Animal Physiology Module 3 PDF

Module 3 Animal Physiology Chandrashekhar Azad Vishwakarma, PhD Assistant Professor Department of Natural and Applied Sciences, TERI School of Advanced Studies  Contents Animal form and function – Evolution of animal size and shape – Exch...

Module 3 Animal Physiology Chandrashekhar Azad Vishwakarma, PhD Assistant Professor Department of Natural and Applied Sciences, TERI School of Advanced Studies  Contents Animal form and function – Evolution of animal size and shape – Exchange with the environment – Hierarchical organization of body plans – Coordination and control Feedback control maintains the internal environment in many animals – Regulating and conforming – Homeostatis Homeostatic processes for thermoregulation involve form, function and behavior – Endothermy and ectothermy – Variation in body temperature – Balancing heat loss and gain – Acclimatization and Thermoregulation – Physiological thermostats and fever Energy requirements are related to animal size, activity and environment – Energy allocation and use – Quantifying energy use – Minimum metabolic rate and thermoregulation – Influence on metabolic rate – Torpor and Energy conservation : Basic Principles of Animal Form and Functions Fig: How do animals regulate their internal state even in changing or harsh environments? (Source: Lisa, A. U., Michael, L. C., Jane, B. R., Steven, A. W., Robert, B. J., Peter, V. M., & Neil, A. C. (2010). Campbell Biology. Benjamin Cummings/Pearson.)  Basic Principles of Animal Form and Functions Animal Form and Function All animals must obtain nutrients and oxygen, fight off infection, and survive to produce offspring. Due to evolution and adaptation, animals vary in terms of their anatomy (biological structure) and it is further reflected in their form and function. Due to the correlation between structure and function, anatomy often provides clues to physiology (biological function) The body plan or design is the result of a pattern of development programmed by the genome, itself the product of millions of years of evolution. Following major factors involve for the development of biological structure and function: – Evolution of animal size and shape – Exchange with the environment – Hierarchical organization of body plans – Coordination and control  Basic Principles of Animal Form and Functions Animal Form and Function Source: https://explore.ucalgary.ca/our-place-universe-origins-and-evolution-earth  Basic Principles of Animal Form and Functions Evolution of animal size and shape Fig: Various body plans have arisen during the course of evolution. The physical laws that govern strength, diffusion, movement and heat exchange limit the range of animal forms. Any bump on the aquatic animal’s body surface decide, it will be runner or flyer. Example: Tuna and other ray-finned fish can swim at speed upto 80 km/hr. sharks, penguins, dolphins are seals are also relatively fast swimmers. T. rex was fast runner or walker? Source: Lisa, A. U., Michael, L. C., Jane, B. R., Steven, A. W., Robert, B. J., Peter, V. M., & Neil, A. C. (2010). Campbell Biology. Benjamin Cummings/Pearson  Basic Principles of Animal Form and Functions Exchange with the environment Fig: Animals exchange nutrients, waste products gases with their environment. This exchange imposes an additional limitation on body plans. Exchange occurs as substances dissolved in an aqueous solution move across the plasma membrane of each cell. The rate of exchange is proportional to the membrane surface area whereas the amount of materials is proportional to the total body volume. Source: Lisa, A. U., Michael, L. C., Jane, B. R., Steven, A. W., Example: single-cell amoeba has sufficient Robert, B. J., Peter, V. M., & Neil, A. C. (2010). Campbell Biology. Benjamin Cummings/Pearson membrane area for exchange whereas in multicellular organisms, exchange will take place through the plasma membrane of each cell.  Basic Principles of Animal Form and Functions Exchange with the environment Fig: Source: Lisa, A. U., Michael, L. C., Jane, B. R., Steven, A. W., Robert, B. J., Peter, V. M., & Neil, A. C. (2010). Campbell Biology. Benjamin Cummings/Pearson  Basic Principles of Animal Form and Functions Hierarchical organization of body plans Cells form a working animal body through their emergent properties, which arise from successive levels of structure and functional organization. Many organs have more than one physiological role. Example: Pancreas, produces enzymes of the digestive system but also regulates sugar in the blood. The specialized and complex organ systems of Source:https://www.bbc.co.uk/bitesize/a animals are built from a limited set of cell and rticles/zrp3ydm tissue types. Four main types of animal tissue: Epithelial (eg. skin) Connective (eg. Cartilage) Muscle (eg. cardiac) Nervous (eg. brain)  Basic Principles of Animal Form and Functions Hierarchical organization of body plans Source: Lisa, A. U., Michael, L. C., Jane, B. R., Steven, A. W., Robert, B. J., Peter, V. M., & Neil, A. C. (2010). Campbell Biology. Benjamin Cummings/Pearson  Basic Principles of Animal Form and Functions Coordination and control The organ system must act in concert with one another to function effectively. Animals have two major systems for coordinating and controlling responses to stimuli: The endocrine: here signaling molecules are released into the bloodstream. Nervous systems: neurons transmit