There are three main ways to achieve biological progress.
1. Aromorphosis is a large, fundamentally new, significant macroevolutionary change that increases the general level of organization of a group of organisms, as a result of which the vital activity of organisms is enhanced. Aromorphoses provide significant advantages in the struggle for existence, make possible the transition to a new habitat. Aromorphoses in animals include the appearance of live births, the ability to maintain a constant body temperature, the emergence of a closed circulatory system, and in plants – the appearance of a flower, vascular system, the ability to maintain and regulate gas exchange in the leaves.
2. Idiadaptation is a progressive, but small evolutionary change that enhances the adaptability of organisms to environmental conditions. Idiadaptation is not accompanied by a change in the main features of the organization, a general increase in its level and an increase in the intensity of the vital activity of the body. An example of idioadaptations is the protective coloration of animals or the adaptation of some fish (flounder, catfish) to life near the bottom – flattening of the body, coloring to the color of a pound, the development of antennae, etc. Another example is adaptation to flight in some species of mammals (bats, flying squirrels) ) Examples of idioadaptation in plants are manifold adaptations to cross-pollination of a flower by insects or wind, adaptations to seed dispersal. Idiocaptations lead to the emergence of lower taxonomic groups (species, genera, families).
3. Degeneration leads to a simplification of organization, the loss of a number of systems and organs, and is often associated with a transition to a parasitic lifestyle. Simplification of the organization of the parasite affects primarily the systems necessary for life in an open environment, but superfluous inside the host – the organs of orientation, digestion, movement, etc.
With a general simplification of organization, 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.