2. (a) Changes in the environment affect the
distribution of living organisms.
• For example, the changing distribution of some bird
species and the disappearance of pollinating insects
including bees.
(b) Animals and plants are subjected to
environmental changes.
3. Changes may be caused by living or non-living factors.
Non-living (abiotic) factors:
Living (biotic) factors:
• Temperature
• Light
• Oxygen – air polution
• Water
• Disease
• Predation
• Competition
– for: food, light, water, space.
4. Native to the UK
(indigenous)
Introduced to the UK in the
19th century
8. Greys carry disease
60% of grey squirrels in England and Wales carry
the squirrel pox virus. While they are immune to the
disease it is deadly to reds.
Greys crowd out the reds
Greys eat seven times more food per hectare than
reds. They aggressively compete for food, crowding
out reds until eventually only greys are left.
