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Chapter 5: Evolution and Community Ecology

Chapter 5: Evolution and Community Ecology. Mr. Manskopf Notes Can Also Be Found at http://www.manskopf.com. Section 1: Evolution. Describe the four primary mechanisms of biological evolution Describe how speciation and extinction affect the diversity of life on Earth.

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Chapter 5: Evolution and Community Ecology

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  1. Chapter 5: Evolution and Community Ecology Mr. Manskopf Notes Can Also Be Found at http://www.manskopf.com

  2. Section 1: Evolution • Describe the four primary mechanisms of biological evolution • Describe how speciation and extinction affect the diversity of life on Earth. • TERMS: evolution, gene mutation, genetic drift, natural selection, fitness, adaptation, artificial selection, speciation, extinction.

  3. Incredible Diversity of Life • 1.5 to 1.8 million known species • Possibly 13-20 million • Tropical Rain Forests, Coral Reefs and everywhere else

  4. Evolution • What makes you, YOU? What makes each species unique and different?

  5. Genes • Sequences of DNA codes for each particular trait • Tall, small, blue eyes, human, goldfish, pine tree • Evolution is a change of genes over time

  6. Evolution • “Change over time” • Change of Gene Pool over time • Why would genes change over time?

  7. 4 Ways Evolution Occurs • Mutation • Migration • Genetic Drift • Natural Selection

  8. Mutation Accidental change in DNA that can give rise to variation among individuals

  9. Migration Movement of individuals into (immigration) or out of (emigration) a population Sometimes called “Gene Flow”

  10. Gene Flow (Migration)

  11. Genetic Drift • Evolution that occurs by chance • Natural Disasters • Run in with human nets, etc.

  12. Natural Selection • Process by which traits useful for survival and reproduction are passed on more frequently than those that are not

  13. 3 Conditions for Natural Selection • Organisms produce more offspring than can survive. • Nature has limitations (limiting factors) • Struggle for survival

  14. 3 Conditions for Natural Selection (2) Individuals vary in characteristics, some of which are heritable • Not every species is same • Some fish are faster, darker, smaller • Genes different • Heritable Differences

  15. 3 Conditions for Natural Selection (3) Individuals vary in fitness, or reproductive success • Survival of Fittest • Fittest for its environment • Adaptation: an inherited trait that increases an organisms chance of survival and reproduction.

  16. http://www.youtube.com/watch?v=xkwRTIKXaxg • Travel to Ecuador to see how the process of natural selection operates

  17. Adaptations Desert plants have small or no leaves at all The insect that blends in and is able to survive may be more likely to reproduce.

  18. White coat of polar bear helps in hunting Results of natural selection all around us NATURE SELECTS Adaptations Big ears of desert jack rabbit allow it to cool off quickly Long neck of giraffe allow it to reach food

  19. Did You Know?Darwin privately researched natural selection for two decades before publishing On the Origin of Species.

  20. Impacts of Natural Selection: Resistance

  21. Resistance Resistance: the ability of one or more organisms to tolerate a chemical designed to kill it • Able to survive and reproduce • Pesticide resistance • Antibiotic resistance

  22. Why is this a problem?

  23. Artificial Selection: How Humans Use Evolution Artificial Selection: selective breeding of organisms by humans • Selecting certain desirable traits • Size, sweetness, color, shape, • Very common

  24. Artificial Selection

  25. Artificial Selection Selecting desirable traits and breeding only those with those traits.

  26. Speciation: How did we get millions of species?

  27. Speciation • Process by which new species are generated • Can occur in a number of different ways; the most important way is called allopatric speciation– Geographic Isolation • Has resulted in every form of life on Earth— today and in the past

  28. The canyon is a barrier to dispersal by small mammals, and as a consequence the isolated populations can diverge.

  29. http://www.youtube.com/watch?v=S4wnJp6sq_I

  30. Extinction • The disappearance of species from Earth • Generally occurs gradually, one species at a time, when environmental conditions change more rapidly than the species can adapt • There are five known mass extinction events, each of which wiped out a large proportion of Earth’s species.

