Learning Target: Principles of Natural Selection I Can…Describe the four main principles of natural selection and relate them to the process of evolution. I Will… Define relevant vocabulary terms including Summarize the four principles of natural selection Apply the principles to a simulated event Evolution Artificial selection Variation Natural selection Adaptation Fitness 1

Evolution by Natural Selection: It’s all about Advantage and Change Evolution by Natural Selection: It’s all about Advantage and Change If you were a predator, which fish would you more likely see as prey? 2

Evolution – process of biological change by which descendants come to differ from their ancestors Variation – differences in heritable physical traits (phenotypes) of an individual from those of other individuals within the group to which it belongs Interspecific – members of different species Intraspecific – members of same species Adaptation – a feature (variation version) that allows an organism to better survive its environment Can lead to genetic change over time 3

Artificial selection - process by which humans change a species by breeding it for certain beneficial or desirable traits. Only works with heritable traits Passed through DNA Agriculture Dog breeds Antibiotic resistant bacteria ( unintentional ) 4

Natural selection - mechanism by which individuals have inherited beneficial adaptations. Fitness – measure of the ability to survive and produce more offspring relative to other members of the population in a given environment Survive longer Healthier Produce more offspring that inherent DNA Over time shifts the genetic percentages in a population 5

Four Key Principles to Theory of Natural Selection 1.Variation – heritable difference that exist in population are the basis for natural selection (differences based on genetic instructions) a)Inherited from parents to offspring b)Random mutations (Change in DNA) 2.Adaptation – Certain genetically based traits give organisms an advantage to ecosystem pressures a)Both environmental and community a.Better at competition (food, shelter, mates) b.More likely to survive and produce offspring that survive 6

Four Key Principles to Theory of Natural Selection 3.Overproduction - Increase in offspring equals increase in chances of survival of those offspring (and the genetic traits they inherit) a)BUT, also increases competition for resources b)Remember Carrying Capacity 4.Descent with Modification - Over time, natural selection favors certain genetically-based adaptations a)Genetic trait increases in the population as long as selective pressure remains and trait is beneficial 7

Trait: Body color Brown – B (dominant) Green – b (recessive) 8

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Learning Check √: Principles of Natural Selection The peppered moth comes in a color variation of light and dark. Trees in England that were covered with lichens provided camouflage against predators for the light moths. Then the pollution from the industrial revolution killed off the lichen changing the tree bark to a dark color. 1.Which version of the peppered moth had a higher population number prior to the industrial revolution? Explain why. 2.What do you think happened to the color variation in the moths after the industrial revolution? Explain why. You may watch a related YouTube video on peppered moths at: 11