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- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
Assessing the Microbiological A timely exploration of the coordinated functions of microbiological communities and the impacts of global climate change on microbial life Ecosystems function like interlocking puzzles and ultimately the health of an ecosystem depends upon the niche activities of its microbial communities. Assessing the Microbiological Health of Ecosystems summarizes our understanding of how microbial community processes are organized and the mechanisms by which activities of their constituent species are coordinated. The authors collectively present a basis for understanding what produces healthy microbial components of an ecosystem, thereby supplying a foundation for achieving one of the eventual future goals of environmental microbiology: to diagnose and correct the integrative nature of microbial activities when ecosystems fail. Assessing the Microbiological Health of Ecosystems will prove to be a valuable resource to environmental microbiologists, ecologists and integrative biologists. The book will: * help researchers and students to understand the commonalities of processes, techniques, and discoveries in the study of microbial communities * contribute to understandings of how microbial communities coordinate their function, discussing how the relative rates and effective integration of community microbial processes are currently measured * provide insights into the composition of a healthy microbial ecosystem By learning to recognize what constitutes and produces a healthy microbial ecosystem, we gain significant ground on the path towards being able to diagnose and correct the health of ailing microbial ecosystems. Assessing the Microbiological Health of Ecosystems will help new generations of scientists discern new ways to carry these efforts forward.
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Table of Contents
Cover
Title Page
Copyright Page
Dedication
List of Contributors
Preface
1 Ecosystems Function Like Interlocking Puzzles
1.1 Introduction
1.2 Three People Who Historically Defined the Concept of an Ecological Niche
1.3 How Does a Species Become Established in a Niche?
1.4 Relationship Between the Requirements of Niche and Habitat
1.5 Using Visual Analogies to Represent the Concept of a Species Niche as Being a Multidimensional Space Which has Complex Surface Geometry
1.6 Competition for the Control of Niche Space
1.7 Defining the Concept of Genetic Hyperspace
1.8 Conclusions
Acknowledgements
References
2 Human and Climatic Drivers of Harmful Cyanobacterial Blooms (CyanoHABs)
2.1 What are CyanoHABs?
2.2 Human and Climatic Drivers of CyanoHABs
2.3 Nutrient Management
2.4 Climatic Drivers
2.5 The Ultimate Challenge of the Twenty‐First Century: Controlling HABs Against a Backdrop of Changing Climatic Conditions
2.6 Summary
Acknowledgements
References
3 Biodegradation of Environmental Pollutants by Autochthonous Microorganisms – A Precious Service for the Restoration of Impacted Ecosystems
3.1 Introduction
3.2 Environmental Pollutants of Major Concern
3.3 Current Remediation Technologies Targeting Pharmaceuticals, Pesticides, and Petroleum Hydrocarbons
3.4 Role of Environmental Microorganisms on the Removal of Pharmaceuticals, Pesticides, and Petroleum Hydrocarbons
3.5 Filling in the Gaps – Autochthonous Microorganisms as Tools for the Bioremediation of Environmental Pollutants
3.6 Final Considerations
3.7 Acknowledgments
References
4 Early Biofilm Accumulation in Freshwater Environments on Different Types of Plastic
4.1 Introduction
4.2 Background
4.3 Results
4.4 Discussion
4.5 Summary
References
5 Identification of Sentinel Microbial Communities in Cold Environments
5.1 Introduction
5.2 Microorganisms as Sentinels of Global Warming
5.3 Microorganisms as Sentinels of Contamination
5.4 How Biogeochemical Cycles Can Change
5.5 Causes of Alterations in Microbial Communities
5.6 Human Activities That Can Be Influenced by Microbial Communities Alterations
5.7 Methods and Techniques to Identify Sentinel Microorganisms
5.8 Conclusion
Acknowledgments
References
6 Analyzing Microbial Core Communities, Rare Species, and Interspecies Interactions Can Help Identify Core Microbial Functions in Anaerobic Degradation
6.1 Introduction
6.2 Defining Key Microorganisms and Core Communities in Anaerobic Degradation Systems
6.3 Core Definitions Applied to Anaerobic Digester Microbial Communities
6.4 Rare Species, Diversity Indices, and Links to Presence of Core Communities
6.5 Network Analysis
6.6 Defining Core Microbiota for Functionality
6.7 Concluding Remarks and Future Prospects
References
7 Role of Microbial Communities in Methane and Nitrous Oxide Fluxes and the Impact of Soil Management
7.1 Introduction
7.2 The Role of Microorganisms in Methane and Nitrous Oxide Fluxes
7.3 Methane and Nitrous Oxide Emission Mitigation Strategies
7.4 Summary and Conclusions
References
8 Impact of Microbial Symbionts on Fungus‐Farming Termites and Their Derived Ecosystem Functions
8.1 Introduction
8.2 Ancient Association of Co‐Diversifying Symbiont Community
8.3 Microbial Contributions to Nutrient Cycling
8.4 Microbial Contributions to Colony Health
8.5 How Termite Activity and Microbial Processes Affect the Ecosystems Within Which They Reside
8.6 Interactions with and Impacts on Humans
8.7 Conclusions
Acknowledgments
References
9 The Ecosystem Role of Viruses Affecting Eukaryotes
9.1 Introduction
9.2 Three Historically Important Discoveries Regarding the Viruses that Affect Eukaryotes
9.3 The Chalk Cliffs of Dover Represent an Ecosystem Impact Associated with Viruses of Phytoplankton
9.4 Examples of Viral Induced Phenotypic Changes in Fungal Hosts
9.5 Ecological Interactions Between Viruses and Insects
9.6 Endogenous Viruses Enable Placentation in Vertebrates
9.7 Summary
Acknowledgments
References
Index
End User License Agreement
List of Tables
Chapter 1
Table 1.1 Examples of physical and chemical characteristics which a locatio...
Chapter 2
Table 2.1 Various bloom‐forming cyanobacterial genera, potential toxins the...
Chapter 3
Table 3.1 Recent studies reporting the biodegradation of pharmaceuticals by...
Table 3.2
Recent studies reporting the biodegradation of pesticides by bacte...
Table 3.3 Recent studies reporting the biodegradation of petroleum hydrocar...
Chapter 5
Table 5.1 Characteristics of cold environments on Earth.
Table 5.2 Sentinel microorganisms in cold environments.
Table 5.3 Sentinel microorganisms of acidification.
Chapter 6
Table 6.1 Review of previous studies on the core microbiome in anaerobic di...
