Changes due to Selection Pressures
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)