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The term paraphyly, or paraphyletic, derives from the two Ancient Greek words παρά (pará), meaning "beside, near", and φῦλον (phûlon), meaning "genus, species", [2] [3] and refers to the situation in which one or several monophyletic subgroups of organisms (e.g., genera, species) are left apart from all other descendants of a unique common ancestor.
Thus you can't exclude B and C to form a paraphyletic group A+D, for example, since once B is excluded its entire sister group must be included. This prevents ever being able to make a paraphyletic group equivalent to mammals+birds. To make a paraphyletic group by excluding two taxa/clades, they have to be in "separate lines". Thus in this tree
The traditional dicots are thus a paraphyletic group. [4] The eudicots are the largest monophyletic group within the dicotyledons. They are distinguished from all other flowering plants by the structure of their pollen. Other dicotyledons and the monocotyledons have monosulcate pollen (or derived forms): grains with a single sulcus.
Many commonly named groups – rodents and insects, for example – are clades because, in each case, the group consists of a common ancestor with all its descendant branches. Rodents, for example, are a branch of mammals that split off after the end of the period when the clade Dinosauria stopped being the dominant terrestrial vertebrates 66 ...
A paraphyletic grouping meets 1. but not 2., thus consisting of the descendants of a common ancestor, excepting one or more monophyletic subgroups. A polyphyletic grouping meets neither criterion, and instead serves to characterize convergent relationships of biological features rather than genetic relationships – for example, night-active ...
A paraspecies (a paraphyletic species) is a species, living or fossil, that gave rise to one or more daughter species without itself becoming extinct. [1] Geographically widespread species that have given rise to one or more daughter species as peripheral isolates without themselves becoming extinct (i.e. through peripatric speciation) are examples of paraspecies.
The term polyphyly, or polyphyletic, derives from the two Ancient Greek words πολύς (polús) 'many, a lot of', and φῦλον (phûlon) 'genus, species', [8] [9] and refers to the fact that a polyphyletic group includes organisms (e.g., genera, species) arising from multiple ancestral sources.
This section needs to be updated.The reason given is: Highly outdated; for example, "Exopterygota" is almost certainly considered paraphyletic by most phylogenetic studies in the last 10 years at least by now, as most of them instead recognise at least Polyneoptera and sometimes Paraneoptera (e.g. [9]), with the Paraneoptera more closely related to Holometabola than Polyneoptera..