Chapter 7
Table 7.1 Biotic and abiotic processes that potentially lead to nitrous oxi...
Table 7.2 Main sources of GHG emissions from different agricultural managem...
Chapter 9
Table 9.1 A master list of viral families and unassigned (floating) genera ...
Table 9.2 Viral families that have endogenous presence in eukaryotes.
Table 9.3 Examples of beneficial viral related phenotypic changes in eukary...
List of Illustrations
Chapter 1
Figure 1.1 Wooden interlocking puzzle. This photograph shows a wooden puzzle...
Figure 1.2 A California Thrasher in Morro Bay California USA. Joseph Grinnel...
Figure 1.3 Direct Redrawing of Hutchinson's Niche Space Concept. This illust...
Figure 1.4 Simplified Redrawing of Hutchinson's Niche Space Concept. This is...
Figure 1.5 The flat surfaces of polyhedrons. Polyhedrons would be some of th...
Figure 1.6 Three dimensional picornavirus models. These images are geometric...
Figure 1.7 Vladimir Bulatov sculptures. I am presenting these images of prin...
Figure 1.8 Bathsheba Grossman geometric art. This image shows a three dimens...
Figure 1.9 Richard Deacon sculpture. This photograph shows a metal sculpture...
Figure 1.10 Subodh Gupta sculpture. I am using this as being visually analog...
Figure 1.11 Koala. The koala (
Phascolarctos cinereus
) belongs to the order D...
Figure 1.12 Mexican collared anteater. Tamandu belong to the order Pilosa an...
Figure 1.13 North Atlantic right whale mother and calf. This is a public dom...
Figure 1.14 Raspberry aphids. This image is titled “Raspberry aphids feeding...
Figure 1.15 Mutually exclusive forms in a three dimensional space. This figu...
Figure 1.16 Aluminum casting of a fire ant nest, genus
Solenopsis
. Each biol...
Figure 1.17 Aluminum castings of
Aphaenogaster
and
Camponotus
nests. These t...
Figure 1.18 Phylogenetic tree drawn in two dimensions. This image shows a ph...
Figure 1.19 Phylogenetic tree depicted as trajectories in genetic hyperspace...
Figure 1.20 Smoky quartz with included tourmaline. This image is being used ...
Figure 1.21 Double terminated quartz point with included tourmaline. This im...
Chapter 2
Figure 2.1 Photomicrographs of representative coccoid (a, b), filamentous no...
Figure 2.2 Harmful cyanobacterial blooms (CyanoHABs), viewed for space and i...
Figure 2.3 Effect of temperature on growth rates of major phytoplankton grou...
Figure 2.4 Conceptual diagram illustrating the various external and internal...
Figure 2.5 Conceptual diagrams showing (top) the ecosystem‐scale roles of ph...
Chapter 3
Figure 3.1 Biotic and abiotic factors that can influence the bioremediation ...
Chapter 4
Figure 4.1 The distribution of water on, in, and above the Earth.
Figure 4.2 Water use in gallons for household activities.
Figure 4.3 Source and use of freshwater in the United States in 2015.
Figure 4.4 Trends in population and freshwater withdrawals by source, 1950–2...
Figure 4.5 Repeating subunit for: (a) polyethyl terephthalate (PET); (b) hig...
Figure 4.6 Production and subsequent dissemination and distribution of plast...
Figure 4.7 Management of plastic waste in U.S.
Figure 4.8 Percentage of material solid waste by U.S. in 2018.
Figure 4.9 Percentage of material solid waste recycled by U.S. in 2018.
Figure 4.10 Ocean shoreline depicting plastic accumulation at Orion, Bataan,...
Figure 4.11 Percentage of bacterial phyla present on various plastic types o...
Figure 4.12 Percentage of bacterial families present on various plastic type...
Chapter 5
Figure 5.1 Frozen environments threatened by climate change. (a, b) Glacier ...
Figure 5.2 Alteration in the exchange of microorganisms between different ec...
Figure 5.3 Glacial surfaces pigmented by microorganisms.
Figure 5.4 Key microbial processes in cold environments susceptible of envir...
Figure 5.5 The carbon cycle.
Figure 5.6 The nitrogen cycle.
Figure 5.7 The iron cycle.
Figure 5.8 The silica cycle.
Figure 5.9 The sulfur cycle.
Figure 5.10 The global temperature trend over the Cenozoic (the past 65.5 Ma...
Figure 5.11 Global mean annual temperatures for the period from 1880 to pres...
Figure 5.12 Relationship among environmental drivers and consequences for th...
Figure 5.13 Methods and techniques to identify sentinel microorganisms.
Chapter 6
Figure 6.1 Venn diagram summarizing stated outcomes (in written form) in 12 ...
Figure 6.2 Illustration of the development of different anaerobic degradatio...
Figure 6.3 Characteristics of (a) the bacterial community and (b) the archae...
Figure 6.4 Example of (a) a co‐occurrence correlation network comprising dif...
Figure 6.5 Functional community structure decoupling from community composit...
Figure 6.6 Fraction (%) of uncharacterized functions encoded in bacterial ge...
Chapter 7
Figure 7.1 Overview of microbial processes and taxa involved in methane and ...
Chapter 8
Figure 8.1 Diversity of termite species and microbes across the fungus‐farmi...
Figure 8.2 Plant biomass decomposition process and microbial contributions t...
Figure 8.3 Fungus‐farming termite ecosystem services and impacts on humans. ...
Chapter 9
Figure 9.1 Rhombic Dodecahedron as a line drawing and a sculpture. The left ...
Figure 9.2 Tobacco mosaic virus symptoms on common tobacco. This image shows...
Figure 9.3 Components of a Pasteur–Chamberland filter. This image shows a ce...
Figure 9.4 Emergency hospital during an influenza epidemic at Camp Funston, ...
Figure 9.5 Image of Sekhmet. This photograph is of a sculpture titled, “Bust...
Figure 9.6 Colorized image of an apoptotic coronaviral infected cell. The na...
Figure 9.7
Emiliania huxleyi
, its bloom and sedimentary deposits. This figur...
Figure 9.8
Melanoplus
grasshoppers that have been killed by the fungus
Beauv
...
Figure 9.9 Chestnut blight on a tree in the United States. This image shows ...
Figure 9.10 Chestnut blight on a tree in Europe. This image shows the destru...
Figure 9.11
Dichanthelium lanuginosum
hydrothermal tolerant grass. The grass...
