WJEC A2 Biology Student Unit Guide: Unit BY5: Environment, Genetics and Evolution

WJEC A2 Biology Student Unit Guide: Unit BY5: Environment, Genetics and Evolution

Dan Foulder

Language: English

Pages: 88


Format: PDF / Kindle (mobi) / ePub

Perfect for revision, these guides explain the unit requirements, summarise the content and include specimen questions with graded answers.

Each full-colour New Edition Student Unit Guide provides ideal preparation for your unit exam:

Feel confident you understand the unit: each guide comprehensively covers the unit content and includes topic summaries, knowledge check questions and a reference index
Get to grips with the exam requirements: the specific skills on which you will be tested are explored and explained
Analyse exam-style questions: graded student responses will help you focus on areas where you can improve your exam technique and performance

Biology Under the Influence: Dialectical Essays on the Co-evolution of Nature and Society

Biology Under the Influence: Dialectical Essays on the Co-evolution of Nature and Society

Spontaneous Evolution: Our Positive Future and a Way to Get There From Here

Drawing the Map of Life: Inside the Human Genome Project



















There is variation in the two populations. As long as there is no interbreeding, Sample student then, over time, through natural selection they could become different species. answers 4/8 marks awarded (a) Continuous variation is correct but ‘the line is continuous’ cannot score the mark for explanation. (b) This is correct and gains the mark. Genetic drift is also an acceptable answer. (c) The student scores 2 marks here, 1 mark for ‘no interbreeding’ and 1 mark for ‘natural selection’. The

potential food available to primary consumers. NPP = GPP – energy used in respiration by the plant Herbivores have a lower efficiency of energy conversion compared to carnivores. This is because of the different diets of herbivores and carnivores. The diet of a herbivore contains a large amount of difficult to digest molecules such as cellulose. This means that herbivore digestion is relatively inefficient. In contrast to this carnivore digestion is relatively efficient due to the large amount of

conservation strategies in the BY5 specification. Agricultural exploitation As the world’s population increases and becomes richer, the pressure on agricultural food production has increased. This has led to: L Increased mechanisation More and more machines are used in farming. This has necessitated the use of bigger fields, so hedgerows (important habitats) have been removed. This has reduced biodiversity. L Monoculture This is the growth of a single crop. This creates problems in terms of

DNA replication is important in both mitosis and meiosis and occurs during interphase. (b) This answer is correct and scores 1 mark. (c) The student has drawn the correct bands in both tubes so scores the available marks. (d) This answer is too simplistic to score either of the 2 marks available. Student B (a) Interphase (b) In adenine (c) Light Heavy 1st generation 64 WJEC A2 Biology DNA replication Question 1 (d) This investigation showed DNA was semi-conservatively replicated as it

interbreeding’ and 1 mark for ‘natural selection’. The remaining 3 marks are for naming the type of speciation occurring (allopatric), mentioning how genetic drift could also lead to speciation and explaining what would happen once the populations had become different species (unable to interbreed to produce fertile offspring). 72 WJEC A2 Biology Variation and evolution Question 6 Student B (a) The graph shows continuous variation. A variable such as body mass is controlled by a number of

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