Evolutionary physiology is the study of the biological

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

physiological Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemica ...

structures and processes; that is, the manner in which the functional characteristics of individuals in a population of

organism In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells ( cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fu ...

s have responded to

natural selection Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Cha ...

across multiple

generation A generation refers to all of the people born and living at about the same time, regarded collectively. It can also be described as, "the average period, generally considered to be about 20–⁠30 years, during which children are born and gr ...

s during the history of the population. It is a sub-discipline of both

physiology Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemic ...

and

evolutionary biology Evolutionary biology is the subfield of biology that studies the evolutionary processes (natural selection, common descent, speciation) that produced the diversity of life on Earth. It is also defined as the study of the history of life ...

. Practitioners in the field come from a variety of backgrounds, including physiology, evolutionary biology,

ecology Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overl ...

, and

genetics Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar work ...

. Accordingly, the range of

phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (biology), morphology or physical form and structure, its Developmental biology, developmental proc ...

s studied by evolutionary physiologists is broad, including life history, behavior, whole-organism performance, functional morphology,

biomechanics Biomechanics is the study of the structure, function and motion of the mechanical aspects of biological systems, at any level from whole organisms to organs, cells and cell organelles, using the methods of mechanics. Biomechanics is a branch of ...

anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having i ...

, classical physiology,

endocrinology Endocrinology (from '' endocrine'' + '' -ology'') is a branch of biology and medicine dealing with the endocrine system, its diseases, and its specific secretions known as hormones. It is also concerned with the integration of developmental event ...

biochemistry Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology and ...

, and

molecular evolution Molecular evolution is the process of change in the sequence composition of cellular molecules such as DNA, RNA, and proteins across generations. The field of molecular evolution uses principles of evolutionary biology and population genet ...

. The field is closely related to

comparative physiology Comparative physiology is a subdiscipline of physiology that studies and exploits the diversity of functional characteristics of various kinds of organisms. It is closely related to evolutionary physiology and environmental physiology. Many uni ...

and

environmental physiology Ecophysiology (from Greek , ''oikos'', "house(hold)"; , ''physis'', "nature, origin"; and , ''-logia''), environmental physiology or physiological ecology is a biological discipline that studies the response of an organism's physiology to envi ...

, and its findings are a major concern of

evolutionary medicine Evolutionary medicine or Darwinian medicine is the application of modern evolutionary theory to understanding health and disease. Modern biomedical research and practice have focused on the molecular and physiological mechanisms underlying he ...

. One definition that has been offered is "the study of the physiological basis of fitness, namely, correlated evolution (including constraints and

trade-off A trade-off (or tradeoff) is a situational decision that involves diminishing or losing one quality, quantity, or property of a set or design in return for gains in other aspects. In simple terms, a tradeoff is where one thing increases, and anot ...

s) of physiological form and function associated with the environment, diet,

homeostasis In biology, homeostasis ( British also homoeostasis) (/hɒmɪə(ʊ)ˈsteɪsɪs/) is the state of steady internal, physical, and chemical conditions maintained by living systems. This is the condition of optimal functioning for the organism and ...

, energy management,

longevity The word " longevity" is sometimes used as a synonym for " life expectancy" in demography. However, the term ''longevity'' is sometimes meant to refer only to especially long-lived members of a population, whereas ''life expectancy'' is always ...

, and mortality and life history characteristics".

History

As the name implies, evolutionary physiology is the product of what were at one time two distinct scientific disciplines. According to Garland and Carter, evolutionary physiology arose in the late 1970s, following debates concerning the metabolic and thermoregulatory status of

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

s (see physiology of dinosaurs) and

mammal-like reptiles Pelycosaur ( ) is an older term for basal or primitive Late Paleozoic synapsids, excluding the therapsids and their descendants. Previously, the term ''mammal-like reptile'' had been used, and pelycosaur was considered an order, but this is ...

