ScienceVerseLearning path: Natural selection
The concepts to learn before Natural selection, in order. Each step links to its page and, where one exists, its quiz.
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Your path
- InheritanceDirect prerequisite
Inheritance is how genetic information passes from parents to offspring. Working with garden peas in the 1850s and 1860s, Gregor Mendel showed that traits are passed on as discrete units — what we now call alleles of genes — rather than blending together, and that a cross between two heterozygotes gives a predictable 1:2:1 genotype ratio and, under complete dominance, a 3:1 phenotype ratio. A Punnett square turns those rules into expected offspring frequencies.
- Natural selectionYour goal
Natural selection is the process by which individuals whose inherited traits suit their environment tend to survive and reproduce more, so those traits become more common in the population over generations. Charles Darwin and Alfred Russel Wallace proposed it independently in 1858, and it is the only known mechanism of adaptive evolution. It has been measured directly in the wild — in Darwin's finches, in peppered moths, and in bacteria that become resistant to antibiotics.