5.2 Adaptation5.2 Adaptation1. Explain how a species 1. Explain how a species

adapts to its niche.adapts to its niche.

2. Describe convergent 2. Describe convergent evolution and co-evolution and co-evolution, and relate evolution, and relate each to the concept of each to the concept of niche.niche.

3. Predict changes that 3. Predict changes that may occur in an may occur in an ecosystem if biodiversity ecosystem if biodiversity is reduced is reduced

Evolution and AdaptationEvolution and Adaptation• Ecosystems change over time. Mountains rise Ecosystems change over time. Mountains rise

and erode, rivers change course, and climate and erode, rivers change course, and climate factors such as temperature and rainfall may factors such as temperature and rainfall may vary dramatically.vary dramatically.

• A change in the environment will affect the A change in the environment will affect the niches of the organisms in that environment. niches of the organisms in that environment. – Evolution is a change in the characteristics of a Evolution is a change in the characteristics of a

population of organisms over time. Evolution population of organisms over time. Evolution happens when some individuals have genetic happens when some individuals have genetic variations that allow them to produce more variations that allow them to produce more offspring than other members of the population. offspring than other members of the population. Over time, these changes, or adaptations, will be Over time, these changes, or adaptations, will be passed from generation to generations. passed from generation to generations.

Evolution and AdaptationEvolution and Adaptation• ... our ancestors had larger jaws, so there ... our ancestors had larger jaws, so there

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

Evolving in a NicheEvolving in a Niche

• Evolution causes populations of Evolution causes populations of organisms to be adapted to specific organisms to be adapted to specific niches in the environment. This niches in the environment. This reduces competition with other species. reduces competition with other species.

• Ecologists call an organism with a small Ecologists call an organism with a small niche a niche a specialized speciesspecialized species. The koala . The koala is an example of a specialized species. is an example of a specialized species. It feeds only on the leaves of the It feeds only on the leaves of the eucalyptus trees. Specialized species eucalyptus trees. Specialized species are often vulnerable to extinction. are often vulnerable to extinction.

Evolving in a NicheEvolving in a Niche• Ecologists call a species with a wide Ecologists call a species with a wide

niche a generalized species. A niche a generalized species. A generalized speciesgeneralized species has several has several alternate food sources and is more alternate food sources and is more likely to survive in a changing likely to survive in a changing environment.environment.– Generalized species such as mice or Generalized species such as mice or

cockroaches survive well in areas altered cockroaches survive well in areas altered by human activity because they can by human activity because they can easily change their behaviors to fit new easily change their behaviors to fit new environmental conditions.environmental conditions.

Convergent EvolutionConvergent Evolution

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

Convergent EvolutionConvergent Evolution

Co-evolutionCo-evolution

• Species that interact closely may become adapted Species that interact closely may become adapted to one another through a process called co-to one another through a process called co-evolution.evolution.– Co-evolution can occur as a result of feeding Co-evolution can occur as a result of feeding

relationships. Plants and caterpillars are an example of relationships. Plants and caterpillars are an example of co-evolution. Many plants have poisonous chemicals co-evolution. Many plants have poisonous chemicals that prevent insects from eating them. Some that prevent insects from eating them. Some caterpillars have the ability to resist these poisons. caterpillars have the ability to resist these poisons. They can feed on plants that other insects cannot eat. They can feed on plants that other insects cannot eat. These caterpillars often become specialized and feed These caterpillars often become specialized and feed only on the poisonous plants. The plant and caterpillar only on the poisonous plants. The plant and caterpillar have co-evolved: As the plant adapted to producing have co-evolved: As the plant adapted to producing poisonous chemicals, the caterpillar adapted by resisted poisonous chemicals, the caterpillar adapted by resisted them.them.

HomeworkHomework

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