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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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1 2

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