50 likes | 233 Vues
EVOLUTION. Natural Selection. Natural Selection. Darwin’s mechanism for evolution Read this: A mechanism of evolution whereby members of a population with the most successful adaptations to their environment are most likely to survive and reproduce. Write this:
E N D
EVOLUTION Natural Selection
Natural Selection • Darwin’s mechanism for evolution • Read this: • A mechanism of evolution whereby members of a population with the most successful adaptations to their environment are most likely to survive and reproduce. • Write this: • Those with traits that make them successful pass on those genes to the next generation. • How did Darwin arrive at this idea?
Natural Selection • Malthus- when resources are limited, only a % of offspring survive. • overproduction of offspring; • limited resources (food, water) • only some survive and reproduce
Natural Selection • Artificial selection • By selecting desired traits, humans chose who reproduces and passes on traits. • Ex.: wild mustard plant modified into broccoli, cauliflower, cabbage, brussel sprouts, kale, kohlrabi.
Natural Selection • Classic Example: Peppered Moths • Slept on trees which were light colored b/c of lichens. More light moths survived. • Industrial revolution- pollutants killed lichens, dark colored bark now exposed. More dark moths. • Why? • Predators (birds) ate most visible moths.