Presentation on theme: "Animal Physiology Zool 4230 General objectives: 1. Gain factual knowledge 2. Learning fundamental principles, generalizations, or theories."— Presentation transcript:
Animal Physiology Zool 4230 General objectives: 1. Gain factual knowledge 2. Learning fundamental principles, generalizations, or theories
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
Figure 1.12 Performance in an oxygen-poor environment
Migrating Pacific salmon
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)
Figure 1.1 The study of physiology integrates knowledge at all levels of organization (Part 2)
Physiologys two central questions Origin– why do modern-day animals possess the mechanisms they have? Mechanism– how do modern-day animals carry out their functions?
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 animals 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)
Figure 1.4 Structures similar in performance & adaptive significance can differ dramatically (Part 2)
Natural selection Two basic concepts Fitness– link to adaptation Environment– habitat –Biome: problems encounter –Design and strategy –Behavioral modification
Environmental components Environmental Component –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
Figure 1.10 Butterfly biogeography
Figure 1.11 A thermophilic (heat-loving) lizard common in North American deserts
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 animals 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
Figure 1.6 Mixed conformity and regulation in a single species
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
Figure 1.7 Heat acclimation in humans as measured by exercise endurance
Figure 1.14 Marine invertebrates have body fluids similar to seawater in their concentration of salts
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
Figure 1.18 Physiological variation among individuals of a species
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.
Feedback Loops Sensor: –Detects deviation from set point. Integrating center: –Determines the response. Effector: –Produces the response.
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)
Positive Feedback Action of effectors amplifies the changes. Is in same direction as change. Examples: –Oxytocin (parturition). –Voltage gated Na + channels (depolarization).
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.