Animal Physiology Zool 4230   General objectives: 1.      Gain factual knowledge 2.      Learning fundamental principles, generalizations, or theories

Physiology is the study of life processes: Study of physiology Physiology is the study of life processes: ·     How living systems work, from the molecular level to organ systems and to the whole organism ·     How the organism responds to physical activities and to the environment around it, whether it is the vacuum of space or the depths of the ocean ·     How disease can affect living systems ·     How the genome translates into function both within the cell and the whole organism

Table 1.4

Comparative physiology Environmental physiology Introduction Comparative physiology Environmental physiology Evolutionary physiology

Figure 1.17 The comparative method anphys-fig-01-17-0.jpg

Figure 1.12 Performance in an oxygen-poor environment anphys-fig-01-12-0.jpg

Migrating Pacific salmon anphys-opener-01-0.jpg

Goal- to maintain life Need Nutrients Oxygen Water Survival need Goal- to maintain life Need Nutrients Oxygen Water Maintain body temperature Atmospheric pressue

Figure 1.1 The study of physiology integrates knowledge at all levels of organization (Part 1) anphys-fig-01-01-1.jpg

Figure 1.1 The study of physiology integrates knowledge at all levels of organization (Part 2) anphys-fig-01-01-2.jpg

Physiology’s two central questions Origin– why do modern-day animals possess the mechanisms they have? Mechanism– how do modern-day animals carry out their functions?

Why do modern-day animals possess the mechanism they have? The Study of Origin Why do modern-day animals possess the mechanism they have? Products of evolution The study of evolutionary origins reveals the significance of mechanisms Reliance on indirect reasoning– very rarely understood

Key process of evolutionary origin Natural selection- increase in frequency of genes that produce phenotypes that improves an animal’s chances of survival and reproduction within the environment Adaptations- aid the survival and reproduction Adaptive significance evolved by natural selection

Figure 1.4 Structures similar in performance & adaptive significance can differ dramatically (Part 1) anphys-fig-01-04-1.jpg

Figure 1.4 Structures similar in performance & adaptive significance can differ dramatically (Part 2) anphys-fig-01-04-2.jpg

Fitness– link to adaptation Environment– habitat Natural selection Two basic concepts Fitness– link to adaptation Environment– habitat Biome: problems encounter Design and strategy Behavioral modification

Environmental components Stress Biotic– direct and indirect effects of other organisms, e.g. competition Abiotic– physical and chemical Magnitude of fluctuations Long term– tsunami outcome Short term– lunar or daily cycle Resource/energy availability

Figure 1.9 Fish around Antarctica spend their entire lives at body temperatures near –1.9°C anphys-fig-01-09-0.jpg

Figure 1.10 Butterfly biogeography anphys-fig-01-10-0.jpg

Figure 1.11 A thermophilic (“heat-loving”) lizard common in North American deserts anphys-fig-01-11-0.jpg

Adaptation Adaptation Traits observed– result of selection Natural selection adjusts the frequency of genes that code for traits affecting fitness Short term compensatory changes Acclimation Acclimatization

Responses to changes in environmental conditions Avoidance Conformity Regulation Behavior

Conformity and regulation Two principal types of relations between an animal’s internal and external environment Conformity/regulation Conformity- an animal permits internal and external conditions to be almost equal Regulation- an animal maintains internal constancy with external variability

Figure 1.5 Conformity and regulation anphys-fig-01-05-0.jpg

Figure 1.6 Mixed conformity and regulation in a single species anphys-fig-01-06-0.jpg

Advantages and disadvantages of conformity and regulation Regulation- disadvantage– costs energy Regulation- advantage– permits cells to function independently of outside condition Conformity- disadvantage- cells within the body are subject to change when outside condition changes Conformity- advantage– avoids energy costs of maintaining organization

Responses to environmental change Acute response Chronic response Acclimation Acclimatization Evolutionary response

Figure 1.7 Heat acclimation in humans as measured by exercise endurance anphys-fig-01-07-0.jpg

anphys-tab-01-02-0.jpg

Figure 1.14 Marine invertebrates have body fluids similar to seawater in their concentration of salts anphys-fig-01-14-0.jpg

Mechanisms of adaptation Molecular level Genes/DNA Any changes at the DNA level Changes in protein expression Core of adaptation Anything that controls protein properties and degradation

Genotype and environmental interaction

Protein synthesis and degradation Control of gene expression Intracellular proteolytic mechanisms Degradation may occur In cytoplasm In endoplasamic reticulum Ubiquitin (marker protein)serves as degradation signal

Six steps at which gene expression can be controlled

Activation of G protein by extracellular signal

Interaction of two G proteins with a single cAMP-producing adenyl cyclase, giving both stimulatory and inhibitory pathways

Extracellular control signals Growth factor Hormones Neurotransmitters

Size and scaling Body-size relations are important in making prediction of the species’ physiological and morphological traits. Length, area, and volume Isometric scaling Allometric scaling

Figure 1.8 Length of gestation scales as a regular function of body size in mammals anphys-fig-01-08-0.jpg

Figure 1.18 Physiological variation among individuals of a species anphys-fig-01-18-0.jpg

Maintaining constancy of internal environment. Homeostasis Maintaining constancy of internal environment. Dynamic constancy. Within a certain normal range. Maintained by negative feedback loops. Regulatory mechanisms: Intrinsic: Within organ being regulated. Extrinsic: Outside of organ, such as nervous or hormonal systems. Negative feedback inhibition.

Sensor: Integrating center: Effector: Feedback Loops Sensor: Detects deviation from set point. Integrating center: Determines the response. Effector: Produces the response.

Reverses the deviation. Produces change in opposite direction. Negative Feedback Defends the set point. Reverses the deviation. Produces change in opposite direction. Examples: Insulin decreases plasma [glucose]. Thermostat. Body temperature.

Negative Feedback (continued)

Action of effectors amplifies the changes. Positive Feedback Action of effectors amplifies the changes. Is in same direction as change. Examples: Oxytocin (parturition). Voltage gated Na+ channels (depolarization).

Confidence in rational ability, honesty and humility. Scientific Method Confidence in rational ability, honesty and humility. Specific steps in scientific method: Formulate hypothesis: Observations. Testing the hypothesis: Quantitative measurements. Analyze results: Select valid statistical tests. Draw conclusion.