Mechanisms of Evolution P. 105 EQ: How does evolution happen? Natural Selection Genetic Drift Gene Flow Mutation Recombination

Natural Selection Produces changes in POPULATIONS, not individuals Process by which random evolutionary changes are selected for by nature in a consistent, orderly, non-random way Organisms best adapted to their environment have a better chance of surviving and reproducing Produces changes in POPULATIONS, not individuals

Natural Selection Organisms with traits that are better suited for a specific environment are called the “fittest” because their traits are best fit for their environment Because their traits are best suited for their environment, the most fit individuals will tend to survive more often than others with less-desirable traits for their environment Because they are more likely to survive, they are more likely to reproduce a lot (live longer) This which will pass their better–suited traits on to future generations

Natural Selection Elements of natural selection: inherited variation production of large # of offspring that won’t all survive & finite supply of environmental resources result in competition Adaptation Descent with modification occurs over time “survival of the fittest” A trait that helps an organism survive and reproduce, and can be passed down to it’s offspring, is called an adaptation.

Who will survive? Why? Predict the amount (%) of light and dark individuals in the moth population.

Industrial Revolution happens… Pollution was sent into the atmosphere. This killed the lichen that lived on the tree trunks. Soot also collected on the tree trunks. These 2 events caused the tree trunks to darken.

Who will survive? Why? How did you do?? Before the Industrial Revolution, about 99% of the moths were light. In just 50 years after the Industrial Revolution began, 98% of the moths were dark. Explain why this happened. Your answer should include a discussion of predation, survival, and inherited traits. Predict the amount (%) of light and dark individuals in the moth population.

Speciation 2 species arise from one (wolf → dogs) Requires Reproductive Isolation Geographic – physically separated Sexual Selection Differences – different times/rituals Anatomical – they have to fit (think about a mouse & elephant…) Allopatric Speciation - occurs when 2 or more populations of a species are geographically isolated from each other Allele frequencies in these populations change Members of each population become so different that they can no longer reproduce Adaptive Radiation - when multiple species have a common ancestor (ex: Darwin’s Finches)

Natural Selection Domesticating dogs – wild dogs were trained by man and bred (artificial selection) for desired traits. After a few generations of this, the wild dogs were not able to breed with the domesticated dogs – this means the domesticated dogs are a new species