Flashcards
Natural selection
Cards in this deck (16)
- 1Who wrote his theory of natural selection 150 years ago?Over 150 years ago Charles Darwin wrote his theory of natural selection.
- 2What did this theory explain?Over 150 years ago Charles Darwin wrote his theory of natural selection to explain how evolution might happen.
- 3What does this theory say?It says that if animals and plants are better adapted to their environment, they and the following generations are more likely to survive.
- 4He did not know exactly how adaptations were passed on. We now know that when organisms reproduce, their genes are passed on to the next generation. How can the modern version of natural selection be summarised?The modern version of natural selection can be summarised like this:
- Within any species there is variation.
- Organisms produce far more young than will survive, so there is competition for limited resources such as food.
- Only those best adapted will survive, which is called survival of the fittest.
- Those that survive pass on successful adaptations to the next generation in their genes. - 5Over time, the changes produced by natural selection may result in a new species. Only when can this happen?This only happens if different groups of organisms cannot mate for a long time.
- 6Why might organisms be prevented from mating?The organisms may be prevented from mating because they live in different areas.
- 7What is this?This is geographical isolation.
- 8How else may organisms also be prevented from mating?They might be prevented from mating because of behavioural isolation.
- 9If each group evolves differently over time what could happen?If each group evolves differently they might over time become different enough to be classified as separate species.
- 10Why is natural selection difficult to study?Natural selection is difficult to study because it usually takes thousands of years to see the effect.
- 11Some examples have been studied over shorter time spans. Give two examples of this.- More and more bacteria are developing resistance to antibiotics.
- Peppered moths are dark or pale in colour. Dark moths are better camouflaged in polluted areas, so more of them survive. - 12Why at first did many people disagree with Darwin's ideas?At first many people disagreed with Darwin's ideas:
- Some people thought he did not have enough evidence to back up his theory.
- Many people disagreed because they thought God had created all species. - 13Why now is Darwin's theory much more widely accepted?Now Darwin's theory is much more widely accepted. This is because:
- it explains a lot of observations
- it has been discussed and tested by a wide range of scientists - 14There have been other attempts to explain evolution. Before Darwin, Jean Baptiste de Lamarck had a different theory. What was this called?Called the law of acquired characteristics.
- 15What did this theory say?This said, for example, that giraffes acquired long necks to feed, and this characteristic was passed on.
- 16What have we discovered more about so that theories like Lamarck's have been proved incorrect and Darwin's theory has become more widely accepted?As we have discovered more about how genes are passed on, theories like Lamarck's have been proved incorrect and Darwin's theory has become more widely accepted.
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- GCSE Science Year 10 Flashcards on Natural selection, created by annjb2898 on 27/05/2014.
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