Question

For Questions 22-23, Exa population interaction experiment between two al mine the Figure Below. It shows the results of an interspecific 300 250 š 200 150 100 50 0 Euglena in Mix --Closterium in Mix 士Euglena Alone -*-Closterium Alone 1 2 3 45 67 8 Days 22) The preceding figure is consistent with which ecological interaction? A) Competition: Closterium excludes Euglena B) Competition: Euglena excludes Closterium. C) Both species compete, but coexist. D) Euglena seems to exhibit a commensal interaction with Closterium. E) The two species drive each other extinct 23) Based on the preceding figure, you could conclude. A) Gause's principal is supported, Euglena excludes Closterium in mixed culture. B) Although the results do not match Gause's his principal is still supported by this experiment (the data may have been due to experimental error). C) The two species are not likely to coexist in nature. D) Since the results do not match Gause's principal, the experiment was a failure and conclusions cannot be drawn. E) The two species do not compete for an important, limiting resource. 24) According to evolutionary biologists, in a species where males do not provide parental care, why is the female expected to be choosier than a male when selecting a mate? A) Generally, female fitness is determined by the availability of resources and not the number of mates B) Females contribute more of their genes to their offspring. C) Females generally invest more, in terms of parental care or reproductive effort and C None of the above

Answer 1

22)Since, the population of Clostridium is same in both alone as well as in mix , hence Euglena has no exclusion effect on Clostridium because as per Gause's principle, two species competing for the same resource cannot coexist at constant population values. Since, population values for Clostridium is constant.

Euglena seems to exhibit commensal interaction with Clostridium as Euglena is benefitted while Clostridium has neither loss nor benefit. Hence, the correct answer is option D.

23) Option E is correct as there is no decline in any population level in mix.