Today we will talk about what evolution is in biology, what significance it has. Of course, speaking about this topic, we cannot ignore the evolutionary theory of Charles Darwin, who proposed it to the world that exists to this day.
So what is evolution in biology? By this concept it is customary to understand gradual changes that are not very striking. But as a result of this process, fundamental changes also appear. Evolution in biology can even lead to the formation of new species of living things or a radical change and adaptation of old ones. What is the significance of evolution in natural science? Of course, the key. You will understand this when you finish reading this work.
Evolution
Now let's talk a little about the key concept of our article. What is evolution in biology? It is important to understand that this phenomenon is irreversible and directly related to the historical process, the development of wildlife. We can consider the evolution of individual parts of the biosphere or, in general, of the entire living planet. Remember that only a living organism can evolve.
Previously, evolution was opposed by such a concept as “revolution”. But in the course of a diligent study of these two processes, it became clear: evolution and revolution are quite difficult to distinguish from each other. Why? Evolution can last millions of years or pass quickly. So the boundaries between these two processes are very blurred.
Some believe that man is the result of evolution, that is, we are descended from ancient monkeys. This theory was put forward by the famous scientist Charles Darwin. And the theory was called evolutionary. Believe it or not, everyone decides independently, because now there are many other possible hypotheses. But since we are talking about evolution in our work, we cannot ignore Darwin's theory. We propose to start it right now.
Darwin Theory
For the first time, Charles Darwin was able to explain to humanity what evolution is in biology. We also mention that his theory was based on the works of T. Malthus, who introduced the world in 1778 to his "Treatise on Population." After studying this work, Charles Darwin was able to formulate the basic laws, forces that drive evolution. What is T. Malthus's work about? He explained what would happen to us if population growth were not constrained by any factors.
We also note that Darwin shifted the theory of Malthus to other living systems, his main contribution to science is an explanation of how evolution occurs. He first introduced the concept of "natural selection." We can also mention the fact that another scientist (A.R. Wallace) was able to come to the same conclusion. Then Darwin and Wallace teamed up and made a joint report at a meeting in 1858, and already in 1859 C. Darwin presented the world the work “The Origin of Species”.
Modern theory
So, what is evolution in biology, a definition according to the theory of Charles Darwin, we have already provided. But there is also a modern (it is also called synthetic) theory of evolution. We suggest to consider it briefly.
The theory of neo-Darwinism is a Darwin-Wallace theory updated in the 20th century. This happened as a result of updating and adding new data in the areas of:
- genetics;
- paleontology;
- molecular biology;
- ecology;
- ethology.
Why is this theory called synthetic? Precisely because it is a synthesis of the main positions presented by Charles Darwin.
Laws of evolution
Before we outline the basic laws, we suggest that you consider what evolution is in biology, an example of this will be a good helper for us. Take the blue butterfly that lives on the Samoan Islands. They began to exterminate parasites, which were dangerous for males. In just a year of such an attack, the number of males increased to 40 percent. No, the parasites remained to exist in the neighborhood, only the butterflies they were no longer a hindrance. This is what evolution looks like.
The laws:
- the rate of evolution is not the same;
- the formation of new species occurs in simple forms;
- cases of regressive evolution are noted;
- evolution occurs due to certain factors (mutations, natural selection, gene drift).
Evolutionary factors
We learned what evolution is in biology and its essence. Let's talk about factors now. They were obtained as a result of studying and systematizing all the accumulated knowledge related to evolution. This is the only way to see and understand the driving forces that allow many species (less adapted to survival) to remain on our planet.
So, there are only three main factors:
- mutation process ;
- population waves;
- group isolation.
Selection forms
Speaking of evolution, we can distinguish several forms of natural selection:
- stabilizing;
- moving;
- disruptive.
The first type is aimed at maintaining the stability of a particular type. Consider the example on sparrows. During a severe storm, 136 dying birds were found. 64 of them died because they had either short or long wings. Medium-sized individuals survived, as they were more resilient.
The motive is manifested as follows: the disappearance of limbs in snakes or eyes in cave animals, fingers in ungulates and so on. That is, an organ (or part of it) that the animal does not need simply disappears.
An example of a disruptive selection can be snails (more precisely, their color). If the soil is brown, then the shell has a brown or yellow hue.