Figure 9.12 Honey bee with normal wings versus virally associated wing defor...
Figure 9.13
Varroa destructor
mites on honeybees. The
Varroa destructor
mite...
Figure 9.14 Asian giant hornet. The Asian giant hornet
Vespa mandarinia
is e...
Figure 9.15 Caterpillars infected by nuclear polyhedrosis viruses. These ima...
Figure 9.16 Gypsy moth adults. This figure shows adults of the gypsy moth (
L
...
Figure 9.17 Gypsy moth damage to trees. This image shows a wooded area that ...
Figure 9.18 Wild black raspberry plant and feeding aphids. The upper image o...
Figure 9.19 Beetle larva ingesting an aphid. Members of the family Coccinell...
Figure 9.20 Wingless and winged morphs of aphids. The upper left image shows...
Figure 9.21 Cocoons of
Glyptapanteles liparidis
wasps on a gypsy moth caterp...
Figure 9.22 Cocoons of
Cotesia congregata
wasps on a tobacco hornworm caterp...
Figure 9.23 Female
Aedes aegypti
mosquito. Females of the mosquito species
A
...
Figure 9.24 Human children Rachel Hurst and Allen Hurst. This image shows th...
Figure 9.25
Mabuya dominicana
. Lizards of the genus
Mabuya
use an endogenous...
Guide
Cover Page
Title Page
Copyright Page
Dedication
List of Contributors
Preface
Table of Contents
Begin Reading
Index
WILEY END USER LICENSE AGREEMENT
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Assessing the Microbiological Health of Ecosystems
Edited by
Christon J. Hurst
Cincinnati, OH
USA
and
Universidad del Valle
Santiago de Cali, Valle del Cauca
Colombia
This edition first published 2023© 2023 John Wiley & Sons Ltd
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions.
The right of Christon J. Hurst to be identified as the author of the editorial material in this work has been asserted in accordance with law.
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Library of Congress Cataloging‐in‐Publication DataNames: Hurst, Christon J. (Christon James), 1954‐ editor.Title: Assessing the microbiological health of ecosystems / edited by Christon J. Hurst, Cincinnati, Ohio, United States of America and Universidad del Valle, Santiago de Cali, Valle del Cauca, Colombia.Description: First edition. | Hoboken, NJ : Wiley, 2023. | Includes index.Identifiers: LCCN 2022042571 (print) | LCCN 2022042572 (ebook) | ISBN 9781119678328 (Hardback) | ISBN 9781119678304 (oBook) | ISBN 9781119678236 (Adobe PDF) | ISBN 9781119678298 (e‐Pub)Subjects: LCSH: Microbial ecology. | Ecosystem health.Classification: LCC QR100 .A85 2023 (print) | LCC QR100 (ebook) | DDC 579/.17–dc23/eng/20220913LC record available at https://lccn.loc.gov/2022042571LC ebook record available at https://lccn.loc.gov/2022042572
Cover Design: WileyCover Image: © Allen Nutman. The cover art for this book shows a fossil stromatolite, the oldest known microbial ecosystem, and this rock is 3.7 billion years old. This image appears courtesy of Allen Nutman and the editor very much appreciates his allowing use of the image. The wavelike row across the middle of the image is the stromatolites.
Dedication
In addition to my microbiology efforts in Cincinnati, Ohio, where I was born and live, I have had the privilege of professional association with the scientists and engineers at the Meléndez and San Fernando campuses of Universidad del Valle in Santiago de Cali, Valle del Cauca, Colombia. I hold a Lifetime Visiting Professor appointment in engineering at Universidad del Valle and there I have taught professional and graduate level courses in engineering as well as public health. I was awarded that position in 1996 as Resolution 292‐96, dated February 8 1996. The resolution authorizing my position was signed by Carlos Dulcey Bonilla who then was the Vicerrector Académico, and by Secretary General Juan Manuel Jaramillo Uribe. It is a fully academic position which received approval by both the Faculty Senate and the university’s Governing Council. The signed resolution is mounted in a gilded frame and has been on the wall in front of my desk since that year. When I was awarded that position, I knew it likely would be the highest honor which I would receive during this lifetime. I hosted a celebration including champagne and my favorite dessert, which is carrot cake, at the university when I received that signed resolution. The date of the celebration was March 4th 1996, chosen because “March fourth” metaphorically is a good date for beginning such an important collaboration. Every fifth year since then I have celebrated that event on March 4th with champagne and carrot cake.
“Christon J. Hurst at Ciudad Universitaria Meléndez in Cali, Colombia, celebrating receipt of his Lifetime Visiting Professorship from Universidad del Valle, March 4th 1996”
Among the people who attended the celebration in 1996 was Iván Ramos, who was then one of the deans of engineering at Universided del Valle. Iván eventually served the university for 12 years as its Rector Académico. I appreciated that whenever I asked him the question, Iván always reminded me that my position remained in effect even though my sense of connection with the university in Cali has often been only via internet collaboration.
“Iván Enrique Ramos Calderón, Profesor y Rector Académico Emérito, Universidad del Valle”
With a sense of gratitude and humility, I proudly dedicate my efforts on this book project to my colleagues in Cali, past and present, and to Universidad del Valle.
List of Contributors
Marina AlcázarCenter for Astrobiology (CSIC‐INTA), Madrid, Spain
Paula AlcázarCenter for Astrobiology (CSIC‐INTA), Madrid, Spain
Diogo A. M. AlexandrinoCIIMAR – Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Matosinhos, Portugal
C. Marisa R. AlmeidaCIIMAR – Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Matosinhos, Portugal
Magdalena CalusinskaEnvironmental Research and Innovation Department, Luxembourg Institute of Science and Technology, Belvaux, Luxembourg
Maria F. CarvalhoCIIMAR – Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Matosinhos, PortugalSchool of Medicine and Biomedical Sciences (ICBAS), University of Porto, Porto, Portugal
Cristina CidCenter for Astrobiology (CSIC‐INTA), Madrid, Spain
Carlos De LeónUniversity of Delaware, Ammon‐Pinizzotto Biopharmaceutical Innovation Center, Newark, DE, USA
Joana P. FernandesCIIMAR – Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Matosinhos, PortugalFaculty of Sciences, University of Porto, Porto, Portugal
Mark A. GalloB. Thomas Golisano Center for Integrated Sciences, Niagara University, Lewiston, NY, USA
Eva García‐LópezCenter for Astrobiology (CSIC‐INTA), Madrid, Spain
Xavier GouxEnvironmental Research and Innovation Department, Luxembourg Institute of Science and Technology, Belvaux, Luxembourg
Rene HooverUniversity of Delaware, Ammon‐Pinizzotto Biopharmaceutical Innovation Center, Newark, DE, USA
Christon J. HurstCincinnati, OH, USAUniversidad del Valle, Santiago de Cali, Valle del Cauca, Colombia
N’Golo A. KonéUniversité Nangui Abrogoua, Unités de Formation et de Recherches des Sciences de la Nature (UFR‐SN), Abidjan, Côte d’IvoireCentre de Recherche en Écologie (CRE), Station de Recherche en Ecologie du Parc National de la Comoé, Bouna, Côte d’Ivoire.
