching the front of its body forward, and then pulling the back of its body up to the front. 6. What characteristics distinguish an annelid from other worms? All annelids are bilaterally symmetrical, have external and internal segmentation, a coelom (a fluid-filled body cavity), and two body openings. Lab 21: Classification of Arthropods Analysis The answers are intended only as samples. Answers also depend on how students completed the lab and on the random data generated by the computer. 1. Many species of arachnids are predators, but they have no teeth or jaws. How do they obtain nutrients from their prey? Spiders release digestive enzymes that liquefy the internal organs of their captured prey. They then suck up the liquefied food. This feeding process is known as extracellular digestion. 2. Arthropods are the most diverse group of animals. Describe some characteristics of arthropods that may have contributed to their great evolutionary success.
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Answers will depend on students’ choices but should include facts similar to the following:
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