Question

Why are fossils considered as a major evidences of evolution? What is genetic
drift and how it is responsible for speciation? How it is different from
geographical isolation?​

Answer 1

Answer:

Explanation:

Fossils are the preserved remains or traces of animals, plants, and other organisms from the past. Fossils are important evidence for evolution because they show that life on earth was once different from life found on earth today.

Genetic drift - drastic change in the frequency of particular genes and the prevention of gene flow between the different populations is also taken into account. Here mutations also plays an important role to create sudden shift in gene frequencies

Geographic isolation is known to contribute to divergent evolution, resulting in unique phenotypes. Oftentimes morphologically distinct populations are found to be interfertile while reproductive isolation is found to exist within nominal morphological species revealing the existence of cryptic species. These disparities can be difficult to predict or explain especially when they do not reflect an inferred history of common ancestry which suggests that environmental factors affect the nature of ecological divergence. A series of laboratory experiments and observational studies were used to address what role biogeographic factors may play in the ecological divergence of Hyalella amphipods. It was found that geographic isolation plays a key role in the evolution of reproductive isolation and divergent morphology and that divergence cannot be explained by molecular genetic variation