Alessandra LagomarsinoResearch Centre for Agriculture and Environment, Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria (CREA‐AA), Firenze, Italy
Guangshuo LiDepartment of Biology, University of Copenhagen, Copenhagen East, Denmark
Tong LiuDepartment of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
Ana P. MuchaCIIMAR – Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Matosinhos, PortugalFaculty of Sciences, University of Porto, Porto, Portugal
Robert MurphyDepartment of Biology, University of Copenhagen, Copenhagen, Denmark
Hans W. PaerlUniversity of North Carolina at Chapel Hill, Institute of Marine Sciences, Morehead City, NC, USA
Roberta PastorelliResearch Centre for Agriculture and Environment, Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria (CREA‐AA), Firenze, Italy
Michael PoulsenDepartment of Biology, University of Copenhagen, Copenhagen East, Denmark
Justinn Renelies‐HamiltonDepartment of Biology, University of Copenhagen, Copenhagen East, Denmark
Suzanne SchmidtDepartment of Biology, University of Copenhagen, Copenhagen East, Denmark
Veronica M. SinotteDepartment of Biology, University of Copenhagen, Copenhagen East, Denmark
Maria WesterholmDepartment of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
Preface
Ecosystems evolve to function like interlocking puzzles whose pieces are their constituent niches. All of the niches need to be occupied and the efforts of their inhabitants must correctly fit together in order for the ecosystem activities to be balanced. Initially and ultimately, the health of an ecosystem depends upon the niche functions of its microbial communities.
The authors of this book summarize our current understanding of how environmental microbial communities are organized, present insight into the ways that constituent species coordinate their functions, explain how the effective integration of microbial processes is measured, and offer comparisons of the characteristics that have been observed for healthy versus unhealthy systems.
An eventual future goal of environmental microbiologists will be diagnosing and correcting the integrative nature of microbial activities when ecosystems fail. Collectively, the knowledge presented in this book helps to provide a basis for recognizing what produces healthy microbial components of an ecosystem and provides a foundation for achieving that future goal.
The primary audience for this book will be environmental microbiologists, ecologists and integrative biologists. Our goal as the authors of this book is to help new generations of our colleagues discern the ways to carry these efforts forward, and those new generations will achieve accomplishments of which we now can only dream.
Christon J. HurstCincinnati, OH, USA
1Ecosystems Function Like Interlocking Puzzles: Visually Interpreting the Concept of Niche Space Plus a Brief Tour Through Genetic Hyperspace
Christon J. Hurst
Cincinnati, OH, USA
Universidad del Valle, Santiago de Cali, Valle del Cauca, Colombia
CONTENTS
1.1 Introduction
1.2 Three People Who Historically Defined the Concept of an Ecological Niche
1.2.1 Joseph Grinnell's 1917 Description of an Ecological Niche
1.2.2 Charles Elton's 1927 Description of an Ecological Niche
1.2.3 Evelyn Hutchinson's 1957 Description of an Ecological Niche
1.3 How Does a Species Become Established in a Niche?
1.4 Relationship Between the Requirements of Niche and Habitat
1.4.1 Defining a Species Habitat Requirements and Inclusion of the Physiological Boundaries Concept
1.4.2 Hutchinson's Description and Depiction of Niche Space
1.5 Using Visual Analogies to Represent the Concept of a Species Niche as Being a Multidimensional Space Which has Complex Surface Geometry
1.5.1 A Broader Consideration of the Variables that Would Define Niche Space
1.5.2 Imagining that Interactions Between Species Occur at the Surfaces of Their Niche Spaces
1.5.3 Three Mammal Species as Examples of Niche Space Interactions: The Koala, the Mexican Collared Anteater, and the Northern Atlantic Right Whale
1.5.4 One Insect Species as an Example of Niche Space Interactions, the Raspberry Aphid
1.6 Competition for the Control of Niche Space
1.6.1 Opportunities, Intrusions and Challenges Result in the Control of Niche Space
1.6.2 Using Visual Analogies for There Being Different Ways to Occupy the Same Total Volume of Niche Space
1.7 Defining the Concept of Genetic Hyperspace
1.7.1 Using Visual Analogies to Help Understand the Concept of Genetic Hyperspace
1.7.2 Examples of Organisms Whose Symbioses Represent Interlocking Niche Spaces and Parallel or Common Genetic Trajectories
1.7.3 Relating the Concept of Genetic Trajectories and the Host Specificity of Viruses
1.8 Conclusions
Acknowledgements
References
1.1 Introduction
The niche of a species is defined by the ecological activities which its members perform. The habitat of a species describes those physical locations where members of that species can reside. Distinguishing niche from habitat can therefore be done by understanding that “Habitat” means “This is where I live” and “Niche” means “This is what I do here.” There is a connection between the two concepts of habitat and niche, because a group that is performing ecological functions associated with its occupation of a specific niche must have a place in which members of that group can reside, and that place of residence is of course the species habitat. This presentation uses the concept of niche that was proposed by Charles Elton (Elton 1927), and which often is termed the Eltonian niche.
Each ecosystem contains its own characteristic set of niches and coevolution optimizes the ability of various species to occupy those niches. Occupation of a niche involves utilization of resources that are present, contribution to the resources available, and interactions with other species which share the ecosystem.
This chapter presents the use of geometric sculptures as visual analogies to depict a niche as being a mathematically defined theoretical space called “Niche space.” These sculptures also help with understanding the interlocking nature of niche functions. The niches that successfully create an ecosystem can be considered as if they were pieces of an interlocking puzzle, as suggested by the puzzle shown in Figure 1.1. All pieces of the puzzle, all functions of the ecosystem, must be present and they must successfully fit together in order for the ecosystem to work. Not everything represents happiness within the interlocking communities because, in addition to activities that are cooperations, the ecological functions include competitions and predation.
