Evolutionary theory is a scientific explanation that describes how species of living organisms change over time through a process of descent with modification. This theory proposes that all living organisms share a common ancestry and that the diversity of life arises from gradual changes and adaptations that accumulate over generations.
Key figures involved in the research of evolutionary theory include Charles Darwin and Alfred Russel Wallace. In the mid-19th century, Charles Darwin proposed the concept of natural selection, which suggests that organisms with advantageous traits are more likely to survive and reproduce, passing those traits to their offspring. This leads to the gradual accumulation of favorable traits in a population over time.
General findings of evolutionary research include:
Common Ancestry: The idea that all living organisms share a common ancestor and have evolved divergently from it over millions of years.
Adaptation: Organisms are well-suited to their environments due to natural selection favoring traits that enhance survival and reproduction.
Fossil Record: Fossils provide evidence of past life forms and their transitional stages, offering insights into the history of life on Earth.
Homology: Similarities in structure and function of different species' body parts (homologous structures) suggest shared ancestry.
Embryology: Similarities in embryonic development patterns among different species point to common evolutionary origins.
Biogeography: Distribution patterns of species around the world provide insights into migration and evolution.
Evolution is considered a theory rather than a law because of the way scientific terminology is used. In science, a "law" generally describes a consistently observed phenomenon, often expressed through mathematical equations, like Newton's Law of Gravity. A "theory," on the other hand, is a comprehensive explanation that encompasses a broad range of observations, facts, and hypotheses. The term "theory" doesn't imply uncertainty; instead, it reflects the highest level of understanding that science aims to achieve. Evolutionary theory has been supported by an immense body of evidence from various fields of biology, paleontology, genetics, and more, making it one of the most well-substantiated and widely accepted scientific explanations.