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14 Cards in this Set
- Front
- Back
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What is adaption |
The process by which an organism or species become better suited to its environment |
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What is variation? |
Is a difference between cells, individual organisms, or groups of organisms of any species caused either by genetic differences (genotype variation) or by the effect of environmental factors on the expression of the genetic potentials (phenotype variation) |
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Natural selection |
Is survival of the fitest according to Darwins theory |
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Process of natural selection |
1. There is variation between organisms 2. The number of natural populations remain fairly constant even though they reproduce in far greater numbers. 3. There is struggle for survival. 4. Some variations help organisms survive. Organisms with less favourable characteristics die out. 5. The variations with survival value passed on to the following generations, so over millions of years species become better adapted to their environment. |
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Selection pressures |
- competition (food, water, mates, territory) -climate -predation -disease |
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Problems because of artificial selection |
-reduces variation -more susceptible to disease -less able to reproduce on its own |
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Evidence of evolution |
Fossil fuel record- a fossil can form if the dead body of animal or plant is quickly covered by sediment |
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Embryo comparisons |
Presents the changes evolving and changing from the past. |
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DNA comparisons |
Extracts DNA from cells and compare the genetics information of two organisms. This can show the difference between two organisms |
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Gene pool |
All the different genes in a group of organisms. |
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Geographical isolation |
Population of animals, plants or other organisms that are separated from exchanging genetic material. |
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Comparative anatomy |
The arangement and order of bones, and the shapes and sizes of organisms, are compared to one another |
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Darwins theory: |
-an organism can develop further or degenerate only due to continuous variations. -struggle for existence is very important -only useful variations are trasferred to the next generation. -based on survival of the fittest. |
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Lamarcks theory |
-considers new needs or desire produce new structures and change habits of the organism. -an organism is constantly used it would be better developed whereas disuse of organ results in its degeneration -does not require struggle for existence. - all the acquired characters are inherited to the next generation. |
