wunder beta🌿 How Natural Selection Works
Variation, a struggle to survive, differential survival, and heredity, the four ingredients of Darwin's big idea, and how they reshape a species over generations.
What you’ll learn
- The Four IngredientsState the theory of natural selection and explain its four requirements: variation, overproduction, differential survival, and heredity.Natural selection, described by Darwin, is the process by which organisms better matched to their environment survive and reproduce more. It requires four ingredients: variation among individuals, more offspring than can survive, differential survival and reproduction of the best-matched, and heredity so helpful traits are passed on.
- Selection in ActionSequence the steps of natural selection and apply them to the rock pocket mouse, and describe the limits of what selection can do.Natural selection follows four steps: variation exists, the environment favors some variations, the favored survive and reproduce more, and offspring inherit the trait. The rock pocket mouse shows this, with fur color matching the rock. Selection cannot plan ahead, works on populations over generations, and always depends on the environment.
Questions this course answers
Who described the theory of natural selection?
Charles Darwin described natural selection in his 1859 book 'On the Origin of Species'.
Why is variation necessary for natural selection?
Variation provides the differences among individuals that natural selection can favor; without it, there is nothing to select.
In natural selection, what does it mean to be the 'fittest'?
The 'fittest' are those best matched to their environment, most likely to survive and reproduce, not simply the strongest.
Why must a helpful trait be heritable to matter for natural selection?
A trait must be heritable, passed through genes to offspring, so that it can spread through the population over generations.
Why are mostly dark rock pocket mice found on black lava rock?
On black rock, light mice are easily seen and eaten by owls, so dark mice survive and reproduce more, becoming common.
Which is something natural selection cannot do?
Natural selection cannot plan ahead; it can only favor variations that already exist in a population.
Grounded in trusted sources
- Understanding Evolution (UC Berkeley)
- National Geographic
- Britannica
- Smithsonian
Every Wunder lesson is built from real, reputable sources — never invented.
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