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| All Units | > | Unit 13 - Adaptation | > | Investigation 2 - Adaptation | > | Thinking About the Question |
Thinking About The Question
How do populations adjust to changing environments?
How do populations adjust to changing environments?
In the natural world, the environment is constantly changing. The weather in a region may get wetter or drier. A plant species that some animal depended on for food may be displaced by another plant species. A new predator or competing species may spread into the area.
Suppose a region gradually has less and less rainfall over many years. It has a mixture of plants, some of which are more tolerant of drought than others. Describe what you think will happen to the plant life in the region.
Now suppose that the seeds of a certain kind of cactus are not all the same. Some of them sprout even if there is little rain. Others produce plants whose leaves conserve internal moisture better when it gets dry. Others have slightly deeper root systems. Describe how you think that cactus species might change over many generations.
An individual cactus can't 'learn' to have a deeper root system. Yet over many generations, this species may develop a deeper root system if it helps with survival in times of drought. How do you think this is possible?
This final question -- how plant and animal populations change in response to their environment -- is at the center of evolution. This model of sheep and grass will help you explore it.
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