EVERYDAY SCIENCE

Detailed explanation-1: -Darwin thought of evolution as “descent with modification, ” a process in which species change and give rise to new species over many generations. He proposed that the evolutionary history of life forms a branching tree with many levels, in which all species can be traced back to an ancient common ancestor.

Detailed explanation-2: -In the 1850s, Darwin wrote an influential and controversial book called On the Origin of Species. In it, he proposed that species evolve (or, as he put it, undergo “descent with modification"), and that all living things can trace their descent to a common ancestor.

Detailed explanation-3: -Universal common ancestry (UCA) is a central pillar of modern evolutionary theory. As first suggested by Darwin, the theory of UCA posits that all extant terrestrial organisms share a common genetic heritage, each being the genealogical descendant of a single species from the distant past.

Detailed explanation-4: -The theory of evolution states that all life has a common ancestry. The direct proof of evolution would be knowledge of lines of descent, that is, actual specimens showing gradual transition from form to form. Fossils provide such evidence. The fossil record shows that birds were evolved from reptiles.

Detailed explanation-5: -Homologous features If two or more species share a unique physical feature, such as a complex bone structure or a body plan, they may all have inherited this feature from a common ancestor. Physical features shared due to evolutionary history (a common ancestor) are said to be homologous.