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VICBiologyQuick questions
Unit 4: How does life change and respond to challenges over time?
Quick questions on Evolution by natural selection (Darwin, Wallace, fitness, adaptation): VCE Biology Unit 4
9short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is the conditions for natural selection?Show answer
Natural selection occurs whenever four conditions are met:
What are selection pressures?Show answer
A selection pressure is any factor that causes differential survival or reproduction. Common examples include:
What is fitness?Show answer
Fitness is the relative reproductive success of an individual or genotype: how many viable, fertile offspring it leaves compared with others. It is measured by descendants, not by strength or longevity.
What is adaptation?Show answer
An adaptation is a heritable trait that increases an organism's fitness in its environment. Adaptations can be:
What is change in allele frequency?Show answer
Evolution at the population level is measured by a change in allele frequency in the gene pool. If the allele for grey beetle colour rises from 30 per cent to 80 per cent of the population over twenty generations, the population has evolved.
What is other mechanisms of evolution?Show answer
Although natural selection is the focus, three other mechanisms also change allele frequency:
What is q1?Show answer
State the four conditions required for natural selection to operate, as proposed by Darwin and Wallace. [4 marks]
What is q2?Show answer
In a wheat field, 80 percent of plants carry rust-resistance allele R. Calculate (a) allele frequency of R, (b) expected genotype frequencies under Hardy-Weinberg, and (c) the new allele frequency if 10 percent of resistant plants and 50 percent of susceptible plants die from rust. [3 marks]
What is q3?Show answer
Refer to MRSA in hospitals. (a) Explain how variation in resistance arose initially. (b) Identify the selection pressure.