Evolution Evolution The process of change over time

Evolution

Evolution • The process of change over time.

Darwin's Theory was an English naturalist, geologist and biologist, best known for his contributions to the science of evolution. He made three important observations about evolution on his travel on the HMS Beagel in 1831 1. The world includes a tremendous diversity of living things throughout a wide range of habitats. 2. Animal species, like those in the Galapagos islands. That are related, can have different habitats in the same area. 3. Fossils or preserved remains of ancient organisms, resembled many organisms alive today.

Darwin's Theory Darwin observations led him to develop the scientific theory of evolution which explains how modern organisms evolved over long periods of time by natural selection.

Darwin's Theory Adaptation – a trait that helps an organism survive and reproduce. Example: you move to a colder location at first it seems really cold to you but eventually your body gets use to the change in temperatures.

Darwin's Theory Natural selection- process by which individuals that are better adapted to their environment are more likely to survive and reproduce than other members of the same species.

An example of natural selection How many blue circles do you see?

An example of natural selection How many blue circles do you see?

Darwin's Theory Factors that affect process of natural selection: Overpopulation- species produce more offspring than can survive. .

Darwin's Theory Factors that affect process of natural selection: Variation- difference between individuals.

Darwin's Theory Factors that affect process of natural selection: Competition- resources are limited species must compete to survive.

Evolution of populations Three sources of genetic variation: Mutations- Change in genetic material of a cell. Genetic Recombination- during sexual reproduction each chromosome in a pair moves independently during meiosis. In humans this can produce over 8, 000, 000 gene combinations. Lateral gene transfer- passing of genes from one organism to another.

Evolution of populations Gene pool- consists of all genes. Including all the different alleles, that are present in a population. Hardy Weinberg principle- states that allele frequencies will remain constant, or have genetic equilibrium, unless factors cause those frequencies to change.

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