Kategoriak: All - mutation - natural selection - genetics - adaptation

arabera yasmine sabri 17 years ago

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Mechanisms of Evolution

The process of evolution encompasses several mechanisms that contribute to the diversity and complexity of life on Earth. Adaptation through natural selection allows organisms to become well-suited to their environments, while vestigial structures serve as evidence of non-adaptive traits.

Mechanisms of Evolution

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