Sunday, 12 April 2015

CSP-2015: Key to the Ecology and Science and Technology Test-1 Dt.15.02.2015

CSP-2015: Key to the Ecology and Science and Technology Test-1 Dt.15.02.2015

1.
c
21.
d
41.
d
61.
c


2.
b
22.
d
42.
a
62.
d


3.
b
23.
b
43.
c
63.
b


4.
d
24.
c
44.
a
64.
a


5.
c
25.
a
45.
d
65.
b


6.
b
26.
d
46.
b
66.
c


7.
b
27.
c
47.
d
67.
a


8.
b
28.
a
48.
a
68.
b*


9.
c
29.
d
49.
c
69.
d


10.
d
30.
b
50.
d
70.
a


11.
c
31.
b
51.
d
71.
c




31
d






12.
b
32.
a
52.
c
72.
c


13.
c
33.
a
53.
d
73.
b


14.
b
34.
a
54.
a
74.
b


15.
d
35.
d
55.
b
75.
a


16.
b
36.
d
56.
d
76.
a


17.
a
37.
d
57.
a
77.
a


18.
c
38.
a
58.
b
78.
b


19.
a
39.
b
59.
b
79.
a


20.
a
40.
d
60.
c
80.
c



Explanation:
1. Competition is a negative interaction among the living organisms. The competitors can be plants or animals. Among the plants, the competition is for accessing light, water, nutrients etc. The instant question is more related to competition among the animals. All the animals require a space for their stay and survival called “territory”, resources to grow, reproduce, and survive. It is no doubt that the abiotic /non-living environment such as light, temperature, water etc. play a predominant role in the maintaining the ecosystem and sustaining the life, but it has no role in the competition among the biotic elements in a niche for food, nesting ground or territory. Hence correct option for Q 1 is “c”.

2. As we have seen supra, competition is a negative interaction between two species [Inter species competition] or members of a same species [Intra species competition]. In constant ecological factors or in an ecosystem with constant abiotic factors, two species fighting for a same resource can’t co-exist and in the fight, one species with superior features will sustain the same place and another species would disappear from the scene. It is paraphrased as Gause’s law of competitive exclusion or just Gause's law. It states that two species competing for the same resource cannot coexist at constant population values, if other ecological factors remain constant. When one species has even the slightest advantage or edge over another then the one with the advantage will dominate in the long term. One of the two competitors will always overcome the other, leading to either the extinction of this competitor or an evolutionary or behavioral shift toward a different ecological niche. In the case of narrow niche overlapping, both species may continue to exist. 

3. For a happy living of a living organism, there shall not be any competition for 1. Habitat or special niche, 2. Nutrition or Food niche, 3. Reproductive or nesting niche and 4. Abiotic or physical and chemical niche

4. The green plants fix the potential energy in the form of organic food from the inorganic components in the presence of Sunlight in the process of “Photosynthesis”. They are called “Producers”. They are preyed upon by herbivores such as rabbit, deer, grasshoppers etc. These herbivores are consumed by carnivores such as Lizards, Tigers, wolves etc. Thus all the living beings depend on these green plants for their energy needs either directly or indirectly. However, Sun is the ultimate source of all the energy on the Earth.
Circulation of materials is the order of the Nature. In the nature, all the materials are required to be circulated across the living or biotic and non-living environment. This work is done by detritus feeders/detrivores and de-composers. The detrivores feed on the dead and decaying organic matter or detritus and break down them into smaller pieces and thus increases the surface area for the bacteria and fungi for further microscopic decomposition. Thus, the role of detritus feeders is to facilitate the decomposition of organic matter by the bacteria and fungi. The Decomposers act at microscopic level and breakdown the complex organic compounds into their constituent inorganic materials. In the process, the energy is released which is consumed by the decomposers, bacteria and fungus.  

8. Primary producers are organisms in an ecosystem that produce biomass from inorganic compounds (autotrophs). The autotrops are two types, 1. Photo-autotrops or green plants and 2.Chemotrophs.
The photo-autotrophs [as the name indicates] are green plants, containing chlorophyll fix the potential engery in chemical compounds in the presence of Sun light by utilizing inorganic elements such as Carbon dioxide, CO2, minerals and water. In this process, Oxygen is released as a by-product. Examples: Green Plants, Blue-green Algae or Cyano-bacteria and a number of other unicellular organisms such as Euglena, Volvox etc. Thus, the Photosynthesis maintains atmospheric oxygen levels and supplies all of the organic compounds and most of the energy necessary for life on Earth.
Chemotrophs are organisms that obtain energy by the oxidation of chemical compounds, either organic or inorganic compounds in their environments. Those organisms utilizing organic compounds for their energy needs are called Chemoorganotrophs and those utilizing inorganic compounds are called Chemolithotrophs. Examples: Bacteria and Archaea [a kingdom of single-celled organisms that usually live in harsh environments]
The ability of chemoautotrophs to make their own food from chemicals enables them to live in rather extreme conditions. Some bacteria that are chemoautotrophs are found in deep-sea thermal vents and/or very acidic environments. These are believed to be some of the earliest living organisms since they would have been able to live off of the chemicals that were present early on in existence of the earth. Some of the chemicals that they use are iron, nitrogen, sulfur and magnesium.
Nitrogen-fixing bacteria are another example of chemoautotrophs. They use the nitrogen that is located in the soil as an energy source and convert it into nitrates. This supplies an organic food source for themselves and nearby plants. Cyanobacteria are a type of nitrogen-fixing bacteria that live in water as opposed to soil.
[Additional information: Fungi and other organisms who gain their biomass from oxidizing organic materials are called decomposers and are not primary producers. However, lichens located in tundra climates are an exceptional example of primary producers. It is to be noted that lichen represent the symbiosis or symbiotic relationship between a decomposer, Fungus and a photo-autotroph, photosynthetic algae. In certain lichens, there is an additional nitrogen fixing cyanobacteria, under the protection of a fungus.]

