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Fossil Evidence
Fossil Evidence
If one looks at the fossil record, it is clear that simple life forms gradually evolved into more complex ones. Here you can see the skeleton of a horse and its predecessors.
Anatomical Evidence
Anatomical Evidence
These species above all have the same initial structure, but they have evolved to uses each structure differently. Different species share similar physical features or homologous structures.
The wing of a bird and the forelimb of a human are homologous.
These features were present in a common ancestor.
Homologous Structures = Common Ancestry
Embryological Evidence
Embryological Evidence
Embryology is the study of embryos. Darwin noticed that the similar structures found in different embryo species show how they share the same genetic information. For example, fish embryos and human embryos both have gill slits. In fish, the slits develop into gills, but in humans they disappear.
The greater the similarity in structure, the more closely related the species are and the more recent their common ancestor is. This shows that animals are similar and develop in a similar manner. It implies that we have common ancestors. We evolved differently over time but we all started out the same.
Biochemical Evidence
Biochemical Evidence
In the diagram above, scientists have investigated the chemical differences between the species. Gorillas and humans have only one amino acid difference, thus, we are very closely related. We are less related to frogs because there are 67 amino acid differences.
All life shares the same genetic material, DNA. Our DNA is 99.9% the same as your friend. The percentage of genes or DNA that organisms share records their similarities. We share more genes with organisms that are more closely related to us. For example, humans and chimpanzees are 96% genetically the same.
Cats and humans are 90% the same. Humans and mice are 85% the same. Cows share 80% of genetics.
Fruitflies share 61%.
Chickens share 60% of our DNA. So do bananas.
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