[Mission 2024] STATIC QUIZ, 19 September 2023 – Environment

Solution: d)

Ecotone

• 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.

Niche

• 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.

Solution: c)

Fresh Water Ecosystem

Freshwater ecosystems are classified as lotic (moving water) or lentic (still or stagnant water).

Lotic water system includes

• freshwater streams,
• springs,
• rivulets,
• creeks,
• brooks, and

Lentic water bodies include

• pools,
• ponds,
• some swamps,
• bogs and

They vary considerably in physical, chemical and biological characteristics.

Solution: b)

Pyramid of Energy

• An energy pyramid is most suitable to compare the functional roles of the trophic levels in an ecosystem.
• An energy pyramid, reflects the laws of thermodynamics, with the conversion of solar energy to chemical energy and heat energy at each trophic level and with loss of energy being depicted at each transfer to another trophic level.

Hence the pyramid is always upward, with a large energy base at the bottom.

Bioaccumulation

• It refers to how pollutants enter a food chain.
• In bioaccumulation, there is an increase in the concentration of a pollutant from the environment to the first organism in a food chain.

Biomagnification refers to the tendency of pollutants to concentrate as they move from one trophic level to the next.

Solution: b)

Statement 2 is incorrect.

CORAL REEFS

Coral has a symbiotic relationship with ‘zooxanthellae’ microscopic algae which live on coral

Types of reefs :-

Fringing reef / Patch reefs are isolated and discontinuous patches, lying shoreward of offshore reef structures as seen in the Palk bay, Gulf of Mannar and Gulf of Kutch.

Barrier reefs are linear offshore reef structures that run parallel to coastlines and arise from submerged shelf platforms. Barrier reefs are seen in Nicobar and Lakshadweep.

Atolls are circular or semicircular reefs that arise from subsiding sea floor platforms as coral reef building keeps ahead of subsidence. The examples are the atolls of Lakshadweep and Nicobar.

Functions of Coral Reefs

• Coral reefs are natural protective barriers against erosion and storm surge.
• The coral animals are highly adapted for capturing plankton from the water, thereby capturing nutrients
• Largest biogenic calcium carbonate producer
• They provide substrate for mangroves.

Causes of coral bleaching:–

Temperature (Major Cause):- Coral species live within a relatively narrow temperature margin, and anomalously low and high sea temperatures can induce coral bleaching. Bleaching is much more frequently reported from elevated sea water temperature.

Solution: d)

TYPES OF BIODIVERSITY

Based on the three elements of biodiversity, that is, genes, species and ecosystems, biodiversity is considered to be of three types:

Genetic diversity: It can be understood as the diversity of genes within a particular species. This diversity ensures that some species can survive disruptions.

Species diversity: It refers to the variety of species within a particular geographical region. For example, humans and chimpanzees have about 98.4 percent genes which are the same.

Species diversity is measured by :- species richness, which means the number of different species per unit area in a region.