Variation with a Species (Edexcel IGCSE Biology)
Revision Note
Did this video help you?
Types of Variation
Variation is defined as differences between individuals of the same species
Variation can be caused by:
differences in genes brought about by random fertilisation of gametes
environmental factors
a combination of both
Environmental Variation
Characteristics of all species can be affected by environmental factors such as climate, diet, accidents, culture and lifestyle
In this instance ‘environmental’ simply means ‘outside of the organism’ and so can include factors like climate, diet, culture, lifestyle and accidents during lifetime
Examples include:
an accident may lead to scarring on the body
eating too much and not leading an active lifestyle will cause weight gain
being raised in a certain country will cause you to speak a certain language with a certain accent
a plant in the shade of a big tree will grow taller to reach more light
Genetic and Environmental Causes
Discontinuous variation is usually caused by genetic variation alone
Continuous features often vary because of a combination of genetic and environmental causes, for example:
tall parents will pass genes to their children for height
their children have the genetic potential to also be tall
however if their diet is poor then they will not grow very well
therefore their environment also has an impact on their height
Another way of looking at this is that although genes decide what characteristics we inherit, the surrounding environment will affect how these inherited characteristics develop
You've read 0 of your 5 free revision notes this week
Sign up now. It’s free!
Did this page help you?