Evolution

Evolution: The generation-to-generation change in the proportion of different inherited genes in a population that accounts for all of the changes that have transformed life over an immense amount of time

Oh dear, natural selection is at it again! Gary Larsen

Evidence of Evolution Evidence of Evolution Geographic Distribution of Organisms Similar animals in different locations are products of different lines of evolutionary descent.

Embryology Similar early development

Vestigial Structures Some organs & structures become unnecessary as species evolve Tail bone Ear muscles Wisdom teeth Tonsils

Evidence of Evolution Fossil

Fossils

Transitional Fossils

DNA & Proteins The code of life is universal Similarities and differences help put together a picture of the evolutionary family tree

Homologous Body Structures Section 15-3 Homologous Body Structures Turtle Alligator Bird Mammals Typical primitive fish

Homologous Body Structures

Vertebrate Hemoglobin

Mechanisms of Evolution Mutations Changes in DNA that are not fatal or harmful create variation within species that results in differential survival of individuals – “survival of the fittest”

Mechanisms of Evolution Natural Selection The process by which individuals with beneficial inherited characteristics (adaptations) survive better and therefore reproduce more than other members of the species

Requirements for Natural Selection Variation within a species of inheritable characteristics – beneficial characteristics are called adaptations Overproduction of offspring causing competition for resources Differential survival and reproduction of individuals over many generations