generic cycles, theory of

views updated May 14 2018

generic cycles, theory of A theory which envisages a life cycle for a species or genus that resembles that of an individual. The first stage is characterized by vigorous spread; the second by maximum phyletic activity giving rise to new forms; the third marks a phase of decline in area, owing to competition within the offspring species; and the fourth and final stage sees the extinction of the species. Although in many ways a useful analogy, there is no evidence that species become senile and die out spontaneously.

A Dictionary of Ecology MICHAEL ALLABY

generic cycles, theory of

views updated May 11 2018

generic cycles, theory of A theory that envisages a life cycle for a species or genus that resembles that of an individual. The first stage is characterized by vigorous spread; the second by maximum phyletic activity giving rise to new forms; the third marks a phase of decline in area owing to competition within the offspring species; and the fourth and final stage sees the extinction of the species. Although in many ways a useful analogy, there is no evidence that species become senile and die out spontaneously.

A Dictionary of Plant Sciences MICHAEL ALLABY

generic cycles, theory of

views updated May 18 2018

generic cycles, theory of A theory that envisages a life cycle for a species or genus analogous to that of an individual. The first stage is characterized by vigorous spread; the second by maximum phyletic activity giving rise to new forms; the third marks a phase of decline in area due to competition within the offspring species; and the fourth and final stage sees the extinction of the species. Although in many ways a useful analogy, there is no evidence that species become senile and die out spontaneously.

A Dictionary of Zoology MICHAEL ALLABY