[DAY 12] 60 DAY RAPID REVISION (RaRe) SERIES for UPSC Prelims 2024 –ENVIRONMENT, CURRENT AFFAIRS & CSAT TEST SERIES!

Solution (c)

Allopatric Speciation 

• Occurs when a species separates into two separate groups which are isolated from one another.
• A physical barrier, such as a mountain range or a waterway, makes it impossible for them to breed with one another.
• Each species develops differently based on the demands of their unique habitat or the genetic characteristics of the group that are passed on to offspring.

Peripatric Speciation

• When small groups of individuals break off from the larger group and form a new species, this is called peripatric speciation.
• As in allopatric speciation, physical barriers make it impossible for members of the groups to interbreed with one another. The main difference between allopatric speciation and peripatric speciation is that in peripatric speciation, one group is much smaller than the other.
• Unique characteristics of the smaller groups are passed on to future generations of the group, making those traits more common among that group and distinguishing it from the others.

Parapatric Speciation

• In parapatric speciation, a species is spread out over a large geographic area.
• Although it is possible for any member of the species to mate with another member, individuals only mate with those in their own geographic region.
• Like allopatric and peripatric speciation, different habitats influence the development of different species in parapatric speciation.
• Instead of being separated by a physical barrier, the species are separated by differences in the same environment.

Solution (c)

1. Evaporation, one of the major processes in the cycle, is the transfer of water from the surface of the Earth to the atmosphere. By evaporation, water in the liquid state is transferred to the gaseous or vapour The main factors affecting evaporation are temperature, humidity, wind speed and solar radiation
2. Condensation is the transition process from the vapour state to the liquid state. When the air moves up and reaches sufficient height, the air becomes so cool that the water vapour present in it condenses to form tiny droplets of water, which appear as clouds.
3. Precipitation: Many tiny water droplets come together (as clouds) and fall down as rain, snow or hail. It may form streams and rivers finally reaching ocean or can also get collected in ponds & lakes.
4. Percolation also known as infiltration is the movement of water though the soil, and it’s layers by gravity. Most of this water becomes available to us as ground water stored in aquifer.

All of the above given water sources acts as a Storage which again evaporates to form water vapour completing the Water Cycle or Hydrological cycle.

Solution (d)

Solution (a)

Solution (c)

Notes:

Ecological Succession-

• The gradual and fairly predictable change in the species composition of a given area is called ecological succession.
• During succession some species colonise an area and their population become more numerous whereas populations of other species decline and even disappear.
• The entire sequence of communities that successively change in a given area are called sere(s). The individual transitional communities are termed seral stages or seral communities. In the successive seral stages, there is a change in the diversity of species of organisms, increase in the number of species and organisms as well as an increase in the total biomass.
• The present-day communities in the world have come to be because of succession that has occurred over millions of years since life started on earth. Actually, succession and evolution would have been parallel processes at that time. Succession is hence a process that starts in an area where no living organisms are there – these could be areas where no living organisms ever existed, say bare rock; or in areas that somehow, lost all the living organisms that existed there. The former is called primary succession, while the latter is termed secondary succession.
• Examples of areas where primary succession occurs are newly cooled lava, bare rock, newly created pond or reservoir. The establishment of a new biotic community is generally slow. Before a biotic community of diverse organisms can become established, there must be soil. Depending mostly on the climate, it takes natural processes several hundred to several thousand years to produce fertile soil on bare rock.
• Secondary succession begins in areas where natural biotic communities have been destroyed such as in abandoned farm lands, burned or cut forests, lands that have been flooded. Since some soil or sediment is present, succession is faster than primary succession.
• At any time during primary or secondary succession, natural or human induced disturbances (fi re, deforestation, etc.), can convert a particular seral stage of succession to an earlier stage. Also, such disturbances create new conditions that encourage some species and discourage or eliminate other species.
• 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 hydrarch or xerarch, respectively. Hydrarch succession takes place in wet 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 xerarch 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. In primary succession in water, the pioneers are the small phytoplanktons, which are replaced with time by rooted-submerged plants, rooted-floating angiosperms followed by free-floating plants, then reed swamp, marsh-meadow, scrub and finally the trees. The climax again would be a forest.
• In secondary succession the species that invade depend on the condition of the soil, availability of water, the environment as also the seeds or other propagules present. Since soil is already there, the rate of succession is much faster and hence, climax is also reached more quickly.
• All succession whether taking place in water or on land, proceeds to a similar climax community – the mesic.

