Mechanisms of Evolution

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Mechanisms of Evolution

Religion and science are very different things

In religion, beleifs are beyond the natural world

In science only natural causes are used to explain natural phenomena

Causes of mutations

External influences. e.g. exposure to specific chemicals or radiation

DNA fails to copy accurately

Evolution is not a ladder of progress

Adaptation

Non-adaptation: Vestigial structures

Well fitted to thei function and produced by natural selection

Feature common in populations that provides improved functions

Evolution is both observable and testable

Genetic mutation

Artifical seletion in laborotary

Study of living species , e.g Darwin's finches

Fossil record

Biological Evolution

Large-scale:desent of different species from one common ancestor over generations

Small-scale:changes in gene frequency from one generation to another

Descent with modification

Life on earth shares a common ancestor

Natural Selection

Continuation for the best adaptest

Heredity

Differential reproduction

Variation in traits

Sources of Genetic variation

Sex

Can intoduce new gene combinations into populations

Gene Flow

Movement of genes from one population to another

Mutations

Evoultion is based n the accumlation of many mutations

Is change in DNA

Artifical Selection

People instead of nature select organisms to reproduce

Farmers and Breeders

Evoultion in the farm stock

Plants and animals with desirable characterisics to reproduce