Organisms and Populations: MCQ Test

21. Which of the following is an example of an organism that breeds only once in its lifetime (semelparous)?

• Most birds
• Most mammals
• Pacific salmon fish
• Oysters

22. What is the interaction where both interacting species benefit?

• Competition
• Parasitism
• Mutualism
• Commensalism

23. Predation is considered nature's way of transferring energy to higher trophic levels. What other important role do predators play?

• They increase prey population sizes.
• They reduce species diversity in a community.
• They keep prey populations under control and help maintain species diversity.
• They solely serve as food sources for decomposers.

24. The biological control method adopted in Australia to control the invasive prickly pear cactus involved the introduction of:

• Herbicides
• A cactus-feeding predator (a moth)
• Grazing cattle
• A fungal pathogen

25. Which of the following is a chemical defense mechanism evolved by plants against herbivores?

• Thorns
• Cryptic coloration
• Production of poisonous cardiac glycosides (e.g., in Calotropis)
• Rapid flight response

26. Gause's 'Competitive Exclusion Principle' states that two closely related species competing for the same resources cannot co-exist indefinitely. What is the predicted outcome?

• They will evolve into a single hybrid species.
• The competitively inferior one will be eliminated eventually.
• They will learn to share resources equally.
• They will develop mutualistic relationships.

27. What is 'resource partitioning' as a mechanism for co-existence between competing species?

• One species dominates all resources.
• Species divide the available resources, for instance, by choosing different times for feeding or different foraging patterns.
• Species migrate to different habitats to avoid competition.
• One species sacrifices its resources for the other.

28. Which of the following is a common adaptation seen in parasites due to their life cycles?

• Development of complex digestive systems
• Loss of unnecessary sense organs and high reproductive capacity
• Reduced dependence on a host for survival
• Increased locomotion for escaping hosts

29. What type of parasites live inside the host body at various sites like the liver or kidneys?

• Ectoparasites
• Endoparasites
• Brood parasites
• Hyperparasites

30. The interaction between an orchid growing as an epiphyte on a mango branch is an example of:

• Parasitism
• Mutualism
• Commensalism
• Amensalism

31. Lichens represent an intimate mutualistic relationship between which two components?

• Two different types of bacteria
• A fungus and photosynthesising algae or cyanobacteria
• A plant and an animal
• A virus and a host cell

32. How does the Mediterranean orchid Ophrys achieve pollination by a species of bee?

• It offers a large quantity of nectar.
• It traps the bee until pollination is complete.
• It employs 'sexual deceit' by resembling the female bee in size, color, and markings.
• It produces a strong scent that repels other pollinators.

33. Which of the following interactions is characterized by one species being harmed while the other is unaffected?

• Commensalism
• Mutualism
• Amensalism
• Predation