Ardipithecus is a genus of an extinct hominine that lived during the Late Miocene and Early Pliocene epochs in the Afar Depression, Ethiopia. Originally described as one of the earliest ancestors of humans after they diverged from the chimpanzees, the relation of this genus to human ancestors and whether it is a hominin is now a matter of debate. Two fossil species are described in the literature: A. ramidus, which lived about 4.4 million years ago during the early Pliocene, and A. kadabba, dated to approximately 5.6 million years ago. Initial behavioral analysis indicated that Ardipithecus could be very similar to chimpanzees, however more recent analysis based on canine size and lack of canine sexual dimorphism indicates that Ardipithecus was characterised by reduced aggression, and that they more closely resemble bonobos.
A phylogenetic tree, phylogeny or evolutionary tree is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time. In other words, it is a branching diagram or a tree showing the evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical or genetic characteristics. In evolutionary biology, all life on Earth is theoretically part of a single phylogenetic tree, indicating common ancestry. Phylogenetics is the study of phylogenetic trees. The main challenge is to find a phylogenetic tree representing optimal evolutionary ancestry between a set of species or taxa. Computational phylogenetics focuses on the algorithms involved in finding optimal phylogenetic tree in the phylogenetic landscape.
Homo ergaster is an extinct species or subspecies of archaic humans who lived in Africa in the Early Pleistocene. Whether H. ergaster constitutes a species of its own or should be subsumed into H. erectus is an ongoing and unresolved dispute within palaeoanthropology. Proponents of synonymisation typically designate H. ergaster as "African Homo erectus" or "Homo erectus ergaster". The name Homo ergaster roughly translates to "working man", a reference to the more advanced tools used by the species in comparison to those of their ancestors. The fossil range of H. ergaster mainly covers the period of 1.7 to 1.4 million years ago, though a broader time range is possible. Though fossils are known from across East and Southern Africa, most H. ergaster fossils have been found along the shores of Lake Turkana in Kenya. There are later African fossils, some younger than 1 million years ago, that indicate long-term anatomical continuity, though it is unclear if they can be formally regarded as H. ergaster specimens. As a chronospecies, H. ergaster may have persisted to as late as 600,000 years ago, when new lineages of Homo arose in Africa.
Homo rudolfensis is an extinct species of archaic human from the Early Pleistocene of East Africa about 2 million years ago (mya). Because H. rudolfensis coexisted with several other hominins, it is debated what specimens can be confidently assigned to this species beyond the lectotype skull KNM-ER 1470 and other partial skull aspects. No bodily remains are definitively assigned to H. rudolfensis. Consequently, both its generic classification and validity are debated without any wide consensus, with some recommending the species to actually belong to the genus Australopithecus as A. rudolfensis or Kenyanthropus as K. rudolfensis, or that it is synonymous with the contemporaneous and anatomically similar H. habilis.
The dire wolf is an extinct canine. The dire wolf lived in the Americas during the Late Pleistocene and Early Holocene epochs. The species was named in 1858, four years after the first specimen had been found. Two subspecies are recognized: Aenocyon dirus guildayi and Aenocyon dirus dirus. The largest collection of its fossils has been obtained from the Rancho La Brea Tar Pits in Los Angeles.
A living fossil is an extant taxon that phenotypically resembles related species known only from the fossil record. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living fossils commonly are of species-poor lineages, but they need not be. While the body plan of a living fossil remains superficially similar, it is never the same species as the remote relatives it resembles, because genetic drift would inevitably change its chromosomal structure.
Herto Man refers to human remains discovered in 1997 from the Upper Herto member of the Bouri Formation in the Afar Triangle, Ethiopia. The remains have been dated as between 154,000 and 160,000 years old. The discovery of Herto Man was especially significant at the time, falling within a long gap in the fossil record between 300 and 100 thousand years ago and representing the oldest dated H. sapiens remains then described.
Anagenesis is the gradual evolution of a species that continues to exist as an interbreeding population. This contrasts with cladogenesis, which occurs when there is branching or splitting, leading to two or more lineages and resulting in separate species. Anagenesis does not always lead to the formation of a new species from an ancestral species. When speciation does occur as different lineages branch off and cease to interbreed, a core group may continue to be defined as the original species. The evolution of this group, without extinction or species selection, is anagenesis.
Australopithecus anamensis is a hominin species that lived approximately between 4.2 and 3.8 million years ago and is the oldest known Australopithecus species, living during the Plio-Pleistocene era.
