Chapter 1 Introduction - Weber State University
Transcript of Chapter 1 Introduction - Weber State University
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Ecology Behavior Genetics
Evolution
Physiology
Chapter 1 Introduction
ancient Greek physis = "nature, origin“; logia, = "study of"
History of Physiology
Hippocrates (460-370 BC)
wrote about physiology
420 BC Hippocratic School of Medicine
Aristotle (384 BC - 322 BC)
relationship between structure & function pioneer of physiology
Galen (Claudius Galenus ( ~129-200/216)
founder of “experimental physiology”
Greek physician in Rome
Marcello Malphigi (1628-1694)
Italian physician microscope anatomy Malphigian tubules
William Harvey (1578-1657) English physician
1628 publication blood circulation – heart «capillaries» epigenesis
studied fish, amphibians, reptiles, birds & mammals
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Claude Bernard (1813-1878) French physiologist
Walter Cannon (1871-1945) American physiologist
Ivan Pavlov 1891 conditioning reflex 1904 Nobel Prize in Medicine & Physiology
Matthias Schleiden (1804-1881)
German botanist
Theodor Schwann (1810-1882) German physiologist
cell theory
Per Scholander (1905-1980) Swedish
George Bartholomew 1919-2006 American environmental physiology
Peter Hochachka (1937-2002) Canadian biochemical adaptation
Knut Schmidt-Nielsen (1915-2007) Norwegian
Father of Animal Physiology
George Somero (1940- current) American biochemical adaptation
20th century comparative physiology & ecophysiology
C. Ladd Prosser (1907-2002) American
August Krogh (1874-1949) Danish
Physiology: study of functions & their structural components
functions: physical & chemical processes in organisms
How organisms operate Salmon life history
physiologically
1) Fundamental biology of all organisms
2) Non-human health & diseases
3) Human health & diseases
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Applied practical aspects of physiology Comparative approach
squid neuron cells — large axons for implanting electrodes
Frog -- understanding human circulatory system
nonhuman animals “models” understanding human health & diseases
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Central Questions in Physiology
1) What is mechanism by which function accomplished?
How?
Mechanism
a) components of living animal
b) interactions among these components allowing animal to perform
Firefly
2) How did mechanism originate?
Why?
How do you like your eggs cooked, with bacon?
2009 Dante Fenelio
Significance
Inferences from past
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Natural selection
Evolutionary origins
differential survival & reproduction
Adaptation
physiological mechanism/trait, product of evolution by natural selection
Adaptive significance:
reason why trait is asset reason why natural selection favored evolution of trait
Adaptation: mechanism of light production
Adaptive significance: mate attraction
engineering vs tinkering
François Jacob: French biologist 1965 Nobel laureate
engineering: new
tinkering: pre-existing & modify*
not implied
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Mechanistic
Evolutionary
Physiology
Comparative
Environmental
physiological ecology: study of how animals respond to physiologically to environmental conditions
Integrative
synthetic study of function of all animals
study of evolutionary origins
study of mechanisms
synthesis across levels of biological organization, e.g. relations between molecular & anatomical features of organs
animals structurally dynamic
animals organized systems requiring energy maintaining organizations
time & body size fundamental significance in lives of all animals
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Structurally dynamic
Schoenheimer (1930s) first used radioisotopes in research
Organized systems requiring energy maintaining organizations
structurally dynamic losing elements/compounds daily-need to replenish them
Time & body size fundamental significance
Structure relative constant through time but particular atoms constructing molecules of change from time to time
Claude Bernard (1813-1878 physician) Father of Comparative Physiology
Coined: Constancy of “milieu intérieur” = internal environment
Cells bathed tissue fluids/blood constancy of solutes (Na+), pH, temperature within an animal’s body
external environment = conditions outside body
constancy of mammalian blood glucose
“Constancy of the internal environment is the condition for free life”
Animals are able to lead lives of greater freedom and independence to the extent that they maintain a stable internal environment, sheltering their cells from the variability of the outside world
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Conformity
Regulation
internal & external conditions equal
internal constancy against varying external conditions
Homeostasis
Walter Cannon (1871-1945) physician/researcher developed term
expanded Bernard’s constancy of internal mileu to also include existence of regulatory systems that automatically make adjustments to maintain internal constancy
Homeostasis = “the coordinated physiological processes which maintain most of the constant states in the organism.”
observed animals interact with environment which constantly alters stability of internal parameters (e.g. temperature, pH, ion concentrations)
Cannon (1933)
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Homeostasis
Negative feedback
controlled variable
+
-
set point
acclimation
acclimatization
chronic change
chronic response to an environment change under lab conditions
chronic response to several environmental changes under field conditions
phenotypic plasticity
Individual ability to express 2 or more genetically controlled phenotypes
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Internally Programmed Changes in Two Time Frames
1) developmentally
physiological change occurs even external environment constant
2) biological clocks endogenous (daily— circadian)
e.g. metamorphosis
e.g. hemoglobin: HbF (fetus/newborn) α2γ2 ~12 weeks postnatal to HbA adult) α2β2
hibernation
jet lag
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Body Size
scaling: mammalian physiological/morphological traits vary systematically with size
dikdik duiker zebra duiker water buffalo
26.5:32
27: 26
Environment
animals do not live in a vacuum
Environment: all chemical, physical & biotic components of animal’s Immediate surroundings
Microenvironment/microclimate
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Key environmental parameters
temperature
O2
H2O
salinity
pH
pressure
Masking Factors
wind temperature
Temperature
Antarctica rock cod lay eggs, hatch, grow feed & mate at ~-1.9 C
Desert iguana up to 42 C; can survive 48.5 C
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O2
High Altitude
Lower Depth in Oceans
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Temperature effects on Coral Reefs
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Bernard & Cannon: studied mammals & humans presumptuous elevation of mammals “superior” to other taxa
mammalian homeostasis – achievement of evolutionary/ecological success
Proximal causes/cues:
Ultimate causes/cues:
how
why
Questions physiologists ask