9. Marine ecosystems cover approximately 71% of the Earth's surface and contain approximately 97% of the planet's water. They generate 32% of the world's net primary production. They are distinguished from freshwater ecosystems by the presence of dissolved compounds, especially salts, in the water. Approximately 85% of the dissolved materials in seawater are sodium and chlorine. Seawater has an average salinity of 35 parts per thousand (ppt) of water. Actual salinity varies among different marine ecosystems. Freshwater ecosystems cover 0.80% of the Earth's surface and inhabit 0.009% of its total water. They generate nearly 3% of its net primary production. Freshwater ecosystems contain 41% of the world's known fish species. There are three basic types of freshwater ecosystems: Lentic: slow moving water, including pools, ponds, and lakes; Lotic: faster moving water, for example streams and rivers and Wetlands: areas where the soil is saturated or inundated for at least part of the time.
The estuaries are the most productive aquatic ecosystems among the aquatic ecosystems.
12. Ecological pyramids are a graphical representation designed to show the numbers, biomass or energy at each trophic or food level in a food chain from producers to the top consumers in a given Ecosystem. In the ecological pyramid, the producers form the base and the final consumer occupies the apex. Three important pyramids are-Pyramid of Numbers, Pyramid of biomass and Pyramid of energy. The size of the portion of the diagram associated with each trophic level illustrates the amount of energy, biomass, or number of individuals found in each trophic level. These pyramids mirror the food chain in their composition.
Pyramid of Numbers: Pyramid of numbers is usually upright. In other words, the producers or green plants and algae always make up highest numbers in a particular ecosystem. The number of herbivores which eat green plants/algae is lesser than producers. Similarly, the number of carnivores which feed on herbivores, is still less in number than the herbivores.  
In a cropland ecosystem, the crops are more in numbers. The gross hoppers feeding on crop plants are lesser in number and the frogs feeding on them are still lesser. The snakes feeding on the frogs would be fewer in numbers.
Crop---Grasshopper----Frogs---Snakes---Hawks
In a grassland ecosystem, the grasses are maximum in number and the consumers would be tapering till the apex of the pyramid.
Grass--- Grasshopper---Lizard---Hawks
In a pond ecosystem, the number of biotic elements decreases in the following order.
 Phytoplankton---Zooplankton---Fishes-Snakes
However, the Pyramid of number is inverted in case of parasitic food chain, as the number of parasites always outnumbers the host they affect and the number of hyper parasites which inflict on parasites would be always more than the number of parasites
Tree---Birds/hosts---Parasites---Hyperparasites
Pyramid of biomass: Biomass refer to the total weight of living matter per unit area. In an ecosystem, the biomass decreases from the producer level to the consumer level.
Pyramid of biomass of terrestrial ecosystem is upright because at each successive trophic level the biomass tends to decrease, starting from primary produces and ending in top consumers.
In a grassland ecosystem, the biomass of grasses is the maximum, and it gradually decreases towards the consumer level in the following order
Grass---Mouse---Snake---Hawk
Grass---Grasshopper---Lizard---Hawk
In a forest, the biomass of trees is the maximum and the biomass of top consumers is the minimum. The same is depicted as under
Plants---Deer---Fox---Tiger
Plants---Rabbit---Fox---Lion
The pyramid of biomass in aquatic ecosystem is inverted. The biomass of the aquatic plants is would be very less when compared to weight of the fishes and the biomass of fishes would be less than the bigger fishes and their weight is further lesser than the weight of the killer whales/top carnivores in the water.  
Pyramid of Energy: The energy flow in an ecosystem is from the producer level to the top consumer level. At each trophic level 80 to 90% of the energy is lost as a heat. The amount of energy in all food chains decreases from the primary producers to top consumers. Hence, the pyramid of an energy is always upright and never be inverted.
In the given question, the only one food chain which can have inverted pyramid is parasitic food chain.

13. Biomagnification, also known as bioamplification or biological magnification, occurs when the concentration of a substance, such as DDT or mercury, in an organism exceeds the background concentration of the substance in its diet. This increase can occur as a result of:
·         Persistence – where the substance can't be broken down by environmental processes
·         Food chain energetics – where the substance concentration increases progressively as it moves up a food chain
·         Low or non-existent rate of internal degradation or excretion of the substance – often due to water-insolubility
Biological magnification often refers to the process whereby certain substances such as pesticides or heavy metals move up the food chain, work their way into rivers or lakes, and are eaten by aquatic organisms such as fish, which in turn are eaten by large birds, animals or humans. The substances become concentrated in tissues or internal organs as they move up the chain. Bioaccumulants are substances that increase in concentration in living organisms as they take in contaminated air, water, or food because the substances are very slowly metabolized or excreted. Those substances which can be metabolized [destructed into smaller and useful parts] by the living beings will never accumulate in the food chain.
     
