Agriculture and Farming

Agricultural scientists study how plants grow, determining which nutrients plants need and experimenting with selective breeding. This process can lead to higher crop yield. Two contrasting approaches to farming are intensive farming and organic farming.

You need to be able to:

• describe the differences in the structures of some plant cells that enable them to carry out their function (leaf cell, root hair cell)
• describe the similarities and differences between animal and plant cells (chloroplasts, cell wall, large vacuole)
• describe how intensive farming increases crop yields by using artificial fertilisers, pesticides, herbicides and fungicides, and increases meat production by using controlled environments
• describe how organic farming uses the alternative methods of natural fertilisers, natural pesticides and mechanical methods of eliminating weeds in crop production and keeps animals under more natural conditions.

You need to understand:

• how plants make food by photosynthesis and how the rate of photosynthesis may be changed in horticulture in commercial glass houses (carbon dioxide + water => glucose + oxygen)
• why plants need, among other things, the minerals (nitrate, phosphate, potassium and magnesium) which they obtain from soil for healthy growth.

You need to know:

• that nitrates are required for proteins, which are needed for cell growth, and that magnesium is required for chlorophyll.

You should be able to assess the applications and implications of science when:

• comparing the advantages and disadvantages of both types of farming.

You should be able to use data, theories and explanations to:

• evaluate the effect on the environment of the continued use of artificial fertilisers, pesticides, herbicides and fungicides, and the effect of other factors associated with intensive farming (eg field size, monoculture).

In addition to food, we also obtain cotton, dyes, wool and leather from living things. Microorganisms also play an important part in the production of some foods (eg yoghurt, cheese, bread, beer, wine) and medicines such as penicillin.

You need to be able to:

• identify useful products that can be made from living things and name the organism used to produce a particular product
• describe the use of bacteria, yeast and other fungi in food and medicine production (bread, beer, wine, cheese, yoghurt) and antibiotics (eg penicillin).

Agricultural scientists have developed new methods of producing plants and animals with favourable characteristics. Both crops and livestock have been bred so that they produce more food or are more economical to harvest.

You need to be able to:

• explain that selective breeding involves selecting the parents with desired traits, crossing them, selecting from their offspring, and then repeating the process over several generations
• explain that genetic engineering involves the transfer of 'foreign' genes into the cells of animals or plants at an early stage in their development so that they develop with desired characteristics.