KS3 SCIENCE
Curriculum link: Interactions and
Interdependencies (Relationships in an
ecosystem)
BIODIVERSITY AND ECOSYSTEM HEALTH LESSON PLAN
Examine the importance of biodiversity for ecosystem health in Galapagos. This section explains why
species populations fluctuate and what impact this can have on the health of the ecosystem.
LEARNING OBJECTIVES
Resources required: Species index, Population Factors cards, Galapagos Giant Tortoise facts.
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1. FIRE STARTER
Ask students what they think is the most important
species in Galapagos. Which species do many other
species depend on? The species index on the
Discovering Galapagos website might help them
select one. Primary producers play a hugely
important role. But the Galapagos giant tortoise is a
keystone species and so plays a surprisingly large
role on the Islands. Talk about how their population
has greatly declined and what affect this may have
on the other wildlife on Galapagos.
2. GAINING GROUND
Explain to students the difference between densitydependent and density-independent factors.
Students should sort the ‘population factors cards’
in two piles: density-dependent and densityindependent. They should then write a paragraph
justifying their decision for sorting each factor.
3. MAKING WAVES
Discuss as a class how the different population factors
could be managed by conservationists seeking to
maintain healthy ecosystems in Galapagos. An
extended plenary could allow time for a discussion of
‘biodiversity’.
4. FUTURE FOCUS
Students should read the ‘Galapagos giant tortoise
facts’ and identify whether density-dependent and/or
density-independent factors were responsible for their
population decline. They should also consider how
conservationists could manage giant tortoise
populations.
A RESOURCE BROUGHT TO YOU BY THE GALAPAGOS CONSERVATION TRUST (REGISTERED CHARITY NO. 1043470) AND THE ROYAL GEOGRAPHICAL SOCIETY (WITH IBG)
To know that species populations
fluctuate according to a range of factors
To understand biodiversity can improve
the health of an ecosystem
To appreciate that the fluctuation in size
of one species population can affect other
species populations
STUDENTS’ OUTCOMES
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To give examples of factors that affect
species population sizes. Should refer to
density-dependent and densityindependent factors
To explain how biodiversity can improve
the ecosystem health and their ability to
cope with environmental change
To discuss the potential impacts of a
keystone species becoming extinct