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| Question | Answer |
| Name 4 of Darwin's observations | 1. Organisms produce more offspring than survive 2. There is variation in the characteristics of members of the same species 3. Some of these characteristics can be passed on from one generation to the next 4. Individuals that are best adapted to their environment are more likely to survive |
| Outline Darwin's theory of natural selection | 1. Individuals within a population show variation in their phenotypes 2. Selection pressures (environmental factors such as predation, disease and competition) create a struggle for survival 3. Individuals with better adaptations are more likely to survive and have reproductive success - they reproduce and pass on their advantageous adaptations to their offspring 4. Over time, the proportion of the population possessing the advantageous adaptations increases 5. Over generations, this leads to evolution as the favourable adaptations become more common in the population |
| Alfred Russel Wallace, a scientist working at the same time as Darwin, played an important part in developing the theory of evolution by natural selection. What did he do? | He independently came up with the idea of natural selection and wrote to Darwin about it. He provided lots of evidence, e.g... He realised that warning colours are used by some species to deter predators from eating them |
| Why is Darwin usually better remembered than Wallace? | Darwin published his famous book 'On the Origin of Species', making other scientists pay attention to the theory |
| Name the 3 types of evidence used to support evolution | Fossil record evidence Molecular evidence (DNA) Molecular evidence (proteins and other molecules) |
| How do fossil records provide evidence for natural selection? | By arranging fossil in chronological order, gradual changes in organisms can be observed. E.g. the fossil record of the horse shows a gradual change in characteristics (including increasing size, lengthening of limbs and hoof development) |
| How does DNA provide evidence for natural selection? | Evolution is caused by gradual changes in the base sequence of organisms' DNA. So, organisms that diverged away from each other more recently should have more similar DNA. E.g. in eukaryotes, most DNA is found in the cell nucleus. They also have DNA in their mitochondria |
| How do proteins and other molecules provide evidence for natural selection? | Scientists compare the sequence of amino acids in proteins, and compare antibodies |
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