0 046 For Species Five And Seven example essay topic

Introduction A niche is defined as the role of an organism in an ecological community. The goal of this experiment was to investigate six genuses of spiders and how they have developed niche partitioning in order to survive in their community. This was done by observing and collecting data in regards to how each spider specialized in web structure, specifically radius, area, number of rows and mesh style. Further, web placement, specifically height; and orientation, specifically, whether it was a north / south or east / west web and horizontal versus vertical. My hypothesis is that the spiders will utilize niche partitioning by the placement and structure of webs. This is reasonable as it is logical that the placement of webs in various locations would result in the reduce competition for resource.

This then follows that the differential structures would allow the spiders to capture different prey and again reduce competition for food. Materials and Methods The study was conducted at the Delaware Dam State Wildlife Area. Six genuses of spiders of the family Araneidae were identified to be located. Argiope, Neoscona, Tetragnatha, Leucauge, Cyclosa, and Araneus. Argiope Neoscona Tetragnatha Leucauge Cyclosa Araneus We went into the woods and fields in search of webs. Once located, we determined the species of the spider from an identification sheet.

To provide data regarding the web, we measured the height of the web by using a meter stick to calculate the distance from the ground to the web center. Next, we measured the radius of the web with the meter stick with the standard being from the center of the web to the outermost rim. We then counted the number of rows of the web. We next looked at the prey and counted the amount and type of prey that was in the web.

We then measured the body size of the spider and prey utilizing a caliper. We marked the webs that had been counted in order not to duplicate our findings. This process was repeated as we located webs and the data from all experimenters were collected and totaled. Results Niche partitioning can be utilized by placement factors. Therefore, an ANOVA test was utilized to compare the heights of the different webs.

This demonstrated a partitioning in which the height of the webs for species 1 - 65.25, 4-54.80 and 7-57.50 were separated from species 2-98.47, 3-93.19 and 5-88.50. Further, the data showed a possible separation for species 4 & 5 and 5 & 7. Therefore, a t-test was performed: Due to P-Value being 0.118 and 0.133 respectively, this shows that there is no significant difference. This represents that niche partitioning could be accounted by placement for species number one in comparison to species two and three and species two and three in comparison to species four, five and seven; but it does not account for species two and three or species one, four, five, and seven.

Independently, our personal study looked at the placement of the web in regards to how it was attached. Whether it was attached to flowers, weeds, etc. or to trees, shrubs, etc. This showed a strong difference in the species argiope, who placed their webs in grassy weeds, flowers, etc. and species Neoscona and Cyclosa, who hung their webs from shrubs and trees. Though this differentiated some of the species, it did not account for all. Therefore, we looked at the structure of the web.

While species one differentiated itself from species two and three by height, this represented that species two and three differentiated themselves by radius. Further a t-test is performed between four and seven. Species four and seven show minor discrepancy and therefore, t-test is conducted: This test shows that the radius has a significant difference between the two species. In reviewing the web's area: This shows possibility for niche partitioning in regards to area between species one and species two; species two and species three and species one and species three. Therefore, the t-test was done: The This shows no significant difference in area between species one and species two or between species two and species three. However, with a P-Value of 0.002 the area shows a significant difference between species one and species three.

Continuing on, we look at the number of rows in the web. While some overlap, it shows some difference between species five and seven, species four and five and species four and seven and therefore, t-tests are conducted: As P-Values are 0.046 for species five and seven, it shows a significant difference, while species four and five and species four and seven with P-values of 0.202 and 0.399 respectively, indicate no difference. Continuing on with structural differences, we compare mesh size: One-way ANOVA: mesh size versus Genus code Source DF SS MS F P Genus code 5 4.260 0.852 2.47 0.034 Error 195 67.355 0.345 Total 200 71.615 S = 0.5877 R-Sq = 5.95% R-Sq (adj) = 3.54% Individual 95% CIs For Mean Based on Pooled StDev Level N Mean StDev 1 150 0.9148 0.5225 2 19 1.0508 1.1297 3 19 0.6571 0.4007 4 4 0.2388 0.0331 5 4 0.9106 0.3224 7 5 0.4483 0.3553 0.00 0.50 1.00 1.50 Pooled StDev = 0.5877 There appears to be a variety of differences, so t-tests compare: This demonstrates that there is a significant difference in the mesh size of species four and five and species one and five but no difference between species seven and five, species seven and four and species two and three. Another factor in niche partitioning is through orientation.

Therefore, web placement of vertical and horizontal was observed. This shows a niche partition by species seven from species one, two, three and four. Further, there is a slight overlap with species five and therefore, t-tested. However, with a P-Value of 0.356, there is not a significant difference.

A look at the directional orientation resulted in: While, the numbers reflect no mean difference, a t-test between the mean of 1.00 and 1.50 showed all values to be the same. Two-Sample T-Test and CI: N / S (1) E / W (2): 7. MTW, N / S (1) E / W (2): 3 Subset of Radar o ERROR All values in column are identical. Therefore, directional orientation seems not to be a factor in niche separation. Finally, we looked at the prey size and size of the spider.

T-tests were conducted to compare species four and five and five and seven. With P-Values of 0.001 and 0.002 respectively, this shows that there is significant differences in size of spiders four and five and spiders five and seven. A look at prey size: This reflects much overlap, but in reviewing the means, it appears to be quite a range with species three, four and five ranging from 2.0 - 3.0; species one and two at 6.147 and 5.273; while species seven at 11.00. However, with only one prey measured for species five and seven, it is hard to accurately compare this information. Discussion: A niche is defined as the role of an organism in an ecological community; its unique way of life and its relationship to other biotic and abiotic factors.

Niches are developed in order for the organism to reduce competition and therefore, realize their potential within the community. This is accomplished by adaptations by tropic, spatial and temporal means; by placement, structure and orientation. The results seem to show that the spiders definitely participate in niche partitioning. Webs are built at different heights and in different areas (trees vs. weeds) to ensnare different insects of different habitats.

Orientation seemed to follow the same pattern for directional (N / S vs. E / W) though horizontal versus vertical did show some partitioning. Overall, most genuses followed the same pattern. This could be accounted for in that the wind would blow more prey into their webs vertically, whereas the horizontal orientation would have less chance of the wind blowing insects and the spiders would have to rely on insects climbing into the webs. Structure seemed to provide the most comparisons to establish the premise that the spiders were participating in niches. Radius varied amongst species one and two from the balance. Whereas, the area differed between species one and three.

Rows provided a difference between species five and seven and the mesh provided differences between three and one and four and five. Though weather was a factor in that it was unusually cold the morning of our experiment, we captured far more data regarding species one. Species one seemed the most effective in their niche establishment. Their webs were larger, lower to the ground and captured more prey.

Overall, species three seemed to continually overlap in all areas, which could account for the small number seen. My hypothesis was that the spiders would utilize niche partitioning by the placement and structure of webs. The data shows that the placement of webs in various locations would result in the reduced competition for resources and that the differential structures would allow the spiders to capture different prey and again reduce competition for food. Therefore, it can be seen that the orb weaving spiders in Delaware Dam State Park participate in niche partitioning.