15. The excessive apply of nitrogen and phosphate fertilizers in land would reach their final destination during rains or otherwise into the water bodies such as lakes, ponds, rivers and finally to the sea. The lakes generally not rich in nutrients to support excess algae and such lakes have clear and transparent water. The primary producers represent a few microscopic algae, certain under water rooted plants and the clear water allows sunrays reach bottom of the lake and facilitate photosynthesis. The oxygen released by the rooted plants and algae promote oxygen requirement of the plants and animals for their respiration. The BOD [Biological Oxygen Demand of such water would be minimal as the organic matter in the water is very less. With the excess supply of vital nutrients like nitrogen and phosphorus, the algae absorb them and grow beyond the carrying capacity of the pond and create algal blooms on the surface of the water body. These blooms enhance the organic material in the pond or lake. It prevents sun light from reaching the bottom of the pond causing killing of the underwater plants in due course. This deprives pond of oxygen which is required by the animals and plants for their respiration. The BOD and COD [explained below] would go up further depleting the oxygen levels in the water.
     Thus nutrients run-off into the water body first starts the process of “Eutrophication” [Eu means good and trophic means nutrients].  In other words, lakes are provided with rich nutrients with the following effects.
ü  Algal blooms and eutrophication
ü  Acidification of water and destruction of fish
ü  Long term declines in marine and aquatic fisheries and biodiversity
The excess supply of nitrogen and phosphorus would enhance the biomass of the water bodies, but, would not result in destruction of flora and reduction in the biomass of the ecosystem. However, the destruction of plant and animal life in a pond over a long period of time is a consequence of eutrophication of lakes, but NOT due to mere over supply of nitrogen and phosphorus and therefore the correct option is “d”.  

[Biological Oxygen Demand (BOD) versus Chemical Oxygen Demand (COD):  
Biochemical oxygen demand (BOD) is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. The term also refers to a chemical procedure for determining this amount. This is not a precise quantitative test, although it is widely used as an indication of the organic quality of water. The BOD value is most commonly expressed in milligrams of oxygen consumed per litre of sample during 5 days of incubation at 20 °C and is often used as a robust surrogate of the degree of organic pollution of water.
BOD can be used as a gauge of the effectiveness of wastewater treatment plants. It is listed as a conventional pollutant in the U.S. clean water Act. BOD can’t be confused with the amounts of oxygen required by the living animals and plants for their respiration.
The Chemical Oxygen Demand (COD) is the amount of dissolved oxygen which is needed for the oxidation of all organic substances in water in mg/l or g/m3. The COD (Chemical Oxygen Demand) is closely related to the laboratory standard method named Dichromate-Method. This is used as an indicator of pollution in the water bodies and indicative of quality of water.
BOD is similar in function to Chemical oxygen Demand (COD), in that both measure the amount of organic compounds in water. However, COD is less specific, since it measures everything that can be chemically oxidized, rather than just levels of biologically active organic matter.]
19. A mutualistic relationship is when two organisms of different species "work together," each benefiting from the relationship. Organisms in a mutualistic relationship evolved together. Each was part of the other's environment, so as they adapted to their environment, they "made use of" each other in a way that benefited both.
1. The relationship between grazing animals and birds. Ox-pecker (a kind of bird) and white heron are the birds those sit on the grazing animals and eat ticks and other parasites that live on their skin. They warn the grazing animal of the approaching predator by just flying away from the beast. The birds get food and the beasts get pest control and alarm on the approaching predator.
2. The bee and the flower. The bees collect the nectar and help the plants by effecting cross-pollination.
3. The spider crab and the algae. Spider crabs live in shallow areas of the ocean floor, and greenish-brown algae lives on the crabs' backs, making the crabs blend in with their environment, and unnoticeable to predators. The algae get a good place to live, and the crab gets camouflage.
4. The bacteria and the human. A certain kind of bacteria lives in the intestines of humans and many other animals. The human cannot digest all of the food that it eats. The bacteria eat the food that the human cannot digest and partially digest it, allowing the human to finish the job. The bacteria benefit by getting food, and the human benefits by being able to digest the food it eats.

20. Symbiosis is an association between two species where both species benefit and mostly they can’t live separately on their own. For example, Lichens, Corals etc. In lichens, the fungus provide living environment to the soft algae, absorb carbon dioxide, CO2, water and minerals from atmosphere which are essential for photosynthesis. The algae produce food and share with the fungus. In this case, one symbiont would not be able to live without another. Same is the case with the Corals where coral polyps and zooxanthelle algae are in symbiotic relationship with one another.    
Another interesting example of Symbiosis is the co-evolution of flowering plants and the animals that pollinate them. Many plants that are pollinated by insects, bats and birds have highly specialized flowers modified to promote pollination by a specific pollinator that is also correspondingly adapted. The first flowering plants in the fossil record had relatively simple flowers. Adaptive speciation quickly gave rise to many diverse groups of plants, and, at the same time, corresponding speciation occurred in certain insect groups. Some groups of plants developed nectar and large sticky pollen, while insects evolved more specialized morphologies to access and collect these rich food sources. In some taxa of plants and insects the relationship has become dependent, where the plant species can only be pollinated by one species of insect. Honey bees are the main pollinators of flowering plants. Humming birds are chief avian pollinators. Here, due to co-evolution of the plant and animal species, they become obligatory to each another.
Symbiotic relationship can exist between two plant species; one plant and one animal and between two animals. Hence the correct option is “a”.