The concept of niche space additionally can work together with an understanding that the process of evolution is driven by the competitive goals of biological groups. Each individual group will try to maximize its control of the metabolic functions and energy resources which exist in the surrounding ecosystem. The sequential speciation events that result in development of phylogenetic groups at the levels of families, through to their descendant genera and species, represent efforts by those groups to increase the amount of niche space which they can claim. Development of phylogenetic groups is similar to the economic concepts of using vertical integration and horizontal integration for controlling access to material and financial resources.
Figure 1.1 Wooden interlocking puzzle. This photograph shows a wooden puzzle and is a way of visualizing how the niches, and thus the niche spaces, of different species will have evolved to interlock with one another and create an ecosystem.
Source: Alexander Hermes/Wikimedia Commons/CC BY‐SA 3.0.
While each biological group is struggling to gain additional niche space, it simultaneously must defend that niche space which it already occupies. I will use a comparison of metal castings made from subterranean nests that represent different genera of ants to help visualize the concept of there being many different ways to occupy a similar total volume of space.
Niche construction and occupancy of niches are interactive processes in evolution that represent not only each organisms role within its habitat, but they also represent the place of each species in an evolutionary procession. The genetic path which a species creates as it undergoes a stepwise evolutionary process to maximize its capability for occupying an available niche can be visualized as a trajectory through genetic hyperspace. Species which have an obligate symbiotic interdependence will need to establish and maintain themselves on parallel trajectories in genetic hyperspace. When a virus becomes endogenous in a host, the virus and its host establish a single trajectory. I will use crystalline quartz that contains natural tourmaline inclusions as a visual analogy of trajectories in genetic hyperspace.
1.2 Three People Who Historically Defined the Concept of an Ecological Niche
My starting point in considering the concept of ecological niche for this chapter was an examination of three definitions that respectively were published by Joseph Grinnell, Charles Sutherland Elton, and George Evelyn Hutchinson.
1.2.1 Joseph Grinnell's 1917 Description of an Ecological Niche
Joseph Grinnell studied the ecology of a bird species. He then published a concept that each subspecies of the bird had a uniquely identifiable niche. His concept of a niche combined aspects of where a species resides along with the species ecological role (Grinnell 1917).
The bird species which Grinnell described in his 1917 publication was the California thrasher (Toxostoma redivivum), shown in Figure 1.2. In that 1917 publication (Grinnell 1917), Grinnell distinguished three different subspecies of this bird and their respective habitat relationships. When providing a general description, Grinnell indicated that these three subspecies existed within an ecological zone where the characteristics of vegetation supplied what the birds needed for protective cover and for nesting, the zone contained suitable insects and seeds which the birds could eat, plus the zone had correct humidity and sunlight. Grinnell stated that areas which commonly possessed the correct set of characteristics for a species could be said to collectively represent a life zone, and within that zone the functions of its different species collectively constitute an association.
Figure 1.2 A California Thrasher in Morro Bay California USA. Joseph Grinnell (1917) described the niche of a species from his studies of the California Thrasher Toxostoma redivivum.
Source: The title of this image is “Toxostoma redivivum near Morro Bay, California, USA” and it is being used with permission of its author, Michael L. Baird of Morro Bay, California, USA.
Grinnell indicated that subtle differences in climatic characteristics or associated ecosystems distinguished the home ranges for these California thrasher subspecies. According to Grinnell, by residing within its own identifiable locations each subpopulation of the thrasher could be said to occupy its own characteristic niche and each subpopulation existed as part of a particular association of species (Grinnell 1917). His concept of niche therefore represented a combination of describable environmental conditions where members of a species or subspecies could be found, in conjunction with the activities performed by members of that individual species or subspecies. Niche, as thus defined by Grinnell, was a combination of place and purpose.
1.2.2 Charles Elton's 1927 Description of an Ecological Niche
Charles Elton (Elton 1927) examined the behavior of numerous animal species ranging from copepods and aphids to moths, birds of prey, and moderate sized carnivores. Elton then proposed the concept that each species had a niche which represented the ecological role played by members of that species.
Elton's definition of an animals niche included the animals relations to its food and its enemies. He further indicating that a niche can very much be defined by an animals size, and that parallel niches exist in widely separated communities. For example, the niche of a badger or the niche of a mouse can be found in many different places, equally as can the niche of animals that pick ticks from the skin of other animals.
Thus, Elton's definition of niche was that of purpose and independent of place. His proposal has been described as the Eltonian niche, which represents the functional attributes of a species and its corresponding position in a trophic chain.
1.2.3 Evelyn Hutchinson's 1957 Description of an Ecological Niche
Evelyn Hutchinson subsequently proposed the concept of Niche Space along with the concept of biotop (Hutchinson 1957). He used the niche concept previously published by Joseph Grinnell (Grinnell 1917) which represented aspects defining where a species resides. Hutchinson did include one aspect of the ecological role played by members of the species, and that was an indication of the food particles consumed by members of the species.
1.3 How Does a Species Become Established in a Niche?
An ecological niche is a function, or collection of functions, that is part of the metabolic activity which occurs within a defined location. That location is the habitat. Biological life forms constantly are trying to find sources of usable energy which can sustain their metabolic needs and, once an opportunity for obtaining energy is found, evolution will optimize a biological life form to use that energy. The members of a species will need a means to physically reach and remain in reasonable proximity to their energy sources. The members of a species also will need to obtain many other resource materials, including minerals, which are necessary for sustaining the members vital functioning, because without those other resource materials the source of energy cannot be utilized.
The niche of a species includes both its use of those resources plus any additional activities which its members perform, including its associated physical or chemical modifications of the environment.
The members of a species may have necessity for establishing beneficial working relationships with other species which cooperatively can help with the process of obtaining necessary resources. It also may be necessary to establish cooperative interspecies relationships which can help to provide protection in the form of either physical or chemical defense against competitors and predators. Competitors may steal access to the source of energy and predators may consume members of the species as a food source. Some of the relationships which are established with cooperative species will involve providing a bribe in exchange for securing favorable interaction. Bribes can include providing usable resource materials to those other species, and bribes also can involve physically sheltering members of the other species. Many of a species activities will attract attention and often will result in either wanted or unwanted responses by other species. It may be necessary to find a way of avoiding those responses, because even a non‐threatening response may serve as a signal which attracts the attention of competitors and predators.
