16. Reproduction

16.1 Asexual reproduction

Core

• Define asexual reproduction as a process resulting in the production of genetically identical offspring from one parent 

• Identify examples of asexual reproduction from information provided 

Supplement 

• Discuss the advantages and disadvantages of asexual reproduction:

 – to a population of a species in the wild 

– to crop production 

16.2 Sexual reproduction

Core

• Define sexual reproduction as a process involving the fusion of the nuclei of two gametes (sex cells) to form a zygote and the production of offspring that are genetically different from each other 

• Define fertilisation as the fusion of gamete nuclei 

Supplement 

• State that the nuclei of gametes are haploid and that the nucleus of a zygote is diploid 

• Discuss the advantages and disadvantages of sexual reproduction: 

– to a population of a species in the wild 

– to crop production 

16.3 Sexual reproduction in plants 

Core

• Identify and draw, using a hand lens if necessary, the sepals, petals, stamens, filaments and anthers, carpels, style, stigma, ovary and ovules, of an insect-pollinated flower 

• State the functions of the sepals, petals, anthers, stigmas and ovaries 

• Use a hand lens to identify and describe the anthers and stigmas of a wind-pollinated flower 

• Distinguish between the pollen grains of insect-pollinated and wind-pollinated flowers 

• Define pollination as the transfer of pollen grains from the anther to the stigma 

• State that fertilisation occurs when a pollen nucleus fuses with a nucleus in an ovule 

• Describe the structural adaptations of insect-pollinated and wind-pollinated flowers 

• Investigate and state the environmental conditions that affect germination of seeds, limited to the requirement for water, oxygen and a suitable temperature 

Supplement 

• Define self-pollination as the transfer of pollen grains from the anther of a flower to the stigma of the same flower or different flower on the same plant 

• Define cross-pollination as transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant of the same species 

• Discuss the implications to a species of self-pollination and cross-pollination in terms of variation, capacity to respond to changes in the environment and reliance on pollinators 

• Describe the growth of the pollen tube and its entry into the ovule followed by fertilisation (details of production of endosperm and development are not required) 

16.4 Sexual reproduction in humans

Core

• Identify and name on diagrams of the male reproductive system: the testes, scrotum, sperm ducts, prostate gland, urethra and penis, and state the functions of these parts 

• Identify and name on diagrams of the female reproductive system: the ovaries, oviducts, uterus, cervix and vagina, and state the functions of these parts 

• Describe fertilisation as the fusion of the nuclei from a male gamete (sperm) and a female gamete (egg cell/ovum) 

• State the adaptive features of sperm, limited to flagellum and the presence of enzymes 

• State the adaptive features of egg cells, limited to energy stores and a jelly coating that changes after fertilisation 

• State that in early development, the zygote forms an embryo which is a ball of cells that implants into the wall of the uterus 

• State the functions of the umbilical cord, placenta, amniotic sac and amniotic fluid 

• Outline the growth and development of the fetus in terms of increasing complexity in the early stages and increasing size towards the end of pregnancy 

• Describe the antenatal care of pregnant women, limited to special dietary needs and the harm from smoking and alcohol consumption 

• Outline the processes involved in labour and birth, limited to: 

– breaking of the amniotic sac – contraction of the muscles in the uterus wall 

– dilation of the cervix 

– passage through the vagina 

– tying and cutting the umbilical cord 

– delivery of the afterbirth 

Supplement 

• Compare male and female gametes in terms of size, structure, motility and numbers 

• Explain the adaptive features of sperm, limited to flagellum, mitochondria and enzymes in the acrosome 

• Explain the adaptive features of egg cells, limited to energy stores and a jelly coating that changes after fertilisation 

• Describe the function of the placenta and umbilical cord in relation to exchange of dissolved nutrients, gases and excretory products and providing a barrier to toxins and pathogens (structural details are not required) 

• State that some toxins, e.g. nicotine, and pathogens, e.g. rubella virus, can pass across the placenta and affect the fetus 

• Discuss the advantages and disadvantages of breast-feeding compared with bottle-feeding using formula milk