Lecture 18. Mutualism [Autosaved]

Lecture 18. Mutualism [Autosaved] - If you would like to...

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Unformatted text preview: If you would like to request a regrade, please 1) First look over the answer key (there are two typos on the v. B key – questions 4 and 18, where the wrong letter is given as the correct answer DO NOT ask for a regrade for these – the exams were graded correctly). 1) If you still think there was an error, then you have 2 options. A) You can bring your exam to office hours and discuss it with us (our office hours are listed on the syllabus and on Smartsite). B) You can submit a written request for a regrade in the marked filing cabinet in the BLC. There is a form to fill out, which is posted in the hallway by the BLC and there are copies of the form in the BLC . When you fill out the form, do not just write "My answer is just like the key" or "I deserve more points for number 3"; . EXPLAIN WHY you think your answer is correct . We will BEGIN accepting written requests today. Using either method, the deadline for requesting a regrade is NEXT Friday, November 12 (which is also the date of the next midterm). REGRADE INFO dN/dt = rN[(K-N)/K] The logistic equation - intraspecific competition dN 1 /dt = r 1 N 1 [(K 1-N 1- a 12 N 2 )/K 1 ] Adding interspecific competition Term to account for use of resources (reduction of K) by another species (N 2 ) 12 = competition coefficient indicating he effect of species 2 on species 1. N 1 = number of individuals of species 1 1 = intrinsic growth rate of species 1 K 1 = carrying capacity of species 1 N 2 = number of individuals of species 2 * If a 12 = 1 then species are identical in resource use, and intraspecific competition is the same as interspecific competition How do we conceptualize (and ultimately measure) a ? First, lets (re)define the concept of a niche: moisture nutrients Fundamental niche : defined by physical conditions under which a species can persist moisture nutrients predation competition disease competition Realized niche: alteration of fundamental niche by species interactions Performanc e nutrients Lo Hi Not enough to grow Too much becomes toxic Performanc e Realized niche: species actually occurs over a narrower range of nutrients due to competition from other species nutrients Lo Hi Niche axis (e.g., prey size) Performanc e Performanc e No niche overlap, no interspecific competition, a = 0 Performanc e prey size High niche overlap, strong interspecific competition, a close to, but less than 1 Low niche overlap, weak interspecific competition, a << 1 Complete niche overlap, strong interspecific competition, a = 1 prey size Performanc e Complete niche overlap, a > 1 for effect of blue species on the red one prey size Performanc e Coexistence among competitors occurs when interspecific competition is weak relative to intraspecific competition. In other words, when a 12 and a 21 << 1 ....
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This note was uploaded on 11/29/2010 for the course BIOLOGY 1211 taught by Professor Patricelli during the Spring '10 term at UC Davis.

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Lecture 18. Mutualism [Autosaved] - If you would like to...

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