POPULATIONS

1. POPULATIONS

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

3. 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 What factors could change 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. 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 It is always a struggle for plants and animals to survive

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. 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 How do these adaptations help?

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

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