7th Grade Unit 7 Review

Species over long periods of time evolve. Those that cannot adapt to environmental changes run the risk of going extinct. Bacteria for example can adapt very quickly to environmental changes.

Fossil evidence helps show the common ancestry between extinct species and modern ( extant) species. Fossil evidence is the best evidence that shows how species have changed over long periods of time.

Charles Darwin, in his book " Origin of the Species", written in 1859 discusses that the slow changes in a species is not immediately observed, but only until a great deal of time has passed can we compare how changes have occurred

When environmental pressures/changes occur, such as temperature changes to climates, one response to these changes would be a species would produce offspring that are able to tolerate those temperature changes

Species run the risk of extinction if there are changes to the environment, such as loss of food source, habitat, climate changes

Natural selection relies on advantageous ( something that gives an organism an advantage) traits becoming more common in the population of a given species

Darwin's original theory of evolution has been modified as science has discovered new evidence

Predators can effect populations of their prey. In some cases, the prey may have a variety of colors. Example: in some species males may be bright colored while some males and females may be bright colored, while some males and females may be dull in color. If a predator detects bright colored prey more easily then those populations will decline, while natural selection will favor the increase of those with dull colors as they are less detected by the predator