Worksheet: Variation

In this worksheet, we will practice describing examples of genetic, environmental, continuous, and discontinuous variation.


The graph shows the percentage of a population of plants with a given number of flowers. What type of variation is the number of flowers?

  • ADiscontinuous
  • BContinuous


A group of scientists want to investigate the effect of different soil conditions on plant growth. They cloned a plant to get a total of 7 plants and grew them in different nitrate concentrations for 14 days. They then repeated this with a different species of plant. The table given shows their results.

Nitrate Concentration (ppm) Overall Plant Growth (mm) Species 1 Overall Plant Growth (mm) Species 2
5 16 24
10 18 28
15 20 31
20 22 36
25 26 39
30 28 42
35 30 44

The scientists cloned the plants so they were genetically identical. Which of the following best explains why this was important?

  • ABecause the plants all looked the same
  • BBecause any changes in growth would be due to genetic variation alone
  • CBecause any changes in growth would be due to environmental variation alone
  • DBecause the plants would all grow the same amount

Which of the following conclusions is correct, based on the data given?

  • APlant growth is due to genetic factors alone.
  • BPlants of the same species will grow the same amount, no matter where they are grown.
  • CPlant growth is due to environmental factors alone.
  • DPlant growth is due to genetic and environmental factors.

Is plant growth an example of continuous or discontinuous variation?

  • AContinuous
  • BDiscontinuous


What is the correct key term for the variation that is caused by where an organism lives and what it interacts with?

  • AEnvironmental variation
  • BGenetic variation
  • CEpidemic variation
  • DExternal variation


Give the correct key term for the differences in the characteristics of organisms.

  • AVariation
  • BGenotypes
  • CSymptoms
  • DDifferentiation
  • EPhenotypes


Give the correct key term for the variation that is caused by differences in alleles that are inherited or caused by mutations.

  • AEnvironmental variation
  • BGenetic variation
  • CMutagenic variation
  • DGeneric variation


Give the correct key term for the physical characteristics of an organism.

  • AMorphology
  • BGenotype
  • CPhenotype
  • DVariation
  • EGenome


The graph given shows the frequency of different stem lengths in a population of plants.

What type of variation does this graph show?

  • AContinuous
  • BDiscontinuous

Which of the following best explains how this graph shows a normal distribution?

  • AThe mode is smaller than the median.
  • BThe mean is the same as the median and the mode.
  • CThe mean is larger than the median.
  • DThe mean, median, and mode are all different values.

Variations in the stem length can be caused by mutations. Which of the following correctly defines mutations?

  • AChanges in the sugar–phosphate backbone of DNA
  • BChanges in the DNA base sequence
  • CA section of DNA that codes for a protein
  • DChanges in the phenotype

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