Understanding the niche of a species necessarily includes knowledge about those other living beings for whom this species does in turn provide a source of nutrients and energy. Knowing the predators of a species helps to tell us the positions which members of that species occupy in trophic chains.
The requirements of a niche determine the physical and physiological attributes of a species which would occupy that niche (Hurst 2016a). The same niche can exist in many different locations (Elton 1927), hence the concepts of niche meaning function, and habitat meaning location, can be distinguished from one another. The occupants of similar niches will have a commonality of their physiological traits, and often will have a commonality of their physical appearance (Elton 1927; Hurst 2016a). Those commonalities correspond to the necessary requirements for claiming occupancy within their niche.
1.4 Relationship Between the Requirements of Niche and Habitat
No species can survive homelessness and no work can be done unless there is a location where that work can be accomplished. For these reasons, the niche which a species might occupy will remain vacant unless there is a habitat where members of the species can reside.
1.4.1 Defining a Species Habitat Requirements and Inclusion of the Physiological Boundaries Concept
Achieving residence in a habitat requires that members of a species first must be able to reach a place where they can satisfy the energetic and other nutritional needs of their niche by using resources which are available in that location. The resources needed by a species may come from either living or nonliving sources.
It is not alone sufficient that a physically defined place or collection of places satisfies a species energetic and other nutritional needs. That place or places must also meet additional specific requirements in order to suitably qualify as either a permanent or even a temporary habitat for a particular given species. Those additional requirements will be a combination of physical and chemical characteristics which favorably match the species vital physiological requirements and this has been defined as the physiological boundaries concept (Hurst 2016b). Examples of those characteristics are listed in Table 1.1.
Table 1.1 Examples of physical and chemical characteristics which a location must favorably match in order to serve as a habitat, the required characteristics differ for each species.
Source: The source of this information is Hurst (2016b).
Factors with broad applicability
Ambient temperature
Ambient pressure (barometric or hydrostatic)
Ambient level of ionizing radiation
Distance to suitable resting surface
Inclination angle of the surface
Potential for adherence to the surface
Potential toxicity of the surface
Metal ions (elemental ions which are necessary versus detrimental)
Natural and synthetic toxins (includes antibiological compounds)
Photoperiod and level of required versus detrimental wavelengths
Factors which could apply to species using atmospheric respiration
Atmospheric gases
Carbon dioxide
Carbon monoxide
Chlorine
Oxygen
Ozone
Sulfur dioxide
Availability of liquid water including distance to that water
Flow velocity of the surrounding atmosphere
Humidity
Precipitation
Factors which could apply to species using aquatic respiration (includes microbes living in liquid medium)
Dissolved gasses
Carbon dioxide
Carbon monoxide
Oxygen
Ozone
Sulfur dioxide
Dissolved halogens
Chlorine
Iodine
Flow velocity of the surrounding water
pH
Salinity
The physiological boundaries concept (Hurst 2016b) is a mathematical approach which helps to understand how well a particular location could meet the vital physiological requirements of a species. The physiological boundaries concept represents a species physiological requirements as a multidimensional space that descriptively contains a center point enveloped by both an inner vital boundary and an outer vital boundary. Those two boundaries are theoretical closed mathematical surfaces and they are concentric around that center point. At the center point of this space, the environmental conditions are by definition optimal for meeting the physiological requirements of that species and by estimation will support the normal longevity of its members. The mathematically estimated suitability of environmental conditions for meeting the species physiological needs decreases with increasing outward distance from the center of its multidimensional space.
Moving outward from the center, the suitability of environmental conditions decreases until eventually the surface of the species inner vital boundary is reached. The inner vital boundary is defined as a set of environmental conditions that by mathematical estimation meets the minimal requirements which would allow members of a species to survive long enough for completion of their reproductive life cycle by achieving numerical replacement of the species population. Moving further outward from the center, the species mathematically defined outer vital boundary will be reached. The outer vital boundary meets the minimal requirements which would allow members of a species to survive for 1 minute (Hurst 2016b).
Physical locations which do at least meet the requirements of the species inner vital boundary potentially could qualify as permanent habitats for that species. Locations which are less suitable, but meet the requirements for the species outer vital boundary, could qualify as temporary habitats for that species. Calculations that estimate conditions just inside the outer vital boundary would have application for ascertaining short term survival under extreme circumstances. Locations beyond the species outer vital boundary represent barriers to that species. Natural interactions between species can occur only in locations where the vital boundaries of those species would overlap, with a more obvious example being that a species whose vital boundaries require a high mountain terrestrial habitat cannot naturally interact with a species whose vital boundaries require a deep marine aquatic habitat (Hurst 2016b).
The physiological requirements for a species habitat have been established by the evolutionary path which ancestors of that species followed to reach the species present existence (Hurst 2016b). I will return to discussing those paths, which have been described as trajectories in genetic hyperspace (Dawkins 1986), later in this chapter. The potential permanent habitat of a species may be amazingly broad and consists of all physical locations where the combinations of environmental conditions are suitable for permanent residence by the species, meaning that those conditions meet the minimal requirements for the species inner vital boundary. Within that broadly defined potential permanent habitat, a species may be confined to some more narrowly defined set of physical locations where the species is allowed to reside, and those places where the species is allowed to reside collectively are the species operational habitat. Factors which cause that confinement will include the probability of attack by predators and also the probability of competition by other species which would like to claim resources available in the same potential permanent habitat locations.
The process of evolution determines the habitat suitability requirements for members of a species, and once established those requirements cannot be modified unless the species undergoes further evolutionary change (Hurst 2016b). A species actions and interactions within its surrounding habitat may modify the environmental conditions of that habitat and by so doing the species may influence the selection pressures which then act on its population. The modified environment can induce new variation within the population and the environment then select for favorable variants (Stotz 2017). The result is a feedback cycle by which the niche of a species is modified to maximize the ability of that species to function within its habitat.
1.4.2 Hutchinson's Description and Depiction of Niche Space
Evelyn Hutchinson (Hutchinson 1957) described the concept of niche as being a mathematically defined space that represented the physical conditions of a place in which a species permanently could survive.
Hutchinson said that his concept of niche space was delineated by independent environmental variables which could be measured along ordinary rectangular coordinates, with the limiting values permitting the species to survive and reproduce. I have directly redrawn Hutchinson's niche space concept and that is Figure 1.3 of this chapter. Each point within his defined niche space corresponds to a location that would permit the species to exist indefinitely. He stated that if the variables act independently then the shape of this space would be defined as a rectangle, but without independence the shape would be irregular. Once all of the physical and biological factors have been added as independent ecological variables, an n‐dimensional hypervolume would be defined. Every point within that hypervolume would represent an environmental state allowing the species to exist indefinitely.
