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C HAPTER 40: A NIMAL F ORM AND F UNCTION
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Essential Knowledge 2.a.1 – All living systems require constant input of free energy. 2.c.1 – Organisms use feedback mechanisms to maintain their internal environments and respond to external environmental changes. 2.c.2 – Organisms respond to changes in their external environments. 4.b.2 – Cooperative interaction within organisms promote efficiency in the use of energy and matter.
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Introduction Anatomy – The study of structure of organism Physiology – The study of the functions of an organism’s anatomical features Bioenergetics – How organisms obtain, process and use their energy resources
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Constraints Limits to animal shape and size - 1) Physical laws Physics of flight Gravity Laws of hydrodynamics 2) Environment Aqueous requirement for cellular medium Plasma membrane, surface area to volume ratios Hierarchy of living organisms Climate/Weather
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Organizational Levels Illustrate emergent properties Cell – Basic unit of life Tissue – Group of cells with same function Organ – Group of tissues with same function Organ system – Group of organs with same function Individual – All organ systems working together
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Tissue Four Major Types: Epithelial, muscle, connective, nervous Epithelial Tightly packed cells (very little space in b/t) Cover outside of body Line organs and cavities Function: barrier against injury, microbes and fluid loss Classified by: # of layers, shape # of layers – simple and stratified Shape – cuboidal, columnar, squamous
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Tissue, cont. Connective Function: bind and support other tissue types NOT tightly packed Three kinds of protein fibers: Collagenous Elastic Reticular Major types of connective tissue: Loose, adipose, fibrous, cartilage, bone and blood
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Tissue, cont. Muscle Long cells capable of contracting Consumes most of cellular energy work Stimulated by nerve cells Made of proteins called actin and myosin Most abundant tissue in animals Three types: Skeletal, cardiac, smooth
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Tissue, cont. Nervous Sense stimuli and transmits signals Functional unit: Nerve cell (neuron) Specialized to transmit nerve impulses Concentrated in brain (anterior end) Remember? Called cephalization
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Organs and organ systems Systems: Digestive Circulatory Respiratory Immune/lymphatic Excretory Endocrine Reproductive Nervous Integumentary Skeletal Muscular
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Energy Two ways to obtain energy: Heterotroph Autotroph Bioenergetics: The flow of energy through an animal Limits animal’s behavior, growth, repair, regulation and reproduction Determines how much food an animal must consume
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Energy sources Animals are heterotrophs Obtain energy through enzymatic hydrolysis (aka – Cellular Rs) Use food, oxygen to make energy molecules and carbon dioxide (waste product) Most of energy molecules are made into ATP Production and use of ATP generates heat Animal continuously gives off heat This release of heat helps to regulate internal body temp
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Metabolic rate Def – amount of energy animal uses in a given amount of time Measured in calories (C) Can be determined: Monitoring an animal’s rate of heat loss using a calorimeter Measuring oxygen consumption Can use an EKG or heart monitor to measure Measuring carbon dioxide output
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Influences on Metabolic Rate 1) Size Amt of energy to maintain each gram of weight is inversely related to size Small animals = MORE energy per gram of weight 2) Activity More activity = more energy needed 3) Others Size, sex, age, body/environmental temps
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Homeostasis Def - How an animal maintains stable internal environmental conditions Such as: temp, heart rate, metabolism “Steady state” Two schools/groups of animals: Regulators Conformers
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Regulators and Conformers Regulators – use internal control mechanisms to moderate internal changes (despite external fluctuations) Ex: freshwater and saltwater fish Conformers –allow their internal environment to vary with external fluctuations Ex: lizards No organism is SOLELY one or another Animals maintain homeostasis while being BOTH a regulator AND conformer
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Homestatic mechanisms Three functional control mechanisms: 1) Receptor Detects change 2) Control center/Integrator Processes change and sends response to effector 3) Effector Changes internal conditions Ex: a house thermostat
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Positive and Negative Feedback Positive and Negative Feedback Loops Positive and Negative Feedback Loops
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Thermoregulation Def - The process by which animals maintain an internal body temperature Most biological body processes are VERY sensitive to changes in body temp Two strategies: Endotherm Ectotherm
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Endotherm Animals that internally control body temp Ex: Mammals, birds, few reptiles, some fish, most insect species High metabolic rate Maintain high and very stable internal temp Ex: Humans – 98.6 o F Source of heat: metabolic heat (ATP)
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Endotherm, cont. Advantages: Can perform rigorous activities for longer periods of time Elaborate circulatory systems (division of blood) Elaborate respiratory system (oxygen exchange) Maintain stable body temp Disadvantages: Very “expensive” in energy use High metabolic rate Need to consume much more food than ectotherm
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Ecototherm Animals who gain most of heat from environment Ex: Reptiles, amphibians, most invertebrates, fishes Low metabolic rate Regulate body temp by behavioral mechanisms Hibernation Basking in sun Shade seeking
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Modes of Heat Exchange Ectotherms and endotherms exchange heat using the same processes Four processes to do so: Radiation Evaporation Convection Conduction
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Balance of Heat Exchange Ultimate goal: To balance heat loss with heat gain Five adaptations help animals to meet this goal: 1) Insulation 2) Circulatory Adaptations 3) Cooling by Evaporative Heat Loss 4) Behavioral Responses 5) Adjusting Metabolic Heat Production
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Energy Conservation Animals often times encounter periods of time that challenge their heat balancing abilities Ex: extreme temps; food is scarce Torpor – a physiological state in which animal activity is low and metabolism decreases Enables animals to save energy while avoiding dangerous conditions
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Energy Conservation, cont. Hibernation: Long-term torpor Adaptation to winter temp and lack of food Vertebrate endotherms hibernate Body temps decline Saves energy and metabolic rate drops Triggered by shorter days (less daylight) and slight temperature decreases Ex: bears, ground squirrels Bear Hibernating (1:00) Other animals hibernating
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Energy Conservation, cont. Estivation: Summer torpor Adaptation to long periods of high temps and scarce water supply Slow metabolism and inactivity Triggered by long days Ex: frogs, snails, salamanders
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