Key term
Eduqas A-Level Biology A400QS
Biological Molecules
Cell Structure and Organisation
Cell Membranes and Transport
Enzymes
Nucleic Acids and Their Functions
Importance of ATP
Photosynthesis
Respiration
Microbiology
Population Size and Ecosystems
Topic overviewPopulation growth and its measurementThe population growth curve and carrying capacityDensity dependent and density independent factorsSampling abundance and distributionEcosystems, habitats and communitiesEnergy transfer and pyramids of biomassSuccessionDecomposition and the carbon cycleThe nitrogen cycle and human interventionEutrophication and the effects of drainage
Human Impact on the Environment
Classification and Biodiversity
Topic overviewThe need for classification and the taxonomic hierarchyThe three domain and five kingdom systemsCharacteristic features of the five kingdomsAssessing relatedness by physical features and biochemistryThe species concept and the binomial systemBiodiversity, adaptation and natural selectionMeasuring biodiversity in a habitatGenetic and molecular measures of biodiversity
Mitosis and Meiosis
Sexual Reproduction in Humans
Sexual Reproduction in Plants
Inheritance
Variation and Evolution
Application of Reproduction and Genetics
Topic overviewThe Human Genome Project, other sequenced genomes and genomics in healthcareScreening embryos, stem cells and the ethical issuesGenetic fingerprinting, PCR and electrophoresis in forensic workRecombinant DNA and the production of human insulinGenetically modified crops and gene therapy
Adaptations for Gas Exchange
Topic overviewSurface area to volume ratio and gas exchange in small organismsSpecialised respiratory surfaces and the need for ventilationGills and counter current flow in bony fishThe human breathing system and its histologyVentilation and gas exchange in humansThe insect tracheal systemThe angiosperm leaf, stomata and gas exchange
Adaptations for Transport
Topic overviewVascular systems compared across animal groupsThe mammalian heart and blood vesselsThe cardiac cycle and its controlBlood, haemoglobin and dissociation curvesThe Bohr effect, chloride shift and tissue fluidThe root and the uptake of waterThe endodermis and the entry to the xylemXylem, transpiration and cohesion-tensionThe potometer and xerophytes and hydrophytesPhloem and translocation
Adaptations for Nutrition
Homeostasis and the Kidney
The Nervous System
Immunology and Disease: Disease and Its TransmissionImmunology
Immunology and Disease: AntibioticsImmunology
Immunology and Disease: The Immune ResponseImmunology
Human Musculoskeletal Anatomy: Skeletal TissuesMusculoskeletal
Topic overviewCartilage and its three typesThe composition and functions of compact boneBone remodelling and the Haversian systemRickets, osteomalacia, osteoporosis and brittle bone diseaseThe structure of skeletal muscleThe sliding filament theoryFast and slow twitch fibres, and energy for contraction
Human Musculoskeletal Anatomy: Structure and Function of the SkeletonMusculoskeletal
Human Musculoskeletal Anatomy: JointsMusculoskeletal
Neurobiology and Behaviour: The BrainNeurobiology
Neurobiology and Behaviour: NeuroscienceNeurobiology
Variation and Evolution
- 6 subtopics
- 18 things to know
- Component 2
What Variation and Evolution covers
Variation and Evolution is examined in Component 2, Continuity of Life. It covers genetic and environmental sources of variation, investigating continuous variation and the t test, competition and selective agencies, gene pools, genetic drift and selection, the Hardy-Weinberg principle and isolation, speciation and Darwin's theory of evolution.
The 6 subtopics
Each one has its own page.
- Genetic and environmental sources of variationWhy mutation is the ultimate source of all new alleles, continuous variation and why a scar is an example of non-heritable variation.Open →
- Investigating continuous variation and the t testGraph is drawn from grouped continuous data and student's t test used to find out.Open →
- Competition and selective agenciesIntraspecific competition, interspecific competition and competitive exclusion principle.Open →
- Gene pools, genetic drift and selectionFrequency of an allele in a population, evolution in terms of the gene pool and genetic drift.Open →
- The Hardy-Weinberg principleHardy-Weinberg equation relating the two allele frequencies, hardy-Weinberg equation relating the genotype frequencies and four conditions under which the Hardy-Weinberg principle applies.Open →
- Isolation, speciation and Darwin's theory of evolutionGeographical isolation, behavioural isolation and seasonal isolation.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Explain how the repeated use of an insecticide acts as a selective agency.
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Describe how geographical isolation can lead to speciation.
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What is meant by variation?
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Why is a large sample taken when continuous variation is investigated?
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Why is the gene pool of a population described as changing rather than fixed?
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What does the Hardy-Weinberg principle state?
Process
Give three genetic processes that create variation between individuals.
Key term
Give one continuous character that could be measured to investigate variation in a plant species.
Key term
Define evolution in terms of the gene pool.
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State the Hardy-Weinberg equation relating the two allele frequencies.
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Define speciation.
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Give three environmental factors that produce variation between plants of one species.
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How are measurements grouped before they are displayed?
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Define intraspecific competition.
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Define genetic drift.
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State the Hardy-Weinberg equation relating the genotype frequencies.
Key term
What must happen to two populations before they can become separate species?
Take Variation and Evolution further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Student's t test compares the vs The chi squared test compares the
Student's t test compares the: of two sets of measurements. The chi squared test compares the: it compares counts in categories with the numbers expected.
Questions from this topic
Each one with the model answer underneath.
- 1
What is meant by variation?
Model answer
Variation is the set of differences that exist between the individual organisms of a species.
- 2
Give three genetic processes that create variation between individuals.
Model answer
Mutation, the reshuffling of alleles during meiosis, and the random fusion of gametes at fertilisation.
- 3
Explain why mutation is the ultimate source of all new alleles.
Model answer
Every allele began as a change in the base sequence of an existing one, and no other process can produce a form of a gene that was not there before.
- 4
Give three environmental factors that produce variation between plants of one species.
Model answer
The intensity of the light they receive, the supply of mineral ions in the soil and the availability of water.
- 5
Give two environmental factors that produce variation between people.
Model answer
The diet a person eats and the amount of exercise taken.
- 6
Define continuous variation.
Model answer
Continuous variation is variation in which individuals may take any value within a range, with no distinct categories between them.
What is inside Levo
Six ways to work the same material.
Variation and Evolution revision questions
- What does Variation and Evolution cover in Eduqas A-Level Biology?
- 6 subtopics: genetic and environmental sources of variation, investigating continuous variation and the t test, competition and selective agencies, gene pools, genetic drift and selection, the hardy-weinberg principle and isolation, speciation and darwin's theory of evolution. Each one has its own page with questions and model answers.
- How is Variation and Evolution organised?
- By the Eduqas A400QS specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Variation and Evolution, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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