Direct evidence of evolution is the fossil forms of extinct organisms discovered during paleontological research. They show the changes that have occurred in organisms during evolution.

We distinguish between:

• Fossils are the remains or whole organisms, as well as traces of their existence, preserved in sedimentary rocks. Fossilization occurs under anaerobic conditions resulting from the coating of dead organisms with layers of sediments. The most common fossils are hard tissues such as teeth, bones, shells, and crusts. Soft tissues can also rarely be fossilized. Fossils include, for example, ammonites, trilobites, conodonts, graptolites, and skeletal remains of archaeopteryx.

• Prints are prints of body parts of plants or animals preserved between two layers of sedimentary rock. They can be both hard and soft fabrics. Most often these are parts of plant organs (for example, leaves of ferns, horsetails and maces), shells of mollusks and shells of crustaceans. We also include animal tracks, such as dinosaurs.

• castings are formed as a result of filling voids in the rock with fossils (which decomposed and were washed away), crystallized minerals or fine-grained sediments. In this way, casts are created that reflect the shape of the external parts of the body, for example, mollusk shells or trilobite shells. The inner casts, that is, the centers, reflect the internal structure, for example, the inner part of the brain box or plant stems.

Transitional forms are extinct organisms that had the characteristics of two systematic groups, for example, fish and amphibians (Ichthyostega) or reptiles and birds (archaeopteryx).

• living fossils are representatives of extinct groups of organisms that have survived to the present day in a slightly modified form, for example, latimeria, tuatara, ginkgo biloba.

Ecology - definition

Ecology is the science that studies the interdependencies between organisms, as well as between organisms and their living and inanimate environments. The term ecology was introduced into terminology in 1866 by the German biologist Ernst Haeckel.

Basic environmental concepts:

A population is a group of individuals of the same species inhabiting a common territory at a certain point in time.;
biocenosis - all populations living in a certain environment; animate (biotic elements) of the environment;
biotope - an area that is the place of life of a biocenosis; inanimate (abiotic elements of the environment);
ecological niche - all the vital needs of the body (place of residence, food, appropriate temperature, humidity, sunlight, etc.)
ecosystem = biotope + biocenosis; <p>Avec <strong> Genybet </strong>, bénéficiez d’un large choix de courses et de paris en ligne.</p>