[In mutualism, the relationship is facultative [both partners can live independently without any problem], but in symbiosis, the relationship is obligatory, each can’t live without the another]

21. Cross Pollination Definition: Cross pollination is also known as allogamy and is opposite of self pollination. In self pollination, as the name indicates pollen from same flower or different flower from the same tree fertilizes with the female gamete. Cross Pollination occur when pollen grains are transferred to a flower from a different plant. The plants that undergo cross pollination often have taller stamens than their carpels. They use mechanisms to ensure that the pollen grains are spread to other plants' flowers. The process of cross pollination requires the help of abiotic or biotic agents like wind, water, insects, birds, bats, snails and other animals as pollinators. 

[Additional Information:

Abiotic Pollination

Abitoic pollination is a process where the pollination is carried out without the involvement of other organisms. About only 10% of plants are pollinated without animal agents. 

Anemophily

Anempophily is the most common form of abiotic pollination, it is pollination by wind. The flowers that are pollinated by wind show the following characters:
  • They are usually unisexual flowers. 
  • Stamens are exposed freely with versatile anthers.
  • The pollen grains are light, smooth, dry and not easily wetted by rain. 
  • Pollen is produced in enormous quantities. 
  • The stigma is large and well exposed to receive the pollen grains. 
  • The flowers are small, inconspicuous with no color, odor or nectar. 
Examples of wind pollinated plants are coconut, palm, maize, grasses etc. 

Hydrophilly 

Hyrdophily is the pollination by water and it occurs in aquatic plants as they release pollens directly into the surrounding water medium. Not all aquatic plants are pollinated by water, most of them bear flowers above the water surface and are pollinated by wind or insects. 

Biotic Pollination

Biotic pollination is the process of pollination that requires pollinators like some organisms that transfer the pollen grain from the anther to the receptive part or the stigma of the carpel or pistil. 

Entomophily or Insect Pollination 

Entomophily is the pollination carried out by insects. This process of pollination occurs in plants where they have colored petals and a strong odor to attract insects like bees, wasps and some ants, beetles, moths and butterflies. 
The insects visit flowers in order to collect nectar, edible pollen, during this visit the pollen grains gets dusted on the body. When the insect visits another flower the body brushes against the stigma and transfers the pollen to bring about pollination. 
Example: Rose, Poppy, etc.
Some features seen in insect pollinated flowers are:
  • The flowers are large, and brightly colored. 
  • The flowers usually have pleasant fragrance and sweet nectar. 
  • The pollen grains are usually rough and sticky and they show spiny outgrowths. 

Zoophily

It is the pollination performed by vertebrates like birds and bats. Plants that get pollinated by bats and moths are usually have white petals and a strong scent. Plants that are pollinated by birds usually develop red petals and rarely have any odor. 
Example: Species of Arctium (burdock), Acaena and Galium aparine

Ornithophily or Bird Pollination 

Humming birds, sun birds and honey eaters are common bird pollinators. Birds obtain nectar from flowers. Flowers that are pollinated by birds have funnel shaped or tubular corollas and are brightly colored. The floral parts of these plants are leathery and produce large amount of nectar and pollen grains which are sticky. 

Chiroperophily or Bat Pollination 

Pollination by bats happens in the tropics. Bats visit flowers that are large and that emit strong odor. The flowers pollinated by bats produce more nectar and have large number of stamens. 

Anthropophily 

Anthropophily is pollination performed by humans, it is usually artificial pollination used in hybridization techniques.]

22. Commensalism: Its literal meaning is “feeding together”. Commensalism is a relationship in which one organism benefits while the other is neither benefitted nor harmed.
1. Sucker fish and shark [ as explained in the question]
2. The barnacles that grow on whales and other marine animals. The whale derive no benefit from the barnacle, but the barnacles gain mobility, which helps them evade predators, and is exposed to more diverse feeding opportunities.
3. Laying of eggs by the Cuckoo/Koel in the nest of crow would benefit the former in incubation of its eggs and survival of the species where as it would not affect the crow in any manner, except sharing of some food by it to the chick of cuckoo.
 4. The crab, Polyonx lives in the tube made by a Polychaete worm, Chaetopterus, whereby the latter is not affected where as the crab gets protection from enemies, food from outgoing water and oxygen. [Crabs have jointed legs and hence it is an arthropod, arthro means joint and pod means leg whereas Polychaetes are ringed worms belong to the phylum Annelida, meaning ringed worms to which Earth worms and leaches belong to] 
[Additional information: There are four basic types of commensal relationships. Chemical commensalism occurs when one bacteria produces a chemical that sustains another bacteria. Inquilinism is when one organism lives in the nest, burrow, or dwelling place of another species. Metabiosis is commensalism in which one species is dependent on the other for survival. Phoresy is when one organism temporarily attaches to another organism for the purposes of transportation.]

