Birds with larger wingspans will have lower metabolic rates than birds with smaller wingspans. Rationale & Prediction: Birds with larger wingspans will usually have a larger body mass than birds with smaller wingspans, but birds with smaller wingspans must use more energy to travel when foraging and migrating.

Birds with larger wingspans will have lower metabolic rates than birds with smaller wingspans. Rationale & Prediction: Birds with larger wingspans will usually have a larger body mass than birds with smaller wingspans, but birds with smaller wingspans must use more energy to travel when foraging and migrating.

INTRODUCTION

METHODS

DESIGN: The independent variable was wingspan, while the dependent variable was basal metabolic rate. The control group was the effect of body mass on BMR in birds. The experimental group was how wingspan relates to BMR in birds.

SUBJECTS: I tested on birds with wingspans ranging from 94 – 1700 mm. Birds with large wingspans (555-1700mm) were compared to birds with small wingspans (0-555mm).

PROCEDURES: I used the Quaardvark database which provided numerical data on wingspan and BMR for many species of birds. Using scatterplot graphs, these plotted values indicated a positive correlation between wingspan and BMR.

ABSTRACT

METHODS: I tested my hypothesis on birds using their wingspans to determine if birds with larger wingspans had lower metabolic rates that birds with smaller wingspans and that birds with larger wingspans will usually have a larger body mass than birds with smaller wingspans.

RESULTS: I determined my hypothesis that birds with larger wingspans will have lower metabolic rates than birds with smaller wingspans was incorrect, yet my rational that birds with larger wingspans will usually have a larger body mass than birds with smaller wingspans was correct.

BACKGROUND: Physical and chemical processes responsible for maintaining an organism’s life is known as metabolism. Without metabolism, organisms will die. The rate of living theory hypothesizes that an organism with a fast metabolic rate will have a short life span (Speakman 2005). This theory was created by observing that larger animals had lower metabolic rates and outlived smaller animals with higher metabolic rates. When analyzing metabolic rates and aging in organisms, there are many factors to consider such as mutant or natural animals, environmental factors, individual variation within species, etc. (Speakman 2005). Due to these numerous factors, the rate of living theory in now no longer the favored theory with regards to metabolic rate and aging. I predict that birds with larger wingspans will have lower metabolic rates than birds with smaller wingspans based on Speakman’s observations that larger animals had lower metabolic rates than smaller animals.

BACKGROUND: Body mass affects basal metabolic rate in birds and mammals. According to the metabolic-level boundaries theory, metabolic scaling rates should fluctuate between two extreme limits: 2/3 and 1 with the 2/3 limit representing resting or surface constraints and the 1 limit representing mass constraints on energy production such as torpor (low metabolic rate) and vigorous exercise (high metabolic rate) (Glazer 2008). In addition, the overall metabolic rate of organisms will vary due to many reasons including body size, activity level, body surface, environment in which the animal lives, etc.

UNKNOWN: Do birds with larger wingspans have a higher or lower BMR than birds with smaller wingspans?

HYPOTHESIS: Birds with larger wingspans will have lower metabolic rates than birds with smaller wingspans. Rationale & Prediction: Birds with larger wingspans will usually have a larger body mass than birds with smaller wingspans, but birds with smaller wingspans must use more energy to travel when foraging and migrating.

APPROACH: This hypothesis will be tested using data from the Quaardvark database. This data will be used to graph and perform statistical analysis.

RESULTS

PARAGRAPHS: A positive linear relationship was observed between BMR and wingspan in birds, indicating that as average wingspan increased so did BMR. The two groups differed from each other regarding BMR with t (20) = 0.14, p = 0.89. Since the t-stat < t critical, the null hypothesis was accepted indicating no significant differences in BMR between birds with wingspan from 0-555 mm and 555-1700 mm.

A positive linear relationship was observed between average body mass and wingspan in birds, indicating that as average wingspan increased so did body mass. When testing body mass between the two groups, they differed significantly from each with t (7) = 3.88, p = 0.06. Since the t-stat > t critical, the null hypothesis was rejected indicating highly significant differences in body mass between birds with wingspan from 0-555 mm and 555-1700 mm. Thus, the hypothesis that birds with larger wingspans will have lower metabolic rates than birds with smaller wingspans was incorrect, yet the rational that birds with larger wingspans will usually have a larger body mass than birds with smaller wingspans was correct.

FIGURES:

DISCUSSION

FINAL CONCLUDING PARAGRAPH: In conclusion, birds with larger wingspans have a larger body mass and higher metabolic rates than birds with smaller wingspans. With the limited data provided by the Quaardvark database, further analysis should be done for this comparison by obtaining similar data from other researchers on this topic. In addition, other factors including body temperature, environment where organism lives, body surface area, rate of wing flapping, soaring, gliding, migratory patterns, and so on should be included to provide a more accurate picture of wingspan and metabolic rate comparisons.

1ST PARAGRAPH: When comparing the wingspan of birds with BMR and the wingspan of birds with average body mass, a positive linear relationship was observed for both. Thus, as wingspan increased so did the BMR and the body mass. Generally, as body mass increases, so does the basal metabolic rate. However, comparing body surface areas between larger mammals and smaller mammals, metabolic rates will be higher for smaller mammals. Smaller mammals have larger body surface areas to volume ratios and lose heat much quicker to the environment than large mammals. Smaller mammals require higher metabolic rates to maintain their body temperatures. In addition, the smaller an organism’s body mass, the higher its BMR. Therefore, their BMR is much higher per unit of body mass than larger mammals. Environmental temperature also plays a key role in metabolism.

MIDDLE PARAGRAPH: There is a positive correlation between body mass and body temperature with body temperature being intricately linked to metabolic rate (Clarke & Rothery 2008). Body temperature of organisms fluctuate between heat that is supplied or lost to the environment which affects metabolism. Body surface area affects metabolism. Torpor and hibernation also affect metabolism. The amount of energy expelled during rigorous activity affects metabolism. These are factors that were not included in the Quaardvark database. I was limited in obtaining further data that may have correctly proven my theory.

LITERATURE CITED

Clarke A, Rothery P. 2008. Scaling of body temperature in mammals and birds. Functional Ecology. 22(1):58-67.

Glazier DS. 2008. Effects of metabolic level on the body size scaling of metabolic rate in birds and mammals. Proceedings of the Royal Society B: Biological Sciences. 275(1641):1405-10.

Speakman JR. 2005. Body size, energy metabolism and lifespan. Journal of Experimental Biology. 208(9): 1717-30.