For each of the examples given below, suggest whether the variation is caused by genes alone, or by both genes and environment. Blood group in humans Foot size in humans Leaf length in a species of tree Presence of horns in cattle

Genetic variation is the difference in DNA among individuals or the differences between populations. There are multiple sources of genetic variation, including mutation and genetic recombination. Mutations are the ultimate sources of genetic variation, but other mechanisms such as sexual reproduction and genetic drift contribute to it as well. A plant in the shade of a big tree will grow taller as it tries to reach more light. Variation caused by the surroundings is called environmental variation. Here are some other examples of features that show environmental variation: your language, your religion. Hence, it shows that the given example, blood group in humans and presence of horns in cattle genes both are genetic variation. Whereas, the foot size in humans and leaf length in a species of tree genes are environmental variation.

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Cambridge IGCSE® Biology Coursebook Third Edition>Chapter 19 - Variation and Natural Selection>Questions

Mary Jones and Geoff Jones Solutions for Chapter: Variation and Natural Selection, Exercise 1: Questions

Author:Mary Jones & Geoff Jones

Mary Jones Biology Solutions for Exercise - Mary Jones and Geoff Jones Solutions for Chapter: Variation and Natural Selection, Exercise 1: Questions

Attempt the practice questions on Chapter 19: Variation and Natural Selection, Exercise 1: Questions with hints and solutions to strengthen your understanding. Cambridge IGCSE® Biology Coursebook Third Edition solutions are prepared by Experienced Embibe Experts.