Hypothesis: If plants of different or the same species are planted within vicinity of one another that there is a possibility of competition between them then competition will occur and one of the competitors will eventually be eliminated from that specific location.
Methods:
1) Label one envelope for each of the treatments with the pot number, number of mustard seeds and/or wheat plants. Treatments include: differences in density of plants per pot- of plants of the same species, and planting several mixtures of the two species for plants of different species. Do these treatments in separate pots: Pot 1: 2 mustard plants, Pot 2: 2 mustard plants, Pots 3 and 4: 4 mustard plants, Pot 5: 8 mustard plants, Pot 6: 9 mustard plants, Pot 7and 11: 16 mustard plants, Pot 8: 12 mustard plants, Pot 9 and 10: 18 mustard plants, Pot 12: 36 mustard plants, Control Pot A and B: 1 mustard plant. Pot 13 and 14: 2 wheat plants, Pot 15 and 16: 4 wheat plants, Pot 17 and 18: 6 wheat plants, Pot 19 and 20: 10 wheat plants, Pot 21: 21 wheat plants, Pot 22: 20 wheat plants, Pot 23: 35 wheat plants, Pot 24: 34 wheat plants, Control C and D: 1 wheat plant. Pot 25 and 26: 2 wheat and 2 mustard plants, Pot 27 and 28: 4 wheat and 2 mustard plants, Pot 29 and 30: 8 wheat and 2 mustard plants, Pot 31: 20 wheat and 2 mustard plants, Pot 32: 16 wheat plants and 1 mustard plant, Pot 33: 33 wheat plants and 0 mustard plants, Pot 34: 32 wheat and 0 mustard plants. Pot 35 and 36: 2 wheat and 4 mustard plants, Pot 37 and 38: 2 wheat and 8 mustard plants, Pot 39: 4 wheat and 20 mustard plants, Pot 40: 2 wheat and 14 mustard plants, Pot 41: 2 wheat and 28 mustard plants, and Pot 42: 2 wheat and 27 mustard plants.
2) Make a label for each pot, include; pot number, number of mustard seeds and or number of wheat seeds.
3) For each assigned treatment, count out the number of seeds (mustard, wheat or both) needed plus any extra seeds. Since, most likely, only 80-90% of the seeds planted will germinate, the extra seeds will insure that enough plants will germinate for the assigned treatment.
4) Fill a 4 inch pot with artificial soil mixture. Lightly pack the soil down below the rim of the pot.
5) Space the seeds evenly over the soil surface, use the back of a pencil to make a hole to put the seeds, and cover them back up with the soil in the pot.
6) Place pots in a tray, and put under a light source. Leave an empty space between each pot so the plants will have room to grow before they become crowded. Water the plants routinely from either daily to weekly or somewhere in between.
7) Monitor the plants and make observations over the next six weeks. Check back in one week and weed out any extra plants. Carefully remove the entire plant (shoot and root). Make sure both pots for each treatment have the desired number of seedlings for that treatment.
8) Periodically (ideally weekly) check the conditions of the plants. Record your observations on a separate sheet of paper.
9) After 6 weeks, harvest the plants. At this point collect the final data for the experimental results.
Materials:
Results:
Conclusions:
1) Intraspecific competition is very evident in the range of densities we planted. In the pots of varied densities of mustard seeds as the density of seeds grew larger, the per plant biomass decreased. This means that the increased density of the plants decreased the growth and therefore the mass per plant. (See Table 1 for data) Intraspecific competition was also evident in the pots of solely wheat plants. This means as the density of the wheat seeds grew larger, the per plant biomass decreased. (See Table 2 for data)
2) The nature of interaction between Wheat and Mustard plants is definitely interspecific competition, since both plant experienced some disadvantage in its growth in living next one another. In the graphs of the interspecific competition between mustard and wheat plants it was clear that the slope of the lines of best-fit were decreasing, or had a negative slope. (Graph 7) This means that as the number of opposing competitors in each graph increased, the per plant biomass of each plants steadily decreased. However, the mustard plants experienced a greater disadvantage as they had a greater decrease in per plant biomass as the total number of wheat competitors increased than did the wheat plants, which had a smaller decrease in per plant biomass, and therefore had a more negative slope. (See graph 7)
3) From our data, it can be concluded that mustard plants compete more intensely in interspecific competition with wheat plants than intraspecifically, and wheat plants also compete more intensely with interspecific competitors than conspecific ones. Since the graph of interspecific competition on mustard plants had a more negative slope of -.0353, than its intraspecific competition slope of -.0117, means that as the number of competitors increased there was greater decrease in per plant biomass in interspecific competition than intraspecific, so mustard plants are more greatly affected by interspecific competition. Since the graph of interspecific competition on wheat plants had a more negative slope of -.0258, than its intraspecific competition slope of -.0163, means that as the number of competitors increased there was greater decrease in per plant biomass in interspecific competition than intraspecific, so wheat plants are more greatly affected by interspecific competition. Therefore, it can be concluded that these to plant species have very similar resource requirements, and that is why the two species are competing with each other so aggressively, even more intensely than among themselves.
4) From our data, it can be concluded that wheat plants had a stronger more negative effect on the other. Comparing the effect of interspecific competition on wheat and mustard plants, the mustard plants experience a greater decrease in per plant biomass as the number of wheat competitors increased than did the wheat plants as mustard competitors increased, concluding that wheat plants have a greater negative effect on it competitor. The effect of interspecific competition on mustard’s graph line of best fit had a slope of -.0353, and the effect of interspecific competition on wheat’s graph line of best fit had a slope of -.0250, so clearly mustard plants were influenced more negatively than were wheat plants.
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