Extinction

Extinction [ Biology - Ecology ]
Adjective: Extinct

Dictionary of botanic terminology - index of names

Extinction: The death of an entire species, the fact of becoming extinct.
Extinct: Having no living members, as is the case with many organisms known only from fossils.

In biology and ecology, extinction is the total and irreversible ceasing of existence or disappearance a group of related organisms ( species or higher taxa), from a given local habitat, geographic area, or globally in the entire world (The term extinction is also applied to the condition that occurs when the number of individuals in a population falls below the level that will allow for sustainable reproduction or when no living representatives of a species exist in the wild).
The moment of extinction is generally considered to be the death of the last individual of that species.
Extinction is both a natural (dinosaurs, trilobites) and human-induced process (dodo, moa, Thylacine); it is estimated that 99.9% of all species that have ever lived are now extinct. Extiction can result from various human activities, including the destruction of habitats or the overexploitation of species that are hunted or collected as a resource, but the most effective agent in the extinction of species is the pressure of other species.

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Holdfast roots [ Botany ]
Dictionary of botanic terminology - index of names

Some species of climbing plants develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place.

Climbing plants, like the poison ivy (Toxicodendron radicans), Boston ivy (Parthenocissus tricuspidata), and trumpet creeper (Campsis radicans), develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place. Usually the Holdfast roots die at the end of the first season, but in some species they are perennial. In the tropics some of the large climbing plants have hold-fast roots by which they attach themselves, and long, cord-like roots that extend downward through the air and may lengthen and branch for several years until they strike the soil and become absorbent roots.

Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House, 1994