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Transcript of Evolution
-He had a 5 year voyage around the world on the HMS Beagle.
-He was interested in the Pacific Islands, Galapagos Islands, and South America.
-Over his trip, he collected natural specimens like birds, fossils, and plants.
-He wrote things down in his journal during his trip. Natural Selection -He developed a theory that talked about creation of man and that all species derived from common ancestries through natural selection. Darwin's Theory of Evolution -Population are about the same size.
-Most Variation is inherited.
-Food sources are limited.
-Species have great fertility. More off Spring. How Do We Know Evolution Occurred? -Fossils record of change over time.
-Record genetic changes in living organisms.
-Some People have a hard time believing in evolution because of their religious beliefs. Fossil Record 4 types of evolution: Population -Group of organisms that belong to the same species and live in particular place at the same time.
-Population: Number of individual that the population contains. -All species reproduce and survive , passing genetic information of the species from generation to the next.
-They produce more offspring than the environment can support.
-Some will not survive.
-Those Organisms who were more suitable for the environment, were likely to survive.
-Survival of the fittest.
-Main mechanism for evolution. Principles -variations in alleles of genes, occurs in both within the populations.
-it provides the genetic material for natural selection.
-its brought by a mutation, which is a permanent change in the chemical structures of the genes. Genetic Variation -Variation: there is a variation in every population.
-Competition: organisms compete for limited resources.
-Offspring: organisms produce more offspring than can survive.
-Genetics: organisms pass genetic trait on to their offspring.
-Natural Selection: organisms with more beneficial traits are more likely to survive and reproduce. Summarizing 1.) Fossil record
2.) Contemporary homologies
3.) geographical distribution of species 3 kinds of evidence -Remains of plants and animals were found in sedimentary rocks.
-He found that there was some missing links for evolution.
-Some of the gaps were between small dinosaurs and birds.
-2 years after he published his book, a old fossil of the Archaeopteryx was found in Southern Germany. -It is anatomical structures in one species that compared to other anatomical structures in another species, originated from a single anatomical structure in a common ancestor of two species.
1. Analogous: performs same function.
2. Homologous: body parts that are alike because they share the same common ancestor. Homologous Structures 1. Divergent Evolution: involves one species that eventually separates into 2 separate species(example: what once upon a time one species separated into 2).
2. Convergent Evolution: explains 2 or more species that develop similar traits in separate types of environments.
3. Microevolution: change in genetic frequency within a population.
4. Macroevolution: evolution on a scale of separated gene pools. Common Descent -the scientific theory that all living organisms on earth is descended from a common ancestor.
-Darwin used phrase descent with modification to describes the process of evolution. Selection Stabilizing selection: Individuals with the average form of a trait have the highest fitness.
Disruptive Selection: Individual with either extreme variation of a trait have greater fitness than individuals with average form of trait.
Directional Selection: Individuals that display a more extreme form of trait have a greater fitness than individuals with average form of trait.
-Darwin wrote a book a year after he visited London call "The Origin of Species by Mean of Natural Selection."
- 2 Goals from his book:
1.)Wanted to present the large amount of evidence that evolution occurs.
2.)Wanted to explain the variety and distribution of organisms on earth in terms of natural process that are observable every day. Darwin's Book Types of Mating
-Nonrandom Mating: Mating that has not occurred due to chance . (arrange Marriage)
-Random Mating: population mating system in which every female Gamete has an equal opportunity ti be fertilized by every male gamete. 2 Forms of Nonrandom Mating 1.) Interbreeding- Occurs when individuals with similar genotypes are more likely to mate with each other rather than individuals with different genotypes.
2.) Outbreeding- Increases probability that individuals with particular genotypes genotypes with individuals of another genotype. Competition Competition between organisms and animals for survival.
Ex: Predation by bird largerly drives the coevolution of model and mimetic butterflies.