Search results
Results from the WOW.Com Content Network
Evolution of fish to tetrapods. The basic body plan has been phylogenetically constrained. Most terrestrial vertebrates have a body plan that consist of four limbs. The phylogenetic inertia hypothesis suggests that this body plan is observed, not because it happens to be optimal, but because tetrapods are derived from a clade of fishes (Sarcopterygii) which also have four limbs.
Phylogenetic comparative methods (PCMs) use information on the historical relationships of lineages (phylogenies) to test evolutionary hypotheses.The comparative method has a long history in evolutionary biology; indeed, Charles Darwin used differences and similarities between species as a major source of evidence in The Origin of Species.
Biological constraints are factors which make populations resistant to evolutionary change. One proposed definition of constraint is "A property of a trait that, although possibly adaptive in the environment in which it originally evolved, acts to place limits on the production of new phenotypic variants."
The toolkit can drive evolution in two ways. A toolkit gene can be expressed in a different pattern, as when the beak of Darwin's large ground-finch was enlarged by the BMP gene, [62] or when snakes lost their legs as distal-less became under-expressed or not expressed at all in the places where other reptiles continued to form their limbs. [63]
Phylogenetic bracketing is a method of inference used in biological sciences. It is used to infer the likelihood of unknown traits in organisms based on their position in a phylogenetic tree. One of the main applications of phylogenetic bracketing is on extinct organisms, known only from fossils, going back to the last universal common ancestor ...
Phylogenetic reconciliation is the identification of the links between levels through the comparison of at least two associated trees. Originally developed for two trees, reconciliations for more than two levels have been recently constructed (see section Explicit modeling of three or more levels). As such, reconciliation provides evolutionary ...
Marine larval ecology is the study of the factors influencing dispersing larvae, which many marine invertebrates and fishes have. Marine animals with a larva typically release many larvae into the water column, where the larvae develop before metamorphosing into adults.
It has been called a "universal phylogenetic tree in rooted form". [1] This tree and its rooting became the subject of debate. [49] [b] In the meantime, numerous modifications of this tree, mainly concerning the role and importance of horizontal gene transfer for its rooting and early ramifications have been suggested (e.g. [53] [48]).