Variation
Overview
Line up thirty people from the same class and ask them their blood group. You will get four answers and nothing in between: nobody is halfway between group A and group O. Now ask the same thirty to stand against a wall and measure them. This time no two answers are quite alike, and every value between the shortest and the tallest is filled in by somebody. The same room, the same species, two completely different shapes of difference.
Behind both of them sit the two causes this topic names: the alleles an organism inherited, and the conditions it grew up in. You will learn how mutation creates something genuinely new while reproduction only reshuffles what already exists, why a suntan is never passed to a child, and why almost every characteristic you can actually see is the work of both causes together. Then you will handle the numbers, because on this course variation is as much a data skill as a biology one: building a frequency table, estimating a mean from grouped readings, choosing a sample that can carry a conclusion, and spotting the moment a claim runs further than the evidence behind it.
Objectives
- The causes of variation include: genetic variation - different characteristics as a result of mutation or reproduction; environmental variation - different characteristics caused by an organism’s environmental (acquired characteristics).
Mind map
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Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Variation. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Which characteristic of a human population falls into separate groups with no intermediates? A. Body mass B. Hand span C. ABO blood group D. Height Answer: C
- An unbroken range of values for a characteristic in a population is usually caused by A. one gene only, with no environmental effect B. many genes together with environmental effects C. the environment only, with no genetic effect D. a single mutation in one individual Answer: B
- Which of these is an acquired characteristic? A. The ability to roll the tongue B. A suntan gained during a summer holiday C. Blood group A D. Brown eye colour Answer: B
- In a sample of 200 students, 90 were blood group O. What percentage of the sample was blood group O? A. 9% B. 22.5% C. 45% D. 90% Answer: C
- Which process is the original source of new alleles in a population? A. Sexual reproduction B. Asexual reproduction C. Mutation D. Environmental variation Answer: C
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