Reproduction and Development
What you must understand
Compare sexual and asexual reproduction. Learn human reproductive anatomy and the roles of sperm and egg, fertilisation, implantation, placenta and development. Know the menstrual cycle and the roles of oestrogen and progesterone. Understand contraception methods and the transmission of STIs.
In plants, learn flower structure, pollination (wind vs insect), fertilisation, seed and fruit formation, and seed dispersal and germination conditions.
Traps examiners set
- Confusing pollination (transfer of pollen) with fertilisation (fusion of gametes).
- Saying the placenta mixes maternal and fetal blood - it does not; exchange occurs across a barrier.
- Mixing up which hormone peaks when in the menstrual cycle.
- Forgetting that asexual reproduction produces genetically identical offspring.
Worked rule of thumb
When comparing wind- and insect-pollinated flowers, build a table: petals, scent, nectar, pollen amount and stickiness, stigma position. Each feature follows from the pollinator: wind flowers need lightweight pollen and exposed stigmas; insect flowers need attractants.