Draw a labelled diagram of the human adult male reproductive system.

Compare the processes of spermatogenesis and oogenesis

Describe the consequences of the potential overproduction of offspring.

a. scrotum – shown around testes;
b. testes/testis/testicles – shown inside scrotum;
c. epididymis – shown adjacent to testis and connected to sperm duct;
d. sperm duct/vas deferens – double line connecting testis/epididymis to urethra;
e. seminal vesicle – sac shown branched off sperm duct (not off the urethra);
f. prostate gland – shown positioned where sperm duct connects with urethra;
g. urethra – shown as double line linking bladder to end of penis;
h. penis – with urethra passing through it;
Award [1] for each structure clearly drawn and labelled that conforms to the italicized guidelines given.

Remember, up to TWO “quality of construction” marks per essay.

a. both produce haploid cells / both produce (mature/male/female) gametes;
b. both have mitosis at start/in epithelium / both involve mitosis and meiosis;
c. both have cell growth before meiosis;
d. both involve differentiation (to produce a specialised gamete);

A table is not required but both statements in one row of the table above must either be explicitly stated or clearly implied for each mark awarded.

Remember, up to TWO “quality of construction” marks per essay.

a. more (offspring) than the environment can support / carrying capacity reached;
b. increased mortality/lower life expectancy/more deaths;
c. competition (for resources) / struggle for survival;
d. food/mates/nest sites/territory/other example of resource shortage / example of greater need;
e. variation between members of population / example of variation;
f. better adapted more likely to survive / converse; (reject Lamarckian statements such as those who adapt survive)
g. better adapted reproduce / pass on (favourable) genes/traits / converse;
h. natural selection / (survival of fittest) leads to evolution;

Structure of the male reproductive system

As so often in past papers, the diagrams of the male reproductive system were very poor. Many candidates were worryingly ignorant about the internal structure, with organs shown incorrectly or not at all. Connections between the parts of the reproductive system were often incorrect and the position of the prostate gland was almost always wrong. Many male students in later life will suffer from an enlarged prostate with difficulties in urination because the urethra passes through the prostate. For this and other obvious reasons, students should learn in detail about the structure of the male and female reproductive systems. Too many students are too ignorant in this area, despite what they and their teachers may think they know.

Spermatogenesis and oogenesis compared

Most candidates found at least one or two similarities or differences between gamete production in males and females but very few scored really highly on this question. Many answers were constructed in the form of a table with two columns, which made it easier to confine the answer to genuine comparisons, but even so in some answers the statements in the left and right column did not correspond. Other answers consisted of long paragraphs about spermatogenesis and then separate paragraphs about oogenesis. The onus is then on the examiner to find the comparisons within the answer when this is actually the candidate’s task. Few candidates reached 8 marks on this question, which was a challenge but perfectly possible.

Consequences of overproduction of offspring

Some candidates wrote only about humans, with the focus on large families and overcrowded housing. They should have realised that this is not a biological answer to the question and that a general answer about all species was expected.  There were some very good answers that tied in populations rising above the carrying capacity to competition for resources, increased mortality, variation and the survival and reproduction of the better adapted individuals, hence evolution of the species by natural selection.