Question

Question 1 (5 marks) The figure shows the seed size preferences of ants and rodents that occur together in a grassland habitat. Frequency in diet Briefly describe the simple experiments (the approach and the results) that were conducted to investigate the interactions between ants and rodents. Explain whether or not they supported the hypothesis that the rodents and ants compete for seeds. 0.64 0.64-0.70 470 080-020 660-680 0.90-1.17 1.17-1.40 1.40-1.85 185-1.90 1.98-2.36 2.79-3.33 3.33-3.96 3.96-4.70 Question 2 (5 marks) Plant defence strategies against herbivory may be described as inducible or constitutive and direct or indirect. Describe how Central American Acacia species utilise ants of the genus Pseudomyrmex to defend themselves against herbivory and explain which of the above plant defence strategies are adopted. Question 3 (5 marks) Explain how the structure of grasslands in the African savannah is maintained by large mammalian grazers. Your explanation should also provide the three functional characteristics of grazers. Question 4 (5 marks) Describe the characteristic climates of tropical rainforest biomes. This biome is described as the most diverse and most productive. How does this diversity arrive and why is the productivity so high?

Answer 1

Q1) Ants and rodents generally share the same habitat. Both feed themselves on grains. To perform the experiment a simple design can be made. one variable may be added to the experiment i.e seed size. We can offer seeds of different sizes to both the species and record the observations which seed size is suitable for them. on recording the data, we got the information and present it in the graphical form as provided in the question. Form the data, one can easily interpret that rodents prefer to have seed size in the range of 0.64 to 1.85 mm and that ants mostly prefer seeds of small size (less than 0.64 mm) though some ants prefer to have seed size in wide 0.64 - 2.36 mm range. Here it could be suugested that competition occurs between rodents and ants for a particular range of seed size. however, ants can avoid the competition by prefering seed size smaller than 0.64 mm.

Q2) The central American Acacia species have symbiotic association with the pseudomyrmex ants. these ants depend on the host plant for nectar, food they require and shelter in its swollen thorns. the ants behave as bodyguards and prevent the plant from herbivores and other competing plants. the type of defense is known as permanent or constitutive defenese strategy.