Biology Class: _____________
Name: ___________________________
Preliminary biology Assessment Task 1
Field Study Report – Application of Data
Use the data collected at the Gibberagong Environmental Centre to help you answer the following questions.
1. What is the purpose of the field study?
1 mark
To look at the biotic and abiotic factors that affect the distribution and abundance of plants and animals in
a mangrove ecosystem
2. During the field study, vegetation transects were completed. Describe the changes that were observed in the
vegetation along a transect?
2 marks
There was little change in the vegetation along the transect, with only River Mangroves present.
OR There were casuarinas away from the river and as you moved closer to the river, the predominant trees
were mangroves. Near the water there were no plants.
3. As part of the field study, you measured a range of abiotic factors.
(i)
What units was light intensity measured in?
1 mark
Lux
(ii)
Describe the procedure used.
2 marks
(3 or more, or equivalent, of) Remove the cover from the sensor, hold the light meter at about 1 metre
above the ground with the sensor pointing towards the sun’s position, turn the meter on, adjust the
setting level, wait until the reading has stabilised then record. Add 2 zeros after the recorded number.
(iii)
What significance does light intensity have on the distribution and abundance of organisms in this
2 marks
ecosystem?
Some organisms require high levels of light to photosynthesise and will only grow where the level of
light is sufficient. As a result, there is little growth in the areas where the River and grey mangroves
are denser, even of other younger mangroves.
4. Describe the procedure that was used to collect information about the soil pH?
3 marks
Take a small sample of soil from within the selected area. Place it onto the piece of white plastic, add
a
small amount of the indicator solution and mix. Put a small amount of the white powder onto the sample
wait, for colour to develop then compare the pH colour chart and record the indicated pH.
Biology Class: _____________
Name: ___________________________
5. Describe two important roles played by the mangroves in this ecosystem?
(i)
1 mark
The mangrove leaves fall then decompose becoming the detritus which is food for the semaphore and
marsh crabs.
(ii)
The roots of the mangroves hold and stabilise the silt and mud at the edge of the river.
1 mark
6. Name another abiotic factor (apart from light intensity and soil pH) that was observed or measured and
explain how this factor has an effect on the distribution and abundance of a NAMED species?
2 marks
Soil Moisture. As you move away from the river, the silt and mud that forms the soil becomes drier. As a
result, it is harder for the crabs to dig to create holes, or to get food to eat. As a result, the further from the
river, the fewer semaphore and marsh crabs there are, until in the woodland area, there are none at all.
7.
Using the information in your worksheets, draw three food chains.
Mangroves
crabs
heron
Mangroves
crabs
fish
Algae
fish
heron
heron
8. Complete the following table.
Organism
6 marks
obtains food
One adaptation to
Explain how this adaptation
by/from
its environment
helps the organism to survive
Allow the roots of the
Grey Mangrove
Photosynthesis
Pneumatophores
mangroves to obtain
sufficient oxygen in the
waterlogged soil
Hold in the air and wave to
make the crab look larger
Crab
Detritus
3 marks
Large claws
when threatened and
therefore scare away
potential predators
Biology Class: _____________
Name: ___________________________
9. State two impacts humans have had on the part of the ecosystem that you looked at, and suggest a possible
2 marks
solution for each.
i)
Impact: Sewege from housing around area
Solution: Appropriate drainage to prevent sewage entering National Park and the Mangrove
Ecosystem
2 marks
ii)
Impact: Compaction of soil in the Mangrove ecosystem and surrounding area
Solution: Construction of boardwalks to minimise impact on and therefore compaction of the soil
10. State how you would prepare for a field study to determine whether pollution from a factory was affecting
the health of a mangrove ecosystem in the Homebush area along Parramatta River. Include explanations as
to why you would collect information about your chosen abiotic (3 marks) and biotic (2 marks) factors, as
well as how and why you would assess distribution and abundance (4 marks).
Explain what would indicate a healthy system as apposed to an unhealthy system (3 marks).
2 or 3 abiotic Factors = 1 mark
2 abiotic Factors and an acceptable explanation for each = 2 marks
3 abiotic Factors and an acceptable explanation for each = 2 marks
Biotic factors: Named plant and animal or two named plants or two named animals = 1 mark
Reasons = 1 mark
Distribution and Abundance: Quadrat and explanation = 2 Marks
Transect and explanation = 2 Marks
Healthy System/Unhealthy System: 3 marks for:
Comparison to known Healthy System and biotic and Abiotic features similar to that system= healthy
Comparison to known Healthy System and biotic and Abiotic features different to that system,
particularly with lower numbers of crabs, mangroves etc = unhealthy