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Course: Middle school biology - NGSS  > Unit 9

Lesson 2: Adaptation and environmental change
Science
Middle school biology - NGSS
Natural and artificial selection
Adaptation and environmental change
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Adaptation and environmental change

Google Classroom
Review your understanding of adaptation and environmental change in this free article aligned to NGSS standards.

Key points

  • Populations are often affected by changes in their environment. For example, changes in climate can affect how easy it is for organisms to find food or water.
  • After an environmental change, traits that help organisms survive and reproduce in the new environment become more common. Similarly, traits that make organisms less likely to survive and reproduce become less common. This process occurs over multiple generations.
  • As helpful traits become more common, the population adapts, or becomes better suited, to the new environment. The increase in helpful traits in a population over generations describes adaptation by natural selection.
  • If environmental changes are too extreme, populations do not have time to adapt. As a result, the populations may go extinct.
A figure shows two bar graphs. The bar graph on the left is titled Before environmental change. It shows Number of beetles on the y-axis and Beetle color on the x-axis. There are three bars. The bar labeled Light brown goes to about 20 beetles. The bar labeled Medium brown goes to about 30 beetles. The bar labeled Dark brown goes to about 95 beetles. An arrow points from the bar graph on the left to the bar graph on the right. The bar graph on the right is titled After environmental change. It shows Number of beetles on the y-axis and Beetle color on the x-axis. There are three bars. The bar labeled Light brown goes to about 90 beetles. The bar labeled Medium brown goes to about 25 beetles. The bar labeled Dark brown goes to about 15 beetles.
Diagram showing the change in the number of beetles with different colors multiple years after an environmental change. The diagram shows that light brown beetles became more common in the population. So, the environmental change likely favored light brown beetles. Image created with Biorender.com.

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