Animal Physiology Zool 4230 General objectives: 1. Gain factual knowledge

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

2. 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

3. Table 1.4

4. Introduction • Comparative physiology • Environmental physiology • Evolutionary physiology

5. Figure 1.17 The comparative method

6. Figure 1.12 Performance in an oxygen-poor environment

7. Migrating Pacific salmon

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

9. Figure 1.1 The study of physiology integrates knowledge at all levels of organization (Part 1)

10. Figure 1.1 The study of physiology integrates knowledge at all levels of organization (Part 2)

11. 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?

12. 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

13. 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

14. Figure 1.4 Structures similar in performance & adaptive significance can differ dramatically (Part 1)

15. Figure 1.4 Structures similar in performance & adaptive significance can differ dramatically (Part 2)

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

17. 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

18. Figure 1.9 Fish around Antarctica spend their entire lives at body temperatures near –1.9°C

19. Figure 1.10 Butterfly biogeography

20. Figure 1.11 A thermophilic (“heat-loving”) lizard common in North American deserts

21. 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

22. Responses to changes in environmental conditions • Responses to changes in environmental conditions • Avoidance • Conformity • Regulation • Behavior

23. 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

24. Figure 1.5 Conformity and regulation

25. Figure 1.6 Mixed conformity and regulation in a single species

26. 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

27. Responses to environmental change • Acute response • Chronic response • Acclimation • Acclimatization • Evolutionary response

28. Figure 1.7 Heat acclimation in humans as measured by exercise endurance

30. 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

31. Genotype and environmental interaction

32. 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

33. Six steps at which gene expression can be controlled

34. Activation of G protein by extracellular signal

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

36. Extracellular control signals • Growth factor • Hormones • Neurotransmitters

37. 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

38. Figure 1.8 Length of gestation scales as a regular function of body size in mammals

39. Figure 1.18 Physiological variation among individuals of a species

40. 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.

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

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

43. Negative Feedback (continued)

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

45. 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.