State a source of vitamin D in a human diet.

Discuss exposure to sunlight as a source of vitamin D.

Discuss reasons for conservation of biodiversity of a named ecosystem.

fatty fish e.g. mackerel/tuna/sardines/herring etc.;
liver;
eggs;
fortified dairy products;

sunlight stimulates skin to synthesize vitamin D;
less sun exposure/insufficient vitamin D leads to skeletal deformities/rickets;
UV radiation increases the incidence of skin cancer/melanoma;
vegans/vegetarians are more likely to lack vitamin D so need more exposure to sunlight;

name of ecosystem:
e.g. (tropical) rainforest;
ethical reason:
every species has a right to life, regardless of whether it is useful/non useful to humans;
potential of undiscovered medicines;
ecological reasons:
better use of the rainforest may occur by respecting the existing balance in concert with the indigenous people;
native species are adapted to local conditions whereas invasive species are less likely to be in balance;
species in the rainforest are interdependent so loss of species threatens the rest of the community;
deforestation of rainforests increases soil erosion/silting of rivers/flooding/CO₂ atmospheric levels;
economic reasons:
ecotourism is a potential source of income;
aesthetic reasons:
loss of beauty of the system;
artists are inspired by the images/flowers/animals of rainforests;
heritage/cultural reasons:
maintenance of the rainforest preserves human cultural diversity;
Do not award more than [2 max] for each category of reasons e.g. not more than [2] for ecological reasons.

N/A

Surprising how many thought that the sun provided Vitamin D directly and not that the skin is stimulated by sunlight to synthesize it.

(b) seemed to be answered very easily and many candidates scored all five marks. Most candidates mentioned the rainforest in their answer.