POPULATIONS

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

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

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.

Adaptation

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

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

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

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

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

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

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

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

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

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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