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
The Selfish Gene wikipedia , lookup
On the Origin of Species wikipedia , lookup
Evolution of ageing wikipedia , lookup
Population genetics wikipedia , lookup
Theistic evolution wikipedia , lookup
Saltation (biology) wikipedia , lookup
Genetics and the Origin of Species wikipedia , lookup
Inclusive fitness wikipedia , lookup
Sexual selection wikipedia , lookup
Hologenome theory of evolution wikipedia , lookup
10.3 Theory of Natural Selection KEY CONCEPT Darwin proposed natural selection as a mechanism for evolution. 10.3 Theory of Natural Selection Charles Darwin - Biography • Born – England, February 12 1809 • Sailed around the world as a naturalist (scientist who studies nature) • Well educated and interested in natural history • Curious with an analytical nature • Made observations and collected evidence which later supported his hypothesis about how life changes over time 10.3 Theory of Natural Selection Charles Darwin - Travels • Sailed on the ship H.M.S. Beagle in 1831 – From Europe to South America, the Galapagos Islands, New Zealand, Austrailia, the southern tip of Africa, back to South America, and then home to England • The Galapagos Islands – Islands are close together; climates are very different: hot, dry and barren vs. more rainfall and vegetation 10.3 Theory of Natural Selection Darwin observed differences among island species. • Variation is a difference in a physical trait. – Galápagos tortoises that live in areas with tall plants have long necks and legs. – Galápagos finches that live in areas with hard-shelled nuts have strong beaks. 10.3 Theory of Natural Selection Several key insights led to Darwin’s idea for natural selection. – Darwin observed 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 Artificial selection in dogs 10.3 Theory of Natural Selection Artificial selection in horses 10.3 Theory of Natural Selection • Natural selection is when individuals that have inherited beneficial adaptations produce more offspring on average than do other individuals. 10.3 Theory of Natural Selection • Heritability is the ability of a trait (beneficial adaptations) to be passed down. – There is a struggle for survival due to overpopulation and limited resources. •Darwin proposed that adaptations arose over many generations. 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 in organisms VARIATION 10.3 Theory of Natural Selection Natural selection explains how evolution can occur. • There are four main principles to the theory of natural selection. • Adaptation – changes caused by evolution in an organism to better survive in their environment ADAPTATION 10.3 Theory of Natural Selection Natural selection explains how evolution can occur. • There are four main principles to the theory of natural selection. • Overproduction – producing more offspring than will survive OVERPRODUCTION 10.3 Theory of Natural Selection Natural selection explains how evolution can occur. • There are four main principles to the theory of natural selection. DESCENT with MODIFICATION Traits that are heritable and beneficial (like big jaws and teeth) will be passed down to further generations. 10.3 Theory of Natural Selection • Fitness is the measure of survival ability and ability to produce more offspring. 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