I.                   Introduction                                

·   Comparative physiology-- investigate both general principles of organismal function and the exceptions to the general rule 

·   Environmental physiology-- investigate animal's function in and respond to their natural environments, at all stages of their life cycles 

·   Evolutionary physiology--investigate the evolution of traits over long period of time, and within species. To explore the genetic basis of physiological traits, and the magnitude and causes of physiological variation

                 ·      Fig. 1—genotype and environment interaction

 II.      Maintaining life-- necessary life functions

·       Interrelationship among body organ systems

·       Maintaining boundaries

·       Movement

·       Responsiveness

·       Digestion

·       Metabolism

·       Excretion       

·       Reproduction

·       Growth 

III.     Survival needs

·       Ultimate goal-- maintain life

·       Nutrients

·       Oxygen

·       Water

·       Maintenance of body temperature

·       Atmospheric pressure 

IV.    Natural Selection-- two basic concepts

·       Fitness-- linked to adaptation

·       Environment-- kind of habitat in which an animal lives-- biome

·       Problems the animal will encounter

·       Kinds of design and strategy it is likely to show

·       Microenvironment (microhabitat)-- each individual animal has its own environment--both biotic and physical-- commonly modified by its own behavioral choices 

V.   Environmental components: 

   A.  Environmental stress

·       Abiotic-- physical and chemical

·       Biotic-- direct and indirect effects of other organisms, e.g. competition 

   B.   Magnitude of fluctuations

·   Long term changes-- land masses move, sea levels rise and fall…

·   Short term changes-- lunar or daily cycle- important in relation to local microenvironments, and therefore to small animals    

C.    Energy or resource availability-- food chain vs. metabolism    

VI.     Adaptation

·   Characters or traits observed in animals-- result of selection.  For example-- hemoglobin-- better O2 carrier

·    A process-- natural selection adjusts the frequency of genes that code for traits affecting fitness

·    Short term compensatory changes

                                               i.      acclimation,

                                              ii.      acclimatization 

VII.   Responses of animal to changes in environmental condition 

·   Avoidance-- mechanism for getting away from an environmental problem in space or time.  E.g. live in burrows or go into torpor  

·   Conformity-- animals undergo changes of internal state similar to accommodate changes in the external environment.  Animals do not attempt to maintain a homeostatic condition for the whole body 

·   Regulation-- animals maintain some or all of the "normal" internal conditions

·   Behavior 

VIII.  Homeostasis

·       Functions-

                   Maintenance of stable internal conditions

                   Dynamic state of equilibrium

·       Control mechanisms

                   Communication

                             receptor

                             control center

                             effector

                   Interrelationships

·       Negative feedback mechanism

1.    Opposite directional change

2.    Decrease in original stimulus

3.    Nervous system controls

4.    Endocrine system controls

5.    Other system controls

·       Positive feedback mechanisms

1.    Same directional change

2.    Increase in original stimulus

3.    Cascade effect

4.    Cardiovascular system controls

5.    Reproductive system controls

Mechanisms of adaptation

	Molecular level-- determined by genes and their constituent DNA
	Any changes at the DNA level becomes expressed-- protein change

Core of adaptation-- anything that control protein properties and degradation

Proteins are:

1. Product of genetic code in the DNA of a cell
2. Made up of chains of 20 different amino acids
3. Main agents of molecular recognition
4. Perform and integrate chemical and mechanical functions
5. Control rate of reaction of other molecules
6. Control gene expression
7. Controlling protein action

	Activity of ligands-- small molecules that bind onto proteins and alter their conformation-- an allosteric effect
	Allosterically coupled, cooperative allosteric binding, and competitive binding

Protein-- synthesis and degradation

1. Control of gene expression-- fig. 2.7 (Author: WSJ)
2. Intracellular proteolytic mechanisms

	Degradation may occur in the cytoplasm
	Degradation may occur in the endoplasmic reticulum, lysosomes
	Ubiquitin-- marker molecule, link covalently to the destruction-bound protein-- serve as degradation signal
	Certain amino acid confer protection, some stimulate proteolytic attack

Physiological regulation of gene expression

1. Receptors

	Signal molecule act as ligands to the receptor protein
	Receptor protein undergoes a conformational change
	Subsequent changes in intracellular signals
	Intracellular, enzyme-linked, ion-channel-linked, G-protein-linked receptors

2.  Intracellular mediators and second messengers

	Cyclic AMP (cAMP)
	Calcium
	Inositol triphosphate
	Diacylglycerol
	Protein kinase C

3.  Extracellular control signals

	Growth factor
	Hormones
	Neurotransmitters

4.  Feedback systems and metabolic control

Negative and positive feedback

In more complex enzyme control systems with built in amplification-- high gain, i.e. a single signaling molecule can bring about the activation of a large number of enzyme molecule