Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
10.3 Theory of Natural Selection KEY CONCEPT Darwin proposed natural selection as a mechanism for evolution. 10.3 Theory of Natural Selection Several key insights led to Darwin’s idea for natural selection. • Darwin noticed a lot of variation in domesticated plants and animals. • Artificial selection is the process by which humans select traits through breeding. neck feathers crop tail feathers 10.3 Theory of Natural Selection • Heritability is the ability of a trait to be passed down. • There is a struggle for survival due to overpopulation and limited resources. • Darwin proposed that adaptations arose over many generations. • Natural selection is when individuals that have inherited beneficial adaptations produce more offspring 10.3 Theory of Natural Selection Natural selection explains how evolution can occur. • There are four main principles to the theory of natural selection. – Variation-differences come from the genetic code whether inherited from parent or a mutation – overproduction-results in competition for resources – adaptation-a certain variation allows an individual to survive better…more successful individuals are “naturally selected” – descent with modification-natural selection will result in species with adaptations that are well suited for survival and reproduction • Fitness is the measure of survival ability and ability to produce more offspring------SURVIVAL OF THE FITTEST! 10.3 Theory of Natural Selection Natural selection acts on existing variation. • Natural selection can act only on traits that already exist. • Structures take on new functions in addition to their original function. five digits wrist bone 10.3 Theory of Natural Selection Video