What is the basis of biological heredity and variation

The material basis of heredity and variation is chromosomes and genes.

Heredity and variation in living organisms refers to the phenomenon of similarities and dissimilarities between the parents and offspring of organisms. Heredity and variation are one of the fundamental characteristics of living things. In genetics, genotype refers to the genetic composition of an organism, and phenotype refers to the performance of a specific trait in an organism.

For example, the phenomenon of passing traits from parents to children is called heredity, and the phenomenon of differences in trait performance between parents and children is called variation.

Amazing biological heredity and variation.

1.A tree bears fruit, sweet and sour, indicating that the organism has a mutation phenomenon; Plant beans and get beans, and plant melons and get melons, indicating that organisms have genetic phenomena.

2.Chromosomes are mainly composed of two substances, DNA molecules and proteins, which are found in the nucleus of cells, and there is 1 DNA molecule on one chromosome, and each chromosome contains multiple genes. The main genetic material is DNA, which is located on chromosomes.

3.The chromosomes in the somatic cells of the human body exist in pairs, one of them from the father and one from the mother; Genes are present in pairs in somatic cells.

4.A gene is the basic unit of inheritance on a chromosome that controls a trait, and is a segment of the DNA that has a genetic effect, and the gene is located on the DNA. Genes control the traits of an organism by directing the synthesis of proteins to express the genetic information they carry.

Heritable variation is one that is caused by changes in the genetic material (mainly DNA) and can be passed on to future generations. For example, dogs have different coat colors, goldfish are artificially selected by crucian carp, seedless watermelon (change in the number of chromosomes), albinism, hemophilia (genetic change).

Non-hereditary variation refers to those that are caused by environmental factors and cannot be passed on to future generations without changes in genetic material. For example, in the field of the best black, the wheat planted on the fertile land grows vigorously.

According to the biological individual, it can be divided into favorable variants (such as dwarf mutations in wheat) and unfavorable variants (e.g., albino seedlings in wheat).

For example:1Children like parents belong to heredity, and there are more or less differences between children (including twins, twins), which belongs to variation; 2.

Planting melons and getting melons and planting beans and getting beans belong to heredity; 3.A mother gives birth to nine sons, and the nine sons are different and belong to mutations. There are many examples like this.

Children have the same body structure as their parents – head, neck, torso, limbs. This is heredity. But the appearance of the child is not exactly the same as that of the parents, and this is the variation.

The dragon gave birth to nine sons, each of whom was different. That is, there is a similarity between the traits between the child and the parents, which is hereditary; However, the traits between children and parents, and between siblings are not exactly the same, which is a variation.

Heredity and variation in living things are achieved through reproduction and development. There are always more or less differences between the parents and offspring of an organism and between the offspring of the individual, which is the phenomenon of biological variation. Some variations in living things are heritable and some are not.

Heritable variation refers to the variation that an organism can pass on to its offspring, including genetic recombination, genetic mutation, and chromosomal variation. This variation is caused by changes in the genetic material. Non-heritable variations are those caused by external factors such as light, water, etc., and will not be passed on to future generations.

Basic concepts of heredity and variation.

The phenomenon in which the parents of an organism can produce offspring similar to their own is called heredity. The basis of genetic material is deoxyribonucleic acid (DNA), and parents pass on their own genetic material DNA to their offspring, and the inherited traits and species remain relatively stable. The reason why life can continue from generation to generation is mainly due to the fact that the genetic material is passed down from generation to generation in the course of biological processes, so that the offspring have traits similar to those of the previous generation.

However, there is absolutely no exact same between parents and offspring, and between individuals of offspring, that is, there are always more or less differences, and this phenomenon is called variation. Heredity refers to the similarity between parents and children, and variation refers to differences between parents and children and between offspring. The heredity and variation of living things is achieved through reproduction and development.

Heredity and variation are opposites, heredity keeps species going, and variation keeps species evolving.

Heredity and variation are one of the fundamental characteristics of living things. It is a discipline that studies the structure and function of genes, as well as their variation, transmission and expression.

Genetics - the science of studying the heredity and variation of organisms, the study of the structure, function and variation, transmission and expression of genes. The concept of parent-child in genetics is not limited to parents and children or a family, but can also be extended to include a group of many families, which is the object of study in population genetics.

Genes are found in the nucleus, chromosomes, DNA of living things. Chromosomes appear in pairs, so DNA, genes all come in pairs. Normally, there are 23 pairs of chromosomes, 46 DNA molecules, and an infinite number of genes (there are countless genes in one DNA).

The research scope of genetics includes three aspects: the nature of genetic material, the transmission of genetic material and the realization of genetic information. The transmission of genetic material includes the duplication of genetic material, the behavior of chromosomes, the laws of heredity, and the quantitative changes of genes in a population. The purpose of modern genetics is to seek to understand the underlying mechanisms of the entire genetic process.

Heredity and variation are phenomena that are constantly and universally occurring in the biological world, and they are also the basis for speciation and biological evolution.