Solution (a)

Tropical Moist Deciduous Forest:

• These are the most widespread forests in India.
• They are also called the monsoon forests.
• They spread over regions that receive rainfall between 70-200 cm.
• On the basis of the availability of water, these forests are further divided into moist and dry deciduous.
• The moist deciduous forests are more pronounced in the regions which record rainfall between 100-200 cm.
• Dry deciduous forest covers vast areas of the country, where rainfall ranges between 70 -100 cm.
• As the dry season begins, the trees shed their leaves completely and the forest appears like a vast grassland with naked trees all around.
• Tendu, palas, amaltas, bel, khair, axlewood, etc. are the common trees of these forests.

Solution (a)

Notes:

Periphyton: These are organisms which remain attached to stems and leaves of rooted plants or substances emerging above the bottom mud such as sessile algae.

Plankton: Microscopic floating organisms such as algae, diatoms, protozoans and larval forms are called plankton. This group includes both microscopic plants like algae (phytoplankton) and animals like crustaceans and protozoans (zooplankton).

Solution (a)

Notes:

• A Ramsar site is a wetland of international importance under the Ramsar Convention, which is also known as the ‘Convention on Wetlands’ — an intergovernmental environmental treaty established by UNESCO in 1971, and named after the city of Ramsar in Iran, where the convention was signed that year.
• Ramsar recognition is the identification of wetlands around the world, which are of international importance, especially if they provide habitat to waterfowl (about 180 species of birds).
• There is international interest and cooperation in the conservation of such wetlands and a judicious use of their resources.

Solution (b)

Notes:

Photic zone:

• It is the upper layer of the aquatic ecosystems, up to which light penetrates and within which photosynthetic activity is confined.
• The depth of this zone depends on the transparency of water. Both photosynthesis and respiration activity takes place.
• Photic (or ‘euphotic’) zone is the lighted and usually well-mixed portion that extends from the lake surface down to where the light level is 1% of that at the surface.

Aphotic zone:

• The lower layers of the aquatic ecosystems, where light penetration and plant growth are restricted form the aphotic zone. Only respiration activity takes place.
• Aphotic zone is positioned below the littoral and photic zones to bottom of the lake where light levels are too low for photosynthesis.
• Respiration occurs at all depths so the aphotic zone is a region of oxygen consumption. This deep, unlit region is also known as the profundal zone.

Solution (a)

Notes:

Freshwater ecosystems can be divided into two categories:

Lentic ecosystem:

• It entails a body of standing water, ranging from ditches, seeps, ponds, seasonal pools, basin marshes, swamp and lakes.
• These are also known as Pond ecosystem.

Lotic ecosystem:

• It can be any kind of moving water, such as a run, creek, brook, river, spring, channel or stream.
• The water in a lotic ecosystem, from source to mouth, must have atmospheric gases, turbidity, longitudinal temperature gradation and material dissolved in it.

Solution (b)

Note:

Zones of the ocean:

• The Earth is approximately covered with ocean by 71% and ocean contains around 97% of Earth’s water.
• Oceans are the largest habitat region on the Earth and also regulate the global climate.
• The Oceanographers divided the ocean into different layers or zone to study the ocean, such as-

1. Intertidal Zone-

The Intertidal zone is the shallow water near the shore. In the ocean, the Intertidal zone is also called the Littoral zone.

2. Neritic Zone-

The main body of open water farther out from shore, over the Continental Shelf is called the Neritic zone.

3. Oceanic Zone-

The remaining portion of the ocean water beyond the Neritic Zone is called the Oceanic zone.

Types of Neritic Zones:

1. Infralittoral zone– This zone is dominated by the algae and has depth of about 16.40 feet below the low water mark.
2. Circalittoral zone– This zone is dominated by the sessile animals like Oysters.
3. Subtidal zone– It is the lower most part of neritic zone and below the ocean’s intertidal zone. This zone is never exposed to the atmosphere.

Solution (a)

Montreux record:

• The Montreux Record is a register of wetland sites on the List of Wetlands of International Importance where changes in ecological character have occurred, are occurring, or are likely to occur as a result of technological developments, pollution or other human interference.
• It is the principle tool under the Ramsar convention for highlighting wetlands sites in need of priority conservation status. It is maintained as part of the Ramsar Database and is subject to continuous review.
• It is maintained as part of the Ramsar List.
• At present 2 Indian sites are listed under it. (Loktak Lake, Manipur and Keoladeo National Park, Rajasthan)
• In 1993 Chilka lake was also listed in Montreux record due to problem of Siltation. But later in 2002, it was removed from the list as problem tackled by government actions.

