Heredity | Class 10 Science Notes

Variation and Mutation

This section discusses the causes and significance of variation in living organisms. Variation refers to the differences in traits among individuals of the same species. These variations arise due to differences in genetic material and environmental influences. Genetic variation is primarily caused by mutations, which are changes in the DNA sequence. Mutations can occur spontaneously or due to external factors such as radiation or chemicals. Some mutations may be harmful, beneficial, or neutral. Variation is essential for evolution as it provides the raw material for natural selection. It allows populations to adapt to changing environments and survive over time. The section also explains that variation can be continuous (e.g., height, skin colour) or discontinuous (e.g., blood groups, flower colour). Understanding variation helps in fields like breeding, conservation, and medicine. The section emphasizes that while heredity transmits traits, variation introduces new traits, contributing to biodiversity.

📊 Diagram: No specific diagram in this section.

🧪 Activity: Studying variation in traits such as blood groups and height in a class or community.

🔗 Connection: This section concludes the chapter by summarizing heredity concepts and their importance in biology.