Investigate, using secondary sources, evidence in support of Darwin and Wallace’s Theory of Evolution by Natural Selection, including but not limited to:
- Biochemical evidence, comparative anatomy, comparative embryology, biogeography
- Techniques used to date fossils and the evidence produced
The theory of evolution by natural selection, as with all theories in science, requires evidence to support it. Some of the evidence for evolution includes Biochemical evidence, comparative anatomy, comparative embryology, bio-geography as well as fossil dating methods.
Darwin/Wallaces theory for evolution stipulates the most suited individuals in a species will be selected by the selective pressures created by change in the environment. The following techniques provide evidence for this theory.
Biochemical evidence, what do all living things have in common? Biochemical instructions which contain the blue print for assembling it. This is in the form of RNA or DNA. This acts as evidence for evolution since it is common for all species suggesting everything emerged from a common species.
Comparative anatomy, this looks at the similarities between the structural features of organisms between different species. The pentedactil limb is an example of this. The flipper of a whale, a human hand and a horse’s front leg all have the same pentedactil bone structure acting as evidence for evolution.
comparative embryology, this looks at how embryos from different animals look identical in the early stages.
Bio-geography, this can look at the fossil and current distribution of animals and plants allowing scientists to piece together an image of where animals where before the super continent broke up. This also shows links between species which have diver-gently evolved due to this, further demonstrating evolution.
Fossil dating, this uses techniques such as carbon dating which is used to determine the age of the sample and applying them to fossils. By determining the age of the fossil, scientists can piece together a timeline of evolutionary changes hence allowing us to determine the tree of life. This is known as absolute fossil dating. This links everything back to one species hence demonstrating the theory of evolution.
Relative fossil dating assumes that the fossil which is deepest in the ground is older then the more shallow fossils. Since they die and dirt is deposited on top of them, this makes sense logically. This method, however, may have possible errors and can only compare fossils found in same regions.
A transitional fossil is kind of an in between fossil. It is like the evolutionary stepping stone between two species acting as evidence for evolution.
- Biochemical evidence e.g DNA can be found in most cells
- Comparative anatomy e.g pentedactil limb
- Comparative embryology e.g Most animals (humans through to fish) embryo initially looks identical
- Bio-geography e.g patagia geographical spread of
- Fossil dating e.g carbon dating fossils and finding sequential evolution
Provide an example for each of these types of evidence for evolution. [ Not an exam style question]
- Biochemical evidence
- Comparative anatomy
- Comparative embryology
- Fossil dating
Using the example of pentadactyl limb link the evolutionary relationships between horses, humans and whales. [3 marks]
With three different types of evidence, evaluate whether the model for evolution by natural selection fits the evidence. [6 marks]