GCSE Biology - Inheritance, variation and evolution
GCSE·2 mins·01/11/21

GCSE Biology - Inheritance, variation and evolution


Inheritance, variation and evolution is a fascinating topic within biology as increasing knowledge of genes, reproduction and mutations has contributed to the discovery of selective breeding and genetic engineering; these processes will have many potential benefits such as saving millions of lives. It is important to have revised cell biology prior to revising this topic. When tackling questions, you will need the following materials:

  • Calculator
  • Sharp pencil
  • Pencil


This topic builds upon cell biology by diving into deeper detail concerning sperm and egg cells in animals and pollen and egg cells in plants. You will need to be able to highlight the differences between sexual and asexual reproduction; make sure you also know what each process involves, requires and their technical name (such as mitosis/meiosis). You also need to be familiar with the structure of DNA and the definition of a genome, also explaining why it is important. An understanding of genetic inheritance, inherited disorders, sex determination, variation and evolution and classification will also be required.

Exam techniques GCSE:

A great exam technique that I constantly recommend is the use of diagrams. Drawing sperm, pollen and egg cells makes it easier to visualise the structure. It will also be beneficial to label the diagrams, especially from memory to highlight which parts you are more or less confident in. I have provided some more examples of how to use diagrams, like homeostasis. Here is an example:

Within this topic you may be asked to list advantages and disadvantages of sexual and asexual reproduction. A great way to revise this is to write out a pros and cons list for both forms of reproduction, this will allow you to answer such questions much quicker giving you time to focus on the hard parts of your exam. Example:

You may be asked to recall the process of protein synthesis, genetic engineering and cloning. When revising longer processes a good technique is to draw a flowchart, diagrams can also be included for visualisation. This will help you remember the process in steps which make it easier to learn and prevent you from missing any content out.

Throughout this topic you will be expected to understand the terms gamete, allele, homozygous etc. Revising this using flashcards makes the memorising much easier. To properly use flashcards, on one side write the term and on the other write the definition.

Within the subtopic of sex determination, you may be asked to carry out a genetic cross to show sex inheritance. When drawing a Punnett square, in order to gain high marks, make sure you draw straight lines using a ruler and sharp pencil. It will also be helpful to label it showing which one is the mother/father and label which sex each offspring will be. Here is an example:

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Haris Shoaib

Medical Student at King's College London| 7 years teaching experience | DBS ✅

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