This set of Class 12 Biology Chapter 13 Multiple Choice Questions & Answers (MCQs) focuses on “Population Interactions-2”.
1. Who does a pilot fish accompanies for feeding on falling pieces of food?
a) Shark
b) Hermit crab
c) Dolphin
d) Lobster
View Answer
Explanation: The pilot fish accompanies a shark for feeding on falling pieces of food. It may also accompany rays or turtles. It is an example of commensalism in which pilot fish gains food without harming another organism.
2. What is a relationship between organisms of different species where an organism is benefited and other is harmed called?
a) Parasitism
b) Commensalism
c) Mutualism
d) Competition
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Explanation: A relationship between organisms of different species where an organism is benefited and other is harmed is known as parasitism. The organism which is benefited is known as parasite while the harmed one is called the host.
3. What is a relationship in which larval development of one organism occurs inside or on the surface of another organism resulting in the death of the host called?
a) Symbiont
b) Parasitoid
c) Commensalism
d) Mutualism
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Explanation: A relationship in which larval development of one organism occurs inside or on the surface of another organism resulting in the death of the host known as a parasitoid. Parasitoids include species of beetles, flies, wasps, and worms.
4. Where do ectoparasites reside?
a) Within the blood
b) In the intercellular spaces of host
c) Within the cells
d) On the surface of the host
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Explanation: The ectoparasite is organisms that reside on the surface of the host. Some examples of ectoparasites are fleas, lice, mites, ticks, etc. These are obligatory parasites.
5. Where do endo-parasites reside?
a) Within the cells of the host body
b) On the surface of the host body
c) Outside the skin of the host
d) Outside the host environment
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Explanation: The endo-parasites reside within the cells of the host body. These may be obligatory intercellular or intracellular parasites. Some examples of endo-parasites are few protozoans, tapeworms, nematodes, helminths, etc.
6. What is an organism carrying another organism to the host called?
a) Parasite
b) Vector
c) Pathogen
d) Bacteria
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Explanation: The organism carrying another organism to the host is called a vector. A vector itself does not cause disease but transfers the pathogen to host. Some major vectors are plasmids, cosmids, viral vectors, and artificial chromosomes.
7. Who transmits malaria-causing protozoan?
a) Protists
b) Male Anopheles mosquito
c) Fungi
d) Female Anopheles mosquito
View Answer
Explanation: A female anopheles mosquito is a vector that transmits the malaria-causing protozoan called Plasmodium. Anopheles gambiae is one of the best-known vectors that transmit Plasmodium falciparum.
8. In which the organism’s abdomen does Sacculina live?
a) Shark
b) Dolphin
c) Crab
d) Cattle
View Answer
Explanation: Sacculina is a genus of barnacles that resides inside the gut of a crab. It is a parasite that shows adverse effects on crabs such as it hinders the normal metabolism of crab and also reduces its reproduction capacity.
9. What is a relationship in which one parasite feeds on another parasite which in turn feeds on its host called?
a) Pathogen
b) Vector
c) Vehicle
d) Epi-parasite
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Explanation: A relationship in which one parasite feeds on another parasite which in turn feed on its host is called epi-parasite. These are also known as secondary or hyper parasites. An example is a bacterium in an insect’s gut that feeds on cattle.
10. What is a protozoan living in the digestive tract of a flea living on a dog is an example of?
a) Endo-parasitism
b) Klepto-parasitism
c) Hyper-parasitism
d) Ecto-parasitism
View Answer
Explanation: A protozoan living in the digestive tract of a flea living on a dog is an example of Hyper-parasitism. It is also known as secondary or epi-parasite. It is a relationship in which one parasite feeds on another parasite which in turn feeds on its host.
11. In which interaction does a parasite steal food gathered by the host?
a) Adelpho-parasitism
b) Klepto-parasitism
c) Endo-parasitism
d) Ecto-parasitism
View Answer
Explanation: A phenomenon of a parasite stealing food gathered by a host is observed in klepto-parasitism. It is parasitism by theft in which an organism benefits at another organism’s expense. These are opportunistic feeders because independent feeding is costly.
12. Which is an example of a parasite, in which the host species is closely related to the parasite and is a member of the same family or genus?
a) Endo-parasite
b) Klepto-parasite
c) Adelpho-parasite
d) Ecto-parasite
View Answer
Explanation: Adelpho-parasite is an example of a parasite, in which the host species is closely related to the parasite and is a member of the same family or genus. It is a type of hyper-parasitism which commonly seen is Encarsia perplexa, Trissolcus basalis and members of the family Aphelinidae.
13. What is Encarsia perplexa example of?
a) Klepto-parasite
b) Adelpho-parasite
c) Endo-parasite
d) Ecto-parasite
View Answer
Explanation: Encarsia perplexa, a wasp of the family Aphelinidae is an example of adelpho-parasite. It is a parasitoid of the citrus blackfly and is a native of India and Vietnam. It was recorded as a new species in 1998.
14. What is the reason for energy flow from one organism to another?
a) Competition
b) Mutualism
c) Commensalism
d) Predation
View Answer
Explanation: Predation is the reason for energy flow from one organism to another. It 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.
15. Which organisms eat each other and form various levels of the food pyramid?
a) Carnivore
b) Omnivores
c) Herbivore
d) Decomposer
View Answer
Explanation: The carnivores eat each other and form various levels of the food pyramid. It derives its energy and nutrient requirements from killing and eating other animals. These are the predators and the organisms they eat are called prey.
Sanfoundry Global Education & Learning Series – Biology – Class 12.
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