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Biologists most often define biodiversity as the "totality of genes, species and ecosystems of a region". [8] [9] An advantage of this definition is that it presents a unified view of the traditional types of biological variety previously identified: taxonomic diversity (usually measured at the species diversity level) [10]
Mosaic evolution – Evolution of characters at various rates both within and between species; Parallel evolution – Similar evolution in distinct species; Quantum evolution – Evolution where transitional forms are particularly unstable and do not last long; Recurrent evolution – The repeated evolution of a particular character
The result of four billion years of evolution is the diversity of life around us, with an estimated 1.75 million different species in existence today. [ 71 ] [ 72 ] Usually the process of speciation is slow, occurring over very long time spans; thus direct observations within human life-spans are rare.
Biogeography is a synthetic science, related to geography, biology, soil science, geology, climatology, ecology and evolution. Some fundamental concepts in biogeography include: allopatric speciation – the splitting of a species by evolution of geographically isolated populations; evolution – change in genetic composition of a population
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]
Evolutionary taxonomy, evolutionary systematics or Darwinian classification is a branch of biological classification that seeks to classify organisms using a combination of phylogenetic relationship (shared descent), progenitor-descendant relationship (serial descent), and degree of evolutionary change.
For biodiversity evolution and species preservation, it is crucial to compare the dynamics of ecosystems with models (Leigh, 2007). An easily accessible index of the underlying evolution is the so-called species turnover distribution (STD), defined as the probability P(r,t) that the population of any species has varied by a fraction r after a ...
Molecular evolution is the process of selective changes (mutations) at a molecular level (genes, proteins, etc.) throughout various branches in the tree of life (evolution). Molecular phylogenetics makes inferences of the evolutionary relationships that arise due to molecular evolution and results in the construction of a phylogenetic tree. [6]