Chap 15 Questions

Chap 15 Questions - process of molting the shell splits and...

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Sarah Edwards Mr. LaRock OCS 1005 15 April 2008 Chp. 15 Questions 1. The first animal-like creatures were single-celled organisms. They began to prosper in the ocean during the oxygen revolution, a time of radical change in the Earth’s atmosphere which occurred between 2 billion and 400 million years ago. This changed the atmosphere from 1% oxygen to about 20% and ozone was also created to protect the Earth and its inhabitants. Cells began to stick together and form colonies and this is where true animals evolved. Many descendants of early forms of animal life are not represented today because of their inability to adapt to changing situations, like environment. Some animals that were once abundant, like trilobites, have died out. 2. Arthropods grow by molting (shedding) their external skeleton. An arthropod does not get bigger between molting by substituting body mass for water in its tissues. During the
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Unformatted text preview: process of molting the shell splits and falls away. 3. Jawless fish, cartilaginous fishes, bony fishes, amphibians, reptiles, birds, and mammals are the seven classes of vertebrates. Amphibians have no permanent marine representatives, although all of them depend on the constant flow of water through their bodies to remove waste. Too much water could cause an amphibian to dehydrate and die and this is why they are not permanently marine. 4. Odontoceti whales are active predators who have teeth to catch prey. They are believed to be intelligent and search for their prey using echolocation. More is known about this type of whale. Mysticeti, or baleen whales, have no teeth, but feed through filters of baleen. We know comparatively little about mysticeti whales....
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Chap 15 Questions - process of molting the shell splits and...

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