Plesiomorphy and symplesiomorphyIn phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, and synapomorphy all mean a trait shared between species because they share an ancestral species. Apomorphic and synapomorphic characteristics convey information about evolutionary clades and can be used to define taxa.
CladisticsCladistics ( ; from Ancient Greekkládos 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived characteristics (synapomorphies) that are not present in more distant groups and ancestors.
Phenotypic traitA phenotypic trait, simply trait, or character state is any distinct variant of a phenotypic, or observable, characteristic of an organism; it may be either inherited or determined environmentally but typically occurs as a combination of the two. For example, having eye color is a character of an organism, while blue, brown and hazel versions of eye color are traits.
Homology (biology)In biology, homology is similarity in anatomical structures or genes between organisms of different taxa due to shared ancestry, regardless of current functional differences. Evolutionary biology explains homologous structures as retained from a common ancestor after having been subjected to adaptive modifications for different purposes as the result of natural selection.
PhylogeneticsStudy of evolutionary relationships between organismsOne small clade of fish, showing how venom has evolved multiple times.In biology, phylogenetics () is the study of the evolutionaryhistory of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical data and observed heritable traits of DNA sequences, proteinamino acid sequences, protein structure, and morphology.
Terrestrial locomotionTerrestrial locomotion is the method of movement of an organism on land. Organisms employ many different methods of movement for a variety of reasons. Terrestrial locomotion is of great interest to the study of evolution, which determines that aquatic organisms adapted to terrestrial environments. Animal locomotion on land experiences buoyancy and friction to a lesser extent, and gravity to a greater extent.
FurFur is the soft, thick growth of hair that covers the skin of almost all mammals. It consists of a combination of oily guard hair on top and thick underfur beneath. The guard hair keeps moisture from reaching the skin; the underfur acts as an insulating blanket that keeps the animal warm. The fur of mammals has many purposes: protection, sensory, waterproofing, and camouflaging, with the primary purpose being thermoregulation.
GaitGait is the pattern of movement of the limbs of animals, including humans, during locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on speed, terrain, the need to maneuver, and energetic efficiency. Different animal species may use different gaits due to differences in anatomy that prevent use of certain gaits, or simply due to evolved innate preferences as a result of habitat differences.
EvolutionChange in the heritable traits of populationsEvolution is the change in the heritable characteristics of biological populations over successive generations. It happens when individuals in a population vary in their genetic characteristics and in the numbers of their surviving offspring. Mutation introduces new genetic variation, and processes such as genetic drift, gene flow, and natural selection result in some genetic variants becoming more or less common over time.
Most recent common ancestorA most recent common ancestor (MRCA), also known as a last common ancestor (LCA) or concestor (a term coined by Nicky Warren), is the most recent individual from which all organisms of a set are inferred to have descended. The most recent common ancestor of a higher taxon is generally assumed to have been a species. The term is also used in reference to the ancestry of groups of genes (haplotypes) rather than organisms.
HypothesisA hypothesis (pl.: hypotheses) is a proposed explanation for a phenomenon. A scientific hypothesis must be based on observations and make a testable and reproducibleprediction about reality, in a process beginning with an educated guess. If a hypothesis is repeatedly independently demonstrated by experiment to be true, it becomes a scientific theory.
TaxonIn biology, a taxon is a group of one or more populations of an organism, or organisms, as seen by taxonomists to form a biological unit; (taxon: back-formation from taxonomy; pl.: taxa). Although neither is required, a taxon, once its description has become established, is usually known by a particular name and is given a particular ranking.*As an Amazon Associate I earn from qualifying purchases.