Good Science Victorian Curriculum Year 7
Digital sample of Matilda's newest publication, Good Science Victorian Curriculum Year, authored by Emma Craven and Aaron Elias. For more information visit www.matildaeducation.com.au or email Katrina Tucker, katrinatucker@matildaed.com.au
Digital sample of Matilda's newest publication, Good Science Victorian Curriculum Year, authored by Emma Craven and Aaron Elias. For more information visit www.matildaeducation.com.au or email Katrina Tucker, katrinatucker@matildaed.com.au
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BIOLOGICAL SCIENCES<br />
3.5<br />
HUMAN IMPACTS<br />
ON ECOSYSTEMS<br />
LEARNING INTENTION<br />
At the end of this lesson I will be<br />
able to describe how ecosystems<br />
can be affected by human<br />
activity.<br />
KEY TERMS<br />
biodiversity<br />
the variety of organisms<br />
in an ecosystem<br />
deforestation<br />
the removal of trees to make<br />
land suitable for other uses<br />
non-biodegradable<br />
does not break down in the<br />
environment<br />
pesticides<br />
chemicals used on farms to<br />
protect crops by killing pests<br />
urbanisation<br />
the creation of urban areas<br />
such as cities<br />
1<br />
Human activities often use fossil fuels and non‐biodegradable<br />
materials to meet demand for food, energy and technologies.<br />
This can damage food webs, such as by polluting air and<br />
removing forests.<br />
Even a seemingly small change in the environment can<br />
have a dramatic impact on the feeding relationships in an<br />
ecosystem. The balance between producers, consumers<br />
and decomposers in a food web can be easily disturbed.<br />
Urbanisation and deforestation damage<br />
food webs<br />
Urbanisation is the replacement of natural ecosystems with urban<br />
areas such as cities and suburbs. This is due to the constant need<br />
for more space for increasing human populations. As cities grow,<br />
the surrounding land is cleared and many of the organisms in the<br />
ecosystem die.<br />
Deforestation is the removal of large trees to make space for urban<br />
landscapes and farms. Big trees are the main producers in forest<br />
ecosystems, as well as homes and food sources to many herbivores<br />
and pollinators. All organisms within food webs are affected by<br />
deforestation, because they all depend on the original energy source<br />
from these producers.<br />
Removing trees can increase soil erosion and water pollution. This is<br />
because the roots of the trees no longer hold the soil together or filter<br />
the water flowing through the ecosystem.<br />
What is deforestation?<br />
LITERACY LINK<br />
SPEAKING<br />
Write a speech that argues for<br />
significantly decreasing levels<br />
of deforestation in Australia.<br />
Figure 3.10 The land covered by this<br />
new housing development previously<br />
had large trees and an ecosystem for<br />
a variety of organisms.<br />
NUMERACY LINK<br />
UNITS<br />
The area of an ecosystem was<br />
measured to be 1250 hectares.<br />
Convert 1250 hectares into<br />
square metres.<br />
Hint: 1 ha = 10 000 m 2 .<br />
44 GOOD SCIENCE VICTORIAN CURRICULUM 7
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