Download Evidence of Evolution and more Cheat Sheet Biology in PDF only on Docsity! Evolution is defined as a change in the allele frequency in a population gene pool over successive generations. Evolution is a Darwinian concept as it was first discovered by the naturalist Charles Darwin. This theory was first developed in Darwin's book “On the Origin of Species”. He suggested that species evolve over time and so do their heritable and/or behavioral traits. These changes help an organism better adapt to its environment so it can survive for longer, and also have many offspring. The evidence for this evolution can be observed in various areas of biology. The anatomical/ embryological, molecular biological, direct observational and archaeological sources of evidence will be the main focus. 1. Anatomical evidence: This source observes the physical similarities in species to uncover a common ancestor. Physical features that species share due to a common ancestor (aka evolutionary history) is a homologous similarity. Some homologous characteristics can only be observed in embryos. For example, the embryos of all vertebrates have a tail and slits for gills during their early stages of development. However, over their stages of growth, this structures evolve to form distinctive features of each respective species. For instance, in humans, the tail becomes the tailbone and the gill slits transform into our jaws and inner ear. Some structures are present in the embryos but they continue to develop for some species and in others, they remain underdeveloped if there is no use for it. These are called vestigial structures and are considered to be evolutionary “leftovers”. The tailbone in humans in an example of such a structure, and so are the hind legs in whales. 2. Molecular biological evidence: On a molecular scale, differences and similarities in DNA of different species can be observed in order to link them to a common ancestor. At a simplified level, all living organisms share four basic similarities: i. they share the same genetic material i.e. DNA ii. they share very similar genetic codes as well iii. the genetic processes in these organisms, such as translation and transcription are common