For this chapter, by using the philosophy of Charles Elton (Elton 1927) I am describing the concept of a species niche as an ecological role which represents the total collection of its biological activities. Hutchinson's concept of niche, as did Grinnell's 1917 publication (Grinnell 1917), included aspects of the locations where a species resides, which I consider to be the “habitat” of a species.
There is only one aspect of Figure 1.3 that is an attribute which considers a species ecosystem function, and thus represents an aspect of the species ecological role. That aspect is the size of the food particles which the subject species could ingest.
There is a connection between the two concepts of habitat and niche, because the group which occupies a specific niche by performing the ecological functions associated with that niche needs a place in which the group can reside, and that place is of course the habitat.
Later in this chapter I will explain my belief that the concept of niche, and thus niche space, also applies in a larger context to members of a genus as a group. In a still larger context, these concepts apply to members of a family as a group, and apply to perhaps even higher taxonomic levels.
Figure 1.3 Direct Redrawing of Hutchinson's Niche Space Concept. This illustration shows “Two fundamental niches defined by a pair of variables in a two‐dimensional niche space.” The left side of this figure shows the potential distribution of two predator species relative to water temperature and also indicates the sizes of particles which each of those two species will ingest as food. Competitive exclusion results in only one of those species being able to persist in the intersection region of physical space. The lines joining equivalent points in the niche space and biotop space drawings indicate the relationship of these two physical spaces. The right hand panel represents the physical distribution of these two predatory species which defines their respective habitats, and includes a temperature depth curve of the kind usual in a lake during summer. The objects shown as circles in the right side “Biotop space concept” part of this figure are presumed to be food particles. Some of these particles are too large to be ingested by either species 1 or 2. Others of the food particles are shown as being too small to be ingested by either species 1 or 2, perhaps because the energy value associated with those smaller sized particles is not considered sufficient for consumption by either species 1 or 2. There are food particles of ingestible size which will not be consumed by either species 1 or 2 because those food particles occur either too shallowly or too deeply in the water column. This drawing shows niche space as having only two mathematically defined dimensions. Hutchinson's proposal (Hutchinson 1957) was that when all ecological factors relative to a species have been considered, the result would be definition of an n‐dimensional hypervolume.
Source: This image is being used courtesy of its author, Christon J. Hurst.
This is the text which accompanied Figure 1.3, which was Hutchinson's illustration. His words (Hutchinson 1957) described the figure as “Two fundamental niches defined by a pair of variables in a two‐dimensional niche space. Only one species is supposed to be able to persist in the intersection subset region. The lines joining equivalent points in the niche space and biotop space indicate the relationship of the two spaces. The distribution of the two species involved is shown on the right hand panel with a temperature depth curve of the kind usual in a lake in summer.”
A species functions within its habitat. Both the left side and right side drawings of Figure 1.3 depict habitat areas in a lake, showing territories which could be claimed by these two species. Species 2 could reside in the areas marked as being claimed by either species 1 or species 2. However, species 1 is dominant within the contested territory, indicated by the cross‐hatched area of the left side drawing. The contested territory is noted in the right side drawing as being claimed by species 1. Species 1 will claim all of the potential food resources in that contested territory. Species 2 can claim only those food resources available in the deeper, colder part of its potential territorial range.
The products that one life form generates by using available energy sources will in turn become the basic resources for other species. The result of this activity is creation of energy chains. These connections also are described as trophic chains or food chains, and they represent the fact that a consumers niche often is based upon stealing resources. That stealing may be accomplished by ingesting the creator species, and often helps to balance the ecology of an ecosystem which otherwise would be overwhelmed or blocked by accumulation of uncycled resources.
For me, the variables of depth and temperature presented for these two species depicted in Figure 1.3 represent characteristics which describe their respective habitats. The size of those objects which these species 1 and 2 ingest represents an aspect of their ecological roles, thus I would consider the size of their food particles to be a characteristic which contributes to describing the niches of species 1 and 2. Those ingested food particles may be presumed as prey species, and they are shown as circles in the right side “Biotop space concept” part of this figure. Some of these food particles are shown as being too large to be ingested by either species 1 or 2. Others of the food particles are shown as being too small to be ingested by either species 1 or 2, perhaps because the energy value associated with those smaller sized particles is not considered sufficient for them to be consumed by either species 1 or 2. There are food particles of ingestible size which will not be consumed by either species 1 or 2 because those food particles occur either too shallowly or too deeply in the water column, outside the defined habitats of either species 1 or 2. Presumably, there will exist other predatory species that reside outside the defined habitats of species 1 and 2. Those other predatory species would ingest the food particles present in more shallow zones and deeper zones. The food particles which are considered either too large or too small to be ingested by either species 1 or 2 may be consumed by other, more specialized predatory species residing in the same habitat areas as do species 1 and 2.
This drawing (Figure 1.3) shows niche space as having only two mathematically defined dimensions. Hutchinson's proposal was that all of the ecological factors relative to a species have to be considered, with the result being that niche space is a defined n‐dimensional hypervolume. Again, by Hutchinson's definition of niche, that hypervolume would have to include environmental variables such as temperature and depth. Because the niche definition which I am using is that of Elton, my definition of niche would not include the depth and temperature where members of a species reside as those characteristics are not part of the species ecological function, although the metabolic capabilities of a species will limit the habitat areas in which members of the species can reside. I also will define a niche space as being a hypervolume. However, the defining variables which I would consider for a niche space will be ecological functions, for example those which describe interaction of a virus with its host and biological vectors, plus any metabolic changes which the virus induces in either its hosts or its biological vectors. I also would include as variables the activities of the virus with regard to its effects upon the genetic functions and phylogenetic characteristics of the host and vectoring species. Many viruses induce phenotypic changes in their host, and some of those include genotypic changes which the virus induces in either its hosts or its biologically vectoring species, all of which would be included in describing the viral niche.
