Define habitat, population, community and ecosystem.

Outline how energy flows through an ecosystem.

Discuss the benefits and possible harmful effects of altering species by one example of genetic modification.

habitat:
the environment in which a species normally lives / the location of a living organism / OWTTE;

population:
a group of organisms of the same species who live in the same/specific area at the same time/interact; (some reference to common
place and time is required)

community:
a group of populations/species living and interacting with each other in an area / OWTTE;

ecosystem:
a community and its abiotic environment / OWTTE;

producers/plants/autotrophs convert light energy into chemical energy/make food by photosynthesis;
such as sugars/organic compounds;
producers eaten by primary consumers, these by secondary consumers, (these by tertiary consumers)/energy moves up trophic levels;
only a small percentage/10–20 % of the energy is passed along food chain;
energy lost in the form of heat;
energy lost by (cell) respiration;
energy lost as not digested/lost in feces;
energy lost through death of organisms;
passed to detritivores/saprophytes/decomposers;
energy is not recycled;

DNA is universal (genes can be transferred among species);
gene modification is the transfer of genetic material between species;
named example; (e.g. glyphosate resistant crops)
source of gene; (e.g. bacteria)
function of gene; (e.g. resistance to herbicides)
modified organisms; (e.g. soya beans)

argument in favour/benefit of named example; (e.g. increase in crop yield)
argument in favour/benefit of named example; (e.g. reduction in use of herbicides)
argument in favour/benefit of named example; (e.g. glyphosate breaks down into naturally occurring components so glyphosate resistant crops are justified)

argument against/risk of named example; (e.g. (application of) glyphosate could cause cancer in future)
argument against/risk of named example;  (e.g. could be transferred to wild plants)
argument against/risk of named example;  (e.g. genetically modified crops may cause allergies)

Many candidates were correct with all of their definitions in 6(a). Since these involved pure recall, it showed that candidates had studied the topic. Where trouble occurred, it was confusion between population and community

Overall, 6(b) was well answered with very few outright errors. Energy flow was well understood with accurate terminology being used.  The ideas most frequently missed were: sugars/organic compounds as products of photosynthesis and the loss of energy. The latter included loss by (cell) respiration, loss as undigested material/feces and loss through death of organism. Also, not many candidates wrote that energy is not recycled.

Although 6(c) asked for the benefits and possible harmful effects of genetic modification using one example, it was appropriate to begin the answer by explaining that genetic modification involves the transfer of genes among different species based on the universality of DNA. This was rarely done. When naming the example, the source of the gene was usually not included, whereas its function and the modified organism were often given. Several examples of non-existent GMOs were cited. Some have ceased to be manufactured while others have not got out of the research laboratory. Pros and cons tended to be generic instead of true applications of the arguments to the named GMO. Some candidates used different examples for different points in favour and against as opposed to discussing with one relevant named example. Finally, a few candidates confused GMOs with selective breeding or cloning.