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Basic Principles of Animal Form and Function Not a process of conscious invention but the result of a pattern of development programmed by the genome Physical constraints on size and shape – physical laws that govern strength, diffusion, movement, and heat exchange Ex) fusiform body shape/convergent evolution http://www.captseaweed.com/dolphinvideos.html#stampede http://www.discovery.com/tv-shows/sharkweek/videos/how-sharks-swim/ http://www.livescience.com/24122-why-insectsare-not-bigger.html Exchange with the Environment – such as? - recall lab with agar cubes How is exchange accomplished in more complex animal? https://cms.webstudy.com/WebstudyFileSyst em/testovaci/GetFile/293875/Ch%2022/Ch22 a/figure_22_22b_labeled.jpg http://sphweb.bumc.bu.edu/otlt/MPHModules/PH/Ph709_RespiratoryHealth/Termi nalBronchiole-Alveoli.png http://biowiki.ucdavis.edu/@api/deki/files/ 2070/Figure_41_03_03.png?revision=1 What are the advantages of a complex body plan compared to a simpler one? Hierarchical Organization of Body Plans – cells tissues organs organ system(table 40.1 p. 855) Largest organ? Function? Multifunctional organ? Function? Tissue Structure and Function – 4 main categories 1. epithelial 2. connective 3. muscle 4. nervous Epithelial Tissue – outside covering/lines organs and cavities tight junctions barrier against mechanical injury, pathogens, and fluid loss Cell shape – cuboidal, columnar, or squamous Simple, stratified, or pseudostratified Shape is related to function Connective tissue – bind and support other tissues in the body/sparse population of cells scattered throughout an extracellular matrix 6 major types – loose c.t., cartilage, fibrous c.t., adipose tissue, blood, and bone Connective tissue fibers – collagenous, elastic, and reticular Collagenous – strength and flexibility Elastic – easily stretched, but resilient Reticular – thin and branched/join c.t. to adjacent tissue Cell types – fibroblasts –secrete protein of extracellular fibers and macrophages – roam to engulf foreign particles and debris of dead cells Muscle Tissue – responsible for body movement/actin and myosin/energy consuming Types – skeletal, cardiac, and smooth Nervous tissue – to sense stimuli and transmit signals in the form of nerve impulses from one part of animal to another Neurons, glial cells Coordination and control – endocrine and nervous/gradual vs immediate and rapid response Hormones – only cells with receptors respond/cells can have more than 1 receptor type/slow acting but can be long lasting Nerve impulse – axons Impulse received by: other neurons, muscle cells, endocrine cells, and exocrine cells Both chemical and electrical Fast acting, short duration Regulating and Conforming – regulate internal conditions despite fluctuations in the environment/internal conditions conform to external conditions May regulate some internal conditions and not others http://www.bbc.co.uk/education/guides/zg 2xxnb/revision/6 Homeostasis – steady state or internal balance Ex) body temperature, pH of blood, solute concentration of glucose in blood - Mechanisms – see Fig. 40.8 – set point, stimulus, sensor, response - Feedback Loops – negative(a response that reduces the stimulus) vs positive(amplify the stimulus – do not usually contribute to homeostasis) - Ex) exercise produce heat sweat evaporative cooling - acclimatization – temporary change during an animal’s lifetime http://www.higherpeak.com/altitudechart.html Thermoregulation – critical to survival – why? Endothermy and ectothermy – birds and mammals vs amphibians, lizards, snakes, turtles, many fishes, and most invertebrates Heat generated by metabolism vs gained from environment Variation in body temperature – poikilotherm vs homeotherm(constant body temperature) Balancing heat loss and gain – conduction, convection, radiation, and evaporation Insulation – reduces flow of heat between an animal and its environment Ex) hair, feathers, layers of fat Circulatory Adaptations – regulate blood flow/heat flow Vasodilation – increase in diameter of blood vessels Vasoconstriction – reduces blood flow and heat transfer Countercurrent exchange – the flow of adjacent fluids in opposing directions that maximizes transfer rates of heat or solutes Cooling by evaporative heat loss – water absorbs heat when it evaporates Panting, sweating Behavioral responses – hibernation, migration Sun or shade for ectotherms Bees huddle together