I have simplified for you the drawing of Hutchinson, and that simplification is Figure 1.4 of this chapter. By looking at Figure 1.4 you can see more easily that species 1 and 2 contest against each other for surviving and claiming food resources in the shallower and thus warmer part of the physical location, or zone, that could be inhabited by these two species. Looking at the right side of Figure 1.4, marked Biotop space concept, species 2 could reside in the entirety of those habitat areas shown either as blue or purple. Species 1 can reside only in the relatively more shallow and warmer section of this habitat area. Species 1 is dominant over species 2. Because of that interspecies dominance, species 1 claims the contested habitat area where both species could reside, and that area is depicted in purple. Species 2 therefore is restricted to residence in the lower, cooler part of its potential habitat area as depicted in blue. It also can be seen in the right side of this image that parts of this habitat are either too shallow and warm, or too deep and cold, to serve as residence for either species 1 or 2.
Figure 1.4 Simplified Redrawing of Hutchinson's Niche Space Concept. This is a redrawing of Figure 1.3. I have deleted the vertical and horizontal lines from the left side of the image and simplified the presentation by using color as a substitution for those arrows which in Figure 1.3 connect predator species shown in the left side versus the size of their respectively associated food shown in the right side. This redrawing also is intended to simplify the perception that species 1 and 2 are in competition with regard to the depth associated temperature of an aquatic habitat. The color purple represents habitat space and food which could be appropriate for either species 1 or 2, but will be claimed by species 1 because species 1 is physically dominant over species 2. In this figure, red represents food particles that would be claimed by predatory species 1 without contest. Blue represents food particles that would be claimed by predatory species 2 without contest. Purple represents food particles that will be contested and claimed by species 1, because species 1 is dominant. Gray represents food particles that will not be consumed by either species 1 or species 2. Some of those food particles depicted in gray would be considered either too large for ingestion by species 1 and 2, or could be considered so small that they are not energetically “worth the effort” of being pursued. Still others of those food particles depicted in gray will not be eaten because they are present beyond the habitat ranges of species 1 and 2. Presumably there are additional predatory species which would consume the food particles depicted in gray.
Source: This image is being used courtesy of its author, Christon J. Hurst.
In Figure 1.4, the food particles available for consumption are depicted as colored circles in the right side of the drawing. Species 1 can eat the same size food particles as does species 2, and species 1 additionally can eat some particles that are larger than could be consumed by species 2. In this figure, the color red represents food particles which will be eaten by species 1 but are too large for consumption by species 2. Those food particles which exist in the contested habitat area and could be consumed by either of these species will be claimed by species 1 and are shown in purple. The food particles which will be ingested by species 2 are shown in blue. There are additional food particles that will not be consumed by species 1 and 2 because those food particles either are too large or too small for consumption by species 1 and 2, or because those food particles are present outside the potential habitat areas of either species 1 or 2. Those food particles that will not be ingested by either species 1 or species 2 are shown in gray.
The original drawing of Hutchinsons Niche space (the left side of Figure 1.3) indicated that there was an upper temperature range in which neither species 1 nor species 2 could reside. However, his drawing of biotop (the right side of Figure 1.3) indicated that the depth profile in which both species could reside extended to the waters surface. In this redrawing, which appears as Figure 1.4, I have added to both the right and left sides the presence of that upper zone which would be thermally uninhabitable by either species 1 or 2.
1.5 Using Visual Analogies to Represent the Concept of a Species Niche as Being a Multidimensional Space Which has Complex Surface Geometry
Visual analogy can be used to help understand that the actions which occur between species contribute to definition of the interlocking nature of the niches occupied by those species. I will be using the surfaces of polyhedrons, models of viral surfaces, and geometric sculptures to represent this analogy.
1.5.1 A Broader Consideration of the Variables that Would Define Niche Space
If we could mathematically define the niche space occupied by a species as representing the complete ecosystem function of that species, then it would require us to include more variables than just the sole consideration expressed by Evelyn Hutchinson (Hutchinson 1957) which had been to represent a species function as the size of particles that are ingested.
The list of variables which contribute to defining a niche, and thus to defining that as a niche space, would include all of the actions and metabolic functions of its occupant species. The list would include those ways in which members of the species autotrophically or heterotrophically obtain the resources required for meeting their energy requirements. Furthermore, we need to consider as variables those ways by which a species obtains substances such as ions, minerals, and vitamins that it cannot synthesize but requires for successful usage of its energy sources. We also need to consider as variables the means through which a species accomplishes maintenance of both its beneficial and its defensive associations including coordinating its own actions and metabolic activities with the activities of its mutualistic microbial and macrobial symbionts. The niche definition additionally would include those ways by which its occupant species contributes provisions for the metabolic needs of other species, including the fact that members of any particular species will be consumed by species which occupy other niches. Contributing to the needs of other species includes being attacked by pathogenic microorganisms. Those considerations collectively result in the evolution of niches whose occupant species are optimal representations of ecological resource management.
1.5.2 Imagining that Interactions Between Species Occur at the Surfaces of Their Niche Spaces
Evolution produces interlocking niches which represent the interactions between species.
Hutchinsons drawing of a species niche space included only a few variables and those created a rectangle (Hutchinson 1957). We can begin to increase the number of variables which define a species niche space if we consider the surfaces of fairly simple polyhedrons, as depicted by the drawings shown in Figure 1.5, to represent niches. Each edge of these polyhedrons could be imagined as representing one of the variables defining the niche and the vertices then would represent parameter values which are characteristic for that species. Each of the different surfaces on these polyhedral shapes could represent an interaction that occurs between members of this species and some other species. This increase in the number of variables and complexity of the surface geometry still is not sufficient for us to fully visualize the niche interactions of a species.
The bottom image in Figure 1.5 is a regular icosahedron. If we visualize a niche space as having the basic form of a polyhedron, and we imagine that interactions with other species occur at the surfaces of the polyhedron, then subdividing a polyhedral surface as depicted in Figure 1.6 could help us to visually perceive a niche space that represents a greater number of mathematical variables and perhaps imagine there to be a greater number and greater complexity of its ecological interactions. Figure 1.6 shows two images which illustrate regular icosahedra that have greater mathematical complexity because of their subdivided edges and faces. These are depictions of a picornavirus capsid (family Picornaviridae).
The ecological functions and interactions that define a species niche are optimized by evolution and these functions will interlock with the activities, and thus interlock with the niches, of other species. We can find visual analogy for interdependence between the niches of different species by examining the surface geometry of those sculptures shown in Figures 1.7 and 1.8. Those sculptures are being used to represent the idea that each ecological niche can be perceiving as a continuous multidimensional volume of niche space, whose mathematically defined surface represents the numerous variables and their parameter ranges which describe the ecological interactions of that species.
Figure 1.5
