Science Year 11 Biology: A Local Ecosystem
Content:
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Students draw on existing knowledge of their own local area and expand on their understanding of biological concepts that
can be identified through careful analysis of biotic and abiotic factors.
Students gain field experience of both an aquatic and terrestrial ecosystem as they:
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observe and measure some of the abiotic environmental factors to which the main plant and animal species are
adapted
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study some of the trophic, competitive and symbiotic interactions between organisms.
Students gain information and analyse their findings in order to report on aspects of the local environment that have been
affected by people and propose realistic solutions to the problems that exist.
Students:
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1/11
Gather information from first hand observations to construct a local food web.
Explain trophic interactions between organisms in an ecosystem using food chains and food webs.
Describe the role of decomposers in ecosystems.
Measure a number of abiotic factors to compare the mangrove and saltmarsh environments.
Use quadrats to estimate the size of a population in an ecosystem.
Collect, analyse and present data to describe the distribution of species whose abundance has been estimated.
Consider the accuracy of population estimation strategies.
Identify factors determining the distribution and abundance of a species in each environment.
Examine trends in population estimates for some plant and animal species within an ecosystem.
Justify the use of different sampling techniques to make population estimates when total counts cannot be performed.
Identify some adaptations of living things to factors in their environment.
Identify and describe in detail adaptations of a plant and an animal from the local ecosystem.
Analyse trends in a plant population using a transect.
Identify examples of allelopathy, parasitism, mutualism and commensalism in an ecosystem and the role of organisms in
each type of relationship.
Identify the impact of humans on the ecosystem studied.
1.0 Abiotic variables in the mangrove ecosystem
Date:
Abiotic Factor
Location:
Average
Range
Your
Within
Result Range?
Yes / No
Time:
Equipment Used
Air
Temperature
12-26°C
Wind speed
0-2.0 m/s
Humidity
60-90%
Light Intensity
Soil
400-600lux
Temperature
13-23°C
Soil Type (content)
High clay
content
Soil Moisture
Wet
Soil pH
Water
5.5-8
Temperature
16-23°C
Water pH
6-8
Turbidity
< 40 NTU
Salinity
15-35ppk
1.1 Describe the method for measuring two abiotic factors.
1.2 Based on your results above, evaluate the current state of this environment?
1.3 What are the implications for aquatic organisms if results fall outside the average range for
the following abiotic factor?
Water salinity (/)
Turbidity ()
Water pH (/)
2/11
2.0 Abundance and distribution of an estuarine plant and animal in
the Badu Mangroves (total area 380,000 m2)
Date:
Time:
Location:
Methodology:
Quadrat No.
(Distance
from creek)
1
5m
2
10m
3
4
5
6
7
8
9
10
Tot area Average
per m2
(density
)
Tot sampled
15m
Seedlings
Crab holes
Seedling abundance = density x total area =
x
380,000
=
2.1 Sketch a graph from your data to show the trends. 2.2 Identify the factors that may determine the
distribution and abundance of these
organisms?
Seedlings
A
_____________________________________
b
_____________________________________
u
n
_____________________________________
d
_____________________________________
a
n
_____________________________________
c
e
Creek
Key:
Distance
Seedlings
Path
Crab holes
Crabs
_____________________________________
_____________________________________
_____________________________________
_____________________________________
_____________________________
2.3 Can you identify any advantages or limitations of the method used to estimate population?
2.4 Calculation of abundance of mature mangroves in 380,000m2 forest.
Number of mature mangrove trees in 50sq. metres
How many 50 sq. metre sections in the forest?
Population of mature trees
(a) =
(b) =
(a)____ X (b)_____ =
Comment on the reason why the abundance of seedlings is significantly different from that of
mature trees.
3/11
3.0 Adaptations of the Grey Mangrove (Avicennia marina) and a
mangrove animal to the mangrove ecosystem
Seeds
Root System: Pneumatophores
Characteristics of the
mangrove ecosystem
Leaves
Mangrove Animal
4/11
4.0 Student planned investigation into adaptations of mangroves
to factors in their environment
Date:
10
Location:
9
8
7
6
5
4
3
Time:
2
1
0
1
2
3
4
5
6
7
8
9 10
Instructions:
In small groups, design a simple investigation to answer the following question:
What is the relationship between the height of pneumatophores and tidal inundation?
Aim:
Hypothesis:
Equipment:
Methodology: (Hint: will your data be reliable, valid and reproducible?)
Discussion:
Conclusion:
5/11
4.0 Student planned investigation continued…
Results:
Discussion: Discuss your findings, including any difficulties you encountered in carrying out
your investigation.
Explain how your data could be more reliable?
Describe how your data could be more valid?
Conclusion: Evaluate whether your results support your hypothesis?
6/11
5.0 Vegetation profile of the intertidal wetland plant communities
Aims:
Key:
To determine the distribution of vegetation and changes in mangrove height along a transect.
To identify factors in the environment that might be causing the observed vegetation profile.
Mangrove
Location:
12
Height (m)
10
Saltmarsh
8
6
Casuarina
4
2
0
10
20
30
40
50
60
70
80
90
100
Distance (m)
5.1 State and justify the height and distribution trend from the above transect profile.
7/11
6.0 Abiotic variables in the saltmarsh community
Date:
Location:
Abiotic factor
Air Temp
Light
Intensity
Time:
Wind
velocity
Humidity
Soil Temp
Soil
moisture
Results
Salinity
Up to
100 ppk
Are the above
results  to
the mangroves
6.1 Comment on the impact of differences in abiotic factors within the saltmarsh and mangrove
environments
6.2 Identify adaptations of saltmarsh plants (Sarcocornia quinqueflora) to factors in the
environment. (You can use drawings if you wish.)
7.0 Relationships between organisms in this ecosystem
Match the following relationship terms (Allelopathy, Parasitism, Mutualism, Commensalism)
to the definitions in the table below.
Relationship
Definition
This is a relationship that is mutually
beneficial for both organisms.
Example
This happens when a plant releases
a chemical to inhibit the growth of
other plants.
A relationship that benefits one
organism and does not harm the other.
In this relationship, one organism
benefits, but the host organism is
harmed.
8/11
8.0 Trophic Interactions
8.1 In the table below list organisms observed (include at least TWO plants and TWO animals).
Suggest their food source, and any organisms that feed on them. Use the following key to
indicate type of organism: (P) - Producer, (C) - Consumer, (D) - Decomposer.
Organism
Type
Energy / Food source
Eaten by
8.2 Construct a food web showing the trophic relationships between the organisms in your
table. Use arrows to show the direction of energy flow.
8.3 Using your food web above, discuss what would happen to the balance of this system if you
remove the:
a) producer
b) consumer
9/11
9.0 Identify the impact of human activities on the ecosystem
Human Activity
Impact
Management Strategy
Historic dump sites
- Strathfield Tip
- State Rail Wrecking Yards
Leachate Polluted ground water, creeks and wetlands
Leachate Drainage System- captures the leachate in a
series of pipes that flow into an evaporation pond
Bund Walls
Storm water canal (Powells Ck)
& stormwater drains
Recreational activities
- Visitors, cyclists
Transport & Roads
10/11
Notes:
11/11