Natural selection notes
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Natural selection is the process by which organisms with traits that help them survive and reproduce in their environment become more common over generations. When resources are limited, competition arises between organisms. Those with useful adaptations, like camouflage, are more likely to live on and pass their traits to offspring. Over time, natural selection leads populations to become dominated by organisms with adaptations suited to the environment.
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Natural selection notes
- 2. Resources: • stuff in the environment that is needed for survival • often limited (can be used up)
- 4. Competition: The effort of 2 or more organisms acting independently to get resources that are in short supply.
- 5. Variation: • Differences in shape, structure, or function • Caused by sexual reproduction or mutation Dangling earlobe Attached earlobe
- 6. Adaptation: A useful trait that helps an organism to survive, and which gives it an advantage in its environment. camouflage
- 7. Overpopulation: • Too many organisms in one environment • Can lead to competition
- 9. Overpopulation can lead to competition. 1
- 10. Due to competition, some organisms (with useful traits) will live on… 2 ...but others will die. Also called “survival of the fittest”
- 11. The usefulness of a trait depends on the resources and environment. brighter stripes (+) attracting a mate? (-) more visible to predators? skinny body (+) hide or live in small holes? (-) not so strong for defense? Speedy swimmer (+) fast escapes (-) needs lots of energy (food!)
- 12. Organisms that have useful traits (adaptations) will survive and then reproduce. They pass the traits on to their offspring. 3
- 14. END RESULT: The environment now has a lot more organisms that have certain traits. This is NATURAL SELECTION. (Nature chooses the traits that will increase in the population. 4