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Edward Hitchcock's fold-out paleontological chart in his 1840 Elementary Geology. Although tree-like diagrams have long been used to organise knowledge, and although branching diagrams known as claves ("keys") were omnipresent in eighteenth-century natural history, it appears that the earliest tree diagram of natural order was the 1801 "Arbre botanique" (Botanical Tree) of the French ...
Evolution is the change in the heritable characteristics of biological populations over successive generations. [1] [2] It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, resulting in certain characteristics becoming more or less common within a population over successive generations. [3]
The development and spread of antibiotic resistant bacteria provides evidence that evolution due to natural selection is an ongoing process in the natural world. Natural selection is ubiquitous in all research pertaining to evolution, taking note of the fact that all of the following examples in each section of the article document the process.
The outcome of evolution is not a perfectly designed organism. The end products of natural selection are organisms that are adapted to their present environments. Natural selection does not involve progress towards an ultimate goal. Evolution does not strive for more advanced, more intelligent, or more sophisticated life forms. [25]
To find new venoms, scientists turn to phylogenetics to screen for closely related species that may have the same useful traits. The phylogenetic tree shows which species of fish have an origin of venom, and related fish they may contain the trait. Using this approach in studying venomous fish, biologists are able to identify the fish species ...
Evolution captures both the history of an organism via its phylogeny, and the history of natural selection working on function to produce adaptations. [6] There are several reasons why natural selection may fail to achieve optimal design (Mayr 2001:140–143; Buss et al. 1998).
The exact outcome of the two processes depends both on the rate at which new mutations occur and on the strength of the natural selection, which is a function of how unfavourable the mutation proves to be. [110] Genetic linkage occurs when the loci of two alleles are close on a chromosome. During the formation of gametes, recombination ...
Natural selection – Mechanism of evolution by differential survival and reproduction of individuals Sexual selection – Mode of natural selection involving the choosing of and competition for mates; Mutation – Alteration in the nucleotide sequence of a genome; Gene flow – Transfer of genetic variation from one population to another