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
Sexual selection wikipedia , lookup
Sociobiology wikipedia , lookup
Evolving digital ecological networks wikipedia , lookup
Natural selection wikipedia , lookup
Saltation (biology) wikipedia , lookup
Evolutionary history of life wikipedia , lookup
Hologenome theory of evolution wikipedia , lookup
The Descent of Man, and Selection in Relation to Sex wikipedia , lookup
Inclusive fitness wikipedia , lookup
Koinophilia wikipedia , lookup
What is variation? Agenda for Wednesday May 18th 1. Variation lab Test tomorrow How do we get variation? Agenda for Thursday May 26th 1. Theories notes Variation • What is variation? Examples. • How do we get variation? • Can everybody have the same types of variation? Explain. • Gene pool – set of genes available in a population Jean Baptiste de Lamarck • Use and Disuse • Inheritance of Acquired Characteristics – Organisms acquire traits and pass these traits to offspring Lamarck’s Influence Incorrect • Not all traits acquired get passed on Important • Introduced change over time • Realized organisms are changing Charles Darwin • Naturalist • Traveled on the HMS Beagle (1831-1836) • South America, Galapagos Islands, Australia • Wrote The Origin of Species Galapagos Islands • small group of volcanic islands • no land mammals or amphibians The Journey Home • Characteristics of many plants and animals vary greatly among the islands • Hypothesis: Separate species may have arose from an original ancestor Finches • All had differentiated into 14 species • different beaks specialized for a particular food source • Conclusion – ancestral group of finches colonized islands – Absence of competitors allowed finches to gradually become specialized People influenced Darwin • Charles Lyell • Malthus – populations can grow exponentially – the are limited by war, disease, or resources • This led to Darwin’s idea that there’s a struggle for existence Darwin’s Theory • Humans can breed for certain traits – Dogs – Domestic plants • Could also happen in nature – Over time this could produce new species Darwin’s Theory • Natural selection – organisms best suited for the environment reproduce more successfully – Survival of the fittest • Over several generations organisms with favorable traits increase 1. Variation within a population 2. Variations are passed on 3. More offspring are produced than can survive 4. Organisms that survive have favorable variations (adaptations) Modification by Natural Selection • Fitness – genetic contribution to next generation • Environment “selects” traits – Favorable traits depend on demands of env’t Reproduce more Greater fitness Better adapted Summary of Darwin • Natural Selection – organisms best adapted to the environment survive and reproduce • the population is the unit of evolution – individuals do not evolve during their lifetimes What is natural selection? Agenda for Friday May 27th 1. Finish notes 2. Breeding bunnies lab 3. Theories coloring 35 30 25 20 15 10 5 0 1 2 3 4 5 6 7 8 9 10 11 • Cheetahs are able to run faster than 60 miles per hour when chasing prey. How would a biologist explain how the ability to run fast evolved in cheetahs, assuming their ancestors could run only 20 mph? • A long time ago, some cheetahs were faster than the others • The cheetahs that could run faster were able to catch their prey and were better able to survive • The slow cheetahs died off, or weren’t able to reproduce as successfully • The cheetahs that survived were the ones that could run faster How does gene pool relate to variation? Agenda for Wednesday May 21st 1. Finish theories notes How did the heavy coat in polar bears evolve if their ancestors had thinner coats? 1. A long time ago, some polar bears had thicker fur than others 2. The thicker coat was favorable 3. The polar bears with thin coats died off. 4. The ones with thicker coats survived and reproduced. Peppered Moths Theory of Evolution • Evolution – change in the inherited traits of a population of organisms over time – NOT new species arising from pre-existing species