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BIOLOGY, M3 EQ-Bank 9

Researchers have observed significant changes in cane toad populations since their introduction to Australia.

Describe one modern-day adaptation discovered in cane toads how it relates to the process of natural selection.   (3 marks)

Show Answers Only
  • Recent studies have revealed that cane toads at the invasion front in Australia have evolved to disperse more rapidly than their ancestors.
  • These modern toads have developed longer legs, allowing them to hop faster,  cover greater distances and colonise new areas more quickly than initially predicted.
  • These changes support natural selection by demonstrating an inherited trait that is passed to offspring and becomes more common in the population.
  • However, researchers have also found that faster “front line” cane toads are more likely to be eaten, breed less and have more spine arthritis than their ancestors.
  • The natural selection principle of traits that enhance survival and reproductive success being passed on is seemingly contradicted by these findings.
Show Worked Solution
  • Recent studies have revealed that cane toads at the invasion front in Australia have evolved to disperse more rapidly than their ancestors.
  • These modern toads have developed longer legs, allowing them to hop faster,  cover greater distances and colonise new areas more quickly than initially predicted.
  • These changes support natural selection by demonstrating an inherited trait that is passed to offspring and becomes more common in the population.
  • However, researchers have also found that faster “front line” cane toads are more likely to be eaten, breed less and have more spine arthritis than their ancestors.
  • The natural selection principle of traits that enhance survival and reproductive success being passed on is seemingly contradicted by these findings.