Textbook Question
Among vertebrates, the large intestine exists only in lineages that are primarily terrestrial (amphibians, reptiles, and mammals). Propose a hypothesis to explain this observation.
Ch. 41 - Animal Nutrition
Freeman8th EditionBiological ScienceISBN: 9780138276263
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Table of contents
- Ch. 1 - Biology: The Study of Life13
- Ch. 2 - Water and Carbon: The Chemical Basis of Life14
- Ch.3 - Protein Structure and Function10
- Ch.4 - Nucleic Acids and the RNA World10
- Ch. 5 - An Introduction to Carbohydrates10
- Ch. 6 - Lipids, Membranes, and the First Cells11
- Ch. 7 - Inside the Cell10
- Ch. 8 - Energy and Enzymes: An Introduction to Metabolism10
- Ch. 9 - Cellular Respiration and Fermentation11
- Ch. 10 - Photosynthesis12
- Ch. 11 - Cell-Cell Interactions12
- Ch. 12 - The Cell Cycle8
- Ch. 13 - Meiosis12
- Ch. 14 - Mendel and the Gene23
- Ch. 15 - DNA and the Gene: Synthesis and Repair15
- Ch. 16 - How Genes Work16
- Ch. 17 - Transcription, RNA Processing, and Translation16
- Ch. 18 - Control of Gene Expression in Bacteria16
- Ch. 19 - Control of Gene Expression in Eukaryotes12
- Ch. 20 - The Molecular Revolution: Biotechnology, Genomics, and New Frontiers15
- Ch. 21 - Genes, Development, and Evolution12
- Ch. 22 - Evolution by Natural Selection16
- Ch. 23 - Evolutionary Processes13
- Ch. 24 - Speciation15
- Ch. 25 - Phylogenies and the History of Life13
- Ch. 26 - Bacteria and Archaea15
- Ch. 27 - Diversification of Eukaryotes16
- Ch. 28 - Green Algae and Land Plants16
- Ch. 29 - Fungi18
- Ch. 30 - An Introduction to Animals9
- Ch. 31 - Protostome Animals15
- Ch. 32 - Deuterostome Animals17
- Ch. 33 - Viruses16
- Ch. 34 - Plant Form and Function16
- Ch. 35 - Water and Sugar Transport in Plants16
- Ch. 36 - Plant Nutrition13
- Ch. 37 - Plant Sensory Systems, Signals, and Responses16
- Ch. 38 - Flowering Plant Reproduction and Development16
- Ch. 39 - Animal Form and Function17
- Ch. 40 - Water and Electrolyte Balance in Animals16
- Ch. 41 - Animal Nutrition16
- Ch. 42 - Gas Exchange and Circulation16
- Ch. 43 - Animal Nervous Systems16
- Ch. 44 - Animal Sensory Systems16
- Ch. 45 - Animal Movement11
- Ch. 46 - Chemical Signals in Animals16
- Ch. 47 - Animal Reproduction and Development16
- Ch. 48 - The Immune System in Animals16
- Ch. 49 - An Introduction to Ecology15
- Ch. 50 - Behavioral Ecology16
- Ch. 51 - Population Ecology16
- Ch. 52 - Community Ecology20
- Ch. 53 - Ecosystems and Global Ecology17
- Ch. 54 - Biodiversity and Conservation Ecology18
Chapter 41, Problem 13b
Minnows are mainly carnivorous, eating insects and other small animals. However, herbivory has evolved independently in minnows several times.
What changes in digestive structure and function are associated with the evolution of herbivory?
Researchers compared the relative gut length—the length of the digestive tract divided by body length—in four species of herbivorous minnows and four species of carnivorous minnows. The results are shown in the graph provided here. Based on these data, what conclusion can you draw about the relationship between diet and gut length?
Verified step by step guidance1
Examine the graph provided, which compares the relative gut length of herbivorous and carnivorous minnows. Note that relative gut length is calculated as the length of the digestive tract divided by body length.
Observe that the herbivorous species have a significantly longer relative gut length compared to the carnivorous species. This is indicated by the higher bars for herbivorous species in the graph.
Understand that a longer gut length in herbivorous species is likely an adaptation to their diet, which consists mainly of plant material. Plant material is generally harder to digest and requires more time and surface area for effective nutrient absorption.
Recognize that the shorter gut length in carnivorous species reflects their diet of insects and small animals, which are typically easier to digest and require less digestive tract length for nutrient absorption.
Conclude that the data suggests a strong relationship between diet and gut length, where herbivory in minnows is associated with an increased gut length to accommodate the digestion of plant material.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Digestive Adaptations
Herbivorous animals often exhibit specific adaptations in their digestive systems to efficiently process plant material, which is typically more fibrous and harder to digest than animal matter. These adaptations can include longer gut lengths, specialized stomach compartments, and the presence of symbiotic microorganisms that help break down cellulose.
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05:11
Digestion and Digestive Tracts
Relative Gut Length
Relative gut length is a measure that compares the length of the digestive tract to the body length of an organism. This metric is crucial for understanding dietary habits, as herbivorous species generally have longer guts to facilitate the breakdown of complex plant materials, while carnivorous species tend to have shorter guts due to the easier digestibility of animal proteins.
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03:54Interpreting Branch Length
Evolutionary Ecology
Evolutionary ecology examines how evolutionary processes shape the interactions between organisms and their environments, including dietary adaptations. The evolution of herbivory in minnows illustrates how changes in diet can lead to significant morphological and physiological changes, such as increased gut length, which enhance survival and reproductive success in specific ecological niches.
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02:45History of Evolutionary Theory Example 1
Related Practice
Textbook Question
Minnows are mainly carnivorous, eating insects and other small animals. However, herbivory has evolved independently in minnows several times.
What changes in digestive structure and function are associated with the evolution of herbivory?
Like cichlids, minnows use their pharyngeal jaws to process food. Suggest some possible structural differences between the teeth on the pharyngeal jaws of carnivorous and herbivorous minnows.
Textbook Question
Minnows are mainly carnivorous, eating insects and other small animals. However, herbivory has evolved independently in minnows several times.
What changes in digestive structure and function are associated with the evolution of herbivory?
Which of the following is true of the digestive tracts of minnows?
a. They are incomplete but have both a mouth and an anus.
b. They are complete, facilitating compartmentalization of digestion in different organs.
c. They are incomplete, with no accessory organs.
d. They are complete and include a large gastrovascular cavity.
Textbook Question
Minnows are mainly carnivorous, eating insects and other small animals. However, herbivory has evolved independently in minnows several times.
What changes in digestive structure and function are associated with the evolution of herbivory?
Suggest a function of the difference in relative gut lengths of herbivorous and carnivorous minnows.
Textbook Question
Minnows are mainly carnivorous, eating insects and other small animals. However, herbivory has evolved independently in minnows several times.
What changes in digestive structure and function are associated with the evolution of herbivory?
Which minnows, herbivorous or carnivorous, should exhibit higher cellulase activity in the gut? Explain.
Textbook Question
Minnows are mainly carnivorous, eating insects and other small animals. However, herbivory has evolved independently in minnows several times.
What changes in digestive structure and function are associated with the evolution of herbivory?
Why did the researchers compare relative gut length instead of absolute gut length?