Introduction to Evolution

Evolution is the change in the characteristics of a species over several generations. In this section, we will cover:

Evidence for Evolution

There are several types of evidence that support the theory of evolution:

• Fossil record: Shows how species have changed over time
• Comparative anatomy: Similarities between species suggest common ancestry
• Embryology: Similarities in embryonic development across species
• Molecular biology: DNA and protein similarities between species

Mechanisms of Evolution

The two main mechanisms of evolution are:

1. Natural selection: Organisms with traits that are advantageous for survival and reproduction are more likely to pass on their genes to the next generation.
2. Genetic drift: Random changes in allele frequencies, more pronounced in small populations.

Speciation

Speciation is the formation of new species. It occurs when populations of a species become reproductively isolated from each other and diverge genetically over time. Speciation can be allopatric (due to geographic isolation) or sympatric (occurring in the same geographic area).

Evolutionary History and Phylogeny

Evolutionary history refers to the relationships between species and how they have evolved over time. These relationships are often represented using phylogenetic trees, which show the ancestry and divergence of species based on shared derived characteristics.