Transcript This Land is My Land, A Study of Intraspecific Competition Among

This Land is My Land, A
Study of Intraspecific
Competition Among
Marigolds (Tagetes patula)
K. D. Farley
Undergraduate Student
Environmental Biology
Tennessee Tech University
Cookeville, TN 38505
A Summary
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?The Question? How do plants effect each
other in high population density areas?
-Objectives- To observe and measure how
population density effects;
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The number of matured seeds (survival rate)
Plant stem, leaf, and root size and wieght
-Hypothesis- Population density will have no
significant effect on plant community growth.
A Summary
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-The Plan- Planting different size
communities in identical areas, with the only
variable being population density, measure size
and weight after three to four weeks.
!Don’t Tell Me, I Know! (Expected Results)
The greater the density, the more competition
will exist for sustenance, hence the less the
struggling plant will grow more.
Introduction
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I have noticed that flowers that are planted
close together are often of smaller size than the
same kind of plant planted solitarily.
Experiments have shown that, between
competing species, a plant that needs less
nutrients to survive will exclude and live
longer and healthier than its competitor
(Dybzinski 2007).
Introduction
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Studies have also concluded that community
size can affect the outcome of certain species
in competitive exclusion (Fletcher 2005).
Although these studies take in consideration
population densities among different species,
how do plants react in dense populations
among their own kind.
Introduction
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It has also been claimed that plants competing
for nutrients have sacrificed reproduction for
root mass (Hutchings 2007).
But would the plants sacrifice stem and leaf
growth for their root size?
Objective
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The objective of this experiment is to observe
and measure how population density effects
the number of matured seeds (survival rate) as
well as plant stem, leaf, and root size and
weight.
Hypothesis
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Hypothesis – Plants in high population areas will
grow less than the plants in less crowded areas
Null hypothesis - Population density will have no
significant effect on plant community growth.
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Population Density – number of plants in per volume of
soil with limited nutrients and light.
Community Growth – average growth of the plant
population (weight, leaf number, blooms, root mass, etc.).
Methods/Materials
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Materials
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Eight identical flowering pots (4in by 4in plastic
pots)
Marigold seeds
Potting soil
Ruler
Measuring cup
Heat lamp (regular light if heating lamp cannot be
found)
Methods/Materials
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Methods
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Plant four different population densities in four different pots. The first
pot should have 1 seed, the second pot should have 4 seeds, the third
pot should have 8 seeds, and the fourth pot should have 16 seeds.
Simply follow the potting instructions on the seed container.
Repeat previous step for another test group if desired.
Once the seeds are potted, give each pot the same amount of water and
sunlight. It is crucial that the only variable among the different pots is
the number of seeds in each pot.
After allowing the plants to grow for several weeks it will be time
measure and collect the data. Keep track of which pot each plant came
from. Carefully measure the length of the stem, number of leaves,
number of blooms (pedals), weight of the leaves, of the stems, and of
the root systems.
Expected Results/ Benefits
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The more densely populated the environment
the less an individual plant will grow.
Once an understanding of growth effecting
density is obtained, then applications could be
developed for use in the agriculture industry.
Timeline
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9/03/2007 purchase materials
9/05/2007 set up project
9/12/2007-10/17/2007 carry out experiment
10/17/2007 collect results and raw data
Timeline
Budget
Item
Cost
Amount
Total
Seeds
$0.97p/bag
1
$0.97
Pots
Stolen
8
$0.00
Water
Free
As needed
$0.00
Labor
$1,000,000.00
p/hr
12
$12,000,000.00
Works Cited
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Dybzinski, R., and D. Tilman. 2007. Resource Use Patterns Long-Term
Outcomes of Plant Competition for Nutrients and Light. American
Naturalist 170: 305-318.
Fletcher, R. J. Jr., and J. L. Orrock. 2005. Changes in Community Size
Affect the Outcome of Competition. The American Naturalist 166: 107111.
Gudelj, I., and C. R. MacLean. 2006. Resource Competition and Social
Conflict in Experimental Populations of Yeast. Nature 441: 498-501.
Hutchings, M. J., M. Semchenko, and E. A. John. 2007. Challenging the
Tragedy of the Commons in Root Competition: Confounding Effects of
Neighbor Presence and Substrate Volume. Journal of Ecology 95: 252-260.
Tilman, D. 2007. Resource Competition and Plant Traits: a Response to
Craine et al. 2005. journal of Ecology 95: 231-234.
?Questions?