1. 5.2 Adaptation 1. Explain how a species adapts to its niche. 2. Describe convergent evolution and co-evolution, and relate each to the concept of niche. 3. Predict changes that may occur in an ecosystem if biodiversity is reduced

2. Evolution and Adaptation Ecosystems change over time. Mountains rise and erode, rivers change course, and climate factors such as temperature and rainfall may vary dramatically.Ecosystems change over time. Mountains rise and erode, rivers change course, and climate factors such as temperature and rainfall may vary dramatically. A change in the environment will affect the niches of the organisms in that environment.A change in the environment will affect the niches of the organisms in that environment. –Evolution is a change in the characteristics of a population of organisms over time. Evolution happens when some individuals have genetic variations that allow them to produce more offspring than other members of the population. Over time, these changes, or adaptations, will be passed from generation to generations.

3. Evolution and Adaptation... our ancestors had larger jaws, so there was room in the human mouth for 32 permanent teeth, including third molars—wisdom teeth. But now our jaws are smaller. The result: There’s no longer room in most of our mouths to house 32 teeth. So the last teeth we develop—our wisdom teeth—often become impacted, or blocked from erupting.’2... our ancestors had larger jaws, so there was room in the human mouth for 32 permanent teeth, including third molars—wisdom teeth. But now our jaws are smaller. The result: There’s no longer room in most of our mouths to house 32 teeth. So the last teeth we develop—our wisdom teeth—often become impacted, or blocked from erupting.’2

4. Evolving in a Niche Evolution causes populations of organisms to be adapted to specific niches in the environment. This reduces competition with other species.Evolution causes populations of organisms to be adapted to specific niches in the environment. This reduces competition with other species. Ecologists call an organism with a small niche a specialized species. The koala is an example of a specialized species. It feeds only on the leaves of the eucalyptus trees. Specialized species are often vulnerable to extinction.Ecologists call an organism with a small niche a specialized species. The koala is an example of a specialized species. It feeds only on the leaves of the eucalyptus trees. Specialized species are often vulnerable to extinction.

5. Evolving in a Niche Ecologists call a species with a wide niche a generalized species. A generalized species has several alternate food sources and is more likely to survive in a changing environment.Ecologists call a species with a wide niche a generalized species. A generalized species has several alternate food sources and is more likely to survive in a changing environment. –Generalized species such as mice or cockroaches survive well in areas altered by human activity because they can easily change their behaviors to fit new environmental conditions.

6. Convergent Evolution The independent development of similar adaptations in two species with similar niche is called convergent evolution. The wings of birds and bats are an example of convergent evolution. Birds and mammals are different types of animals, and the bird and bat evolved flight independently. However, both species evolved wings as an adaptation to a niche that required flying through the air.The independent development of similar adaptations in two species with similar niche is called convergent evolution. The wings of birds and bats are an example of convergent evolution. Birds and mammals are different types of animals, and the bird and bat evolved flight independently. However, both species evolved wings as an adaptation to a niche that required flying through the air.

7. Convergent Evolution

8. Co-evolution Species that interact closely may become adapted to one another through a process called co-evolution.Species that interact closely may become adapted to one another through a process called co-evolution. –Co-evolution can occur as a result of feeding relationships. Plants and caterpillars are an example of co-evolution. Many plants have poisonous chemicals that prevent insects from eating them. Some caterpillars have the ability to resist these poisons. They can feed on plants that other insects cannot eat. These caterpillars often become specialized and feed only on the poisonous plants. The plant and caterpillar have co-evolved: As the plant adapted to producing poisonous chemicals, the caterpillar adapted by resisted them.

9. Homework Find three species that have gone through an adaptation process. List the three species, their adaptations, and the cause of their adaptation – changes in the environment.