Population and species are concepts that students become familiar with in general biology lessons. Both terms are associated with the designation of a group of plants or animals that are united by a number of parameters. But what are these parameters? How to use terms correctly? And what's the difference between them? Let's try to find out.
Population - it is a community, an aggregate, a group of animals, plants or fungi of the same species that live in a certain area for a certain period of time. Population as a term is actively used in biology, ecology, medical geography, and demography. For example, the gazelle population in the Daursky Reserve, the wildebeest population in the Ngorongoro crater, or the lion population in the same crater of the Ngorongoro volcano.
Species are living organisms that are most similar to each other, if we do not take into account gender differences, metamorphoses, different life cycles and age-related changes. Individuals must interbreed fertilely within the species. Crossbreeding with other species does not produce offspring. Animals, plants or fungi of the same species can be found all over the earth. Examples are blackbird, Indian elephant, rose gull, bowhead whale. Traditionally, a specific name consists of two words. The binary system was introduced by Carl Linnaeus. The name of the living creature is duplicated in Latin: the Indian elephant - Elephas maximus, the gray wolf - Canis lupus. The binary system was introduced by Carl Linnaeus.
As we said, a population is a group of living organisms that belong to the same species. They are confined to a certain geographic area or environment, which prevents them from coming into contact with other members of their species. But this isolation does not affect the group's ability to reproduce. If we take the same Ngorongoro crater, then 15 thousand wildebeests live in it. This amount is enough for the animals to find mating partners and produce healthy offspring. But there, in the crater, is home to a hundred lions. Studies have shown that all lions have 15 common ancestors. This suggests that this population will be weakened by closely related interbreeding, leading to the emergence of various genetic diseases.
If animals or plants leave the boundaries of their reservation, they are able to produce healthy and large offspring, interbreeding with representatives of their own species living in other territories.
The founders of evolutionary theories consider the population to be the smallest unit of the evolutionary process that can lead to the formation of new species. The classics are the studies of Charles Darwin in the Galapagos Islands. An isolated population of finches was found on each of them, which eventually developed into a separate species.
A species is a collection of individuals that are similar in a number of criteria. The first of these is morphological - appearance - appearance. Even a child will find outward differences between a Himalayan bear and a brown bear, an Indian and African elephant, a humpback and bowhead whale.
In second place is the cytogenetic criterion, when the number, size, shape and structure of chromosomes isolated from the cells of living organisms are analyzed. For example, in the Kyrgyz vole mouse, scientists have counted 54 chromosomes, and in the Eastern European vole - 52. The karyotype allows you to divide species that have significant external similarity. Cytogenetic analysis, in addition to counting chromosomes, includes a comparison of DNA and protein molecules of the same type.
The third criterion is ecological-geographical. This means that most species have a specific habitat: the African elephant in Africa, the Indian elephant in India, the Himalayan bear in China, and the coyotes in North America. Sometimes the areas of distribution of closely related species are layered and crossed.
The fourth criterion is reproductive isolation, when animals can reproduce successfully only within their species. For example, a mule that is the result of crossing a mare and a donkey is incapable of reproduction. This is due to the different number of chromosomes in the parent.
- The concept of “species” is broader than “population”.
- The number of living organisms of one species is greater than the size of the population, provided that it is not the only habitat and existence of this species.
- Individuals of the same species of different populations are capable of producing numerous offspring. Individuals of different species do not produce suchoffspring.