Biology Report: Comparing Digestive System Lengths in Animals - 2019

This report investigates the digestive systems of various animals, focusing on the relationship between diet and the length of the digestive tract. The study compares the digestive systems of herbivores, carnivores, and omnivores, with a hypothesis that animals consuming leafy greens and vegetables will have longer digestive systems. The research involved dissecting specimens like pigs, rats, and sardines to measure their small and large intestines. The findings revealed variations in digestive system lengths across different species, with female pigs having the longest and sardines the shortest. The report includes a literature review exploring existing research on digestive physiology and the influence of diet on digestive tract morphology, referencing sources such as books and websites. Although the study had some limitations, the report suggests areas for future research and provides valuable insights into the digestive processes of various animals and the impact of diet on digestive system length.

0Running head: DIGESTIVE SYSTEM
Digestive system:
Name of the student:
Name of the University:
Author’s note

Abstract:
The digestive system of different organism varies because of variations in diet, habitat
and size of the animals. The major classification for animals includes herbivores, carnivores and
omnivores. This paper aimed to investigate about the length of the digestive systems of
herbivores, carnivores and omnivores and the impact of diets on the length of the digestive
system. The significance of conducting research in this area was to gain idea regarding the
different dietary patterns in the different animal groups. The research hypothesis was that animal
consuming leafy greens and vegetables will have longer digestive systems compared to those
consuming meat. The experiment was done with specimen of 2x pig, rat, squid, 2x sardine, 2x
cane toad, mullet and for each specimen dissection of the stomach was done and the digestive
system was pulled out to measures the small and large intestine. The comparison of the length of
digestive system of different animals revealed that female pigs had the longest digestive system
and sardines had the smallest digestive system. However, the validity of the research was found
to be low as exact dissection was not done. Hence, to get valid and reliable findings in the future,
it is recommended to improve the site for dissection of each animal.
Literature review:
The gastrointestinal systems of animals play multiple function of digestion,
osmoregulation and protection. Karaso and Douglas (2013) gave the evidence that the
morphology, physiology and biochemistry of the digestive system has impact of food chemistry
and types of food taken by animals. The study by Wang et al. (2003) further confirmed the above
concept by investigating about the relationship between food habits and digestive tract
morphology of six rodents. After removing the digestive tracts and measuring the length of the

stomach after stretching the stomach to full length, it was found that herbivores group had the
largest intestine compared to other omnivorous species of rodents. In case of omnivores, the
length of intestine varied because of variations in proportion of seeds and foods taken by the
animals. In addition, stomach length was longer for herbivores compared to omnivores. This
study gave the implication that hind gut is a reliable indicator for estimating food habits
compared to small intestine. However, as this study was done only with rodents, conducting
further research with other types of animal was necessary to further confirm the study findings.
The information regarding the digestive system was found from the book by Ballard
(2009) too. The information summarizes about the morphology of the human digestive systems
and the length of each part of the digestive tract. The significance of this source of information is
that it gives idea about length of digestive systems for omnivores. Hence, the information from
this source can help to interpret whether digestive tract for other carnivores group differs
compared to human beings or not. The website by VetSci also gave information regarding the
digestive systems of carnivores, omnivores and herbivores. The significance of this website is
that it covered details related to digestive systems for different animals. It gave comprehensive
details about the similarities and difference in digestive system for each species. Hence, this
source can help to further proceed with future studies on link between food pattern and diets and
validate the findings obtained by taking data from the website. This is not an experiment based
evidence, however the data is reliable and consistent with other evidence.
The review of evidence related to digestive systems of different animals also helped in
the extraction of a video which provided information about the digestive system of pigs. The
video revealed similarity between the digestive systems of pigs and humans. The comparison
between the length of different organs in the digestive such as oesophagus, stomach, large and

small intestine revealed that the length of the digestive system is greater for pigs compared to
humans. The information is credible as it was gathered first hand using dissection and process
used was credible (Mosley et al., 2012). Hence, this finding can further be confirmed by
conducting future research on evaluation of digestive systems for different categories of animals.
The gap in the above design is that no research established the link between diet and length of
digestive tract. This should be further examined with robust research design so that interaction
between diet patterns and morphological functions of the digestive system can be understood.

References:
Ballard, C. (2009). The Digestive System (Vol. 12). Capstone Classroom.
Karasov, H. W., & Douglas, A. E. (2013). Comparative digestive physiology. Comprehensive
Physiology, 3(2), 741-783.
Mosley, M., Guts, BBC. prod. (Films Media Group, 2012).
VetSci. 'Comparative Digestion', (n.d.), < http://vetsci.co.uk/2010/05/14/comparative-digestion/#
> accessed 11 June 2019.
Wang, D. H., Pei, Y. X., Yang, J. C., & Wang, Z. W. (2003). Digestive tract morphology and
food habits in six species of rodents. FOLIA ZOOLOGICA-PRAHA-, 52(1), 51-56.