Evolution

What is it? Changes that occur in a population over time, in response to the environment.

Lamarck Acquired characteristics can be passed down form generation to generation Organisms evolve over time due to the impact of the environmental factors acting on them

Darwin Natural Selection: organisms best suited to survive will pass their traits down 1.Survival of the fittest 2.Struggle for existence (competition for resources, produce more young than can survive) 3.Variation and adaptation

The Giraffe, Darwin and Lamarck LamarckDarwin Use and disuse Passing on of acquired characteristics Increasing complexity No extinction Variation Inheritance Differential Survival Extinction Lamarck: long necks of giraffes due to reaching for higher levels…offspring would inherit the trait… Darwin: longer necks were a result of adapting to the environment…short neck giraffes died off

BREED ORGANISMS FOR PARTICULAR TRAITS Selective Breeding

Fossils The preserved remains of plants and animals

Aging a Fossil Carbon dating Measure the amount of C-14 (an isotope of Carbon) remaining in the fossil Calculate according to half life ( the time it takes for half the amount of a substance to degrade)

Vestigial Organs Served a prior purpose Organism has evolved and no longer serves a purpose Example: human tail bone, snakes have tiny pelvic bones with limb bones, blind salamanders having eyes

Vertebrates All vertebrates shared a common ancestor. How do we know this? What evidence is there for this? They have evolved from common ancestry, sharing certain inheritable traits. The backbone is the most evident.

Mutation Permanent changes to the DNA sequence resulting in structural changes in a gene Peppered Moths: occurred over last two hundred years