Natural Selection and Genetic Modification

What Natural Selection and Genetic Modification covers

Natural Selection and Genetic Modification is examined in Paper 1, Biology 1. It covers natural selection and antibiotic resistance, fossil and stone tool evidence for human evolution, the five kingdoms and the three domains of classification, selective breeding, and genetic engineering and its stages.

The 7 subtopics

Each one has its own page.

• Natural selection and antibiotic resistanceNatural selection from mutation, competition and survival of the best suited, how an advantageous allele spreads and new species form, why acquired characteristics are not selected, how antibiotic resistance and MRSA arise, finishing antibiotic courses and not prescribing them for viruses, and percentage calculations.Open →
• Fossil evidence for human evolutionThe Ardi, Lucy and Turkana Boy fossils, their ages, species and brain volumes, what their feet, legs and skeletons show about climbing and walking upright, calculating the time between fossils, and the trend in human evolution they reveal.Open →
• Stone tool evidence for human evolutionPebble tools, hand axes, flint points and hafted tools across 2.5 million years, what growing complexity suggests about brain size, and dating tools by rock layers and radiometric methods.Open →
• Five kingdoms and the three domainsThe older five kingdom classification and what it was based on, Carl Woese's three domains of Archaea, Bacteria and Eukarya, the genetic and chemical evidence for them, why archaea were separated from bacteria, and why genetic analysis classifies organisms more reliably than appearance.Open →
• Selective breedingHow the individuals showing a characteristic are chosen and bred over generations, the traits sought in crops and livestock, the gain in food production, and the loss of variation.Open →
• Genetic engineering and modern agricultureGenetic engineering and why a human gene works in a bacterium, insulin-making bacteria and golden rice, transgenic organisms, its advantages over selective breeding, engineered human insulin, the risks and ethical objections, a risk shared with selective breeding, and labelling and the long-term effects of GM organisms.Open →
• The stages of genetic engineeringRestriction enzymes and sticky ends, why the gene and vector are cut with the same enzyme, ligase, plasmids and viruses as vectors, the stages of inserting a human gene into a bacterium, recombinant plasmids, and why bacteria make useful host cells.Open →

What you need to know

Answer each one before you reveal it.

Take Natural Selection and Genetic Modification further

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Commonly confused

Pairs that lose marks when they are blurred together.

• Selective breeding vs Genetic engineering

  Selective breeding: choosing parents showing a desired characteristic and crossing them over many generations. Genetic engineering: inserting a gene from another organism to add a characteristic in one generation.

• Ardi vs Lucy

  Ardi: 4.4-million-year-old skeleton whose big toe stuck out sideways like a thumb. Lucy: 3.2-million-year-old skeleton with arched feet and human-like hips.

• Three domains vs Five kingdoms

  Three domains: classification into Archaea, Bacteria and Eukarya from molecular evidence. Five kingdoms: older classification based on observable features such as cell structure.

Questions from this topic

Each one with the model answer underneath.

1. 1

   What is meant by natural selection?

   Model answer

   It is the process in which individuals whose characteristics best suit their environment are most likely to survive, reproduce and pass on the alleles for those characteristics.

2. 2

   Where does the variation that natural selection acts on originally come from?

   Model answer

   Random mutations in DNA, which are then mixed into new combinations by sexual reproduction.

3. 3

   Explain why only some individuals in a population survive long enough to reproduce.

   Model answer

   More offspring are produced than the habitat can support, so individuals compete for limited food, water, space and mates.

4. 4

   Explain why an advantageous characteristic becomes more common in a population over time.

   Model answer

   Individuals with it survive and breed more successfully, so the allele for it is passed to a larger share of each new generation.

5. 5

   A population of mice on dark volcanic rock contains both dark-furred and light-furred individuals. Explain how the population changes over many generations.

   Model answer

   Dark mice are better camouflaged from predators, so they survive and breed more often and the allele for dark fur becomes more common.

6. 6

   Explain how natural selection can eventually give rise to a new species.

   Model answer

   If two populations become separated and face different conditions, different alleles are selected in each until the two groups can no longer breed together to give fertile offspring.

What is inside Levo

Six ways to work the same material.

Natural Selection and Genetic Modification revision questions

What does Natural Selection and Genetic Modification cover in Edexcel GCSE Combined Science Biology?

7 subtopics: natural selection and antibiotic resistance, fossil evidence for human evolution, stone tool evidence for human evolution, five kingdoms and the three domains, selective breeding, genetic engineering and modern agriculture and the stages of genetic engineering. Each one has its own page with questions and model answers.

How is Natural Selection and Genetic Modification organised?

By the Edexcel 1SC0 specification, subtopic by subtopic, so it matches the order you are taught it in.