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Biology Presentation

Transcript: A structure, behavior, or physiological process that helps an organism survive and reproduce in a particular environment. A gene mutation refers to a change in nucleotide sequence of a specific gene. Change in single base of a gene sequence The hat drank the milk Silent Mutations Synonymous mutation Deletions can involve either the loss of a single base or the loss of a larger portion of DNA All depends on environmental conditions. Envision a population of beetles... Variation in phenotypes. One trait is preferred by the predator, creating differential reproduction. Heredity Final outcome? What if they mate at a rate different than the occurence of that genotype in the population? Jean Baptiste Lamarck Acquired characteristics could be transmitted from one generation to the next. All of the resulting mice had tails. Only direct mutation in DNA of gametes. Modern evidence- Epigenetics Columbia University Medical Center Roundworms that developed resistance to a virus passed on this trait to future generations. Via viral silencing RNA's working independently of the genome. Mice were given mental stimulation at a young from a young age. Improved memory capacity. Passed it on to their offspring after returning to normal conditions. The use of warning coloration to advertise that a prey is dangerous or unpalatable Predators quickly learn to aviod the prey once they have unpleasent experiences The prey is now easily identifiable Advertises to potential predators The ability of an organism to avoid detection Fritz Muller Nymphalidae limentis Unpalatable to predators Mimic developed due to supergene Mimicry works due to population numbers Henry Bates Female-limited polymorphic mimicry 11 alleles Mimicry gene- H Models vary, but they are most commonly distasteful species of Danaidae and Acraeidae Regulatory gene hypothesis Controls the expression of several unlinked genes Supergene hypothesis Mimicry gene is actually a tightly linked cluster of genes Genes with related functions for pattern are located close together on the chromosome Imitates cypress pine tree Example of crypsis Gene Flow African Swallowtail Methyl groups (CH3) attach themselves to specific parts of DNA molecules. Translocation Genetic Drift vs. Environmental factors Aposematism Hybridization- exchange of genes between species Genetic Mutations German biologist August Weismann disproved it by cutting the tails off of a population of mice. Duplication Poison Dart Frog HOW DO ADAPTATIONS DEVELOP? Dendrobates pumilio Dendrobates leucomelas Missence Mutations Deletion Crypsis Slight chemical modifications in DNA and DNA- associated proteins Auditory clicks Natural Selection Completely Random Mimicry Viceroy Butterfly Non-Random Mating Dendrobates auratus Point Mutation The cat drank the milk Nonsense Mutations Dendrobates tinctorus Titan Stick Insect Inversion Coral snake Occurs during cross-over phase of meiosis Batesian Lamarckism Mullerian

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