Daily Static MCQs Quiz for UPSC, IAS, UPPSC/UPPCS, MPPSC. BPSC, RPSC & All State PSC Exams
Subject : Environment & Ecology
1. Consider the following statements regarding Phosphorus and Phosphorus Cycle:
1. Phosphorus cycle is largely atmospheric and easily
dissolves in water from air.
2. Phosphorus occurs as a mineral in phosphate rocks and enters the Phosphorus
cycle from erosion and mining activities.
3. Phosphorus is responsible for excessive growth of rooted and free-floating
microscopic plants in water bodies.
How many of the above statements is/are correct?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer: (B)
Explanation: Phosphorous cycle is mainly terrestrial. The main storage for phosphorus is in the earth’s crust. On land phosphorus is usually found in the form of phosphates. It occurs in large amounts as a mineral in phosphate rocks and enters the cycle from erosion and mining activities. By the process of weathering and erosion phosphates enter rivers and streams that transport them to the ocean. Being an important nutrient, phosphorous promotes eutrophication in lakes. Along with nitrogen related compounds it leads to undesirable situations like algal bloom. Hence, statement 1 is incorrect.
2. Why do exotic species post a threat to an indigenous ecosystem such as in a Lake or an isolated island in the Andamans?
1. Such species compete with the local or native species for
food.
2. They may be predators of local species.
3. Such species may cause diseases in native species.
How many of the above statements is/are correct?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer: (C)
Explanation: Exotic species introduced to new environments often reset the ecological conditions in that new habitat, threatening the species that exist there; this is the reason that they are also termed invasive species. Invasive species that are closely related to rare native species have the potential to hybridize with the native species; harmful effects of hybridization have led to a decline and even extinction of native species. Invasive species can change the food web in an ecosystem by destroying or replacing native food sources. The invasive species may provide little to no food value for wildlife. Lakes and islands are particularly vulnerable to extinction threats from introduced species. Hence, all are correct.
3. Consider the following statements:
1. Ecotone is the unique functional role or place of a
species in an ecosystem.
2. Niche is a zone of junction between two or more diverse ecosystems.
Which of the above statements is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Answer: (C)
Explanation:
- Ecotone is a zone of junction between two or more diverse ecosystems. For e.g. the mangrove forests represent an ecotone between marine and terrestrial ecosystem. Other examples are – grassland, estuary and river bank.
- A niche is the unique functional role or place of a species in an ecosystem. It is a description of all the biological, physical and chemical factors that a species needs to survive, stay healthy and reproduce. A niche is unique for a species, which means no two species have exact identical niches. Niche plays an important role in the conservation of organisms.
Hence, both statements are correct.
4. Consider the following statements regarding ocean acidification:
1. It largely occurs due to the high absorption of
nitrogenous based acidic compounds.
2. Introduction of sea grasses can reduce the impact of acidification.
Which of the above statements is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Answer: (B)
Explanation: Ocean acidification refers to a reduction in the pH of the ocean over an extended period of time, caused primarily by uptake of carbon dioxide (CO2) from the atmosphere. Nitrogenous compounds contribute fraction to ocean acidification. Sea grass has ability to control ocean acidification. Hence, statement 1 is incorrect.
5. Which of the following are Tropical Grasslands?
1. Savanna
2. Campos
3. Prairie
4. Llanos
5. Steppe
How many of the above options are correct?
(a) Only two
(b) Only three
(c) Only four
(d) All five
Answer: (B)
Explanation: Grasslands are known by different names in different regions.
Tropical Grasslands are:
- East Africa- Savanna
- Brazil- Campos
- Venezuela- Llanos
Temperate Grasslands are:
- Argentina- Pampas
- America- Prairie
- Africa- Veld
- Asia- Steppe
- Australia- Down
Hence, option (b) is correct.
