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EVOLUTION

EVOLUTION. Intro to Evolution Objective 9. What is Evolution ? EVOLUTION --. A change over time. Intro to Evolution Objective 9. organize. Why Should We Study Evolution ? Scientists use evolution to ______________ biology .

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EVOLUTION

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  1. EVOLUTION

  2. Intro to EvolutionObjective 9 • What is Evolution? • EVOLUTION-- A change over time

  3. Intro to EvolutionObjective 9 organize Why Should We Study Evolution? • Scientists use evolution to ______________ biology. • It helps us understand relationships between species in ________________. • It explains the development of _______________ resistance and ___________________ resistance. • It explains how viruses such as _____________________________ can change. • Understanding relationships between organisms can help us make conclusions in _______________ ___________. ecosystems antibiotic insecticide AIDS and the Flu Medical research

  4. Intro to EvolutionObjective 9 2 Types of Evolution: • Microevolution (______ of Evolution)—change that occurs within any given species over time. Example: A population of bacteria develops ______________________. • Macroevolution (_____________ of Evolution) refers to the changes among species over time. Example: the replacement of dinosaurs by ___________________). Law Antibiotic resistance Theory Mammals

  5. Natural SelectionObjectives 7-9 Charles Darwin proposed his theory of evolution in 1844. **Evolution works at the POPULATION level—NOT at the ________________ level** 2 Types of Evolution: • Microevolution (______ of Evolution)—change that occurs within any given species over time. Example: A population of bacteria develops ______________________________. • Macroevolution (_____________ of Evolution) refers to the changes among species over time. Example: the replacement of dinosaurs by ___________________). individual Law Antibiotic resistance Theory Mammals

  6. Natural SelectionObjectives 7-9 How does Natural Selection (Microevolution) work? MAIN IDEA: Natural selection changes the frequency of certain ______________within a population ______________________ as the population ____________________ to its environment. Genes Gene Pool Adapts

  7. Natural SelectionObjectives 7-9 variation 1. All species have natural genetic ____________ as a result of ____________ mutation. • Variation-- Question: What causes variation within a species? random Differences in characteristics within a species Mutations and Crossing Over

  8. Natural SelectionObjectives 7-9 2. The environment presents many challenges (selective pressures) to _________________. Examples: predator-prey interactions, ________________ shortage, changes in _______________________ conditions) Survival resource environmental

  9. Natural SelectionObjectives 7-9 3. There is a struggle for survival. Struggle = __________________. The _________ individuals will be able to survive (those whose ____________ give them an advantage). • Question: Are the fittest individuals the same in all environments? competition fittest genes No!! – different traits provide an advantage in different environments

  10. Natural SelectionObjectives 7-9 Traits (Genes) 4. _______________ from the survivors are passed on to their offspring. The frequency of the survivors’ genes will increase in the population over time as the population _____________ to its environment. • Adaptation—any variation that allows an organism to ___________________ successfully. adapts reproduce

  11. What are the adaptations here?

  12. Natural SelectionObjectives 7-9 5. Individuals (and species) that are not able to survive and reproduce will die off (become ________________). Their _____________ will become extinct with them. Extinct Traits (Genes)

  13. Natural SelectionObjectives 7-9 Example of Natural Selection In 1973 Peter and Rosemary Grant began a study of the finches on the Galapagos Islands. They noticed that some finches had large beaks while others had smaller more slender beaks. Both birds with small beaks and those with large beaks seemed to feed primarily on small, soft seeds. While the Grants were on the Islands a drought occurred. During a drought, plants produce only a few seeds. These seeds tend to be larger and tougher. Birds with small beaks are not able to eat these seeds. The Grants found that after several dry years the average size of the birds’ beaks had increased.

  14. Natural SelectionObjectives 7-9 • Questions: 1. In this example what variation was present in the finches? 2. What was the selective pressure? 3. What change occurred within the population during the dry years? 4. Use the theory of natural selection to explain how this change occurred. Size of the beaks in Finches Drought causing the absence of seeds The size of the beaks The Larger beak gene became more popular in the population and the thin, small beak genes decreased.

  15. BehaviorObjective 11 Behavior – refers to the actions and mannerisms made by organisms, systems, or artificial entities in conjunction with their environment

  16. BehaviorObjective 11 What is the affect of natural selection on behavior? Behaviors will be maintained or removed based on their overall contribution to the _____________ of an individual. The behavior must be ____________________ because natural selection changes the frequency of that _____________ (alleles) in the gene pool. fitness genetic gene

  17. BehaviorObjective 11 Example: Read the passage below and answer the questions that follow. Animals display various behaviors for many reasons. Generally, behaviors can be linked to a goal of survival or reproduction. One famous biologist, Niko Tinbergen, noticed that Common Black-headed Gulls would meticulously remove the eggshell fragments from their nests after their offspring hatched. In an attempt to understand this behavior, he painted chicken eggs so that they were camouflaged into the backgrounds where the gulls lived and nested. He then placed some broken eggshells near them. He then noted how many eggs were discovered and eaten by Carrion crows. He observed that crows were able to easily notice the white interiors of the broken shells and consumed many more of the camouflaged eggs near the broken shells than camouflaged eggs with no broken shells near them. (Taken from Holt Biology Skills Worksheet p13)

  18. BehaviorObjective 11 1. What question was Tinbergen attempting to answer with his experiment? 2. Why did Tinbergen set up one area with camouflaged eggs and no shell fragments? Why do gulls remove the shells? Experimental control

  19. BehaviorObjective 11 3. Explain how you would interpret the behavior of the gulls based on this experiment. 4. How is the behavior of the gulls linked to natural selection? Gulls remove shells to keep predators from eating the other eggs Gulls who remove shells have more offspring live so the gene that makes them remove shells is passed on.

