Relationship Between BMR and Primary Diet Type

Citations

Introduction

Background

Studies show that in birds and mammals, a higher body mass also means a higher BMR; discuss Speakman paper

According to Speakman, birds and mammals with higher body masses live longer than those that are smaller.

Hypothesis

Herbivores have a higher mean body temperature, therefore have a higher BMR than carnivores (Clarke and O'Conner 2014)

Herbivores require warmer body temperature than carnivores.

A higher average body mass positively correlates to a higher average BMR

Approach

Compare average body mass to average BMR in both birds and mammals

Compare primary diet (herbivore vs carnivore) and average BMR in mammals

Method

Abstract

Birds (Aves) and Mammals (Mammalia) were used when comparing body mass and BMR

Mammals were used when comparing primary diet and average BMR

Data was extracted using Quaardvark for all data points

Data was organized by filtering for average body mass and average BMR for both birds and mammals

Data was organized by filtering for mammals and primary diet (herbivore and carnivore) Omnivore was excluded.

Using data to assess how primary diet correlates to average basal metabolic rate (BMR) in mammals

Retrieving data by extracting it using Quaardvark, and comparing the data. Then using a two sample t-test to discover relationship between two variables (body mass vs bmr, primary diet vs bmr)

Using data to compare how body mass affects average BMR in birds and mammals

Strong positive correlation between body mass and BMR in birds and mammals. In mammals, herbivores present higher average BMR than carnivores.

Discussion

Statistical analysis shows a positive relationship between average body mass and average BMR in both birds and mammals.

Herbivores present a higher mean body temperature, which causes a higher average BMR than in carnivores who have a lower mean body temperature.

According to Clarke and O'Connor, herbivores require a warmer body than carnivore do to the high maintance costs of their longer guts

Highest mean body temperature in foliovores and granivores

Herbivores have to support fermintation by their gut microbes

According to Speakman, birds and mammals that have a higher average body mass have a higher average BMR

According to Glazier, metabolic rate also relates to energy expenditure and also digestion and insulation.

Due to herbivores complicated digestion of plants and leaves, it requires a complicated digestive process, and digestion is faster in warmer bodies (Clarke and O'Connor)

Summary

Even though body size plays a big part in average BMR, due to the complicated digestive process of herbivores, they will have a higher mean body temperature that will increase BMR as well.

Results

The t Stat value in both mammals and birds was greater than the two tail critical value when comparing the data, which shows there is a significant difference between body mass and BMR.

In mammals, The average BMR in herbivores was significantly higher than the average BMR in carnivores.

Citations

Performing two sample t-tests with the data comparing body mass and BMR for birds and mammals to determine statistical significance.

Speakman JR. Body size, energy metabolism and lifespan. The Journal of Experimental Biology. 2005;208(9):1717–1730. https://doi.org/10.1242/jeb.01556. doi:10.1242/jeb.01556

Glazier DS. Effects of metabolic level on the body size scaling of metabolic rate in birds and mammals. Proceedings of the Royal Society B: Biological Sciences. 2008;275(1641):1405–1410. https://doi.org/10.1098/rspb.2008.0118. doi:10.1098/rspb.2008.0118

Clarke A, O’Connor MI. Diet and body temperature in mammals and birds. Global Ecology and Biogeography. 2014;23(9):1000–1008. https://doi.org/10.1111/geb.12185. doi:10.1111/geb.12185