bio5b lecture 9: Form & Function and Energetics

• evolution and diversification tells us how organisms changed over millenium
• anatomy is the study of the biological form of an organism
• physiology is the study of the biological form of an organism
• Anatomy is the study of the biological form of an organism
• Physiology is the study of the biological functions an organism performs
• Form and function in animals are closely correlated
• Evolution & Diversification explains how organisms changed over time
• Chemical reactions in cells relate to intracellular communication and whole animal performance
• Chemical reactions within tissues, organs, and systems work together to carry out organ function
• Tissue types found in vertebrates include epithelial, connective, muscle, and nervous tissues
• Epithelial tissue covers the body and can be cuboidal, columnar, or squamous in shape
• Connective tissue contains sparsely packed cells scattered throughout an extracellular matrix
• Muscle tissue consists of skeletal, smooth, and cardiac muscles
• Nervous tissue includes neurons and glial cells that help nourish, insulate, and replenish neurons
• Homeostasis is used by organisms to maintain internal balance regardless of external environment
• Feedback control mechanisms, such as negative and positive feedback, help maintain internal balance
• Negative feedback helps return a variable to a normal range or set point
• Positive feedback loops occur in animals but are less common and involve amplification of signals
• Positive feedback amplifies the signal, causing the system to keep increasing or decreasing its output
• Positive feedback requires something external to stop the signal
• Alterations in Homeostasis:

  • Set points and normal ranges can change with age or show cyclic variation
  • Homeostasis can adjust to changes in the external environment through acclimatization
• Thermoregulation is the process by which animals maintain an internal temperature within a tolerable range
• Endothermic animals generate heat by metabolism, while ectothermic animals gain heat from external sources
• Organisms exchange heat through conduction, convection, radiation, and evaporation
• Five general adaptations to help animals thermoregulate:

  • Insulation
  • Circulatory adaptations
  • Cooling by evaporative heat loss
  • Behavioral responses
  • Adjusting metabolic heat production
• Insulation:

  • Major thermoregulatory adaptation in mammals and birds
  • Skin, feathers, fur, and blubber reduce heat flow between an animal and its environment
• Circulatory Adaptations:

  • Arrangement of blood vessels in mammals and birds allows for countercurrent exchange
  • Transfer heat between fluids flowing in opposite directions
• Cooling by Evaporative Heat Loss:

  • Many animals lose heat through the evaporation of water in sweat
  • Panting increases the cooling effect in birds and mammals
• Behavioral Responses:

  • Both endotherms and ectotherms use behavioral responses to control body temperature
• Adjusting Metabolic Heat Production:

  • Some animals can regulate body temperature by adjusting their rate of metabolic heat production
  • Heat production is increased by muscle activity such as moving or shivering
• Size and Metabolic Rate:

  • Large animals have a more efficient use of energy per gram of body mass than small animals
  • Small animals lose a greater percentage of the heat they produce to maintain body temperature than large animals
• Torpor and Energy Conservation:

  • Torpor is a state of low activity and decreased metabolism to save energy
  • Hibernation is a long-term adaptation to winter cold and food scarcity
• Estivation enables animals to survive long periods of high temperatures and scarce water supplies
• Daily torpor is exhibited by many small mammals and birds and seems adapted to feeding patterns
• • How an animal's body surface area and volume change with size
  • Metabolic rate and why large animals have a lower per gram cost of living
  • The difference between torpor and hibernation
• Understand:

  • The relationship between chemical reactions in cells and whole animal performance
  • Chemical reactions within tissues, organs, and systems work together to carry out organ function
  • Tissue types found in vertebrates
  • The difference between regulation and conforming in physiological systems
  • Homeostasis, regulation, and feedback (negative and positive)
  • In positive feedback, the signal is external to the system
  • Thermoregulation and how endotherms and ectotherms manage their heat budgets
  • How a countercurrent heat exchanger may function to retain heat within an animal body