1. Human impact on the environment
In this lesson you will learn about:
the biological control of pest species
the use of GM crops as an alternative to using fertilisers and pesticides
Success criteria
Explain biological control of pest species works
Explain how GM crops can be used as an alternative to fertilisers and pesticides
Human impact on the environment

2. The biological control of pest species
Can you name any common pest species that damage plants?
(aphids, scale insects)
(rabbits, rats)
Can you think of how these pest species could be controlled without using chemicals?
Human impact on the environment

3. Instead a biological control method is used.
Biological control of pest species is when the pest species numbers are controlled without the use of chemicals.
Instead a biological control method is used.
Rabbits can become a problem for
Landowners if numbers multiply
too much.
Why do you think this is?
A solution is to introduce the
virus myxomatosis which infects
and kills many of the rabbits
Human impact on the environment

4. The biological control of plant pest species includes:
Ladybirds to kill aphids and scale insects
Caterpillar moths to kill cacti
Why use these methods instead of chemicals?
Human impact on the environment

5. The alternative is to use pesticides against the insects and plants.
These chemicals can be harmful to non-pest species directly and in run-off into fresh water.
Human impact on the environment

6. You have heard of GM crops before.
GM crops can be used as an alternative to using fertilisers and pesticides.
You have heard of GM crops before.
How can GM crops be used instead of these chemicals?
Human impact on the environment

7. Pest resistance will give
Drought resistance can be transferred to the GM crop which will give better growth in dry conditions
Pest resistance will give
enhanced yields for crops that might otherwise show a lesser yield
Human impact on the environment

8. Other GM crops include:
Alfalfa (Medicago sativa)
Argentine Canola (Brassica napus)
Bean (Phaseolus vulgaris)
Carnation (Dianthus caryophyllus)
Chicory (Cichorium intybus)
Cotton (Gossypium hirsutum L.)
Creeping Bentgrass (Agrostis stolonifera)
Eggplant (Solanum melongena)
Flax (Linum usitatissumum L.)
Maize (Zea mays L.)
Melon (Cucumis melo)
Papaya (Carica papaya)
Petunia (Petunia hybrida)
Plum (Prunus domestica
Polish canola (Brassica rapa)
Poplar (Populus sp.)
Potato (Solanum tuberosum L.)
Rice (Oryza sativa L.)
Rose (Rosa hybrida)
Soybean (Glycine max L.)
Squash (Cucurbita pepo)
Sugar Beet (Beta vulgaris)
Sugarcane (Saccharum sp)
Sweet pepper (Capsicum annuum)
Tobacco (Nicotiana tabacum L.)
Tomato (Lycopersicon esculentum)
Wheat (Triticum aestivum
You could research one of them, and share with class
if time allows
Human impact on the environment

9. There are a lot of GM crops and the science is relatively new.
There are differences of opinion about GM crops and their benefits.
But remember to look at the science.
Human impact on the environment