Covering Lessons 01–05: sexual vs asexual reproduction, fertilisation in animals, reproduction in plants/fungi/bacteria/protists, mammalian reproduction, and manipulation of reproduction in agriculture.
Which statement best explains how reproduction ensures continuity of a species?
Which comparison of sexual and asexual reproduction is correct?
Which feature is most strongly associated with external fertilisation?
Which statement correctly describes reproduction in flowering plants?
Which organism-method pair is correctly matched?
In mammalian reproduction, which sequence is correct?
Why is the placenta important during pregnancy?
Which hormone-function pair is correctly matched?
Which agricultural technique is best described as deliberate transfer of pollen between chosen plants?
What is the best evaluation of manipulating reproduction in agriculture?
Compare sexual and asexual reproduction in terms of parent number, genetic variation and suitability under different environmental conditions. (4 marks)
Asexual reproduction usually involves one parent and no gamete fusion, so offspring are usually genetically identical apart from mutation (1 mark). Sexual reproduction involves fusion of gametes and usually genetic input from two parents, producing greater variation (1 mark). Asexual reproduction is often effective in stable environments because it is rapid and efficient (1 mark). Sexual reproduction is often more advantageous in changing environments because variation increases the chance that some offspring will suit the changed conditions (1 mark).
Explain how mammalian reproduction depends on more than fertilisation alone. In your answer, refer to implantation, the placenta and hormonal control. (5 marks)
Fertilisation in mammals occurs in the oviduct and forms a diploid zygote, but successful reproduction requires later steps as well (1 mark). The zygote divides to form a blastocyst, which must implant into the uterine lining for pregnancy to continue (1 mark). The placenta then supports exchange of oxygen, nutrients and wastes between mother and fetus (1 mark). Hormones such as hCG and progesterone help maintain pregnancy after implantation (1 mark). Later, oxytocin contributes to labour and prolactin supports milk production after birth, showing that hormonal control remains essential beyond fertilisation itself (1 mark).
A farmer wants a crop that is high-yielding and uniform, and a herd that produces high milk output. Evaluate how manipulating reproduction can help achieve these goals, and explain one major long-term risk. (4 marks)
Manipulating reproduction can help by using controlled pollination in crops and selective breeding or artificial insemination in livestock to spread desirable traits such as high yield or high milk output (1 mark). This increases productivity and can create more uniform agricultural performance (1 mark). Techniques such as embryo transfer can further increase offspring from valuable parents (1 mark). A major long-term risk is reduced genetic diversity, which can make crops or herds more vulnerable to disease, environmental change or other future pressures (1 mark).
Checkpoint 1 complete — IQ1 Reproduction