. This period was followed by attempts in the early 1980s to integrate

quantitative genetics Quantitative genetics deals with phenotypes that vary continuously (such as height or mass)—as opposed to discretely identifiable phenotypes and gene-products (such as eye-colour, or the presence of a particular biochemical). Both branches u ...

into

, which had spillover effects on other fields, such as

behavioral ecology Behavioral ecology, also spelled behavioural ecology, is the study of the evolutionary basis for ethology, animal behavior due to ecology, ecological pressures. Behavioral ecology emerged from ethology after Niko Tinbergen outlined Tinbergen's f ...

and

ecophysiology Ecophysiology (from Greek , ''oikos'', "house(hold)"; , ''physis'', "nature, origin"; and , '' -logia''), environmental physiology or physiological ecology is a biological discipline that studies the response of an organism's physiology to enviro ...

. In the mid- to late 1980s,

phylogenetic comparative methods Phylogenetic comparative methods (PCMs) use information on the historical relationships of lineages (phylogenies) to test evolutionary hypotheses. The comparative method has a long history in evolutionary biology; indeed, Charles Darwin used diffe ...

started to become popular in many fields, including physiological ecology and

. A 1987 volume titled ''New Directions in Ecological Physiology'' had little ecology but a considerable emphasis on evolutionary topics. It generated vigorous debate, and within a few years the

National Science Foundation The National Science Foundation (NSF) is an independent agency of the United States government that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National ...

had developed a panel title
Ecological and Evolutionary Physiology
Shortly thereafter, selection experiments and experimental evolution became increasingly common in evolutionary physiology. Macrophysiology has emerged as a sub-discipline, in which practitioners attempt to identify large-scale patterns in physiological traits (e.g. patterns of co-variation with

latitude In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north ...

) and their ecological implications. More recently, the importance of a merger of evolutionary biology and physiology has been argued from the perspective of functional analyses,

epigenetics In biology, epigenetics is the study of stable phenotypic changes (known as ''marks'') that do not involve alterations in the DNA sequence. The Greek prefix '' epi-'' ( "over, outside of, around") in ''epigenetics'' implies features that are ...

, and an

extended evolutionary synthesis The extended evolutionary synthesis consists of a set of theoretical concepts argued to be more comprehensive than the earlier modern synthesis of evolutionary biology that took place between 1918 and 1942. The extended evolutionary synthesis w ...

. The growth of evolutionary physiology is also reflected in the emergence of sub-disciplines, such as evolutionary

, which addresses such hybrid questions as "What are the most common endocrine mechanisms that respond to selection on behavior or life-history traits?"

Emergent properties

As a hybrid scientific discipline, evolutionary physiology provides some unique perspectives. For example, an understanding of physiological mechanisms can help in determining whether a particular pattern of phenotypic variation or co-variation (such as an allometric relationship) represents what could possibly exist or just what selection has allowed. Similarly, a thorough knowledge of physiological mechanisms can greatly enhance understanding of possible reasons for evolutionary correlations and constraints than is possible for many of the traits typically studied by evolutionary biologists (such as morphology).

Areas of research

Important areas of current research include: * Organismal performance as a central

(e.g., measures of speed or stamina in

animal locomotion Animal locomotion, in ethology, is any of a variety of methods that animals use to move from one place to another. Some modes of locomotion are (initially) self-propelled, e.g., running, swimming, jumping, flying, hopping, soaring and gliding. Th ...

) * Role of

behavior Behavior (American English) or behaviour (British English) is the range of actions and mannerisms made by individuals, organisms, systems or artificial entities in some environment. These systems can include other systems or organisms as we ...

in physiological evolution * Physiological and endocrinological basis of variation in life history traits (e.g., clutch size) * Functional significance of

* Extent to which species differences are adaptive * Physiological underpinnings of limits to geographic ranges * Geographic variation in

* Role of

sexual selection Sexual selection is a mode of natural selection in which members of one biological sex choose mates of the other sex to mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex (in ...

in shaping physiological evolution * Magnitude of "phylogenetic signal" in physiological traits * Role of

pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a g ...

s and

parasites Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

in physiological evolution and

immunity Immunity may refer to: Medicine * Immunity (medical), resistance of an organism to infection or disease * ''Immunity'' (journal), a scientific journal published by Cell Press Biology * Immune system Engineering * Radiofrequence immunity de ...

