GCSE Biology: Cloning, Speciation and Evolutionary Trees

This material extends the variation and evolution content already in this category, which covers natural selection, selective breeding, antibiotic resistance, genetic engineering and classification. It concentrates on the parts of the inheritance, variation and evolution topic that belong mainly to separate GCSE Biology (for example, the AQA sections on cloning, the theory of evolution, speciation, fossils and extinction) and on the evolutionary tree questions that often appear as data items.

The first part is about cloning. You compare the plant methods — cuttings, used by gardeners for generations, and tissue culture, where small groups of cells grow into identical plants for commercial nurseries or to preserve rare species — with the animal methods: embryo transplants, in which cells are split from an embryo before they become specialised, and adult cell cloning, in which the nucleus of an adult body cell is placed in an unfertilised egg cell whose own nucleus has been removed. A question with three sheep checks that you know where the clone's genes come from. You also weigh up sexual and asexual reproduction: variation and adaptation to change against speed and the need for only one parent.

The second part follows the history of evolutionary theory. You look at the evidence Darwin drew on, why his theory of evolution by natural selection, published in On the Origin of Species in 1859, was accepted only gradually, how Wallace independently reached the same idea and published joint writings with Darwin in 1858, and why Lamarck's idea that changes acquired during a lifetime are inherited is rejected in the vast majority of cases. You then describe the steps of speciation, from the isolation of two populations to the point where they can no longer interbreed to produce fertile offspring.

The final part covers the evidence of the past: the three ways in which fossils form, why the origin of life remains uncertain, how to read an evolutionary tree described in words, and the factors that can drive a species to extinction.

Four formats are offered. The quiz has twelve questions with explanations. The flashcards cover the key terms, from tissue culture and embryo transplant to common ancestor and extinction. The printable written sheet has eight longer questions — describing adult cell cloning, comparing cloning methods with a short calculation, explaining speciation with an example, explaining the slow acceptance of Darwin's ideas, reading evolutionary relationships and explaining extinction — to complete by hand and photograph for feedback. The oral exam lets you discuss these ideas with an examiner who asks one question at a time and gives brief feedback at the end.

Any numbers in the questions are illustrative.

• Describe tissue culture, cuttings, embryo transplants and adult cell cloning
• Identify which organism a clone is genetically identical to
• Compare the advantages and disadvantages of sexual and asexual reproduction
• Explain why Darwin's theory was only gradually accepted, and describe the contributions of Wallace and the ideas of Lamarck
• Describe the steps of speciation
• Describe how fossils form, interpret evolutionary relationships and explain the causes of extinction

Practice material written by Zestly, based on the DfE GCSE biology subject content and exam-board specification content for separate Biology (for example, AQA GCSE Biology 8461: cloning; theory of evolution; speciation; fossils; extinction). Numbers in the questions are illustrative.