BIOL 4253 E1 Notes.docx - Lecture 1 Describe ecology Ecology affects two important things Distribution and abundance of organisms Animals might avoid

BIOL 4253 E1 Notes.docx - Lecture 1 Describe ecology...

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Lecture 1: Describe ecology. Ecology affects two important things. Distribution and abundance of organisms. Animals might avoid areas where their kind are abundant. o Organismal: The way organisms cope with their environment. Minimize loss of heat or loss of water. o Population: Group of individuals of a single species that occur at the same time at the same place. Must have potential to breed and interact with each other. o Community: Collection of species that occur at the same time and same place. These species must have potential to interact with each other. Ex. Compete for water resources. o Ecosystem: Community plus abiotic and biotic environment. Ex. Organism plus water, air and soil. It’s them plus the resources they interact and exchange with. o Landscape: A collection of ecosystems. Ex. Agroecosystem o Biosphere: The whole earth ecosystem. READING – Natural selection in the wild. Before exam Evolution: A genetic change in a trait over successive generations. OR A change in gene frequency in a population through time. What Causes Evolution? o Natural Selection o Artificial Selection o Genetic Drif o Founder Events o Emigration o Immigration Evolution of Horses are an example of Adaptive evolution o Adaptive Evolution: evolutions change that leads to increases fitness. o Fitness is measure of your contribution to the next generation. o Increase in body size is advantageous for competition or escape, access of resources. o What causes adaptive evolution? Natural Selection. Natural Selection: Differential survivorship or reproduction of phenotypes. o 2 Requirements: Phenotypic variation (Body size) (Snails: different shapes, colors, sizes) Differential survival/reproduction (Body size – higher fitness) o If Natural Selection occurs does that mean evolution has occurred? NO Goldenrods are genetically identical. Experiment with identical plants and fertilize one and not the other. You will get different phenotypes. Fertilized plants will produce more flowers. This meets requirements for Natural Selection. However, there has been no evolution! This has nothing to do with genetics, they were environmentally induced. Directional Natural Selection: Pushes a phenotype to one extreme or the other. Ex. Horses: Act against small individuals. Shifs phenotype to larger phenotype. Ex. Cheetah:
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Act against large individuals. Shif phenotype to smaller phenotype. Ex. Peppered moth: Act against peppered color. Shif phenotype to black color. Lecture 2 Directional Natural Selection is the most common type of natural selection. It favors in one side of the phenotype. o Guppies: number of spots is genetically based. John Endler did an experiment to see if the spot number would evolve. Results are in the slides. Over time the spot number increased. Females prefer males with lots of spots. This is a result of sexual selection.
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