signals along dedicated routes connecting specific locations in the body. The endocrine system is especially well adapted for coordinating gradual changes that affect the entire body such as growth, development, reproduction, metabolic processes and digestion. The nervous system is well suited for rapid response to the environment such as reflexes and other rapid movement. Source: Lisa, A. U., Michael, L. C., Jane, B. R., Steven, A. W., Robert, B. J., Peter, V. M., & Neil, A. C. (2010). Campbell Biology. Benjamin Cummings/Pearson  Basic Principles of Animal Form and Functions Feedback control maintains the internal environment in many animals Many organ systems play a role in managing an animal’s internal environment. Faced with environmental fluctuations, animal manage their internal environment by either regulating or conforming. Regulating and conforming An animal is a regulator for an environmental variable if it uses internal mechanisms to control internal change in the face of external fluctuation. Eg. The river otter However, an animal is a conformer if it allows its internal condition to change in accordance with external changes in the particular variable. Eg. Largemouth bass Basic Principles of Animal Form and Functions Source: Lisa, A. U., Michael, L. C., Jane, B. R., Steven, A. W., Robert, B. J., Peter, V. M., & Neil, A. C. (2010). Campbell Biology. Benjamin Cummings/Pearson  Basic Principles of Animal Form and Functions Homeostasis Homeostasis means the maintenance of internal balance. This means, animals maintain a “steady state” – a relatively constant internal environment – even when the external environment changes significantly. The steady body temperature of a river otter and stable concentration of solutes in a freshwater bass are examples of homeostasis. Example: Human maintain: ~370C (98.60F) A blood pH of 7.4 Blood glucose range of 70-110 mg of glucose per 100 ml of blood Fig: A nonliving example of temperature regulation: control of room temperature (Source: Lisa, A. U., Michael, L. C., Jane, B. R., Steven, A. W., Robert, B. J., Peter, V. M., & Neil, A. C. (2010). Campbell Biology. Benjamin Cummings/Pearson)  Basic Principles of Animal Form and Functions Source: Lisa, A. U., Michael, L. C., Jane, B. R., Steven, A. W., Robert, B. J., Peter, V. M., & Neil, A. C. (2010). Campbell Biology. Benjamin Cummings/Pearson  Basic Principles of Animal Form and Functions Homeostatic processes for thermoregulation involve form, function and behavior Thermoregulation is the process by which animals maintain their body temperature within a normal range. Endothermy and Ectothermy Endothermic means that the animals warmed mostly by heat generated by metabolism. Eg. Humans and other mammals. Endotherms can maintain a stable body temperature even in the face of large fluctuations in the environmental temperature. However, ectothermic means they gain most of their heat from external sources. Eg. Amphibians, many nonavian reptiles and fishes. Fig: Thermoregulation by internal or external source of heat. (Source: Lisa, A. U., Michael, L. C., The ectotherms adjust their body Jane, B. R., Steven, A. W., Robert, B. J., Peter, V. M., & Neil, A. C. (2010). Campbell Biology. Benjamin temperature by behavioral means such as Cummings/Pearson) seeking out shade or basking in the sun.  Basic Principles of Animal Form and Functions Variation in body temperature Poikilotherm (Green word poikilos means varied): an animal whose body temperature varies with its environment. Homeotherm has a relatively constant body temperature. River otter Example: the largemouth bass is a poikilotherm and the river otter is a homeotherm. As described, it might seem that all ectotherms are poikilothermic and all endotherms are homeothermic Balancing heat loss and gain Animals exchange heat with their environment by any Largemouth bass of four processes: Radiation Evaporation Convection Conduction Basic Principles of Animal Form and Functions Source: Lisa, A. U., Michael, L. C., Jane, B. R., Steven, A. W., Robert, B. J., Peter, V. M., & Neil, A. C. (2010). Campbell Biology. Benjamin Cummings/Pearson  Basic Principles of Animal Form and Functions Source: https://www.examples.com/biology/cold-blooded-vs-warm-blooded-animals.html  Basic Principles of Animal Form and Functions Balancing heat loss and gain Animals do this thermoregulation by various mechanisms involved in the integumentary system, the outer covering of the body, consisting of the skin, hair, and nails (claws or hooves in some species). The mechanisms are: Insulation Circulatory adaptations Cooling by evaporative heat loss Behavioral responses Adjusting metabolic heat production  Basic Principles of Animal Form and Functions Balancing heat loss and gain Source: Lisa, A. U., Michael, L. C., Jane, B. R., Steven, A. W., Robert, B. J., Peter, V. M., & Neil, A. C. (2010). Campbell Biology. Benjamin Cummings/Pearson  Basic Principles of Animal Form and Functions Acclimatization in Thermoregulation Acclimatization contributes to thermoregulation in many animal species. In birds and mammals, the acclimatization to seasonal temperature changes often includes adjusting insulation. Eg. Growing thicker coat of fur in winter and shedding it in the summer. Some ectotherms can survive subzero temperatures, producing “antifreeze” proteins that prevent ice formation in their cells. Eg. In the Arctic and Southern (Antarctic) Oceans, these proteins enable certain fishes to survive in water as cold as -2°C. Physiological thermostats and fever The hypothalamus is responsible for thermoregulation in human and other mammals. Within the hypothalamus, a group of nerve cell act as thermostat that promote heat loss or gain.  