variation

Question 1

define variation

Answer 1

differences among individuals in a species

Question 2

define continuous variation

Answer 2

a range of phenotypes with intermediates
height in humans
differences are slight and merge or grade into each other

Question 3

define discontinuous variation

Answer 3

differences are separate and clean cut
no intermediates
blood groups in humans

Question 4

list 2 causes of variation

Answer 4

genetics:
variation is inherited and can be small or large
genetic variation can be due to gene mutation, meiosis and fertilisation

environment:
variation is seen because of the influence of the environment (ie the surroundings of the org) and is not inherited

Question 5

define mutation

Answer 5

spontaneous change in a gene or a chromosome which may produce an alteration in the characteristic under its control

Question 6

examples of gene mutation

Answer 6

sickle cell anaemia

Question 7

example of chromosome mutation

Answer 7

down syndrome
changes number of chromosomes

Question 8

causes of mutation

Answer 8

exposure to high-energy electromagnetic radiation like x rays ultraviolet light and gamma rays
exposure to certain chemicals like mustard gas caffeine formaldehyde colchicine tar in tobacco increase in drugs food preservatives and pesticides

Question 9

can a mutation be passed on or inherited

Answer 9

no will be lost when the organisms dies
however if it occurs in a gamete cell it can be inherited further adding variation to a population

Question 10

sickle cell anaemia

Answer 10

affects the formation of haemoglobin in red blood cells
abnormal haemoglobin causes red blood cells to become distorted or sickle shaped when the oxygen concentration of surroundings is low
more resistant to malaria than people with normal haemoglobin