Variation Flashcards
How do organisms vary ?
Differences in characteristics are knowns as variation.
What is meant by species ?
It is easy to tell the difference between a dog and a fish. A fish has fins and gills, a dog has four legs and is covered in fur. This is because organisms belong to different species. They have lots of different characteristics. It is difficult to tell the different between 2 fish because they have lots of similar characteristics.
How do humans vary ?
Every human in the world is different - even identical twins differ in some ways. The image opposite shows some of the ways people may vary.
What causes variation ?
Some variation is from characteristics the people have inherited from their parents, such as eye color. This is knows as inherited variation. Children usually share some characteristics with their mother and some with their father. They are not identical to either of their parents, as they get a mixture of parents features. An example of inherited variation is lobbed or lobeless ears.
Environmental variation
Variation cause by your surroundings and what happens to you is called environmental variation. For example, your characteristics can be affected by factors such as your diet, education and lifestyle. A person with dyed hair has environmental variation.
Many characteristics are affected by both inherited and environmental variation. You might inherit the characteristic to be tall from your father. However, if you eat a poor diet your rate of growth may be reduced. Inherited characteristics that are not affected by environmental variation include: eye color, blood group and genetic diseases.
