Question

please answer two questions below

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22. David Tilman and colleagues established 120 experimental field plots, containing from 1 to 24 grass species, at the University of Minnesota and measured plant production (total plant cover) in each plot for each of 11 years. The research showed that increasing species richness enhanced the stability of plant production in the plots because a) as species richness increased, more nitrogen remained in the soil. b) different grass species performed better during drought years and wet years. c) increased species richness increased the stability of each species' performance, d) increased species richness increased competitive interactions among the grass species. e) increased species richness made the community more attractive to pollinators. 23. Which of the following is an example of reciprocal adaptation (coevolution)? a) Finches with the largest wingspans and body sizes are found on Islands of the Galapagos where bees are present. b) Lumpy-clawed crabs with the greatest claw strength are found near snail prey with the thickest shells. c) The harmless hoverfly resembles a stinging wasp in body color and pattern. d) Removal of wolves, a major predator of elk, caused elk populations to increase and negatively affect the growth of young aspen trees in Yellowstone National Park. e) Fungus farming by leafcutter ants, bark beetles and termites.

Answer 1

22. Increased species richness enhanced stability of plants in plots because

(b) increased species richness increased competitive interactions among the grass species. This we can conclude by the factors influencing species richness where one of the biotic factor influencing species richness is Competition.

23. (e)Fungus farming by leaf-cutter ants, bark beetles and termites is one of the example for reciprocal adaptation

(co-evolution)

Here the leaf-cutter ants do not eat the leaves but grow fungus on them and eat the fungus. Leaf-cutter ants just use the leaves as a substrate or scaffold to grow fungus and the fungus helps the ants by breaking down cellulose and converting it into edible sugars which ants can harvest and eventually produce their food.