Solution (a)

Chronologically, the following organisms evolved in the sequence given below –

• Corals
• Fishes
• Birds
• Flowering plants

The basic timeline of a 4.6 billion-year-old Earth includes the following:

• About 3.5 – 3.8 billion years of simple cells (prokaryotes).
• 3 billion years of photosynthesis.
• 2 billion years of complex cells (eukaryotes).
• 1 billion years of multicellular life.
• 600 million years of simple animals.
• 570 million years of arthropods (ancestors of insects, arachnids and crustaceans).
• 550 million years of complex animals.
• 500 million years of fish and proto-amphibians.
• 475 million years of land plants.
• 400 million years of insects and seeds.
• 360 million years of amphibians.
• 300 million years of reptiles.
• 200 million years of mammals.
• 150 million years of birds.
• 130 million years of flowers.
• 65 million years since the non-avian dinosaurs died out.
• 5 million years since the appearance of Homo.
• 200,000 years since the appearance of modern humans.
• 25,000 years since Neanderthals died out.

Solution (c)

Adaptation is any attribute of the organism (morphological, physiological, behavioural) that enables the organism to survive and reproduce in its habitat. Many adaptations have evolved over a long evolutionary time and are genetically fixed.

Adaptations by plants in desert areas:

1. Thick cuticle on their leaf surfaces-

• In order to tackle the high rate of transpiration, the leaves have a thick waxy coating known as the cuticle.
• The cuticle is a waxy layer and impervious to water and thus prevent loss of water from the surface.

2. Stomata are arranged in deep pits-

• Due to high temperature, the water is lost from the stomata of the plant as a result of the high rate of transpiration.
• Therefore, the stomata are arranged in deep pits to prevent excessive loss of water.

3. Stomata to remain closed during day time-

• Desert plants photosynthesize by a modified process of photosynthesis called CAM photosynthesis.
• There are less stomata in desert plants as the leaves are modified to form spines and photosynthesis occurs in the green stem.
• The stomata do not open during the day to avoid water loss and only opens during the night for carbon dioxide to enter the plant.
• ​The carbon dioxide is present as an intermediate inside the plant to perform photosynthesis during the day.

4. Flattened stems-

• Desert plants stems are flattened, that is they have absence of leaves or has leaves that have been reduced to thorns or spines to perform photosynthesis in the absence of leaves.
• Fat leaves, fat stems, and fewer leaves are all ways for plants to reduce their water loss in the desert.

Solution (b)

Solution (b)

Note:

Estuary:

• An estuary is a place where a river or a stream opens into the sea (mouth of the river).
• It is a partially enclosed coastal area of brackish water (salinity varies between 0-35 ppt) with one or more rivers or streams flowing into it, and with a free connection to the open sea.
• At the estuaries, freshwater carrying fertile silt and runoff from the land mixes with the salty sea water.
• Estuaries form a transition zone (ecotone) between river environments and maritime environments.
• Examples of estuaries are river mouths, coastal bays, tidal marshes, lagoons and deltas.
• Estuaries are formed due to rise in sea level, movement of sand and sandbars, glacial processes and tectonic processes.
• All the plants and animals in the estuaries are subjected to variations in salinity to which they are adapted (osmoregulation).
• Estuaries are greatly influenced by tidal action. They are periodically washed by sea water once or twice a day based on the number of tides.
• In some narrow estuaries, tidal bores are significant. Tidal bores cause great damage to the estuarine ecology.
• Estuaries create a natural barrier that absorbs the energy of the waves and prevents them from flooding cities.

Solution (c)

Note:

Mangroves:

• Mangroves are a variety of species of broad-leaved trees (10–40 feet high) lying in muddy creeks and tidal estuaries.
• They are located on the intermediate zone between the land and the sea and represent one of the best examples of ecotone.
• They require warm saline water and so they are situated along tropical coastlines.
• Mangrove plants survive in the saltwater zones between water and land.

Importance of Mangroves:

• They protect coastal areas from Tsunamis storm surges and soil erosions; due to their complex root systems which dissipate sea wave energy
• Sediment deposition is a visible feature which arrests coastal erosion and seawater pollution
• Many fish species and other fauna breeds here
• They are an important source of livelihood for communities found in and around mangrove forests:
  1. Collection of Honey
  2. Tanning
  3. Wax
  4. Fishing
  5. They are carbon sinks

Solution (d)

Solution (d)

Solution (b)

Notes:

Geo-heritage Sites:

• Geo-heritage refers to the geological features which are inherently or culturally significant offering insight to earth’s evolution or history to earth science or that can be utilized for education.
• Geological Survey of India (GSI) is the parent body which is making efforts towards identification and declaration of geo-heritage sites/national geological monuments in the country.
• GSI declares geo-heritage sites/ national geological monuments for protection and maintenance.

