þróunarkenning

Evolutionary theory, or þróunarkenning in Icelandic, is the scientific explanation for how life on Earth has changed over vast periods of time. It posits that all living organisms share common ancestors and have diversified through a process of gradual change. The central mechanism driving this change is natural selection, first extensively described by Charles Darwin and Alfred Russel Wallace. Natural selection suggests that individuals within a population vary in their heritable traits. Those with traits that are better suited to their environment are more likely to survive and reproduce, passing those advantageous traits to their offspring. Over generations, this leads to an accumulation of beneficial adaptations, eventually resulting in the emergence of new species.

Modern evolutionary theory, often referred to as the modern synthesis, integrates Darwin's ideas with discoveries in genetics, paleontology, and other biological fields. Genetics provides the understanding of how traits are inherited through DNA and how variations arise through mutations. The fossil record offers evidence of past life forms and demonstrates the transitions between different organisms over geological time. Evolutionary theory is a cornerstone of modern biology, providing a unifying framework for understanding the diversity of life, its history, and its interconnectedness. It is supported by a vast and consistent body of evidence from numerous scientific disciplines.