23. Refer to the carbon cycle in the book followed by you. Carbon, is one of the chief elements of organic matter in different combinations Hydrogen and oxygen atoms. Once the living matter become dead and undergoes decomposition by the detritus feeders and finally by the decomposing bacteria and fungus, the carbon is released into the atmosphere. If the organic matter is submerged underground, become part of the sedimentary layers and due to pressure from top for long periods of time, get converted into coal, fossil fuels, shale gas etc. The chief position of carbon in atmosphere is in the form of Carbon dioxide which is 0.03%.  
           1. Accumulation of un-decomposed organic matter in the under surface of evergreen
               Forests would not release CO2 unless it is acted upon by the decomposers.  
           2. Formation of fossil fuels underground under pressure and passage of time is also
               would not release CO2 into atmosphere.  
           3. Bio-degradation by the decomposers release CO2 into the atmosphere
           4. Respiration of the plants release CO2 into atmosphere. It is to be noted that plants
             do respire. They require oxygen for oxidation of food within their bodies and 
             this  oxidation release of CO2. 
           5. Photosynthesis of Green Plants absorbs carbon dioxide.  
Hence, correct option is “b”.

25. Eutrophication is a process of providing excessive richness of nutrients in a lake or other body of water, frequently due to run-off from the land, which causes a dense growth of plant life.
In other words, it is a process whereby a water body becomes enriched with organic nutrients; (Eu means good and trophic means nutrients or food, a water body full of nutrients). The excessive growth of plants and algae in the initial phase of eutrophication is a consequence or result of it. The slow accumulation of organic matter in the water, rise of BOD and COD and slow death of lake over a period of time are result of eutrophication, but not the eutrophication itself.
Hence, question shall be always understood in a logical and common sense way. Let us not confuse that Eutrophication is accumulation of biomass or accumulation of organic matter in the water body. They are only result of it. Eutrophication simply means over supply of nutrients in a water body and immediate result would be enhancement of biomass due excessive growth of plants and algae. This question is intended to test both definition as well as result of it. Hence, the correct option is “a”.  

26. As explained above, eutrophication enhances the growth of algae and plants and thereby enhances the organic content of the water. The excess organic content and their degradation by living organisms [BOD] and other degradation [COD] causes more and more suspended matter in the water. Thus eutrophication decreases the quality and transparency of water. 

27. All the statements are correct except, 3. Hence answer is “c”. Unlike as given in the given, the penetration of light and rise in water temperature increases the BOD, as the temperatures enhances the decomposition activity. 

28. The Chemical Oxygen Demand [COD] is a measure of impurities found in the water and all other statements are factually incorrect.  

29. The Chemical Oxygen Demand (COD) is the amount of dissolved oxygen which is needed for the oxidation of all organic substances in water in mg/l or g/m3. The COD test is commonly used to indirectly measure the amount of organic compounds in water. Most applications of COD determine the amount of organic pollutants found in surface water such as lakes and rivers, or wastewater, making COD a useful measure of water quality. It is expressed in milligrams per liter (mg/L) also referred to as ppm (parts per million), which indicates the mass of oxygen consumed per liter of solution.COD analysis is a measurement of the oxygen-depletion capacity of a water sample contaminated with organic waste matter. Specifically, it measures the equivalent amount of oxygen required to chemically oxidize organic compounds in water.
Why Measure COD?
COD is used as a general indicator of water quality and is an integral part of all water quality management programs. Additionally, COD is often used to estimate BOD (Biochemical Oxygen Demand) as a strong correlation exists between COD and BOD, however COD is a much faster, more accurate test.

32. The symbiotic association of the mycelium of a fungus with the roots of plants. The majority of vascular plants have mycorrhizae. The fungus assists in the absorption of minerals and water from the soil and defends the roots from other fungi and nematodes, while the plant provides carbohydrates to the fungus

34. Invasive species are plants, animals, or pathogens that are non-native (or alien) to the ecosystem under consideration and whose introduction causes or is likely to cause harm to the Ecosystem and local species. They have several inherent advantages when compared to native species in absorption of water and minerals from soil, resistance to drought conditions and diseases. Thus they emerge as winners in the ecosystem of their invasion. The famous invasive plants in India are 
1. Eichhornia crassipes, commonly known as water hyacinth, is an aquatic plant native to the Amazon basin, and is often considered a highly problematic invasive species outside its native range. It is monocot [plant seed having one cotyledon in the seed] flowering plant, freely float in water due to air sacs in its stem. It would not allow other aquatic plants to grow and has been emerged as major threat to the water bodies due to excessive growth.

2. Parthenium hysterophorus or Congress grass is a species of flowering plant in the aster family, Asteraceae that is native to the American tropics. Common names include Santa Maria Feverfew and White-top Weed.  It is a major agricultural weed in India, draining the energy, manure and money from the farmers. 
3. Lantana camara, also known as big sage, wild sage, red sage, white sage and tickberry, is a species of flowering plant within the verbena family, Verbenaceae, which is native to the American tropics. [Rural kids suck the nectar of these flowers and eat its fruits] [See the pictures of these plants in the net for clarity]  
 This question has been set on two parameters. Whether you know the invasive species by their name or strong in history and culture of India. Neem, Pipal and Banyan trees are mentioned in our Vedas and even in Indus Civilization. Hence they are native plants and definitely not invasive.  Hence, answer is “a”.              

35 and several other questions on lichens and succession on bare rock.