Solution (d)

• Multidrug-resistant tuberculosis (MDR-TB) is TB that does not respond to the two most powerful anti-TB drugs – isoniazid and rifampicin. Hence statement 1 is incorrect.
• It is caused by inappropriate or incorrect use of antimicrobial drugs, or use of ineffective formulations of drugs (such as the use of single drugs, poor quality medicines, or bad storage conditions), and premature treatment interruption.
• Bedaquiline is used to treat multi-drug-resistant tuberculosis (MDR-TB) by targeting the adenosine triphosphate (ATP) synthase enzyme of the TB mycobacteria. Hence statement 2 is incorrect.

Solution (a)

• Madhya Pradesh has the highest tiger population in India accounting for a fifth of the national count with a 50% rise in its population compared to the previous census. Hence statement 1 is correct.
• It is due to its strategy of relocation of both tigers and their prey within the state to establish a balance between the numbers of predators and their prey. Hence statement 2 is correct.
• Madhya Pradesh has effectively reintroduced species like barasingha into habitats like Satpura and Bandhavgarh, and gaur into the Bandhavgarh and Sanjay-Dubri tiger reserves.

Note: The national tiger census is done every four years by the National Tiger Conservation Authority (NTCA) in partnership with state forest departments, conservation NGOs, and the Wildlife Institute of India (WII).

Solution (b)

• Flood management including erosion control falls within the purview of the States. Flood management and anti-erosion projects are formulated and implemented by concerned State Governments from their own resources as per their priority. The Union Government supplements the efforts of the States by providing technical guidance and also promotional financial assistance for the management of floods in critical areas. Hence statement 1 is incorrect.
• The Central Water Commission (CWC) is responsible for predicting and giving early warnings about floods in India. They use a system of 338 forecasting stations across 20 major river basins in 23 States and 2 Union Territories. This helps local authorities prepare for evacuations and take necessary actions. CWC has created flood forecasting models for each basin that use rainfall and runoff data to predict floods up to 5 days in advance and provide advice to the forecasting stations. Hence statement 2 is correct.

Solution (d)

• Ramsar Convention – conservation and wise use of wetlands and their resources.
• CITES – international trade of wild animals and plants does not threaten the survival of the species in the wild.
• Beijing Declaration – various issues involving poverty and violence against women.
• Balem/Belem Declaration – inclusion of indigenous people in biodiversity conservation. It created an alliance for combatting forest destruction, with countries left to pursue their individual deforestation goals. It was adopted at the Amazon Summit organized by the Amazon Cooperation Treaty Organization (ACTO). Hence option d is correct.

Solution (b)

• The Central Bureau of Investigation (CBI) is the nodal body for all matters related to Interpol. Hence statement 1 is correct.
• The CBI assists the Central Vigilance Commission and Lokpal.
• It functions under the superintendence of the Department of Personnel, Ministry of Personnel, Pension and Public Grievances, Government of India – which falls under the prime minister’s office.
• INTERPOL Global Academy Network was launched in 2019 by INTERPOL.
• INTERPOL Global Academy Network boosts skill development for law enforcement globally by providing specialized training to Interpol. Hence statement 2 is correct.
• The CBI Academy is a non-statutory premier training institution in the fields of crime investigation, prosecution, and vigilance. It was established by CBI in 1996.
• The statutory body is a body that is established by an act of parliament. Hence statement 3 is incorrect.

Solution (a)

Context: The Defence Ministry has decided to replace the Microsoft Operating System (OS) in all computers connected to the Internet with the Maya Operating System(OS). Maya OS is a new operating system that is based on Ubuntu, a popular Linux distribution that uses free and open-source software.

• Ubuntu is a popular Linux operating system that can be inspected and modified by anyone. Hence statement 1 is correct.
• Because it is distributed as free and open-source software. It allows Ubuntu to benefit from the collective efforts of thousands of developers and users who contribute to its development and security. Hence statement 2 is correct.

