Ch 40 - animal form and function (3 slides per page)

E convergent evolution mammal phylogeny lungs 12

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Unformatted text preview: Mammal Phylogeny Lungs 12 Physical laws constrain form – Heat & H2O exchange Surface Area to volume ratio (SA:V) affects rate of H2O or heat loss or gain thus body size and shape is constrained by environment A small deer in a cold climate would freeze due to a large SA:V Small animals loose or gain heat & H2O faster than large animals due to higher SA:V 15 Physical laws constrain form – Cell size Surface Area to volume ratio affects rate of H2O, gas, nutrient and waste exchange Thus: Cell size and shape affects rate of exchange with larger cells having more difficulty moving substances in and out Thus: Cell size is limited since if too large can’t maintain cell 1x1x6x1 A large deer in a hot climate would overheat due to a low SA:V 5x5x6x1 So: Organism size is constrained in that to be bigger they must have more cells (i.e. multicellular) not larger cells Figure 6.7 (Campbell 9th ed) Both size AND shape affect SA:V 1 2 8 SA/V 34/8 = 4.25 24/8 = 3 Animals with a long body or limbs loose heat & H2O faster than compact animals due to higher SA:V Figure 40.3 (Campbell 9th ed) 16 Physical laws constrain form - Complexity • Since: ALL cells must exchange materials with the environment 17 Physical laws constrain form - Complexity • Since: ALL cells must exchange materials with the environment (B) Complex organisms have: 2. Folded internal surfaces to increase SA:V • Then: If an organism gets thicker then inner cells can’t exchange nutrients/wastes with environment •Thus: Thickness is constrained. BUT this constr...
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This note was uploaded on 02/12/2014 for the course BIOLOGY 2011 taught by Professor Woo during the Fall '10 term at University of Central Florida.

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