What worries people? Leave and keep individuals with certain indicators and remove the rest, which are less adapted to survive in our harsh world. This process is commonly called artificial selection, and a person plays a very important role in this. But our task today is to get acquainted with natural selection, or rather, we will find out what interspecific struggle is.
Signs that are useful for humans are not always needed and important for animals. Nature is also able to preserve some species, and eliminate some. This process is called the term "natural selection", and interspecies struggle is one of the tools of this process. That is, animals compete with each other for food, water, territory, and so on. This is how species evolve, they are forced to adapt to some factors or simply disappear from the face of the Earth.
Ch. Darwin
For the first time we heard the term "interspecies struggle" from the great scientist Charles Darwin. It is important to note what he meant by the spoken words. Charles Darwin spoke about the struggle for existence in a broad and metaphorical sense. Of course, many species of animals and plants are directly dependent on each other, but in times of famine, living beings begin to fight for resources that allow them to survive and reproduce. Interspecific struggle occurs between individuals of different species (for example, a zebra and a lion, a dove and a sparrow). In the first example, a lion can eat a zebra to satisfy his hunger, in the second example, we presented two types of birds that are fighting for food and territory.
You can give examples from the underwater world, as some species of fish are fighting for food and territory. The most important factor for victory is the reproduction of offspring. Those fish that lay eggs in larger numbers will sooner or later crowd out the other.
Competition
Interspecies struggle for existence is divided into two groups:
- Competition.
- Direct fight.
The first form is the leading one, it is here that contradictions between living beings appear, which favorably affects evolution. Interspecies struggle, the causes of which can be divided into competition for biological needs and the same way to satisfy them, is also divided into:
- Trophic competition.
- Topic.
- Reproductive.
The first type appears if the organismscompete for food, heat from the sun, nutrients and moisture. For example, predators that hunt in the same territory, competing with each other, evolve. Their sense of smell and vision become more acute, their running speed increases.
The second species appears between organisms if they live in the same environment and are subject to the same abiotic factors. This species is the main reason for the development of adaptations for survival in poor conditions.
Reproductive interspecific struggle is common in plants. Those objects that are attracted by color and smell are more likely to be pollinated by insects.
Direct fight
If, during competition, organisms enter into opposition indirectly, that is, with the help of biotic or abiotic factors, then direct struggle is distinguished by a direct collision of individuals. The following species are distinguished here:
- Combating biotic factors.
- Combating abiotic factors.
The first type implies a struggle for food and the possibility of reproduction, that is, it is also divided into trophic and reproductive. In the first case, we are talking about the relationship of plants and herbivores, predators and prey, and so on. This species is more common in interspecific struggle, in intraspecific it is expressed in the form of cannibalism. As a result, plants begin to defend themselves with thorns, poison glands and similar means. Animals also develop defense mechanisms (fast running, heightened sense of smell and vision, keeping a hidden lifestyle …), and if we talk about the fightwith microbes, then immunity is produced.
The second species can be observed in birds when they enter into open confrontation with each other for the opportunity to breed in this particular area and get food for their offspring.
Sometimes it's not so easy to tell if it's a competition or a direct fight. The line between the two concepts is really hard to draw. There is one main difference: when competing, organisms fight indirectly, while when fighting directly, they fight each other.
Correction in the theory of Charles Darwin
We examined the types of interspecies struggle that are included in the general complex of the struggle for existence. It is also important to note that Charles Darwin presented this process to us as a consequence caused by the contradiction between the desire for unlimited reproduction and limited resources. But scientists who later studied the theory made an amendment: the fight is caused not only by the limited territory or lack of food, but also by the excessive aggressiveness of predators.
