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What scientific evidence supports the theory of evolution?

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A vertical geologic time scale chart spanning from 650 million years ago to the present, with colored bands for each era and period. Illustrations and labels highlight key evolutionary events such as the appearance of skeletal elements, first fishes, land plants, amphibians, reptiles, dinosaurs, mammals, and humans. — evolution The geologic time scale from 650 million years ago to the present, showing major evolutionary events.

The theory of evolution is supported by a wealth of scientific evidence from various fields.

Comparative Anatomy

Similarities in the body structures of different species, known as homologies, suggest a common ancestry. For example, the forelimbs of humans, birds, bats, and dolphins share a basic bone structure inherited from a common ancestor, despite their different functions.12

Molecular Biology

The study of DNA and proteins reveals a remarkable uniformity across all living organisms. The genetic code and the basic building blocks of proteins (amino acids) are nearly universal, indicating a shared evolutionary origin. The degree of similarity in DNA sequences between species directly correlates with their evolutionary relatedness.34

Fossil Record

The fossil record documents the history of life on Earth, showing progressive changes in organisms over geological time. Fossils provide evidence of extinct species and transitional forms, illustrating evolutionary lineages and adaptations to changing environments.56

Biogeography

The geographic distribution of species across the globe also supports evolution. Similar species found in geographically close regions, or species on islands resembling those on the nearest mainland, suggest common ancestry and dispersal over time.78