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Chapter 40 . Study Guide and Notes. 1. & 2. How has natural selection/evolution influenced animal body SIZE and FORM?. Physical laws – constrain what natural selection can “invent” Govern strength, diffusion, movement, heat exchange and therefore limit animal forms
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Chapter 40 Study Guide and Notes
1. & 2. How has natural selection/evolution influenced animal body SIZE and FORM? • Physical laws – constrain what natural selection can “invent” • Govern strength, diffusion, movement, heat exchange and therefore limit animal forms Ex. Convergence of body forms in water • Size – thicker skeletons are needed as size increases • Surface area:Volume – regulates size of individual cells • Diffusion across membranes • Thermoregulation of body heat
How do the following organisms exchange materials with their environment? How does their structure help this? • Amoeba • Entire surface is in contact with the environment • Hydra • Simple organization where all or nearly all cells are in contact with the environment • A flatworm • Most cells are in direct contact with environment • Whale • Extensively branched or folded surfaces to increase surface area • Interstitial fluid, blood,
How are complex body plans advantageous over simple body plans? • Can maintain stable internal environment while living in a variable external environment • External skeleton (protection) • Sensory organs (obtain detailed information) • Internal digestion (control release of stored energy) • Filtration system (adjust composition of interstitial fluid bathing animal’s cells)
What is the difference between a Regulator and a Conformer? • Regulator • Uses internal control mechanisms to regulate internal change in the face of external fluctuation. • Mammals • Conformer • Its internal condition conforms to external changes • Reptiles
What is the difference between an endotherm and an ectotherm • Organisms that gain most of their heat from metabolism (cellular respiration) • Mammals and birds • Organisms that gain most of their heat from external sources • Amphibians, reptiles, many fish, most invertebrates
List 5 adaptations for thermoregulation • Radiation • Evaporation heat loss • Convection-- Movement of air or liquid past a surface • A breeze to cool organism down • Dilation/constriction of blood vessels • Conduction – direct transfer • Insulation • Controlled seasonally • Amount of hair, feathers, fat or raising the hair/feathers • Oil secretions to waterproof • Circulatory adaptations • Dilation/construction of blood vessels • Countercurrent exchange • Behavioral responses • Adjusting Metabolic heat production • Shivering, nonshiveringthermogenesis, brown fat
Explain countercurrent exchange • The flow of adjacent fluids in opposing directions that maximizes transfer rates of heat or solutes • Blood vessels are arranged antiparallel to one another • As warm blood passes through arteries, it transfers heat to the colder boold returning from the extremities in the veins • Heat exchange will occur the entire length of the exchanger