Natural selection (2011)
Wednesday's Notes from Class...
Published on: Mar 3, 2016
Transcripts - Natural selection (2011)
Biological Evolution by Natural Selection Biology: Mr. McFadden 4-24-10 Write the Red
Population a localized group of individuals belonging to the same species Wildebeest
What is a species? Biological species concept (Mayr): a population or group of populations whose members have the potential to interbreed and produce viable, fertile offspring (genetic exchange is possible and that is genetically isolated from other populations)
Biological EvolutionWhat is needed:1. Genetic Variation: Differences that occur in a population between individuals. 3 Sources of Variation: Mutations are changes in the DNA. A single mutation can have a large effect, but in many cases, evolutionary change is based on the accumulation of many mutations. Gene flow is any movement of genes from one population to another. Sex can introduce new gene combinations into a population during meiosis & fertilization.
Variation in Phenotype Fig. 18-2a, p.285
Variation in Phenotype Fig. 18-2b, p.285
Variation in Phenotype Fig. 18-2c, p.285
Variation in Phenotype Fig. 18-2d, p.285
Variation in Phenotype Fig. 18-2e, p.285
Variation in Phenotype Variation can exist in: •Form, Shape, or Color •Speed, Intelligence, or Strength •Behavior or senses •Beak Size!!! •The possibilities are endless…
2. Heritability: Thisvariation can be passed tooffspring.
3. Fitness: some individuals are better able to survive and pass their genes to their offspring when they reproduce.
4. Natural Selection: Individuals that survive and reproduce (highest fitness) are those with the genes that are best adapted to their environment (adaptation).
Selective Pressures:o Environmental Change i. Temperature or Habitat Change ii. Earthquakes or Volcanoes
Selective Pressure Cont..Predation
Selective Pressure Cont..Limited Resources i. Food, Water, and/or Habitat
Review of Biological Evolution1. Variation2. Heritability3. Fitness4. Natural Selection
Review: Selective Pressures A pressure put on a species to survive such as an environmental change, predation, or limiting resources. Go to the following website to complete the Planet Earth Evolution “Mini Lesson” http://dsc.discovery.com/ convergence/planet-earth/video- player/video-player.html
Your Task Today Using your Notes and the Planet Earth Videos on Computers in the back, prepare a “mini-evolution” lesson to present to the class TODAY, with your video. 19