Module 3: Animal Physiology

Module 3: Animal Physiology

• Module is about animal physiology
• Chandrashekhar Azad Vishwakarma, PhD is the Assistant Professor
• The module is in the 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 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

Physiology

• Helps understand:
  • Fundamental biology of all animals
  • Human health and disease
  • Health and disease of nonhuman animals of importance in human affairs

Figure

• Pacific salmon migrating upriver to their spawning grounds

The study of physiology

• Integrates knowledge at all levels of organization

Evolution

• Today's animals are products of evolution and are still evolving
• Strong correlation between genetic difference between populations and physical separation

Physiology Organization

• Depends on all levels of organization
  • Cell physiology
  • Systems physiology

Morphology, Biochemistry, and Biomechanics

• Morphology and biochemistry are related to physiology
• Enzymes in muscle cells catalyze reactions that provide energy for contraction

Ecology

• Physiology acts within an ecological context

The mechanism of light production by fireflies (Photinus)

• Light-emitting chemical reactions
• In the dark state, mitochondria intercept O2, and the light-emitting reactions cannot go to completion.
• In the flashing state, nitric oxides produced under nervous control, prevent mitochondria from intercepting O2, and creating pulses of light.

Basic Principles of Animal Form and Function

• Form (anatomy):
  • Insulating layer of fat (blubber) reduces heat loss from most of a penguin's body.
• Function (physiology):
  • Rapid cycles of muscle contraction and relaxation during shivering produce heat at a cellular level.
• Behavior:
  • Packing together in groups of up to several thousand greatly reduces Emperor penguin's exposure to wind and cold.

Animal Form and Function

• All animals obtain nutrients and oxygen, fight off infection, and survive to produce offspring.
• Animal form is due to evolution and adaptation, reflected in their anatomy (biological structure) and form and function.
• Anatomy provides clues to physiology (biological function)
• Body plan or design is a result of development patterns programmed by the genome and millions of years of evolution.
• Major factors in biological structure and function:
  • Evolution of animal size and shape
  • Exchange with the environment
  • Hierarchical organization of body plans
  • Coordination and control

Life on Earth

• The evolutionary timeline displayed from the origin of life to the development of modern human ancestors.

Evolution of animal size and shape

• Various body plans have arisen during the course of evolution.
• Physical laws govern strength, diffusion, movement, and heat exchange, limiting the range of animal forms.
• Any bump on the aquatic animal's bodily surface determines whether it will be a runner or a flyer.

Exchange with the environment

• Animals exchange nutrients, waste products, and gases with their environment.
• This exchange imposes additional limitations on body plans.
• This occurs as dissolved substances in aqueous solution move across the plasma membrane of each cell.
• The rate of exchange is proportional to the membrane surface area, and the amount of material is proportional to the total body volume.

Hierarchical organization of body plans

• Cells form a working animal body through emergent properties arising from successive levels of structure and functional organization.
• Many organs have more than one physiological role.

Organ Systems in Mammals

• Lists organ systems, their major components, and primary functions in mammals.

Coordination and control

• Organ systems must act in concert to function effectively.
• Animals have two major systems for coordinating and controlling responses to stimuli:
  • The endocrine system (signaling molecules released into bloodstream)
  • The nervous system (neurons transmitting signals along dedicated routes connecting specific locations)

Feedback control

• Maintains internal environment in many animals.
• Many organ systems manage an animal's internal environment by regulating or conforming to external fluctuations.

Regulating and conforming

• An animal is a regulator if it uses internal mechanisms to control internal change in response to external fluctuations.
• An animal is a conformer if its internal conditions change based on changes to the environment.

Homeostasis

• Maintains internal balance (steady state) despite environment changes.
• Includes steady body temperature and stable solute concentration.

Variation in body temperature

• Poikilotherm (cold-blooded): body temperature varies with the environment.
• Homeotherm (warm-blooded): body temperature is relatively constant

Balancing heat loss and gain

• Animals exchange heat with their environment by radiation, evaporation, convection, and conduction.

Acclimation

• Acclimatization helps regulate body temperature in many species, like birds and mammals adjusting insulation (e.g., growing thicker fur).

• Some ectotherms (e.g., Arctic fish) survive below-freezing temperatures using "antifreeze" proteins to prevent ice formation.

Physiological thermostats and fever

• The hypothalamus regulates temperature in mammals.
• Hypothalamic nerve cells act as thermostats to regulate heat loss and gain.

Energy requirements

• Related to animal size, activity, and environment.

Quantifying energy use

• Includes how much energy an animal uses to survive, walk, run, swim or fly and the fraction used for reproduction.
• Metabolic rate is the sum of all energy use over a period.

Minimum metabolic rate and thermoregulation

• Basal metabolic rate (BMR) is the minimum rate of a non-growing endotherm at rest, with an empty stomach, and not experiencing stress.
• Standard metabolic rate (SMR) is the minimum metabolic rate of an ectotherm at rest at a specific temperature.

Torpor and energy conservation

• Adaptation to difficult conditions (e.g., extreme temperatures, food scarcity).
• Torpor is a physiologically induced state of reduced activity and metabolism.
• Includes daily torpor, hibernation (a prolonged form of torpor), and super-cooling.

Animal response to environmental changes

• Humans impact the natural world through climate change, habitat destruction, overharvesting, and introducing invasive species.
• These impacts can negatively affect animal habitat choice, reproduction, sensory systems, and physiology.

Mechanisms for Human-Induced Animal Behavior Change

• Describes the links between human impacts, animal behaviors, and ecological implications.