1. POPULATIONS

2. Population size
A population is the number of a species living in a particular area

3. What factors could change a population?
Competition
Predation
Migration
Disease
Natural disasters
War
For food, water and space
Predators will eat prey and reduce the population (including the number of offspring)
Members of the population may leave the area
A disease could kill some of the population
Drought, fire, floods, volcanic eruptions etc could alter the habitat and affect the population
Wars can result in the death of many members of a population

4. What else can affect the numbers and the distribution of a population?
How well are individuals adapted?
This will affect their survival in a habitat.
What else lives there? This may mean competition for food.
There may be predators.

5. Adaptation

6. What is adaptation?
Adaptation describes how a plant of animal is able to survive in various environments
Well adapted organisms can cope with the different aspects of their environment, for example, the temperature

7. It is always a struggle for plants and animals to survive
ANIMALS STRUGGLE :
For food
For water
For protection against weather
Against being eaten by predators
Against disease
Against accidents
PLANTS STRUGGLE:
For water
For light
For minerals in the soil
Against weather
Against disease
Against being eaten

8. How does adaptation help organisms?
Well adapted organisms are better at coping with extremes of weather
They are better at competing for food
They are better at escaping from predators
They are more likely to survive in their habitat and produce offspring

9. An arctic habitat
This sort of habitat can have extremely low temperatures
The ground is covered with white snow for most of the year

10. How are animals adapted to survive in the Arctic?
Animals like polar bears will have a thick insulating coat
They usually have a large amount of body fat
They have a large body size to surface area ratio
They have a camouflaged coat

11. How do these adaptations help?
A thick fur coat
Large body size to surface area ratio
A large amount of body fat
Camouflage
Traps heat to keep warm
Reduces heat loss by radiation
Acts as a food store and to keep warm
White fur is good camouflage to hide from prey

12. A desert environment A desert can have very little rainfall
There is a lot of sunshine during the day
There is very little shade
The temperatures can get very hot
At night it can become very cold

13. How is a camel adapted to survive in the desert?
Camels can store large amounts of water in the fat in their humps
They have feet with a large surface area to allow them to walk on sand
They also have long eye-lashes to stop sand blowing into their eyes

14. How do reptiles survive in the desert?
Most reptiles will find some shade under a rock during the hottest part of the day
When walking on hot sand a lizard will try to touch the ground with only a small area
This lizard keeps swopping feet, and only stands on two feet at a time
This snake keeps a loop of itself off the ground as it moves across the sand sideways

15. How do plants survive the desert?
A cactus has a long tap root to reach water deep under the ground
It has a thick, fleshy stem to store water
It has needle-shaped leaves to prevent water loss through the stomata
The needles help to stop animals from eating it

16. How is the seal adapted to its environment?
Streamlined shape.
Forward-facing eyes for clear vision ahead.
Strong teeth to catch fish.
Flippers to help it swim.
Thick layer of body fat to keep it warm.
Hind legs have evolved into a a strong rudder-like tail.