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Evolution by natural selection is the process by which traits that enhance survival and reproduction become more common in successive generations of a population. It embodies three principles: [7] Variation exists within populations of organisms with respect to morphology, physiology and behaviour (phenotypic variation).
In biology, evolution is the process of change in all forms of life over generations, and evolutionary biology is the study of how evolution occurs. Biological populations evolve through genetic changes that correspond to changes in the organisms' observable traits.
Convergent evolution is the process in which related or distantly related organisms evolve similar characteristics independently. This type of evolution creates analogous structures which have a similar function, structure, or form between the two species. For example, sharks and dolphins look alike but they are not related.
Professor of biology Jerry Coyne sums up biological evolution succinctly: [3]. Life on Earth evolved gradually beginning with one primitive species – perhaps a self-replicating molecule – that lived more than 3.5 billion years ago; it then branched out over time, throwing off many new and diverse species; and the mechanism for most (but not all) of evolutionary change is natural selection.
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype.It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations.
Another process, gastrulation of the embryo, is driven by Myosin II molecular motors, which are not conserved across species. The process may have been started by movements of sea water in the environment, later replaced by the evolution of tissue movements in the embryo. [56] [57]
Genome evolution – Process by which a genome changes in structure or size over time; Hologenome theory of evolution – Organism as host plus microbe community; Models of DNA evolution – Mathematical models of changing DNA; Molecular evolution – Process of change in the sequence composition of cellular molecules across generations
Carcinisation (American English: carcinization) is a form of convergent evolution in which non-crab crustaceans evolve a crab-like body plan. The term was introduced into evolutionary biology by L. A. Borradaile, who described it as "the many attempts of Nature to evolve a crab". [2]