Divergent evolution or divergent selection is the accumulation of differences between closely related populations within a species, sometimes leading to speciation. Divergent evolution is typically exhibited when two populations become separated by a geographic barrier and experience different selective pressures that cause adaptations. After many generations and continual evolution, the populations become less able to interbreed with one another. The American naturalist J. T. Gulick (1832–1923) was the first to use the term "divergent evolution", with its use becoming widespread in modern evolutionary literature. Examples of divergence in nature are the adaptive radiation of the finches of the Galápagos, changes in mobbing behavior of the kittiwake, and the evolution of the modern-day dog from the wolf.
Computational phylogenetics, phylogeny inference, or phylogenetic inference focuses on computational and optimization algorithms, heuristics, and approaches involved in phylogenetic analyses. The goal is to find a phylogenetic tree representing optimal evolutionary ancestry between a set of genes, species, or taxa. Maximum likelihood, parsimony, Bayesian, and minimum evolution are typical optimality criteria used to assess how well a phylogenetic tree topology describes the sequence data. Nearest Neighbour Interchange (NNI), Subtree Prune and Regraft (SPR), and Tree Bisection and Reconnection (TBR), known as tree rearrangements, are deterministic algorithms to search for optimal or the best phylogenetic tree. The space and the landscape of searching for the optimal phylogenetic tree is known as phylogeny search space.
Squalodon is an extinct genus of whales of the Oligocene and Miocene epochs, belonging to the family Squalodontidae. Named by Jean-Pierre Sylvestre de Grateloup in 1840, it was originally believed to be an iguanodontid dinosaur but has since been reclassified. The name Squalodon comes from Squalus, a genus of shark. As a result, its name means "shark tooth". Its closest modern relative is the South Asian river dolphin.
Ichthyornithes is an extinct group of toothed avialan dinosaurs very closely related to the common ancestor of all modern birds. They are known from fossil remains found throughout the late Cretaceous period of North America, though only two genera, Ichthyornis and Janavis, are represented by complete enough fossils to have been named. Ichthyornitheans became extinct at the Cretaceous–Paleogene boundary, along with enantiornitheans, all other non-avian dinosaurs, and many other animal and plant groups.
Dinilysia is an extinct genus of snake from the Late Cretaceous (Coniacian) of South America. Dinilysia was a relatively large ambush predator, measuring approximately 2 m (6.6 ft) long. The skull morphology of Dinilysia is similar to boids, suggesting that it was able to consume large prey. Living in a desert-like environment, Dinilysia is likely a terrestrial or a semi-fossorial animal.
The evolution of the horse, a mammal of the family Equidae, occurred over a geologic time scale of 50 million years, transforming the small, dog-sized, forest-dwelling Eohippus into the modern horse. Paleozoologists have been able to piece together a more complete outline of the evolutionary lineage of the modern horse than of any other animal. Much of this evolution took place in North America, where horses originated but became extinct about 10,000 years ago, before being reintroduced in the 15th century.
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. Genetic changes include mutations, which are caused by damage or replication errors in organisms' DNA. As the genetic variation of a population drifts randomly over generations, natural selection gradually leads traits to become more or less common based on the relative reproductive success of organisms with those traits.
Rimasuchus is an extinct genus of crocodile from the Miocene of Egypt and possibly Libya. Only one species - Rimasuchus lloydi - is currently known. It was previously thought to be a species of Crocodylus, but is now thought to be more closely related to the modern African dwarf crocodiles (Osteolaemus).
The following outline is provided as an overview of and topical guide to evolution:
It is widely agreed that the evolutionary lineage of the grey wolf can be traced back 2 million years to the Early Pleistocene species Canis etruscus, and its successor the Middle Pleistocene Canis mosbachensis. The grey wolf Canis lupus is a highly adaptable species that is able to exist in a range of environments and which possesses a wide distribution across the Holarctic. Studies of modern grey wolves have identified distinct sub-populations that live in close proximity to each other. This variation in sub-populations is closely linked to differences in habitat – precipitation, temperature, vegetation, and prey specialization – which affect cranio-dental plasticity.
This glossary of genetics and evolutionary biology is a list of definitions of terms and concepts used in the study of genetics and evolutionary biology, as well as sub-disciplines and related fields, with an emphasis on classical genetics, quantitative genetics, population biology, phylogenetics, speciation, and systematics. It has been designed as a companion to Glossary of cellular and molecular biology, which contains many overlapping and related terms; other related glossaries include Glossary of biology and Glossary of ecology.
