Back to Course

HSC Biology

0% Complete
0/46 Steps
Lesson 6, Topic 2
In Progress

Changes due to Selection Pressures

Lesson Progress
0% Complete

Cane Toads

Changes in Abundance and Distribution

  • Abundance has increased as they have no predators to kill them
  • Destruction; they were introduced from Hawaii in 1935

Selection Pressures – Change

  • Due to having no predators and natural diseases, the cane toad has become a pest in Australia
  • No successful selection pressure
  • Companion with themselves so they eat each other

Prickly Pears

Changes in Abundance and Distribution

  • Introduced in 1800s
  • Adapted quickly to Australia’s diverse and dry environment

Selection Pressures – Change

  • No predators
  • Cactoblastis moth (biotic pressure which reduced numbers)