Variation
Overzicht
No two individuals of a species are exactly alike, and that variety is the raw material of evolution. Some differences fall into neat, separate categories; others form a smooth range. Understanding which is which, and where new variation comes from, is the bridge between genetics and natural selection.
In this lesson you will define variation, distinguish continuous from discontinuous variation with examples, link each to its causes, investigate both types, and explain mutation as the source of new alleles, including what raises the mutation rate and (for Extended) the other sources of genetic variation in populations.
Doelstellingen
- Describe variation as differences between individuals of the same species
- State that continuous variation results in a range of phenotypes between two extremes; examples include body length and body mass
- State that discontinuous variation results in a limited number of phenotypes with no intermediates; examples include ABO blood groups, seed shape in peas and seed colour in peas
- State that discontinuous variation is usually caused by genes only and continuous variation is caused by both genes and the environment
- Investigate and describe examples of continuous and discontinuous variation
- Describe mutation as genetic change
- State that mutation is the way in which new alleles are formed
- State that ionising radiation and some chemicals increase the rate of mutation
- [Supplement] Describe gene mutation as a random change in the base sequence of DNA
- [Supplement] State that mutation, meiosis, random mating and random fertilisation are sources of genetic variation in populations
Lesnotitie
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Lesevaluatie
Gefeliciteerd met het voltooien van de les op Variation. Nu je de sleutelconcepten en ideeën, het is tijd om uw kennis op de proef te stellen. Deze sectie biedt een verscheidenheid aan oefeningen vragen die bedoeld zijn om uw begrip te vergroten en u te helpen uw begrip van de stof te peilen.
Je zult een mix van vraagtypen tegenkomen, waaronder meerkeuzevragen, korte antwoordvragen en essayvragen. Elke vraag is zorgvuldig samengesteld om verschillende aspecten van je kennis en kritisch denkvermogen te beoordelen.
Gebruik dit evaluatiegedeelte als een kans om je begrip van het onderwerp te versterken en om gebieden te identificeren waar je mogelijk extra studie nodig hebt. Laat je niet ontmoedigen door eventuele uitdagingen die je tegenkomt; beschouw ze in plaats daarvan als kansen voor groei en verbetering.
- Variation is best defined as: A. differences between individuals of different species B. differences between individuals of the same species C. the inheritance of alleles D. a change in the environment Answer: B
- Which is an example of continuous variation? A. ABO blood group B. tongue rolling C. human height D. seed shape in peas Answer: C
- Discontinuous variation is usually caused by: A. the environment only B. genes only C. genes and the environment D. diet only Answer: B
- Mutation is best described as: A. the shuffling of existing alleles B. genetic change that forms new alleles C. a type of meiosis D. an environmental effect Answer: B
- Which factor increases the rate of mutation? A. a balanced diet B. ionising radiation C. regular exercise D. drinking water Answer: B
Beschikbaar in de Green Bridge-app
Download de Green Bridge CBT-app op je telefoon of computer voor toegang tot volledige lesnotities, oefenvragen en meer.
Beschikbaar in de Green Bridge-app
Download de Green Bridge CBT-app op je telefoon of computer voor toegang tot volledige lesnotities, oefenvragen en meer.
Aanbevolen Boeken
Oefen Proefexamenvragen
Wilt u proefexamenvragen over Variation oefenen? Download de Green Bridge CBT-app voor toegang tot proefexamenvragen en volledige oefentoetsen over dit onderwerp.
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