a. natural selection is caused by selection pressures in the environment OR example of a selection pressure 1 mark

b. natural selection requires that variation exists within a species 1 mark

c. variation arises randomly due to mutation OR variation is enhanced by meiosis/sexual reproduction 1 mark

d. over-production of offspring promotes selection OR natural selection occurs when there is competition/overpopulation/predators/environmental changes/changes in selection pressures 1 mark

e. well adapted individuals/individuals with best variations survive to reproduce/survival of fittest 1 mark

f. «frequency of» genes/alleles conferring an advantage are selected for OR genes/alleles conferring a disadvantage are selected against 1 mark

g. genetic divergence/difference increases OR natural selection «genetically» isolates members of a species so eventually they can no longer produce fertile offspring 1 mark

h. genetic divergence» leads to reproductive isolation 1 mark

i. geographical/behavioural/ecological factors may lead to «reproductive» isolation 1 mark

j. prolonged «reproductive» isolation leads to speciation 1 mark

k. up to one additional mark for AHL information 1 mark

a. facilitated diffusion by channel proteins 1 mark

b. active transport by protein pumps OR protein pumps eg sodium-potassium 1 mark

c. cell recognition by glycoproteins/protein receptors 1 mark

d. communication/receptors for hormones/signal molecules 1 mark

e. cell adhesion 1 mark

f. allow up to one additional mark for AHL material 1 mark

a. DNA is unwound/strands are separated «by RNA polymerase» 1 mark

b. new nucleotides attached to template strand «by RNA polymerase» 1 mark

c. complementary base pairing/base pairing with an example OR adenine with thymine/uracil with adenine/cytosine with guanine/guanine with cytosine 1 mark

d. mRNA detaches from template 1 mark

e. DNA rewinds 1 mark