Which of the following can explain why species are able to coexist, even if the competitive exclusion principle is generally true? a) Species may be competitively equivalent, with the outcome of each competitive encounter being essentially random. b) Competitive exclusion may take many generations; prior to that point, there will be coexistence. c) Spatial heterogeneity in the distribution and concentrations of limiting resources can

New Zealand snapper populations were found to be under the influence of genetic drift, suggesting overfishing was still an issue for them, despite the New Zealand fisheries estimating their total population size to be over 3 million. Which of the following is the best explanation for this observation?     A) Pelagic fish, like the New Zealand snapper, often only have a few reproductive individuals, therefore their effective population size is actually much smaller than the total population size.     B) Pelagic fish, like the New Zealand snapper, often have an equal sex ratio which affects the number of breeding individuals.     C) Pelagic fish, like the New Zealand snapper, often have disassortative mating which affects the number of breeding individuals.     D) Pelagic fish, like the New Zealand snapper, often have assortative mating which affects the number of breeding individuals.

A and B please

Populations are unable to sustain exponential growth for very long because environments are not unlimited. Eventually growth rates are reduced by a shortage of food, space or some other factor. These factors constitute what is known as ‘environmental resistance’ and their effect upon growth may produce a logistic growth curve. The data shown in the Table below illustrate this pattern of growth for three species’ populations, each beginning with a population of 10 individuals.     Table 1: Temporal changes in the numbers of individuals of three different species’ populations, observed in the wild. Time (units) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Population 1 10 15 20 28 39 48 57 66 81 88 93 107 108 108 108 108 119 Population 2 10 11 12 14 17 19 21 25 29 33 37 41 40 43 46 49 46 Population 3 10 17 27 39 52 64 67 69 70 78 83 86 88 80 84…