Describe the main directions of evolution.

The main directions in evolution are biological progress and biological regression. Progress is an increase in the adaptability of organisms to the environment, accompanied by an increase in the number and wider distribution of the species. A decrease in the adaptability of organisms to environmental conditions, accompanied by a decrease in the number and a narrowing of the distribution area, is called biological regression. Biological regression is experienced by groups that have not been able to adapt to changes in environmental conditions and have not withstood competition with other groups.

Directions Characteristic Examples Evolutionary significance
Aromorphosis large, large-scale evolutionary changes that lead to the general rise of the organization, increase the intensity of life the appearance of live birth, warm-bloodedness, a closed circulatory system; in plants – the appearance of a flower, vascular system, the ability to maintain and regulate gas exchange in the leaves give an advantage in the struggle for existence, make possible the transition to a new environment
Idioadaptation minor evolutionary changes that do not increase the intensity of life protective coloring of animals, adaptation of some species of fish to life on the bottom, some mammals to flight, in plants – cross-pollination, dispersion of seeds increase the adaptability of organisms to the conditions of a particular habitat
Degeneration evolutionary changes that lead to a simplification of the organization, to the loss of a number of systems or organs parasites have specific adaptations – suckers, hooks, reproductive organs develop transition to a parasitic lifestyle


Aromorphoses: in animals – the appearance of live births, the ability to maintain a constant body temperature, the appearance of a closed circulatory system, in plants – the appearance of a flower, vascular system, the ability to maintain and regulate gas exchange in the leaves. Idiadaptations: protective coloring of animals or adaptation of some fish (flounder, catfish) to life near the bottom – flattening of the body, coloring to the color of the ground, development of antennae, etc .; flight adaptations in some species of mammals (bats, flying squirrels). In plants, adaptations to cross-pollination of a flower with insects or wind, adaptations to disperse seeds. Degenerations: parasites have specific adaptations (often very sophisticated) to the living conditions within the host. In parasitic worms, suckers, hooks appear, reproductive organs receive significant development. Pork tapeworm, lentets and other worms have no intestines, the nervous system is poorly developed, and there is no ability to move. In parasitic plants (dodder) – the absence of vegetative organs (leaf), instead of the roots – suckers.

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