Unit 2 - Construct Genetic Diagrams (H)

In GCSE Biology students will spend some time studying genetics. Learning how to construct and interpret genetic diagrams, such as the Punnet square, will help them to predict the outcomes of genetic crosses.

Scientists in the 19th Century were fascinated by the living world, but there were many things that they still didn't understand. It took Charles Darwin many years to work out and publish his book about evolution by natural selection (titled The Origin of Species) but had he known about genetics, it would have been much easier for him. At the time when Darwin published his book, an Augustinian friar called Gregor Mendel was carrying out a series of experiments with pea plants. He cross-pollinated plants with different characteristics and observed which of these were passed on to subsequent generations. He eventually noticed patterns appearing that could only be explained if some of the 'factors' were dominant and others were recessive. His work was re-discovered in the early part of the 20th Century and from that the science of genetics was born.