What is variability?
Variability is a property of living organisms, which lies in the fact that they can exist in different ways during their individual development during sexual or non-sexual reproduction. Variability in turn is divided into several types:
What is variability in its different forms? Let's look at each type separately.
What is genetic variation?
Hereditary variation is a property that involves changing the phenotype and at the same time, new genotypes appear substantially. Rebuilt all hereditary material. This variability is due to the occurrence of different types of mutations and their combinations in subsequent crosses.
What is Modification Variability?
Now we will find out what is modificational variability. Modification is a type of variability that is controlled by the genotype of the organism and, at the same time, the hereditary material is not rearranged, and the variability itself depends on many environmental factors.
What is mutational variability
Mutational variability is characterized by a change in the hereditary material, and the very structure of the chromosome and genes, their number, can change. As a rule, mutational variability occurs spontaneously.
What is ontogenetic variability
Ontogenetic - is the development and growth, as well as at the stages of development of living organisms. As a rule, with such variability, there is a distinction between younger and older, more adult organisms.
When mutations are preserved and accumulate in the gene pool of populations, a special “reserve of hereditary variability” is formed, which consists of active heterozygotes.
And now let's talk more about the mutations. Mutation is a spontaneous change in the number of chromosomes and their structure. In turn, it is divided into three types:
- Gene mutation. In the material there are processes that lead to the change of old, as well as the emergence of new signs in different directions, including physiological. For example, bacteria can change color and shape.
- Chromosomal mutations are mutations that initially contribute to changes in the structure and number of chromosomes.
- Genomic mutations are divided into polyploidy and autoploidy. Polyploidy: a characteristic set of chromosomes is inherent in each type of organism. Autoploidy: in polyploids, the main set of chromosomes is repeated.
What is the reserve of hereditary variability
This is a "mobilization" reserve of mutations. With the help of this reserve, various combinations and innovations of subsequent generations are captured.
Variability - as a biological concept was considered for a long time, and it has its own history. In fact, it can be said that the study of “variability” originates from the resurgence of such a science as biology, and this is more than 3,000 years ago.
The very first who talked about variability, were walnut natural philosophers - Plato, Thales, Anaximander, Heraclitus. It was Heraclitus who said the phrase, which has become legendary, is even popular now: “Everything flows, everything changes.” He meant that life does not stand still, people begin to learn new things and actively apply their knowledge in practice. And also the fact that when some time passes, everything changes in truth. Later, people began to realize that the processes of variability are biologically important.After all, they watched the trees grow old, how they change their shape and color - and this already became a great interest, people began to conduct experiments, including on people, as a “species”. They themselves experienced youth and aging - and this, as we know, is “volatility”. Over time, people have already made quite a lot, both biological and discoveries in other sciences. And it becomes clear to us that Heraclitus was right: “Everything elapsed, and everything changed.” As you can see, biology is closely tied to human life, because people - these are the subjects of biology - one of the most ancient and interesting sciences on Earth.
And our fascinating article comes to an end. I wish you a pleasant study of biology.