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Early group selection models were flawed because they assumed that genes acted independently; but genetically based interactions among individuals are ubiquitous in group formation because genes must cooperate for the benefit of association in groups to enhance the fitness of group members. [16] Additionally, group selection on the level of the ...
In biology, evolution is change in the heritable characteristics of biological organisms over generations due to natural selection, mutation, gene flow, and genetic drift. Also known as descent with modification .
Since relatives share part of the helper's genetic make-up, enhancing each individual's chance of survival may actually increase the likelihood that the helper's genetic traits will be passed on to future generations. [3] However, some researchers, such as ecology professor Tim Clutton-Brock, assert that cooperation is a more complex process.
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]
A simple cladogram showing the evolutionary relationships between four species: A, B, C, and D. Here, Species A is the outgroup, and Species B, C, and D form the ingroup. In cladistics or phylogenetics, an outgroup [1] is a more distantly related group of organisms that serves as a reference group when determining the evolutionary relationships of the ingroup, the set of organisms under study ...
The age of the Earth is about 4.5 billion years. [1] [2] [3] The earliest undisputed evidence of life on Earth dates from at least 3.5 billion years ago. [4] [5] [6] Evolution does not attempt to explain the origin of life (covered instead by abiogenesis), but it does explain how early lifeforms evolved into the complex ecosystem that we see ...
The genetic regulation of ontogeny and the phylogenetic process is what allows for this kind of understanding of biology. By looking at different processes during development, and going through the evolutionary tree, one can determine at which point a specific structure came about. [6] [7]
The idea of a tree of life arose from ancient notions of a ladder-like progression from lower into higher forms of life (such as in the Great Chain of Being).Early representations of "branching" phylogenetic trees include a "paleontological chart" showing the geological relationships among plants and animals in the book Elementary Geology, by Edward Hitchcock (first edition: 1840).