Reasons for Variety

Reasons for Variety:

Organisms are all adapted to their surroundings. This means that they have variations in their characteristics that allow them to survive in their habitats.

Organisms that come from polar region (e.g. the polar bear) are adapted to the cold. Organisms living near deep-sea hydrothermal vents are adapted to hot temperatures. Organisms living there cope with big temperature changes, complete darkness and huge pressures.


How the Polar Bear is adapted:

• Small ears to stop it losing heat
• Thick fur for insulation
• White fur for camouflage
• thick layer of blubber under the skin for insulation
• Large feet to spread it's weight and stop it sinking in the snow.
• Rough soles to grip the ice.

How Deep-sea Pompeii worms are adapted:

• It's body adapted to pressures over 200 times those at sea level
• It spends its time in a papery tube to protect it from predetors
• No eyes but very sensitive tentacles.
• The worms body is covered in a layer of bacteria to help protect it from the heat. (copes with temp changes from 40C-90C

Discontinuous variation is normally caused by instructions within your cells and is called genetic variation.

If a characteristic shows continuous variation and we take data from a large number of people we often get a graph with a particular shape.
This is called a Normal Distribution Curve. This shows that most individuals measure within the middle part of the range in variation, with  fewer individuals at the extremes of the range.

Characteristics that show continuous variation are normally controlled by both genes and the environment. You may inherit shortness from your parents. This is called Inherited Variation. But, if you don't eat healthily or have an accident that damages your bones you may never grow tall.
Shortness will have been an acquired characteristic which is caused by the environment. This is called Environmental Variation.


Key Words:

Adapted
Habitats
Hydrothermal Vents
Genetic Variation
Normal Distribution Curve
Acquired Characteristic
Environmental Variation


Questions:

1. Which from the polar bears adaptations help it to survive in its habitat?
2. Why doesn't the pompeii worm need eyes?
3. Why is 'gender' an example of discontinuous variation?
4. What is a normal distribution curve?
5. Is human height inherited or acquired? Explain your answer?


What you should've learnt?


How organisms are adapted to their environment and how some organisms have charcateristics that enable them to survive in extreme environments.

How to interpret information of variation using normal distribution curves

Demonstrate an understanding on the causes of variation , including:
a. genetic variation - different characteristics as a result of mutation or reproduction. b. Environmental variation - different characteristics
caused by an organism's environment.