Gause’sexperiments with Paramecium and Didinium showed:a.extinction of the predator, followed by extinction of the prey, in allhabitats.b.coexistence of predator and prey at fairly constant population sizes, inall habitats.c.coexistence of predator and prey, but with oscillating population sizes,in all habitats.d.coexistence of predator and prey at fairly constant population sizes,but only in the presence of refuges and predator reservoirs.e.coexistence of predator and prey with oscillating population sizes, butonly in the presence of refuges and predator reservoirs.

1) A mathematical (differential equation) representation for a metapopulation can be written as dp/dt = cp(1- p) - ep where p is the proportion of patches occupied at time t, c is the rate of patch colonization, and e is the rate of patch extinction.  The term on the left hand side is the ‘rate of change in the proportion of patches occupied.’  The first term on the right hand side of the equation provides the effective gain in patch occupancy as a function of p due to the colonization process, and the term in parentheses represents the fraction of patches not currently occupied.  The second right hand side term provides the effective loss of patch occupancy due to the (local) extinction process. a) Look at the term for the colonization process. How would you modify this term if you wanted to capture the idea that habitat loss destroyed (i.e., made uninhabitable) a proportion D from the patches that are available for colonization ? b) What value of D guarantees complete extinction of…

1. Examine the food webs for Lake Victoria, East Africa (fig 31.2 a,b) before and after the introduction of the Nile perch (Leveque 1995). Calculate the mean food chain length, percent of trophic groups at various levels, and connectance for each food web. Oreochromis Insectivorous Fish Chironomids Chaoborous Man Piscivorous Fish Zooplanktivorous Haplochromines Rastrineobola Zooplankton Detritus/Phytoplankton Lake Victoria in the 1970s Detritivorous Phytoplanktivorous Haplochromines Figure 31.2. (a) Food web structure of Lake Victoria before introduction of the Nile Perch. [continued on next page) Molluscivorous Fish Molluscs

. If the Gopher tortoise is species 1, and a blue indigo snake (that depends on Gopher Tortoise burrows) is species 2: what are the corresponding interaction signs .a. +,+b. +,0c. 0,+ d. 0,-24

What is in the top row of the Leslie matrix? Оа. Number of individuals in the stage class O b. Stage transition rates O C. Fecundity rates O d. Survival rates

Which of the following terms best describes the biological scenario where species that look similar in allopatry look different in sympatry?   a. Character displacement   b. Tempo   c. Fusion   d. Post-zygotic barriers

Part A)  A biologist notices that the same species of Tortoise exists in Texas and Mexico.Yet these tortoises have somewhat different life histories. This is probably due to the diverse array of__that each tortoise has with different components its own environment.a. interactionsb. conversationsc. adaptationsd. all of thesePartB.). If water amounts and food production capabilities decrease, what can happen to carrying capacity?a. increase b. decreasePart C. Alabama should be a desert but it is a lush green environment. What keeps us from being so dry?a. Hadley Cellsb. Ocean Gyresc. Mountainsd. all of the above

A defence mechanism is how the sea cucumber fires its internal organs at attackers. How would this defence mechanism have evolved over time due to pressure from predation and/or competition? Please explain in details.