[Mission 2022] QUIZ – 2022: INSIGHTS STATIC QUIZ, 19 May 2022 – Environment – INSIGHTSIAS

Solution: d)

All the species given above are invasive species.

An alien plant also referred to as exotic, introduced, foreign, non-indigenous or non-native, is one that has been introduced by humans intentionally or otherwise through human agency or accidentally from one region to another. An alien plant that has escaped from its original ecosystem and is reproducing on its own in the regional flora is considered a naturalized species. Those naturalized aliens that become so successful as to spread in the flora and displace native biota or threatens valued environmental, agricultural or personal resources by the damage it causes are considered invasive.

Some of India’s most notorious invasive species include lantana, parthenium, Siam weed, Mexican devil (Ageratina adenophora) and mesquite (Prosopis juliflora). The water hyacinth (Eichhornia crassipes) has invaded many inland water bodies, while alligator weed (Alternanthera philoxeroides) invades both aquatic and terrestrial habitats in India.

Solution: a)

Altitude sickness means the physical distress from difficulty in adjusting to lower oxygen pressure at high altitude. Its symptoms include nausea, fatigue and heart palpitations.

But gradually you get acclimatized and stop experiencing altitude sickness. The body compensates low oxygen availability by increasing red blood cell production, decreasing the binding capacity of haemoglobin and by increasing breathing rate.

Solution: a)

Mutualism describes the ecological interaction between two or more species where each species has a net benefit. Mutualism is thought to be the most common type of ecological interaction, and it is often dominant in most communities worldwide. Example: Fig tree and the pollinator species of wasp.

Brood parasitism in birds is a fascinating example of parasitism in which the parasitic bird lays its eggs in the nest of its host and lets the host incubate them. During the course of evolution, the eggs of the parasitic bird have evolved to resemble the host’s egg in size and colour to reduce the chances of the host bird detecting the foreign eggs and ejecting them from the nest.

Commensalism is a long-term biological interaction in which members of one species gain benefits while those of the other species neither benefit nor are harmed. Example: Sea anemone and clown fish.

Solution: c)

In an aquatic ecosystem, Grazing food chain is the major conduit for energy flow.

As against this, in a terrestrial ecosystem, a much larger fraction of energy flows through the detritus food chain than through the grazing food chain.

Detritus food chain may be connected with the grazing food chain at some levels: some of the organisms of DFC are prey to the GFC animals, and in a natural ecosystem, some animals like cockroaches, crows, etc., are omnivores.
These natural interconnection of food chains make it a food web.

Solution: a)

Ecological Succession is the gradual process by which ecosystems change and develop over time.

Based on the nature of the habitat – whether it is water (or very wet areas) or it is on very dry areas – succession of plants is called hydrach or xerarch, respectively.

Hydrarch succession takes place in wetter areas and the successional series progress from hydric to the mesic conditions.

As against this, xerarch succession takes place in dry areas and the series progress from xeric to mesic conditions. Hence, both hydrarch and xerach successions lead to medium water conditions (mesic) – neither too dry (xeric) nor too wet (hydric).

The species that invade a bare area are called pioneer species. In primary succession on rocks these are usually lichens which are able to secrete acids to dissolve rock, helping in weathering and soil formation.

A keystone species is a species that has a disproportionately large effect on its natural environment relative to its abundance. Without keystone species, the ecosystem would be dramatically different or cease to exist altogether.