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A cladogram (from Greek clados "branch" and gramma "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to descendants, nor does it show how much they have changed, so many differing evolutionary trees can be ...
A branch collar on a common oak (Quercus robur L.). Tree branches are attached to the trunk with a series of trunk collars that annually envelope the branch collar. [1] The branch tissues develop a basal collar first in spring, then trunk tissue envelops the collar later during seasons of growth. [1]
If a phylogenetic tree is reconstructed from DNA sequence data of a particular gene, a hard polytomy arises when three or more sampled genes trace their ancestry to a single gene in an ancestral organism. In contrast, a soft polytomy stems from branches on gene trees of finite temporal duration but for which no substitutions have occurred. [7]
In the diagram, lemurs and lorises are sister clades, while humans and tarsiers are not. A clade A is basal to a clade B if A branches off the lineage leading to B before the first branch leading only to members of B. In the adjacent diagram, the strepsirrhine/prosimian clade, is basal to the hominoids/ape clade. In this example, both ...
Identification keys are sometimes also referred to as artificial keys to differential them from other diagrams that visualize a classification schemes, often in the form of a key or tree structure. These diagrams are called natural keys or synopses and are not used for identifying specimens. In contrast, an artificial identification key is a ...
The pattern of branching in a tree will vary from species to species, as will the appearance of a plant as a tree, herb, or grass. Fourthly, plant morphology examines the pattern of development, the process by which structures originate and mature as a plant grows. While animals produce all the body parts they will ever have from early in their ...
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A tree structure, tree diagram, or tree model is a way of representing the hierarchical nature of a structure in a graphical form. It is named a "tree structure" because the classic representation resembles a tree , although the chart is generally upside down compared to a biological tree, with the "stem" at the top and the "leaves" at the bottom.