1.1 A combination of a
balanced diet and regular
exercise is needed to help
keep the body healthy.
2.1 Our bodies provide an excellent environment for
many microbes which can make us ill once they
are inside us. Our bodies need to stop most
microbes getting in and deal with any microbes
which do get in. Vaccination can be used to
3 Nerves and Hormones
3.1 The nervous system and hormones enable us to
respond to external changes. They also help us to
control conditions inside our bodies. Hormones are
used in some forms of contraception and in fertility
treatments. Plants also produce hormones and
respond to external stimuli.
4.1 Drugs affect our body chemistry. Medical
drugs are developed and tested before being
used to relieve illness or disease. Drugs may
also be used recreationally as people like the
effect on the body. Some drugs are addictive.
Some athletes take drugs to improve
performance. People cannot make sensible
decisions about drugs unless they know their
5 Interdependence and Adaptations
5.1 Organisms are well adapted to survive in their
normal environment. Population size depends on
a variety of factors including competition,
predation, disease and human influences. Changes
in the environment may affect the distribution
and behaviour of organisms.
6 Energy and Biomass in Food Chains
6.1 By observing the numbers and sizes of the
organisms in food chains we can find out
what happens to energy and biomass as it
passes along the food chain.
7 Waste Materials From Plants and
7.1 Many trees shed their leaves each year and most
animals produce droppings at least once a day. All
plants and animals eventually die. Microorganisms
play an important part in decomposing this
material so that it can be used again by plants. The
same material is recycled over and over again and
can lead to stable communities.
8.1 Particular genes or accidental changes in the genes of plants or
animals may give them characteristics which enable them to
survive better. Over time this may result in entirely new species.
There are different theories of evolution. Darwin’s theory is the
most widely accepted.