7.1 Darwin and Natural Selection
Notes
Evolution is the change in the inherited traits of a population over many generations. Charles Darwin explained how it happens with natural selection.
- Darwin studied species on the Galápagos Islands, such as finches with different beak shapes.
- Variation: individuals in a population differ, and many differences are inherited.
- Overproduction: more offspring are born than can survive, so they compete for resources.
- Selection: individuals with helpful traits survive and reproduce more (survival of the fittest).
- Over generations, helpful traits become more common.
- Fitness means how well an organism survives and reproduces, not how strong it is.
- Artificial selection is when humans choose which organisms breed (dog breeds, crops).
Practice
In biology, the "fittest" organism is the one that:
Fitness is measured by reproductive success.
Which of these is required for natural selection to happen?
Selection acts on differences that can be passed to offspring.
Farmers bred wild mustard for large leaves, producing kale. This is an example of:
Humans chose which plants would reproduce.
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