BuyFind

Oceanography: An Invitation To Mar...

9th Edition
Garrison + 1 other
Publisher: Brooks Cole
ISBN: 9781305254282
BuyFind

Oceanography: An Invitation To Mar...

9th Edition
Garrison + 1 other
Publisher: Brooks Cole
ISBN: 9781305254282

Solutions

Chapter 15, Problem 1TC
Textbook Problem

When did the first true animals evolve? What atmospheric changes had to happen before animal life was possible? Are descendants of most of the early forms of animal life represented in the ocean today? Explain why.

Expert Solution
To determine

The time during which the first true animals evolved, the atmospheric changes that had to happen before animal life was possible, whether the descendants of most of the early animal life forms have marine representatives today.

Answer to Problem 1TC

It was during the oxygen revolution between nearly 2 billion and 400 billion years ago that the primary animal-like creatures developed. The atmosphere that had only less than 1 percent free oxygen was altered by the photosynthetic autotrophs into an atmosphere with greater than 20 percent free oxygen, as seen today, during the oxygen revolution. Most of the primitive animal forms had marine representatives; however, at present, much of them do not exist.

Explanation of Solution

The single-celled organisms formed the primary animal-like creatures on the Earth. During the oxygen revolution, they started to flourish in the ocean. Oxygen revolution was the period of an essential transformation in the Earth’s atmosphere. The photosynthetic autotrophs release oxygen into the atmosphere as a byproduct of the process of their food preparation. This process is called photosynthesis. This process added more oxygen into the Earth’s atmosphere.

Due to the action of such photosynthetic autotrophs, the atmospheric composition of the Earth changed from a less than 1 percent oxygen-containing atmosphere to a new atmosphere having greater than 20 percent free oxygen during the oxygen revolution between approximately 2 billion and 400 million years ago.

Aerobic respiration became possible with the increasing abundance of free oxygen. This accelerated disassembly of food particles that primitive animals attained by consuming the autotrophs. The ozone obtained from this oxygen hindered most of the harmful ultraviolet radiations of the sun from reaching the surface of the Earth. This made the survival of life at the ocean surface and later on the land possible.

All groups of primitive marine animals were not able to survive for longer time periods. Certainly, most of those animals would not have made it to the present time. For instance, the trilobites that were abundant during the past have all disappeared. Perhaps, most of the animals in the ancient fossil beds have vanished and may characterize the failed branches in animal evolution that represents exceptional designs that were not appropriate to later environmental settings.

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Chapter 15 Solutions

Oceanography: An Invitation To Marine Science, Loose-leaf Versin
Ch. 15.3 - What evolutionary advances characteristic of...Ch. 15.4 - What are the most valuable shells? What is your...Ch. 15.4 - How does an arthropod growth curve compare with...Ch. 15.4 - Why do you think brittle stars are found in high...Ch. 15.4 - Which group of animals is Earths most successful...Ch. 15.4 - Clams and squid are in the same phylum. How can...Ch. 15.4 - Provide an example of each of the major groups of...Ch. 15.4 - It has been said that arthropods grow without...Ch. 15.4 - What structural system is unique to the phylum...Ch. 15.5 - Whats a notochord?Ch. 15.5 - Do all chordates have backbones?Ch. 15.6 - How are the vertebrates related?Ch. 15.6 - What are the evolutionary advantages of possessing...Ch. 15.6 - Why is this referred to as just one proposed...Ch. 15.7 - What are the classes of living fishes? Which class...Ch. 15.7 - Which class has the largest individuals? Which is...Ch. 15.7 - Are fishes warm-blooded (endothermic) or...Ch. 15.7 - Are most sharks dangerous to human swimmers?Ch. 15.8 - Why does having water and blood flow in opposite...Ch. 15.8 - Why do you suppose a male attaches permanently to...Ch. 15.8 - How do fishes move effectively through such a...Ch. 15.8 - How do fishes breathe?Ch. 15.8 - How does schooling behavior benefit fishes?Ch. 15.9 - Why do you think ridley turtles nest in such large...Ch. 15.9 - How are sea turtles able to find their way back to...Ch. 15.9 - What is an arriabada?Ch. 15.10 - From what group are birds thought to have evolved?Ch. 15.10 - How are seabirds different from land birds?Ch. 15.10 - Which marine birds are the worlds most efficient...Ch. 15.10 - How do penguins differ from other marine birds?Ch. 15.11 - Why do you think baleen whales are generally...Ch. 15.11 - What characteristics are unique to marine mammals?Ch. 15.11 - What are the largest animals ever to have lived on...Ch. 15.11 - What is echolocation? How do whales use it?Ch. 15.11 - How is a seal different from a sea lion? Which...Ch. 15.11 - Why do you think manatees evolved to be so much...Ch. 15 - When did the first true animals evolve? What...Ch. 15 - How can an arthropod grow within a tailored shell?...Ch. 15 - Are all chordates vertebrates? Are all vertebrates...Ch. 15 - Of the living classes of vertebrates, only one has...Ch. 15 - How are odontocete (toothed) whales different from...Ch. 15 - Do you think there are more species of animals on...Ch. 15 - There are more parasitic species of animals than...

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