Solution (c)

• Assam Rifles are one of the six central armed police forces(CAPFs) under the administrative control of the Ministry of Home Affairs. Hence statement 1 is incorrect.
• The other five forces are the Central Reserve Police Force (CRPF), Border Security Force (BSF), Indo-Tibetan Border Police (ITBP), Central Industrial Security Force (CISF), and Sashastra Seema Bal (SSB).
• It is the only paramilitary force with a dual control structure. While the administrative control of the force is with the Ministry of Home Affairs(MHA). But its operational control is with the Indian Army, which is under the Ministry of Defence (MoD).
• It is tasked with maintaining law and order in the Northeast along with the Indian Army and guards the Indo-Myanmar border. Hence statement 2 is correct.
• It was formed in 1835 as a militia called the ‘Cachar Levy’ to primarily protect British Tea estates and their settlements against tribal raids. Hence statement 3 is correct.
• Since its formation in 1835, it has gone on to fight in two World Wars, the Sino-Indian War of 1962.
• It has operated in foreign land as part of the Indian Peace Keeping Force (IPKF) to Sri Lanka in 1987 (Op Pawan) to a peacekeeping role in the North-Eastern areas of India. Hence statement 4 is correct.

Solution (c)

• Spintronics is one of the emerging fields for the next-generation nanoelectronic devices to reduce their power consumption and increase their memory and processing capabilities. Hence statement 1 is correct.
• In these devices, the spin polarisation is controlled either by magnetic layers used as spin-polarisers or analysers. Spin waves can also be used to carry spin currents. Hence statement 2 is correct.
• Spin transistors, spin diodes, and spin filters are some examples of spintronic devices. Hence statement 3 is correct.

Solution (c)

• Convention on Cluster Munitions is an international treaty that prohibits all use, transfer, production, and stockpiling of cluster bombs due to their indiscriminate and long-lasting effects on civilian populations. Hence statement 1 is correct.
• It was adopted in Dublin by 107 States on 30 May 2008 and signed in Oslo on 3 December 2008. It became binding international law when it entered into force on 1 August 2010.
• India, the United States, Russia, Ukraine, Pakistan, and Israel have not signed it. Hence statement 2 is correct.

Solution (d)

Pilibhit Tiger Reserve is spread over two districts of Uttar Pradesh. It forms the part of Terai Arc Landscape in the upper Gangetic Plain. The northern edge of the reserve lies along the Indo-Nepal border while the southern boundary is marked by the river Sharada and Khakra. It bagged the international award TX2 for doubling the number of tigers in the past four years. It has high sal forests, plantations, and grasslands with several water bodies. Wild animals include tiger, swamp deer, Bengal florican, leopard, etc. Hence option d is correct.

Panna Tiger Reserve is located in Madhya Pradesh.

Solution (c)

Total number of possibilities for the first two questions = 3 × 3 = 9.

Total number of possibilities for the next two questions = 4 × 4 = 16.

Total number of possibilities for the last question = 5

Total number of ways in which all the five questions could be attempted = 9 × 16 × 5 = 720

Solution (c)

Let, the unit’s and ten’s digit be ‘a’ and ‘b’ respectively.

Therefore, a + b = 8 and a – b = 18 ÷ 9 = 2

Since, a = (8 + 2) ÷ 2 = 5 and b = 5 – 2= 3

Therefore, the required value is 3 × 35 = 105

Solution (d)

Let the usual tax on the commodity be 100₹ and its usual consumption be 100 units

After changes in various conditions, tax on a commodity is diminished by 20% ie tax is now only 80% consumption increased by 10% ie now consumption is 110 units

previous revenue = 100₹ x 100 units = 10000₹

new revenue = 80₹ x 110 = 8800₹

decrease percent in revenue = change in revenue/original revenue x 100

= (10000 – 8800)/10000 x 100

= 1200/10000 x 100

= 12%

Solution (c)

Numbers between 100 and 1000 = 900

Numbers between 100 and 1000 which do not have digit 6 in any place = 8 x 9 x 9 = 648

Unit digit could take any value of the 9 values (0 to 9, except 6)

Tens Digit could take any value of the 9 values (0 to 9, except 6)

Hundreds digit could take any value of the 8 values (1 to 9, except 6)

So numbers between 100 and 1000 which have atleast one digit as 6 = 900 – 648 = 252

Solution (a)

The passage describes the different elements associated with patriotism and also of the importance of religion. It does not talk about the need for patriotism or history of patriotism, so option (b) and option (d) are ruled out. Although the passage talks about the role of religion, history is not mentioned or implied, So option (c) is also ruled out. We are left with Option (a) which is the correct answer.