Edexcel Biology 2105, also Additional Science 2103

Unit B2

Topic 3 — Energy Flow

Understanding energy flow is the key to sustainable food production in both developed and developing nations. This topic offers students opportunities to prepare and observe animal and plant tissue under the microscope and to design and evaluate experiments on production factors. Consideration of the carbon and nitrogen cycle leads to investigations on the use of fertilisers and farming methods to maximise energy transfer in food production methods.

Students will discuss maximising food production and understand that the world already produces sufficient amounts of food to feed the whole population. How human activities affect the environment will also be explored, including global warming, deforestation and the use of fertilisers.

Guidance for students

Have you ever wondered?
We can feed the world, but how exactly?
What happens if we remove all of one kind of animal – will we ever be able to put them back again?
Should I travel on buses rather than take the car?
Why do some hospitals not allow plants in the hospital wards?
Why do some people put lights in greenhouses?
Why is there a global ban on whaling?
How do fertilisers harm the environment?
Can we set up a biosphere on Mars?

Learning objectives

• Plants provide energy for all other organisms.
• Plants and animals are interdependent due to their use and production of oxygen and carbon dioxide.
• Energy flows through the biosphere and elements are recycled within it.
• Human activities are often unsustainable and there are many associated ethical considerations.

Glossary

You will be expected to be able to recall, explain, describe and use appropriately the following words and phrases:

active transport cytoplasm membrane plant cell
animal cell denitrifying bacteria microorganism predator
biosphere decomposer mineral saltfood production
carbon cycle deforestation nitrifying bacteria respiration
cellulose cell wall disease nitrogen cycle root
chlorophyll fertiliser nitrogen fixing bacteria vacuole
chloroplast global warming nucleus  
combustion glucose photosynthesis  
eutrophication food production osmosis phloem
sustainability transpiration xylem


Information for teachers

ICT is an integral part of the way science works, and students should be given opportunities to experience and explore its use. It is expected that ICT will be used where it enhances the learning and teaching of science and helps to make scientific concepts easier to understand. Some of the learning outcomes have been written deliberately in order to promote discussion and expression of opinion. Where contentious, unresolved or other scientific issues are discussed, it is expected that students will be exposed to the facts, evidence and opinions from all sides of the argument.

Learning outcomes

Learning outcomes, words or statements in bold indicate that this content is designated for Higher tier students only.

Students will be assessed on their ability to:

• recall that plant and animal cells are similar because they contain nuclei, cytoplasm and membranes and that plant cells also have cellulose cell walls, chloroplasts containing chlorophyll and vacuoles B2 3.1
• recall the reactants (carbon dioxide, water) for and products (glucose, oxygen) of photosynthesis B2 3.2
• explore human exploitation of plants, including their use as a food source B2 3.3
• analyse data on the effects of limiting factors on the rate of photosynthesis and draw conclusions B2 3.4
• appreciate the role of mineral salts, such as magnesium, nitrogen, phosphorus and potassium, in the growth of plants B2 3.5
• demonstrate an understanding of now how the mineral salts are taken up in the roots by active transport using energy from respiration B2 3.6
• demonstrate an understanding of and interpret data on the carbon cycle as representing the flow of carbon in nature, including the roles of:
- microorganisms
- photosynthesis
- respiration
- combustion
 		B2 3.7
• describe the importance of nitrogen in the environment, including the roles of
- nitrogen fixing bacteria
- decomposers
- nitrifying bacteria
- denitrifying bacteria
as shown and interpreted in nitrogen cycle diagrams [NB. specific names of bacteria are not required] 		B2 3.8
• explore the evidence that a biosphere could be used to colonise Mars B2 3.9
• describe how the indiscriminate use of nitrogenous fertilisers leads to environmental damage by eutrophication B2 3.10
• appreciate that human populations are increasing and are using resources unsustainably which can lead to massive environmental change, eg deforestation B2 3.11
• describe environmental changes, such as global warming as threatening human life on the planet as we know it B2 3.11
• discuss the social and ethical considerations of the unequal distribution of food B2 3.12
• explain that energy transfer can be maximised in food production by the use of:
- optimum feeding/growing conditions
- disease and predator control
using the examples of fish farms and greenhouses 		B2 3.13

REMOVED

• discuss the ways in which food production can be maximised by the use of optimum feeding/growing conditions, disease and predator control using the examples of fish farms and greenhouses 		B2 3.14
• demonstrate an understanding of how secondary sources of data about global warming can be collected from the internet and briefly summarise the date using ICT.[Yes,it did say summarise the date]! B2 3.15