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The yellow tail is a plesiomorphy and symplesiomorphy for all living species. In 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.
In 1973, M. J. D. White, then at the end of a long career investigating karyotypes, gave an interesting summary of the distribution of chromosome polymorphism. "It is extremely difficult to get an adequate idea as to what fraction of the species of eukaryote organisms actually are polymorphic for structural rearrangements of the chromosomes.
Tinbergen's four questions, named after 20th century biologist Nikolaas Tinbergen, are complementary categories of explanations for animal behaviour. These are also commonly referred to as levels of analysis . [ 1 ]
Semelparity and iteroparity are two contrasting reproductive strategies available to living organisms. A species is considered semelparous if it is characterized by a single reproductive episode before death, and iteroparous if it is characterized by multiple reproductive cycles over the course of its lifetime.
In biology, a ring species is a connected series of neighbouring populations, each of which interbreeds with closely sited related populations, but for which there exist at least two "end populations" in the series, which are too distantly related to interbreed, though there is a potential gene flow between each "linked" population and the next ...
Many scientists see macroevolution as a field of study rather than a distinct process that is similar to the process of microevolution. Thus, macroevolution is concerned with the history of life and macroevolutionary explanations encompasses ecology, paleontology, mass extinctions, plate tectonics, and unique events such as the Cambrian explosion.
Phylogenetic network depicting reticulate evolution: Lineage B results from a horizontal transfer between its two ancestors A and C (blue, dotted lines). Reticulate evolution , or network evolution is the origination of a lineage through the partial merging of two ancestor lineages, leading to relationships better described by a phylogenetic ...
Molecular biology is the study of biology at a molecular level. The field overlaps with other areas of biology, particularly genetics and biochemistry.Molecular biology chiefly concerns itself with understanding the interactions between the various systems of a cell, including the interrelationship of DNA, RNA and protein synthesis and learning how these interactions are regulated.