He began contemplating while aboard HMS Beagle, but it took several years before he came up with his theory of evolution by natural selection. The finches – once they had been identified as different ...

Understanding this phenomenon allowed him to develop his concept of “natural selection” which, in turn, became a core element of his theory of evolution. Darwin observed that with such abundance, ...

A classic example of natural selection at work is the origin of giraffes’ long necks. The ancestors of modern giraffes were animals similar to deer or antelope, with necks of ordinary length.

The idea that social groups can impact evolutionary success has been debated since Darwin first suggested it, over 150 years ...

The proportion of well-adapted organisms in a population can increase over the generations by the process of evolution by natural selection.

Multilevel selection is a controversial concept originally proposed by Darwin. A new study found evidence for it in the wild in a group of marmots scientists have been observing for more than 60 years ...

New alleles produced by mutations can result in plants and animals becoming better adapted to their environment. Variation within a population makes it possible for a population to evolve over ...

Aa Aa Aa Natural selection, genetic drift, and gene flow are the mechanisms that cause changes in allele frequencies over time. When one or more of these forces are acting in a population ...

The early part of the twentieth century saw evolutionary theory embattled by disagreements over Darwin's emphasis on natural selection. The then-newly rediscovered work of Gregor Mendel in the ...

FISHER 1 in 1930 stated his “fundamental theorem of natural selection” in the form: “The rate of increase in fitness of any organism at any time is equal to its genetic variance in fitness ...