Home | | Science 10th Std | Variation

Types of variations | Origin and Evolution of Life - Variation | 10th Science : Chapter 19 : Origin and Evolution of Life

Chapter: 10th Science : Chapter 19 : Origin and Evolution of Life

Variation

Sexual reproduction, which involves meiosis helps in recombination of genes during gametic fusion. This leads to differences in the phenotype of the offspring from its parents. These differences are called variation.

Variation

Sexual reproduction, which involves meiosis helps in recombination of genes during gametic fusion. This leads to differences in the phenotype of the offspring from its parents. These differences are called variation.

Variation is the difference found among individuals of the same species and the offspring of the same parent. Variation is the raw material which plays an important role in evolution. Evolution would not be possible without variation.


Types of variations

Somatic variation: These are the variations which affect the body (somatic) cells of the organisms. They are not heritable. They occur due to environmental factors.

Germinal variation: These variations are produced in germ cells of an organism. They are inherited. They may be present in ancestors or may occur suddenly. They are classified into two types:

1. Continuous variation

2. Discontinuous variation

Continuous variation: These are small variations which occur among individuals of a population. They are also called as fluctuating variations. They occur by gradual accumulation in a population. e.g. skin colour, height and weight of an individual, colour of eye, etc.

Discontinuous variation: These are sudden changes which occur in an organism due to mutations. They do not have any intermediate forms. These large variations are not useful for evolution. e.g. short legged Ancon sheep, six or more digits (fingers) in human, etc.

Discontinuous variation form the basis for Mutation theory proposed by De Vries.

Tags : Types of variations | Origin and Evolution of Life , 10th Science : Chapter 19 : Origin and Evolution of Life
Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail
10th Science : Chapter 19 : Origin and Evolution of Life : Variation | Types of variations | Origin and Evolution of Life


Privacy Policy, Terms and Conditions, DMCA Policy and Compliant

Copyright © 2018-2023 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.