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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CHAPTER 3: ECOSYSTEMS<br />
3<br />
Symbiosis is a close<br />
relationship<br />
Figure 3.5 Ticks are<br />
parasites that eat the<br />
blood of other animals.<br />
Symbiosis is a relationship that exists<br />
between two or more organisms that<br />
live closely together. The parasite–host<br />
relationship (known as parasitism)<br />
is a form of symbiosis, but it is a<br />
relationship in which one species<br />
benefits while the other species<br />
is harmed. There are also some<br />
wonderful examples of helpful<br />
symbiotic relationships in nature,<br />
in which both species benefit from<br />
the closeness of the organisms.<br />
Little oxpecker birds ride around all day on large animals in Africa,<br />
eating the insects and other parasites from their backs. In this example<br />
both organisms get something good out of the symbiotic relationship –<br />
the bird gets tasty food and the large animal gets a beautiful coat free<br />
of parasites and insects.<br />
Another example of this mutual symbiosis is the relationship between<br />
the spider crab and the algae that lives on its back. The algae is<br />
provided with a place to live, and the spider crab is provided with<br />
camouflage from predators.<br />
Is all symbiosis<br />
helpful to both<br />
organisms?<br />
Figure 3.6 Oxpecker birds<br />
get their food by eating<br />
insects and other parasites<br />
from the backs of animals<br />
like this rhinoceros.<br />
CHECKPOINT 3.3<br />
1 Give an example of an<br />
Australian predator.<br />
2 Identify one example of each<br />
of the following.<br />
a Competition<br />
b Predation<br />
3 Consider the food web<br />
in lesson 3.2. How would<br />
competition and predation<br />
change if all the crickets were<br />
eaten so they were no longer<br />
a food source?<br />
4 What resources do plants<br />
compete for in an ecosystem?<br />
5 Venus fly traps are both<br />
producers and consumers.<br />
These plants trap and kill<br />
flies and other insects to gain<br />
energy and nutrients. Identify<br />
the interaction between Venus<br />
fly traps and flies.<br />
ETHICAL CAPABILITY<br />
6 After their introduction<br />
to Australia, cane toad<br />
populations exploded in<br />
Queensland. One proposed<br />
solution to control their<br />
numbers was to introduce a<br />
predator to hunt and kill the<br />
cane toads. What are some<br />
ethical issues (of what is right<br />
and what is wrong) regarding<br />
this proposal?<br />
SUCCESS CRITERIA<br />
I can describe how<br />
competition can affect food<br />
chains and food webs.<br />
I can describe what a<br />
predator is and give an<br />
example of a predator and<br />
its prey.<br />
I can explain what symbiosis<br />
is in my own words and with<br />
an example.<br />
41
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