Uploaded by Christian Alistair

BIOL1003 Assignment3 HELP 2020

Assignment 3: Testing Ecological Interactions
attempt at writing a guide for confused students
1. Write down 5 questions about ecological interactions you think were happening
based on your observations. (5 marks)
Harry Potter makes the following ecological observations near Hagrid’s hut, not quite in the
Forbidden Forest:
a. Puffapods are always be found growing together with bubotubers.
b. Hellebore grows in the shade.
c. Aconite brings more flowers in sunny spots, but grows taller in the shade.
You can make some assumptions here:
puffapods are mutualistic with bubotubers, or
puffapods are root parasites of bubotubers, or
excessive sunlight inhibits seed germination of hellebore, or
hellebore plants prefer humid environments to dry ones, or
aconite shows different life strategies in different environments, or
the biomass of aconite is inversely proportional to light intensity or….
I think that’s 6 assumptions. Turn them into questions:
Are puffapods mutualistic with bubotubers?
Are puffapods root parasites of bubotubers?
Does excessive sunlight inhibit the seed germination of hellebore?
Do hellebore plants prefer humid environments to dry ones?
Does aconite show different life strategies in different environments?
Is the biomass of aconite inversely proportional to light intensity?
You now have 6 questions. You really only needed 5. 1 mark per question, as long as it is
about an ecological interaction.
2. Refine and restate one of your questions as a testable hypothesis. (2 marks)
I choose question e: Do hellebore plants prefer humid environments to dry ones?
Re-state as a hypothesis: Hellebore plants prefer humid environments to dry ones.
This is like 1 mark out of 2. Or 0.5. It’s not really specific enough to be testable. What does
prefer mean? What is humid, and what is dry? You sort of have to go on to thee next steps to
figure this out. Also: this question is asking for a bar graph!!!!!!
3. Introduce the objective of your proposed research using peer-reviewed
references. (2 marks)
Hellebore (Helleborus niger) can be found in such and habitats ranging from such to
somesuch (reference). They live for such and such time before flowering, and produce
lots/not much/no seeds. Articles a and b talk about their abundance (reference) and
distribution (reference) which I will make statements about here. Lost of plants have
very narrow bands of preference for humidity (reference) while some plants really
couldn’t be bothered one way or another (reference).
Please note: there are references to the species, life history traits, and/or the way they
(or similar species if you can’t easily find a paper on them) interact with their
environments. 1 mark for introducing species, one mark for introducing the
interaction or life history trait, whichever is more relevant to your hypothesis. You
only get marks if your statement has a reference
4. Describe in detail the way you propose to conduct your experiment to test your
hypothesis. (2 marks)
Back to my sucky hypothesis. Preference? How do I measure that? OK, let’s go for
something else….. growth? Well, it wasn’t really about seeing bigger plants, or was
it? Actually, going back to my observation it was more about the number of plants
growing. So number of plants per square meter? But how do I measure that in a
controlled way? Is it about more seeds sprouting where it is humid, or more seedlings
dying where it is dry?
So what is “dry”? I will now look it up. In a journal article. Not in google, which
gives me www.jasons-indoor-guide-to-organic-and-hydroponicsgardening.com/plant-growth-and-humidity.html which tells me that ideal humidity for
growing the type of plant most often grown in individual hydroponic setups is 50%
give or take 10%. Instead, I punch in scopus.com.virtual.anu.edu.au to my browser,
and ask it: humidity of dry habitats. It tells me: https://linkinghub-elseviercom.virtual.anu.edu.au/retrieve/pii/S2351989419308327 I read it and it only makes a
reference to what a dry habitat is. Thankfully, there is a reference with a doi link: I
won’t link it here, you get the idea. But in this paper, there is a horrible horrible table
which references something called “Mean ecological indicator value for moisture” or
MEIV for moisture. I have no idea what this is, so I give up with scopus (temporarily)
because it was hard enough to get this far and I feel dumber that when I had started.
Wikipedia to the rescue!!!! It turns out, we are talking about Ellenberg's indicator
values, or Dufrêne & Legendre's indicator values, and that humidity refers to soil
humidity. Although I still know almost nothing, I came up with very impressive
words and am feeling a bit smug. And there are two references at the end of the
Wikipedia entry I can use! I may even read them…. Or just go back to scopus and
type in “measuring soil humidity”
At this point, I have spent 25 minutes on google, scopus and Wikipedia, 2 hours
writing, and it is 1:15 am in the morning. I have to take my son to training in 4 hours.
Let’s get this done:
I will sow the same amount of seeds of hellebore in two identical plots with different
soil humidities (reference of how to manipulate soil humidity) and measuring the rate
of germination (reference of how someone else did this on any plant, but better if
there is a hellebore paper). 1 mark for what you are controlling: soil humidity, 1 mark
for what response you are measuring: germination. Marks for referenced statements
So, if this is what you are measuring, you have to go back and change your hypothesis
to reflect this. You can leave the question alone though.
Old hypothesis: Hellebore plants prefer humid environments to dry ones.
New hypothesis: Hellebore plants will germinate better in humid soil than in dry soil
based on such and such Dufrêne & Legendre's indicator values.
Your hypothetical bar chart is like this now:
Or you go for a more nuanced experiment, and end up with a scatter plot:
5. Explain how your results could refute or confirm your hypothesis. (3 marks)
BAR GRAPH Approach:
If moist soil has a higher germination rate than dry soil, the data confirms the
hypothesis. 1 mark
If moist soil has a higher germination rate than dry soil, the data refutes the
hypothesis. 1 mark
If moist soil has no discernibly different germination rate than dry soil, the data
refutes the hypothesis. 1 mark
If germination rate is directly proportional to soil humidity, the data confirms the
hypothesis. 1 mark
If germination rate is directly proportional to soil humidity, the data refutes the
hypothesis. 1mark
If there is no correlation (R2) between germination rate and soil humidity, the data
refutes the hypothesis. 1 mark
6. Using peer-reviewed journal articles, propose which ecological problem(s) your
project would contribute to solving? (e.g.: conservation, sustainability) (1 mark)
Humid environments need to be protected because many plants can’t grow
elsewhere, OR Dry environments need to be made moister so more plants can
grow OR we need to prevent habitatry from drying out, etc. A reasonable
statement with a reference will get you a mark.
7. Use in-text referencing and include a list of your references in Harvard style. (4
Same as for your first assignment.