BIOLOGY

Adapt and surviving 1

Animal and plants survive in many different environments. This is because they become adapted to that environment. 

Desert animals have adapted to save water: Animals that live in hot, dry conditions need to keep cool and use water efficientely. 

• Large surface area compared to volume,
• Efficient with water,
• Good in hot sandy conditions,

Desert animals adapt as they have:

• Large feet - so their feet doesn't sink in the sand,
• A sandy colour- camouflage,
• Lose less water - from concentrated urine,
• Less sweat,

Arctic animals 2

Arctic animals that live in very cold conditions need to keep warm:

• Small surface area compared to volume,
• Well insulated,
• Good in snowy conditions,

Arctic animals ensure they have these by:

• White fur - camouflage in their surroundings,
• Thick hairy coats - to keep them well insulated,
• Big feet - spreads weight so they don't fall into snow or thin ice,
• Thick layer of blubber got insulator and a energy store

Plants adaptation in the desert 3

Desert dwelling plants make best use of what little water is available:

• Minimising water loss,
• Maximising water absorption,

They do this by:

• Spines instead of leaves - to reduce water loss,
• Small surface area to reduce water loss,
• Stores water in thick stems,

Some animals have armour to avoid their predators - like roses (thorns) catic with (sharp spines) and tortoises (with hard shells)!!Others produce poisons - like bees and poison ivy,

Warning colours!!

The size of populations 4

The size of any population depends on three main factors:

1. Competition - plants for light, water and space - animals for space, food, mates and water,

2. Disease - Infectious diseases can kill members of a population - animals that are fit and healthy stand a better chance of survival,

3. Predation - If a animal gets eaten its population will decrease. 

Organisms compete for resources:

1. Live where they can find resources, 

2. Competition - therefore some habitats only support a certain number of species, 

Red and grey squirrels 5

In 1876 the grey squirrel was introduced to the UK, the native red squirrel was unable to compete very well with the larger grey squirrels - causing the red squirrel population to decrease, 

The grey squirrel is better adapted because: 

• The deciduous woods,

However the red squirrel is best adapted in the coniferous forests because they eat conifer seeds,

Variation in plants and animals 6

Different species look different - heights, wight, nose etc.

These differences are called variation:

• Genetic variation,
• Environment variation,

Different genes cause genetic variation:

• Different characteristics similar to their parents, - characteristics are determined by genes inherited from their parents,
• Most animals get some genes from their mother and some from their father - combining of genes causes genetic variation,
• Some characteristics are only controlled by genes like - colour of plants, eye colour, inherited disorders and blood group,

Variation in plants and animals 7

Characteristics are also influenced by the environment,

• The environment that organisms live and grow cause differences,
• For example in a sunny place you can suntan,
• Basically any difference that has been caused by the conditions something lives in is called environmental variations, 

Plants grown in darkness - tall, spindly and the leaves are yellow,

Plants grown in the sun - luscious and green,

Most characteristics are due to genes and the environment,

• Most characteristics like body weight, eye colour, skin colour, height etc are determined by a mixture of genetic and environmental factors,
• The maximum height a plant can grow to is determined by its genes