Lichen is a lower plant, classified under the group, “Fungi” and represents symbiotic relationship between Alga and Fungus. The fungus absorbs the water, CO2 and minerals from atmosphere and provide living environment to alga and algae will provide food to fungus made by way of photosynthesis. The ‘vegetative’ part of the lichen is called thallus, and this can develop into a morphologically diverse range of structures: multiply branched tufts, flat, leaf-like structures, filamentous structures, aggregations of tiny plates, thin crusts, layers of powdery granules, or hardly any visible thallus at all.

Classification of lichens:

The lichens are named after their body shapes and among them the important ones are- Crustose, Foliose and Fruiticose lichens.

Crustose [Crusty] lichens:

The plant body or thallus forms a crust over the substrate and the edges are flat, un-lobed and closely attached to the substrate. [There is an upper cortex, at least in early development, but no lower cortex and the medulla are in direct contact with the substrate and commonly grow into it to some extent]. The lichen normally cannot be collected / removed intact without collecting a portion of the substrate along with it. Algae are usually dispersed.

These are some of the largest and perhaps most complex lichens. The thallus generally forms flat, leaf-like lobes, with differentiated layers of tissue, the upper and lower cortices (Singular cortex], forming the upper and lower surfaces. The lobes are commonly, but not always, oppressed to the substrate surface, but can be lifted away. The fungus forms the sandwich with the algal mat in the middle. The lichen is attached / fastened to the substrate by small rootlets called “rhizines”
Fruticose (shrubby) lichens:
The thallus is extended up into a tufted or pendant branched structure with fungal layer outside and algal mat within. There are no rhizines in this type of lichens; they are firmly attached to the substrate only at bases and usually with a circular cross section. The branches show vertical growth, appears like a threads. The lichen looks either shrub-like small mounds or beard-like, small tagles looking like Spanish moss when hanging down. 

 

Acts as a biological indicators: Lichens are very sensitive to pollution and there by acts as a “biological indicators” of climate change. The lichens are injured by Sulfur dioxide [SO2] and also show sensitivity to some other pollutants such as heavy metals and ground level ozone. The lichens absorb moisture mostly from the atmosphere and that is the reason they can survive on a substrata like bare rock, bark of the trees, buildings etc.  Lichens are used as a biological indicator for the SO2 pollution, as it is their chief destroyer. In other words, damage to lichens indicates SO2 pollution.

Bio indicators are living organisms those respond in an especially clear way to a change in the environment. The lichens are useful bio-indicators  for air pollution, especially Sulfur dioxide, SO2, since they derive their water and essential nutrients mainly from the atmosphere rather than from the soil. It also helps that they are able to react to air pollutants all year round. Compared with most physical or chemical monitors, they are inexpensive to use in evaluating air pollution

Lichens can also be used to measure toxic elemental pollutants and radioactive metals because they bind these substances in their fungal threads where they concentrate [bio-accumulation] over time. Environmental scientists can then evaluate this accumulation to determine the history of local air and its pollution levels.

 In ecological Succession: The crustose lichens are the pioneers in xeroc succession, followed by foliose and fruticose lichens. The reason is that crustose lichens have simple and scant bodies / thallus which can be supported with least water and other requirements. The size of thallus goes up in foliose lichens requires more water and other requirements and would be still higher in the case of fruticose lichens.

On space experiments: A new study shows that a large percentage of hardy lichens exposed to space conditions for one and a half years remain viable after returning to Earth. The lichen Xanthoria elegans was part of the lichen and fungi experiment (LIFE) on the International Space Station (ISS).
[See the pictures of the different lichens in the net for clarity]
36. Reverse osmosis (RO) is a water purification technology that uses a semipermeable membrane to remove larger particles from drinking water. In reverse osmosis, an applied pressure is used to overcome osmotic pressure, whereby the salts are removed from water against the gradient and pure water is created for domestic use. [Osmosis is the spontaneous net movement of solvent molecules through a semi-permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides. The different aquatic animals such as fresh water, sea water and estuary animals use different methods to maintain stable salt content in their bodies]

39. There is no doubt that abiotic factors such as light, temperature, water and environment too play a major role in survival of an organism and they acts as a limiting factors in different environments. Acclimatization to the newly found environment or changes in the environment is very essential for the survival of the species. Here the question asked is on those biotic factors affecting survival of an organism in the Ecosystem, but not abiotic factors. Hence the correct option is “b”.

40. The succession starts with pioneer community and ends in mature climax community. [Community is a group of different species living in a biome. It include plants and animals] A seral community (or sere) is an intermediate stage found in ecological succession in an ecosystem advancing towards its climax community. In many cases more than one seral stage evolves until climax conditions are attained. A prisere is a collection of seres making up the development of an area from non-vegetated surfaces to a climax community.
A seral community is the name given to each group of plants within the succession. A Primary describes those plant communities that occupy a site that has not previously been vegetated. These can also be described as the Pioneer community. Depending on the substratum and climate, a seral community can be one of the following:
Hydro sere: Community in water
Litho Sere: Community on rock
Psammo sere: Community on sand
Xero sere      : Community in dry area
Halos sere    : Community in saline body (e.g. a marsh)
Seral communities in Secondary succession can be seen in a recently logged coniferous forest. During the first two years, grasses, heaths and herbaceous plants such as fireweed will be abundant. After a few more years shrubs will start to appear; and about six to eight years after clearing, the area is likely to be crowded with young birches. Each of these stages can be referred to as a seral community.
In the far western part of North America, Chaparral plant communities are typically controlled by periodic natural wildfires. In the southern portion of the Coast Ranges and in Southern California chaparral, toyon is often a locally dominant taxon in seral communities transitional between coastal sage scrubs.   

