Sinh học - Chapter 40: Basic principles of animal form and function

Ch. 40 Warm upDefine and give an example of homeostasis.Sequence the organization of living things from cell to biome.Describe negative and positive feedback.Basic Principles of Animal Form and FunctionChapter 40Overview: Diverse Forms, Common ChallengesAnatomy: the study of the biological form (STRUCTURE) of an organismPhysiology: the study of the biological FUNCTIONS an organism performs Structure dictates function!© 2011 Pearson Education, Inc.Figure 40.1Animal form and function are correlated at all levels of organizationSize and shape affect the way an animal interacts with its environmentMany different animal body plans have evolved and are determined by the genome© 2011 Pearson Education, Inc.Cells  Tissues  Organs  Organ SystemsHierarchical Organization of Body Plans© 2011 Pearson Education, Inc.Four main types of tissues:Epithelial: covers the outside of the body and lines the organs and cavities within the bodyConnective: binds and supports other tissues (cartilage, tendons, ligaments, bone, blood, adipose)Muscle: controls body movement (skeletal, smooth, cardiac)Nervous: senses stimuli and transmits signals throughout the animal (neurons, glia)© 2011 Pearson Education, Inc.Coordination and Control Within a BodyEndocrine system: transmits chemical signals (hormones) to receptive cells throughout body via bloodSlow acting, long-lasting effectsNervous system: neurons transmit info between specific locationsVery fast!Info received by: neurons, muscle cells, endocrine cells© 2011 Pearson Education, Inc.HomeostasisMaintain a “steady state” or internal balance regardless of external environmentFluctuations above/below a set point serve as a stimulus; these are detected by a sensor and trigger a responseThe response returns the variable to the set point© 2011 Pearson Education, Inc.Negative Feedback“More gets you less.”Return changing conditions back to set pointExamples:TemperatureBlood glucose levelsBlood pHPlants: response to water limitationsPositive Feedback“More gets you more.”Response moves variable further away from set pointStimulus amplifies a responseExamples:Lactation in mammalsOnset of labor in childbirthPlants: ripening of fruitThermoregulationMaintain an internal temperature within a tolerable rangeEndothermic animals generate heat by metabolism (birds and mammals)Ectothermic animals gain heat from external sources (invertebrates, fishes, amphibians, and nonavian reptiles)Q: Which is more active at greater temperature variations?Q: Which requires more energy?© 2011 Pearson Education, Inc.Figure 40.10Balancing Heat Loss and GainOrganisms exchange heat by four physical processes: radiation, evaporation, convection, and conduction© 2011 Pearson Education, Inc.Five adaptations for thermoregulation:Insulation (skin, feather, fur, blubber)Circulatory adaptations (countercurrent exchange)Cooling by evaporative heat loss (sweat)Behavioral responses (shivering)Adjusting metabolic heat production (“antifreeze”)© 2011 Pearson Education, Inc.Figure 40.12Figure 40.16Metabolic rate: amount of energy an animal uses in a unit of timeBasal metabolic rate (BMR): endotherm at rest at a “comfortable” temperatureStandard metabolic rate (SMR): ectotherm at rest at a specific temperatureEctotherms have much lower metabolic rates than endotherms of a comparable sizeEnergy Use© 2011 Pearson Education, Inc.Figure 40.19Torpor and Energy ConservationTorpor is a physiological state in which activity is low and metabolism decreases Save energy while avoiding difficult and dangerous conditionsHibernation: torpor during winter cold and food scarcityEstivation: summer torpor, survive long periods of high temperatures and scarce water© 2011 Pearson Education, Inc.