Blog
Modern Synthetic Theory Short Note | Evolution Class 12 Notes

In this article we will discuss about Modern Synthetic Theory of evolution:- Genetic Variation, Natural Selection and Isolation
- Modern theory of evolution combining Theory of natural selection and Theory of mutation
- This modern concept of evolution is synthesis of Darwin’s and Hugo de Vries’ theories
- This is also called Synthetic Theory of Evolution
- Synthetic theory of evolution is the result of the work of a number of scientists namely T. Dobzhansky, R.A. Fisher, J.B.S. Haldane, Swell Wright, Ernst Mayr and G.L. Stebbins.
Concept of Modern Synthetic Theory
- Genetic Variation
- Natural Selection
- Isolation
1. GENETIC VARIATION
i) Mutations
- Mutations are sudden heritable changes
- Mutations are of two types
- Chromosomal Mutations: due to changes in chromosome number and changes in structure
- Gene Mutations: Sudden change in a gene is called gene mutation or point mutation
ii) Hybridization
- Mating of unrelated individuals
- Offspring’s are called hybrids
iii) Recombination
- New combinations of genes which are usually caused by the crossing over during gametogenesis
- It is continuous and common source of variation in a sexually reproducing population
iv) Genetic drift
- Elimination of gene or alleles from population
2. NATURAL SELECTION
- Organisms with favorable variation succeed in the struggle for existence
- They are fittest for survival and other animals unfit to survival
- Fitness and unfitness is decided by environment
- Process of selection of organisms with favorable variation is called natural selection
3. ISOLATION
- Isolation is a segregation of populations by some barriers which prevent interbreeding
- The reproductive isolation between the population due to certain barriers leads to the formation of new species
- Blog1 week ago
[PPT] The living world Class 11 Notes
- Blog1 week ago
[PPT] Human Reproduction Class 12 Notes
- Entertainment4 days ago
Ibomma Bappam: Redefines Telugu Streaming Trend
- Blog1 week ago
[PDF] NEET Biology Study Materials Download
- Blog1 week ago
Class 11 Biology Notes Chapter wise PPT
- Blog1 week ago
Class 12 Biology Notes Chapter wise PPT
- Blog1 week ago
Biology Study Notes Class Wise PPT
- Blog1 week ago
Download NEET Biology Study Materials in Tamil