42. In Ecology, the term "population" is interpreted differently in various sciences:
  • In population ecology a population is a group of individuals of the same species inhabiting the same area.
  • In human demography, a population is a set of humans in a given area.
  • In genetics, a population is a group of interbreeding individuals of the same species, which is isolated from other groups.

43. Ecological Niche:
An ecological niche is mode of existence that a species has within an ecosystem.
Essentially it is the sum of all activities and relationships a species has while obtaining and using the resources needed to survive and reproduce.
A species' niche includes:
a. Habitat - where it lives in the ecosystem
b. Relationships - all interactions with other species in the ecosystem
c. Nutrition - its method of obtaining food.
[Additional information: Fundamental Niche: The fundamental niche is the potential niche, in other words the niche that would prevail in the absence of competition and other factors that might constrain its acquisition and use of the resources.
Realized Niche: The actual niche an organism occupies as a result of competition for its resources, problems in acquiring those resources. The realized niche is always smaller than the fundamental niche
Competition Between 2 Different Species for a Niche:
a. 2 Species partially share a niche: both compete in the overlapping parts of the niche for resources, nesting sites, or territory. If the overlap is minimal, both species can coexist.
b. 2 Species have the same niche: both compete head to head in the niche for resources, nesting sites, or territory. One of the species will be superior to the other in utilizing the niche. The 2nd species disappears from the ecosystem.]
44. Insectivorous plants are also called as carnivorous plants. They have poorly developed root systems and are often found in nitrogen-deficient sandy or boggy or acidic soils. In order to get the nitrogen and other nutrients required by them they have modified their leaves as traps for trapping, ‘digesting’ and absorbing insects. The examples are Nepenthes, picture plant, have a tubular leaf to trap insects; the Venus's fly-trap (Dionaea muscipula); the sundews (Drosera) snare insects with a sticky substance and then enclose them in their leaves; Bladderworts (Utricularia) suck insects into their underwater bladders. They  trap spiders, crustaceans, mites, and protozoans, as a nitrogen source. [See the pictures of these plants in net for clarity]
46. A eukaryote is any organism whose cells contain a nucleus and other organelles enclosed within membranes. A prokaryote is a single celled organisms that lacks a membrane-bound nucleus (karyon), mitochondria, or any other membrane-bound organelles. The word prokaryote comes from the Greek “before" and καρυόν (karyon) “ nut or kernel” .  All the intracellular water-soluble components (proteins, DNA, and metabolites) are located together in the same volume enclosed by the cell membrane, rather than in separate cellular compartments. Prokaryotes, however, do possess protein-based micro-compartments, which are thought to act as primitive organelles (protein-bounded and lipid-bounded organelles). Some prokaryotes also have multicellular stages in their life cycles, such as myxobacteria, or create large colonies, like cyanobacteria.

Stenohaline describes an organism, usually fish that cannot tolerate a wide fluctuation in the salinity of water. Stenohaline is derived from the words: "steno" meaning narrow, and "haline" meaning salt. Many fresh water fish, such as goldfish tend to be stenohaline and die in environments of high salinity such as the ocean. Many marine fish, such as haddock, are also stenohaline and die in water with lower salinity.
Alternatively, fish living in coastal estuaries and tide pools are often euryhaline (tolerant to changes in salinity) as are many migratory fishes/species which have life cycle requiring tolerance to both fresh water and sea water environments such as Salmon and herring, Tunas, Eel fishes and Hilsa Ilisha [Pulasa in telugu] .

47. A pheromone is a chemical substance produced by an animal which changes the behavior of another animal of the same species. They can be described as behavior-altering agents. They are also called “ecto-hormones” as they are secreted outside the body with a specific purpose of influencing the behavior of its own species. [Whereas hormones are chemical substances released insider the body and they affect the individual internally.]
Pheromones can be secreted to trigger many types of behaviors, including: Alarm [honey bees], to follow a food trail [ants and termites], Sexual arousal, to tell other female insects to lay their eggs elsewhere, to mark the territory [dogs and most of the wild animals], to bond mother-baby [most of the mammals, including cattle and sheep] etc. The honey bees which are being killed release stress pheromones which attract a swarm of honey bees to attack the killer serve as the best example of the purpose of pheromones. 
48. Peroxy-acyl nitrates, Acyl peroxy nitrates [APN or PANs) are powerful respiratory and eye irritants present in photochemical smog. They are nitrates produced in the thermal equilibrium between organic peroxy-radicals by the gas-phase oxidation of a variety of volatile organic compounds [VOCs]), or by aldehydes and other oxygenated VOCs oxidizing in the presence of NO2.
[For example, peroxyacetyl nitrate, CH3COOONO2:
Hydrocarbons + O2 + NO2 + light → CH3COOONO2
The general equation is;
CxHyO3 + NO2 → CxHyO3NO2 ]
They are good markers for the source of VOCs as either biogenic or anthropogenic, which is useful in the study of global and local effects of pollutants.

