Principle of inheritance and variation Important points For NEET : The principles of inheritance and variation are the two fundamental concepts in genetics that helps to explain how the traits are passed down from one generation to next.
The principle of inheritance states that the genetic material, in form of the genes, is passed from the parents to the offspring through the reproductive cells. These genes contains the instructions for the development of the various physical and the biological traits, such as the eye color, height, and susceptibility to certain diseases. In the sexually reproducing organisms, each parent contributes half of their genetic material to offspring, resulting in a unique combination of the traits in each of the individual.
The principle of variation, on the other hand, refers to differences that exists in between the individuals, even within same species. These variations can be caused by the genetic factors, such as the mutations, as well as the environmental factors, such as diet, exposure to the toxins, and the physical activity. Variation is important because it allows for the natural selection to occur, where the individuals with advantageous traits are more likely to survive and reproduce, passing on their genes to next generation.
Together, principles of inheritance and variation provides a framework for understanding how the genetic material is passed down and how the traits evolves and change over the time. They are the essential concepts in field of genetics and have the important implications for the fields such as medicine, agriculture, and conservation.
Principle of inheritance and variation important points, Principle of inheritance and variation important points, Principle of inheritance and variation important points, Principle of inheritance and variation important points, Principle of inheritance and variation important points, Principle of inheritance and variation important points, Principle of inheritance and variation important points
NCERT biology class 12 chapter 5 – 25 important points on principle of inheritance and variation
There are 25 important points on principle of inheritance and variation important points:
1. The principle of inheritance states that the traits are passed down from the parents to the offspring through transmission of the genetic information.
2. The genetic information is carried by the genes, which are located on the chromosomes.
3. Chromosomes come in pairs, one from each of the parent.
4. The principle of segregation states that each of the parent contributes one of their two copies of a gene to their offspring.
5. The principle of independent assortment states that the genes for different traits are inherited independently of each other.
6. Alleles are the different versions of same gene.
7. Homozygous individuals have the two identical alleles for a gene, while the heterozygous individuals have the two different alleles.
8. The dominant allele is expressed in phenotype of a heterozygous individual, while recessive allele is only expressed when it is present in the two copies.
9. A genotype is genetic makeup of an individual, while a phenotype is observable physical or the biochemical characteristics of an individual.
10. Incomplete dominance occurs when heterozygous phenotype is the intermediate between two homozygous phenotypes.
11. Codominance occurs when both the alleles are expressed in phenotype of a heterozygous individual.
12. Polygenic inheritance occurs when a trait is determined by combined effects of the multiple genes.
13. The environment can also influence expression of the genes.
14. Mutations are the changes in DNA sequence that can be inherited and may lead to the genetic variation.
15. Genetic variation is important for the evolution to occur.
16. Natural selection is a process by which the certain traits become more or less common in a population over time, based on their effects on survival and reproduction.
17. Genetic drift is a random fluctuation of allele frequencies in a population, which can lead to loss of the genetic variation.
18. Gene flow is movement of the genes between the populations, which can introduce new alleles and increase the genetic variation.
19. Evolutionary adaptations are the traits that have evolved through the natural selection to increase an organism’s fitness.
20. Speciation is a process by which new species arise from a common ancestor.
21. Hybridization is a process by which the two different species interbreed and produce offspring.
22. Breeding is a mating of the closely related individuals, which can increase expression of the harmful recessive alleles.
23. Genetic counseling is a process in which the individuals and families are advised about risks and consequences of the genetic disorders.
24. Genome editing technologies such as CRISPR/Cas9 have potential to cure the genetic diseases, but also raise ethical and social concerns.
25. The study of the inheritance and the variation is important for understanding genetic basis of the human health and disease, as well as for conservation of the biodiversity.
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155 out of 200 questions were directly asked from these notes in NEET 2024
