AIM: Explain how a species adapts to its niche and describe convergent evolution and coevolution. DN: Can two species share the same exact niche? Why or why not? HW: Article Summary #1

EVOLUTION AND ADAPTATION

A gradual change in a population of organisms over time EVOLUTION A gradual change in a population of organisms over time Evolution occurs when genetic variation allows certain individuals to better survive in their environment. Over time, these changes (adaptations) will be passed from generation to generation.

Adaptation A genetically controlled change in an organism that helps it to survive and reproduce under a changing environment A change in the environment will affect the niches of the organisms that live in that environment A species may successfully occupy a niche, but if that niche disappears, the species may become extinct. Changes in the environment affect the evolution of populations

ADAPTATIONS

EVOLVING IN A NICHE 5 species of warblers live in the forests of the northeastern United States All 5 species feed on the insects in spruce trees Although they may seem to compete with each other, each species feeds in a different part of the tree Their niches overlap slightly, but are different enough to allow all 5 species to coexist

5 species of Warblers

Specialized Species An organism with a small niche Vulnerable to extinction (any small change in the environment can affect it) Example: Koala Bear Eats only leaves of eucalyptus trees

Generalized species An organism with a big niche Has several food choices making it more likely to survive a change in the environment Example: Cockroaches and Mice Can easily change their behaviors to fit new environmental conditions

CONVERGENT EVOLUTION The independent development of similar adaptations in two species with similar niches If niches in two ecosystems are similar, the organisms that evolve there may also look similar

The Dolphin (mammal) and the ichthyosaur (extinct reptile) are examples of convergent evolution

(they need each other to survive) Coevolution Two species adapt (through evolution) to improve their own survival and rely on one another for survival. (they need each other to survive) Example: Acacia trees and stinging ants The tree provides a nesting site for ants The ants protect the trees from animals and other insects ONE CANNOT SURVIVE WITHOUT THE OTHER!!!!

Acacia Tree and Stinging Ants

What is evolution? What is a specialized species? Give an example. What is a generalized species? Give an example. Why are generalized species more adaptable to changes in the environment. Explain convergent evolution and give one example. Why does convergent evolution happen?. What is coevolution? Provide an example of coevolution. Why do species such as the warblers evolve to avoid competition with other species? What would happen to the ant colony living on an acacia tree if that tree was chopped down? What does your answer imply about the effect of destroying an organism’s habitat?

Review Questions Why do species such as the warblers evolve to avoid competition with other species? Explain convergent evolution and give one example. Why does convergent evolution happen? What would happen to the ant colony living on an acacia tree if that tree was chopped down? What does your answer imply about the effect of destroying an organism’s habitat?