Example of variation: a mother gives birth to nine children, and nine children are different. A tree bears sweet and sour fruit. Parents have normal skin color and albino children. You can't find two identical leaves in nature. Peanut fruit has big fruit and small fruit.
Genetic phenomenon refers to the phenomenon that offspring acquire parents' characteristics and traits through gene transmission. Genetics studies this phenomenon.
In the colorful biological world, there are all kinds of variations. Some of these variations are only caused by environmental factors and do not cause changes in biological genetic material, so they cannot be inherited and belong to non-genetic variations.
Some variation phenomena are due to the change of genetic material in germ cells, so they can be passed on to future generations and belong to heritable variation. There are three sources of genetic variation: gene mutation, gene recombination and chromosome variation. There is no evolution without variation, which is the undoubted knowledge of all evolutionists since ancient times. However, about the source of variation and how to interweave (gradual change-mutation) in the process of seed formation.
Examples of biological inheritance and variation
Examples of genetic phenomena:
Generally speaking, the nose is big and high, and the nostril width is dominant. If one of the parents has a straight nose, it is likely to be passed on to the child.
Generally, one parent has dimples, and the other children generally have dimples.
Red-green color blindness, caused by X-linked recessive gene, is about 10% in men, but not common in women. In men, the gene that causes color blindness comes from the mother, who is a color-blind patient or a color-blind gene carrier and has normal vision. The color blindness gene does not come from the father, because the father provided the Y chromosome. Daughters of color-blind fathers are rarely color-blind, but they are often carriers of color-blind genes.
Isodominant inheritance, both genes are expressed. Such as sickle cell anemia; If a person has both normal and abnormal genes, it is possible to produce normal and abnormal hemoglobin.
V-shaped hairline, generally speaking, one parent has a V-shaped hairline, and their children will also have a V-shaped hairline.