* Application of

optimality model In biology, optimality models are a tool used to evaluate the costs and benefits of different organismal features, traits, and characteristics, including behavior, in the natural world. This evaluation allows researchers to make predictions about an ...

ing to elucidate the degree of adaptation * Role of

phenotypic plasticity Phenotypic plasticity refers to some of the changes in an organism's behavior, morphology and physiology in response to a unique environment. Fundamental to the way in which organisms cope with environmental variation, phenotypic plasticity encompa ...

in accounting for individual, population, and species differences * Mechanistic basis of

s and constraints on evolution (e.g., putative

Carrier's constraint Carrier's constraint is the observation that air-breathing vertebrates which have two lungs and flex their bodies sideways during locomotion find it very difficult to move and breathe at the same time, because the sideways flexing expands one lung ...

on running and breathing) * Limits on sustained metabolic rate * Origin of allometric scaling relations or allometric laws (and the so-called

metabolic theory of ecology The metabolic theory of ecology (MTE) is the ecological component of the more general Metabolic Scaling Theory and Kleiber's law. It posits that the metabolic rate of organisms is the fundamental biological rate that governs most observed pattern ...

) * Individual variation (see also

Individual differences psychology Differential psychology studies the ways in which individuals differ in their behavior and the processes that underlie it. This is a discipline that develops classifications (taxonomies) of psychological individual differences. This is distingui ...

) * Functional significance of biochemical polymorphisms * Analysis of physiological variation via

* Paleophysiology and the evolution of endothermy *

Human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...

adaptational

* Darwinian medicine * Evolution of dietary antioxidants

Techniques

Artificial selection Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant ma ...

and experimental evolutionmouse wheel running video
*

Genetic analyses Genetic analysis is the overall process of studying and researching in fields of science that involve genetics and molecular biology. There are a number of applications that are developed from this research, and these are also considered parts of ...

and manipulations * Measurement of selection in the wild *

Phenotypic plasticity Phenotypic plasticity refers to some of the changes in an organism's behavior, morphology and physiology in response to a unique environment. Fundamental to the way in which organisms cope with environmental variation, phenotypic plasticity encompa ...

and manipulation * Phylogenetically based comparisons *

Doubly labeled water Doubly labeled water is water in which both the hydrogen and the oxygen have been partly or completely replaced (i.e. ''labeled'') with an uncommon isotope of these elements for tracing purposes. In practice, for both practical and safety reasons, ...

measurements of free-living energy demands of animals

Funding and societies

In the United States, research in evolutionary physiology is funded mainly by the

. A number of scientific societies feature sections that encompass evolutionary physiology, including:
American Physiological Society "integrating the life sciences from molecule to organism"

Society for Integrative and Comparative Biology
*

Society for Experimental Biology The Society for Experimental Biology is a learned society for animal, cell and plant biologists. It was founded in 1923 at Birkbeck College to "promote the art and science of experimental biology in all its branches". It aims to demonstrate the im ...

Journals that frequently publish articles about evolutionary physiology

* ''

American Naturalist ''The American Naturalist'' is the monthly peer-reviewed scientific journal of the American Society of Naturalists, whose purpose is "to advance and to diffuse knowledge of organic evolution and other broad biological principles so as to enhance t ...

''
''Comparative Biochemistry and Physiology''

''Comprehensive Physiology''

''Evolution''

''Functional Ecology''
* '' Integrative and Comparative Biology''
''Journal of Comparative Physiology''

''Journal of Evolutionary Biochemistry and Physiology''
* ''

Journal of Evolutionary Biology The ''Journal of Evolutionary Biology'' is a peer-reviewed scientific journal published monthly covering the field of evolutionary biology. It is owned by the European Society for Evolutionary Biology. The founding editor-in-chief was Stephen C ...

''
''Journal of Experimental Biology''
* '' Physiological and Biochemical Zoology''

References

External links

People, Labs, and Programs in Evolutionary Physiology

{{DEFAULTSORT:Evolutionary Physiology Physiology Evolutionary biology