This set of Class 12 Biology Chapter 13 Multiple Choice Questions & Answers (MCQs) focuses on “Population Interactions-4”.
1. In which of the following a free-living organism catches kills and eats individuals of other species?
Explanation: Predation is an interaction in which an organism (predator) is benefited by killing another organism (prey). It is the ecological process of energy transfer and best-known examples involve carnivorous interactions.
2. Which is an important predator in the rocky intertidal communities of the American Pacific Coast?
Explanation: Pisater is an important predator in the rocky intertidal communities of the American Pacific Coast that feeds on barnacles, planktons, echinoids, etc. Predation is an interaction in which an organism (predator) is benefited by killing another organism (prey).
3. In which condition the prey might become extinct?
a) When the predator is less
b) When the prey is overexploited
c) When the prey is less
d) When the predator is overexploited
Explanation: The prey might become extinct when the prey itself is overexploited or killed by the predators. Predation is an interaction in which an organism (predator) is benefited by killing another organism (prey).
4. What are insects living on plant sap called?
Explanation: Phytophagous are insects living on plant sap. These insects attack fruits, flowers, leaves, stems, and roots. These are herbivores feeding on herbs (plants).
5. Which one of the following are a morphological means of defense?
Explanation: Thorns of plants are morphological means of defense. They are pointy branches or stems. They protect plants against herbivores. They are the first line of defense in plants.
6. Which one of the following is a chemical produced by plants against grazers and browsers?
Explanation: Opium is the chemical produced by plants against grazers and browsers. These are secondary metabolites. Along with this plants also produce alkaloids, benzoxazinoids, cyanogenic glycosides, glucosinolates, terpenoids, and phenolics for chemical defense.
7. What do South American lakes visiting flamingoes and resident fishes compete for?
b) Small fishes
Explanation: The visiting flamingoes and resident fishes of the South American lakes compete for zooplankton. It is an example of competition. In competition interaction, the fitness of one organism overpowers the presence and fitness of another.
8. Which organism has become extinct in the Galapagos Islands?
c) Abingdon tortoise
Explanation: Abingdon tortoise has become extinct in the Galapagos Islands due to the introduction of goats in that area. This was due to the greater browsing capacity of goats. It is an example of a competition in which the presence of goats lowered the fitness of tortoise.
9. What is the phenomenon called in which two species competing for the same resources can avoid competition by choosing?
a) Resource structuring
d) Resource partitioning
Explanation: Resource partitioning in which two species competing for the same resources can avoid competition by choosing. In this, the resources are divided by the species within an ecological niche. It is an adaptation of interspecific competition.
10. Who dominates on the rocky sea coasts of Scotland?
b) Aquatic plants
c) Larger and competitively superior barnacle Balanus
d) Smaller barnacle Chathamalus
Explanation: The larger and competitively superior barnacle BalanusI dominates the rocky coasts of Scotland. Due to this the smaller barnacle Chathamalus is excluded from that zone. It is an example of ‘competitive release’ which was shown by Connell’s elegant field experiments.
11. What is a mutualistic relationship between a fungus and photosynthesizing algae called?
Explanation: The mutualistic relationship between a fungus and photosynthesizing algae is called lichens. It is a composite organism and has many colors, forms, and sizes. They are used in the food industry, making dyes and have medicinal use.
12. For what purpose does the female wasp use the fruit?
Explanation: The female wasp uses fruit to lay its eggs i.e. oviposition. It also uses the developing seeds of fruits for nourishing its larvae. In return, the wasp helps in the pollination of fig inflorescence.
13. Pseudo-copulation occurs in which of the following flower?
b) The Mediterranean orchid Ophrys
c) Mangifera indica
Explanation: Pseudo-copulation is observed in the Mediterranean orchid Ophrys. It is the process in which the male copulates with the flowers that resemble the female insect of the same species. It is observed in bees, flies, and wasps.
14. Which plant has lost its chlorophyll and leaves in the course of evolution?
Explanation: Cuscuta a parasitic plant has lost its chlorophyll during the course of evolution. It is an obligate, ectoparasitic dodder plant that completely depends on the host for nutrients. It binds to the host with the help of haustoria.
15. The cattle egret shows commensalism with which organism?
a) Grazing cattle
Explanation: The cattle egret shows commensalism with grazing cattle. It is a white-colored bird that eats insects and flies wandering around cattle. It is a relationship in which the egret is benefited while the cattle are neither harmed nor benefited.
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