Basic Principles of Animal Form and Functions Variation in body temperature Physiological thermostats and fever Fig: The thermostatic function of the hypothalamus in human thermoregulation (Source: Lisa, A. U., Michael, L. C., Jane, B. R., Steven, A. W., Robert, B. J., Peter, V. M., & Neil, A. C. (2010). Campbell Biology. Benjamin Cummings/Pearson)  Basic Principles of Animal Form and Functions Energy requirements are related to animal size, activity and environment Life requires energy transfer and transformation. Like other organisms, animals use chemical energy for growth, repair, activity and reproduction. The overall flow and transformation of energy in an animal is its bioenergetics that determines nutritional needs which is related to the animal size, activity and environment. Energy allocation and use Most heterotrophs such as animals, obtain their chemical energy from food which contain organic molecules synthesized by other organisms. Source: Lisa, A. U., Michael, L. C., Jane, B. R., Steven, A. W., Robert, B. J., Peter, V. M., & Neil, A. C. (2010). Campbell Biology. Benjamin Cummings/Pearson  Basic Principles of Animal Form and Functions Energy requirements are related to animal size, activity and environment Quantifying energy use How much energy is needed to survive? How much energy is needed to walk, run, swim or fly? What fraction of energy is used for reproduction? The sum of all the energy an animal uses in a given time interval is called its metabolic rate. Energy is measured in Joules (J) or in calories (cal) and Kilocalories (kcal). 1 kcal = 1000 calories = 4128 joules. To calculate the metabolic rate, researchers report: Rate of food consumption Energy content of the food (~4.5-5 kcal/gm of Source: Lisa, A. U., Michael, L. C., Jane, B. R., Steven, A. W., Robert, B. J., Peter, V. M., & Neil, A. C. (2010). protein or carbohydrate and ~9kcal/gm of fat) Campbell Biology. Benjamin Cummings/Pearson Chemical energy lost in waste products (feces and urine or other nitrogenous wastes)  Basic Principles of Animal Form and Functions Energy requirements are related to animal size, activity and environment Minimum metabolic rate and thermoregulation The minimum metabolic rate of a nongrowing endotherm that is at rest, has an empty stomach and is not experiencing stress is called the basal metabolic rate (BMR). The metabolic rate of a fasting, nonstressed ectotherm at rest at a particular temperature is called its standard metabolic rate (SMR). BMR for humans averages 1600-1800 kcal per day for adult males and 1300-1500 kcal per day for adult females. Influence on metabolic rate Away from being an endotherm or an ectotherm, other key factors age, sex, activity, temperature and nutrition also affect on metabolic rate. Size and metabolic rate Activity and metabolic rate Source: Lisa, A. U., Michael, L. C., Jane, B. R., Steven, A. W., Robert, B. J., Peter, V. M., & Neil, A. C. (2010). Campbell Biology. Benjamin Cummings/Pearson  Basic Principles of Animal Form and Functions Energy requirements are related to animal size, activity and environment Torpor and Energy conservation Despite adaptation for homeostasis, animals may encounter conditions that severly challenge their abilities to balance their heat, energy and material budgets. Example: Certain times of year, their surrounding may be extremely hot or cold or food may be unavailable. A major adaptation that enables animals to save energy in the face of such difficult conditions is torpor, a physiological state of decreased activity and metabolism. Many birds and mammals exhibit daily torpor that is well adapted to feeding patterns. Some bats feed at night and go into torpor in daylight Hibernation is long-term torpor that is an adaptation to winter cold and food scarcity. Eg. Arctic ground squirrel can enter a super cooled stat in which its body temperature dips below 00C.  Animal response to environmental changes The natural world is facing tremendous impact due to human activities in the form of: climate change, habitat destruction, overharvesting, introduction to invasive species etc. Human-altered conditions can undermine the reliability of signals used by animals to assess habitat quality, resulting an impact on habitat choice that impacts negatively on reproductive success. Environmental changes can also impair sensory systems or interfere with physiological processes. The impact on natural world can be understand by: Behavioral plasticity Population level consequences Consequences for species interaction network Source: Gaughan, J., Lacetera, N., Valtorta, S. E., Khalifa, and communities H. H., Hahn, L., & Mader, T. (2009). Response of domestic Ecosystem level consequences animals to climate challenges. Biometeorology for Behaviroal response and the evolutionary adaptation to climate variability and change, 131-170. process Animal response to environmental changes Mechanisms for human-induced animal behaviour change Source: Wilson, M. W., Ridlon, A. D., Gaynor, K. M., Gaines, S. D., Stier, A. C., & Halpern, B. S. (2020). Ecological impacts of human‐induced animal behaviour change. Ecology Letters, 23(10), 1522-1536.