  31. Biodiversity has increased over time, but mass extinctions are also natural events (5 major events) How do we get this data? Did You Know?During the Permo-Triassic extinction 250 million years ago, 70% of all land species and 90% of all marine species went extinct.

  32. Extinctions • Species gone forever • NORMAL • Mass Extinction: short period of time when large number of species go extinct (65 MYA) • Currently in mass extinction…caused by humans • Rapid climate change

  33. Extinctions The zebra mussel has completely displaced 20 native mussel species in Lake St. Clair.

  34. Section 1: Evolution Review • Describe the four primary mechanisms of biological evolution • Describe how speciation and extinction affect the diversity of life on Earth. • TERMS: evolution, gene mutation, genetic drift, natural selection, fitness, adaptation, artificial selection, speciation, extinction

  35. Section 1 Quiz A. A successful individual possesses traits that are different from the traits of the rest of the population. 1) Which of the following best describes a successful individual in evolutionary terms? A. A successful individual possesses traits that are different from the traits of the rest of the population. B. A successful individual produces many offspring that possess unique traits. C. A successful individual is well adapted to its environment and produces offspring that survive to pass on genes. D. A successful individual will be well adapted to its environment and produce a few high quality offspring.

  36. 2) In the history of the world, how many mass extinctions have occurred?A. 5B. 7C. 10D. 13 A. 5

  37. 3) In a mass extinction, the rate of extinction exceedsA. 99 percent.B. 85 percent.C. the rate of environmental change.D. the rate of background extinction. D. the rate of background extinction

  38. 4) A reintroduced population of wolves in a national park is 90% grey and 10% black, consistent with the wolf population in other regions. After several generations in isolation, the national park’s wolf population is 60% grey and 40% black. The wolf population has likely experiencedA. natural selection.B. genetic drift.C. mutations.D. migration. • genetic drift • Evolution that occurs by chance

  39. 5) When the environment changes too quickly for an organism to adapt, what will occur?A) EvolutionB) SpeciationC) Genetic DriftD) Extinction D. Extinction

  40. True or False 6) Two populations of a deer species are separated when a glacier forms. After the glacier melts, the two populations have become different species. This is an example of allopatric speciation. TRUE

  41. Short Answer 7) A disaster wipes out 50 percent of a small population of birds. Prior to the disaster, about half the birds had a green wing patch and half had a blue wing patch. Several generations after the disaster, only 10% have a blue wing patch, and 90% have a green wing patch. What do you infer happened, and why? The bird population experienced genetic drift as the result of a sudden catastrophe. The disaster reduced genetic diversity in the population and changed the proportion of birds with a green wing patch vs. a blue wing patch.

  42. Short Answer 8) Pronghorn are a species of extremely fast hooved mammal that live on the plains of western North America. They are so fast that no current North American predator can catch them. During the ice age, cheetahs occupied North America. Speculate about how pronghorn became so fast. Pronghorn probably evolved in an evolutionary “arms race” with the cheetah population. They became faster and faster to escape from cheetahs, which were probably fast enough to catch them.

  43. Section 2: Species Interaction • Discuss the factors that influence an organisms niche • Compare and contrast predation, parasitism, herbivory • Describe mutualism and commensalism • TERMS: niche, tolerance, resource partitioning, predation, coevolution, parasitism, symbiosis, herbivory, mutualism, commensalism.

  44. Species Interaction What resources are the plants in this picture competing for? Competition for resources all around us

  45. Niche • Describes an organism’s use of resources and functional role in a community • Habitat • Food It Eats • When, How Reproduces • What organisms does it interact with

  46. Niche Impacted By Tolerance and Competition • Affected by an organism’s tolerance—its ability to survive and reproduce under changing environmental conditions • Often restricted by competition

  47. Tolerance Limits

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