Investigating an
ecological niche
AS 3.1
4 Credits
Biozone book pages 14 - 52
Choosing an Organism
Location: Kina Peninsula
Possible organisms:
- Mud crab
- Tube worms
- Flat worms
- Sea Anemones
- Catseyes
- Whelks
Monday 19th of March
Trip one to Kina:
You will only have about an hour to check
out the site.
A hand out will be given for you to fill out.
Try to identify as many rocky shore
organisms as possible.
Think about variables you could
manipulate to investigate an ecological
niche of an organism.
Background Research – Needed
for your INTRODUCTION
Research possible rocky shore organisms
before Monday 19th of March, from the list
in slide 2, or any ones that might interest
you. BE PRACTICAL THOUGH!
Research:
Habitat, ecological niche of organism,
adaptive features of organism,
advantages, disadvantages, feeding,
protection ….
Aim
A formal statement of the purpose of the
investigation.
Example:
To investigate Periwinkle activity in different
salinity concentrations.
Hypothesis
A testable statement of the expected
outcome of the investigation.
Null hypothesis – not necessary (A statement of the expected outcome if
the variable has no effect on the organism)
Example:
Periwinkles will become less active in decreasing
Salinity concentrations.
This is because the tidal zone is exposed to rain
which can decease the salinity concentration.
Method
An accurate description of the materials and
experimental procedure used in the
investigation.
Written in third person.
Method must be detailed enough so that an
independent person could carry out the
investigation with out your help.
Periwinkle Method
Example
1.
2.
3.
4.
5.
6.
7.
8.
9.
Collect sufficient number of similar sized periwinkles (minimum
150)
Collect 1 litre of sea water from flowing sea
Need 1 litre of tap water
Make up 5 different concentrations of sea water (100mls each)
Make sure periwinkles are out of water for at least 30mins prior to
the investigation
Place 10 periwinkles in each of the Petri dishes, add to each Petri
dish 5ml of each of the different concentrations of seawater.
Leave for a set time (10 seconds), then count how many
periwinkles in each Petri dish are active, record.
Repeat the process 1 – 7 three times.
Control – light (carry out in shade), temperature (water room
temperature), amount of seawater (5ml) and number of
periwinkles (10/petri dish) so that it is the same for all trials.
Periwinkle method cont….
Salinity concentrations:
20% - 20mls seawater + 80mls tap water
40% - 40mls seawater + 60mls tap water
60% - 60mls seawater + 40mls tap water
80% - 80mls seawater + 20mls tap water
100% - normal seawater (nothing done to it)
How the controls might effect my investigation:
If light and temperature are not controlled then the periwinkles may not
be exposed to the same conditions. Therefore what they maybe
responding to is not salinity concentration but light or temperature.
Active
The periwinkle is visible. Front part of the
animal is out of the shell (feeding apparatus).
Thursday 22nd March
Must get to me before trip with equipment
requirements. If you see me on Thursday P3 I
may not be able to help you!
Carry out your investigation. If you find you
need to modify your method, make a note of
That in your log book.
Record data - YAY
Recording data
Example only
Trial 1
Trial 2
Trial 3
Average
Seawater concentrations
20%
40%
60%
80%
0
0
3
9
0
0
0
0
0
0
2
0
2.5
10
10
9.7
100%
8
8
8
8
Results
This should be a summary of your findings.
Have tables and graphs accompanied by
explanations.
You can carry out statistical analyses,
however this does not have to be done but
could be a good way to show validity of
results!
Conclusion & Discussion
• A statement of the conclusion(s) from your
findings, it should relate back to your aim
and hypothesis.
• Follow the conclusion with an in-depth
discussion of the biological significance of
your results and how they relate to the
organisms ecological niche.
• If your results do not show this you need
to discuss this discrepancy.
Evaluation
This is where you get to discuss your
Limitations (problems with your investigation):
• Problems encountered and how they may have
effected your investigation
• How the effects of bias were reduced (Random
selection, control of variables)
• Sources of error and how they were eliminated
• The validity of the conclusion (if you use stats)
References
APA – American Psychological Association
format.
NO REFERENCE NO PASS!!!!
Use this website to help you:
http://www.waikato.ac.nz/library/learning/g_apagui
de.shtml
Otherwise look up books in library or go see Miss
Gass
5th Aprils (Thursday)
3.1 is DUE and its Holidays, so YAY
Happy Easter
Hand in to Miss Gass by 3:30pm. If you
can’t find Miss Gass take if to office and
get them to put the time on it and the office
can put it in my pigeon hole.
You must hand in your log book