  20. The Genetics of Natural SelectionObjective 10, 15-18 Natural selection changes the frequency of certain _________within a population _______________ as the population ____________________ to its environment. **Evolution works at the POPULATION level—NOT the _________________ level** Gene Pool—The entire collection of genes among a _______________. Genes Gene pool adapts individual population

  21. The Genetics of Natural SelectionObjective 10, 15-18 Remember that there can be different versions of a gene. Each version of a gene is called an allele. You inherit one allele for each gene from each parent.

  22. The Genetics of Natural SelectionObjective 10, 15-18 Allelic Frequency—the % of a particular allele (choice) within a _______ ______. Gene pool

  23. The Genetics of Natural SelectionObjective 10, 15-18 Example: Sickle Cell Anemia—a recessive genetic disease that affects red blood cells. A-dominant allele S-recessive allele 30 people AA 15 people AS 5 people SS What are the allelic frequencies of A and S? A = 75/100 or 75% S= 25/100 or 25%

  24. The Genetics of Natural SelectionObjective 10, 15-18 • If allelic frequencies remain the same from generation to generation, the population is said to be in ___________ ___________ and the population is NOT evolving. • If the allelic frequencies are changing from generation to generation then we can conclude that ________________________________. Static ??? Frequencies are changing???

  25. The Genetics of Natural SelectionObjective 10, 15-18 • Natural selection is the MAJOR mechanism for changing allelic frequencies. However, there are other mechanisms of evolutionary change. These include genetic drift, gene flow, mutation and recombination. • Genetic Drift—Random change of allelic frequencies in a small population due to chance.

  26. The Genetics of Natural SelectionObjective 10, 15-18

  27. The Genetics of Natural SelectionObjective 10, 15-18 Gene Flow—transfer of genes from one population to another due to immigration or emigration. ***Explain how gene flow can lead to evolutionary change. Gene flow can show how genes move into or out of a population, thus changing the frequencies.

  28. The Genetics of Natural SelectionObjective 10, 15-18 Mutation—any change in a sequence of DNA. ***Explain how mutation can lead to evolutionary change. Mutations can introduce “new” genes into a population and thus changing the Gene Frequencies.

  29. The Genetics of Natural SelectionObjective 10, 15-18 Recombination—exchange of genetic material that occurs due to crossing over. ***Explain how recombination can lead to evolutionary change. Recombination can make new gene combinations and this can change the gene frequencies in a population.

  30. SpeciationObjective 13 How can you tell members of 2 different species apart? What is a species? Physical characteristics, DNA, Behavior A group of organisms that can mate and produce fertile offspring

  31. SpeciationObjective 13 How can natural selection produce a new species? 1. Natural selection causes changes in _____________ _______________ of a population. 2. Different parts of a population might _________________ in different ways. Allelic Frequencies Change

  32. SpeciationObjective 13 mate 3. Due to these changes, the 2 parts of the population are now unable to __________ Reproductive Barrier— 4. If the 2 parts can no longer _____________ this means a new ___________ has evolved. The evolution of a new species from old ones is called ______________ or macroevolution. Any factor that keeps fertile offspring from being produced. mate species speciation

  33. Darwin’s Finches

  34. SpeciationObjective 13 An Example of Speciation: About 50,000 years ago, the region now known as Death Valley had a rainy climate and many lakes and rivers that were interconnected. About 10,000 years ago, the climate began to get much drier and by 4000 years ago the area had become a desert. Lakes and rivers that were once connected were reduced to isolated springs, mostly found in deep clefts between rocky walls, separated by vast expanses of desert. The water in each spring varies in temperature and salinity. Today, many of the springs are inhabited by a tiny fish called a pupfish. Each spring is home to a different species of pupfish that is adapted to that particular pool and found nowhere else in the world.

  35. SpeciationObjective 13 • Describe the reproductive barrier that has separated the various species of pupfish. • Use natural selection to explain how these various species of pupfish could have evolved from a single species. They are too far apart to mate with each other

  36. PhylogenyObjectives 4, 14 Phylogeny— An organism’s phylogeny can be diagramed using a phylogenetic tree. A phylogenetic tree is a branching diagram that shows evolutionary relationships. An organism’s evolutionary history

  37. PhylogenyObjectives 4, 14

  38. PhylogenyObjectives 4, 14 How is the phylogeny of an organism determined? Scientists classify organisms based on their similarities in ________, ______________, and _______________. DNA Anatomy Behavior

  39. PhylogenyObjectives 4, 14 Common Ancestor-- Diversity— A species from which 2 or more species separated The number of different species in an ecosystem

  40. PhylogenyObjectives 4, 14 Why is a more diverse ecosystem more stable? How can natural selection increase diversity? There is more than 1 organism to fill a role, so if one dies there is a “back up”. Example- an ecosystem with only one producer will fall apart if that species goes extinct Natural selection provides a way for new species to evolve which can raise diversity.

  41. Evidence of EvolutionObjectives 1-3, 5-6 1.Fossils- any evidence of an __________________ that lived long ago. Most fossils form in __________________ rock. This type of rock is formed when sediments ( ) form layers and are compressed together. Organic matter trapped between the layers decays slowly and a fossil is left behind. organism sedimentary Dirt and sand

  42. Evidence of EvolutionObjectives 1-3, 5-6 Examples: How do fossils show evidence of evolution? Whole bodies,shells, bones, waste They show us what species used to look like in the past.

  43. Evidence of EvolutionObjectives 1-3, 5-6 2. Biochemistry-- Nearly all organisms share _________, ATP, and many enzymes among their biochemical molecules The more closely related organisms are, the more similar their ________ (and therefore, ___________ __________) will be. DNA DNA Their Traits

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