BIO 1131 Spring 2022 Lab 4 Assignment
Make a copy of this document, fill in your answers during and after your lab in google docs, and then download as a .docx or .pdf file to submit to Canvas by your lab section’s due date.
Reading Scientific Literature
1. What two questions were addressed in this research study?
● How do species allocate their biomass in response to density and nutrient levels?
● Do species’ functional group, life span, and realized niche with respect to nutrients influence their responses?
2. List three independent variables that were tested in this experiment.
● Seedlings
● Density
● Nutrient levels
3. What dependent variable(s) was/were measured?
● Biomass
● Height
● Length
4. Looking at Figure 1, explain in your own words how plant density affected biomass. How
did this differ between individual plant biomass and pot biomass?
● At high nutrient levels and densities, plants produced more total biomass per
pot. However, at low nutrient levels, biomass per pot increased more strongly
with density. When nutrients were abundant, mean biomass per individual was
higher. Density also caused a decrease in mean biomass per individual, but the
effect was stronger when nutrients were abundant. Individual biomass of forbs
was lowest at all densities, while legume biomass decreased less with density
than grass biomass. An interaction between density and nutrients influenced the
mortality of individuals in a pot. At low and intermediate plant densities, almost
all individuals survived, but many plants died at high densities.
5. Summarize the overall findings of this study in your own words.
● In the analysis of 43 herbaceous plant species, the amount of biomass assigned
to roots regularly increased with density, indicating that competition for
below-ground resources may be more substantial than previously thought, even
at relatively high nutrient levels. This research also shows that plants modify
1
Name:
their biomass allocation patterns and the morphology of their roots and stems in
response to nutrient availability and density. The functional type, life span, and
realized nutritional niche of a plant all influence these react