PANs are both toxic and irritating, as they dissolve more readily in water than ozone. They are lachrymators, causing eye irritation at concentrations of only a few parts per billion. At higher concentrations they cause extensive damage to vegetation. Both PANs and their chlorinated derivates are said to be mutagenic, as they can be a factor causing skin cancer.
PANs are secondary pollutants, which mean they are not directly emitted as exhaust from power plants or internal combustion engines, but they are formed from other pollutants by chemical reactions in the atmosphere. Free radical reactions catalyzed by ultraviolet from the sun oxidize unburned hydrocarbons to aldehydes, Ketones and dicarbonyl compounds, whose secondary reactions create peroxyacyl radicals, which combine with nitrogen dioxide to form peroxyacyl nitrates.
Since they dissociate quite slowly in the atmosphere into radicals and NO2, PANs are able to transport these unstable compounds far away from the urban and industrial origin. This is important for troposphere ozone production as PANs transport NOx to regions where it can more efficiently produce ozone.

50 and 52. Adsorption is a process that occurs when a gas or liquid solute accumulates on the surface of a solid or a liquid (adsorbent), forming a molecular or atomic film (the adsorbate). It is different from absorption, in which a substance diffuses into a liquid or solid to form a solution. Thus, this method is used to control the gaseous and liquid pollutants.
An electrostatic precipitator (ESP) is a filtration device that removes fine particles like dust and smoke, from a flowing gas using the force of an induced electrostatic charge minimally impeding the flow of gases through the unit. Electrostatic precipitators are used for capturing fly ash in coal fired power plants.
 [Additional information: Cars with conventional gasoline engines are now routinely fitted with catalytic converters that remove some (though not all) of the pollutants from the exhaust gases.]

54. Estuary is not formed wherever river meets sea. It is formed in the confluence of river and sea where congenial conditions exist for the formation of estuary. Hence, answer is “a”.
55. The Mangrove forests are located in the river mouths where the river meets Sea, hence they are exposed to both fresh and salt water. Thus the mangrove plantations are tolerant to wide verity of saline conditions. They substratum on which these plants grow are poor in oxygen and filled with water. Thus, they got aerial roots for absorbing oxygen for their respiration. The excess salt in the body is secreted out of the body by the leaves. The roots alone cannot support the plant for fastening it firmly to the ground and therefore adventitious roots or supporting roots arising from the aerial stem to support the plant.  Hence answer is “b”.   

56. Sundarbans derive their name due a tree species called Sundari (Heritiera fomes), which is facing big threat from timber mafias. Sundarbans is a very unique tiger habitat, which is the largest mangrove forest in the world. This single extensive mangrove forest is geographically spread in two countries -- India and Bangladesh. India has 40 per cent of Sundarban while its larger part is in Bangladesh. The low area of the landscape is submerged during the high tide and exposed again after every six hours. Trees have special roots for breathing because of water logged soil. These roots called pneumatophores play a very important role in the food chain also. Spotted deer and Rhesus macaque are always feeding on the tender part of these roots. Rhesus macaques are also using these aerated roots for walking on the surface to avoid mud. Sundarbans are unique in housing wide variety of kingfishers such as the pied, brown winged, common, black capped, white throated, collared, stroke billed, Ruddy, among others. Kingfishers are indicators of the role of fishes in the ecosystem. This is also home to a large crocodiles species called saltwater crocodiles. The male saltwater crocodile can attain 1,000 kilogramme weight and 20 feet in length.

The mangroves of west coast of India are not as prominent as in East coast. Hence, the correct option is “d”.  

57. Hunting of wild animals such as tiger, crocodiles and dolphins and carving out of biosphere reserves and national parks are not responsible for/linked to the destruction of Mangrove forests in Indian subcontinent. Hence, the correct option is “a”.

58. Recently, it is found that good quality corals or unbleached corals are found at Malvan in the Sindudurg district of Maharashtra.  Sindudurg is the southernmost district of MR, bordering Karnataka.
               
59. All the statements are correct. The beautiful colors of the corals are due to presence of symbiotic zooxanthellae algae, not because of the coral itself.  

60. Those substances which normally occurring in the environment and acquire the status of a pollutant when their con­centration gets increased due to the unmindful activities of man are called as “Quantitative pollutants”.  For exam­ple, carbon dioxide, if present in the atmosphere at 0.03%, it is not pollutant, but exceeding this levels, it act as a pollutant and causes measurable effects on humans, animals, plants or property. On the other hand, those substances which do not normally occur in nature but are added by man are called as “Qualitative pollutants”, for example, insecticides, pesticides, chloroflouro carbons etc.

62. Ground level ozone is a secondary pollutant and is formed through a complex reaction involving hydrocarbons and Oxides of Nitrogen [NOx] in the presence of Sunlight. PAN is one of the main secondary pollutants of air and discussed elsewhere. Smog is also a secondary pollutant formed from the primary pollutants in the presence of Sunlight. But, Sulphur dioxide is a primary pollutant released from the thermal power plants and industries.

 

63. Two beneficial algal species discovered off the west coast of India

Recently, two beneficial algal species Ulva paschima Bast and Cladophora goensis Bast were discovered off the west coast of India.
They were discovered by Dr. Felix Bast and two research students working with him. These findings were published in the journals PLOS One and Indian Journal of Marine Sciences.

Key Characteristics of discovered algal species

·         Carbon capture properties- These species have excellent carbon capture properties i.e. ability to absorb carbon dioxide from the atmosphere. So it can be used as bio-fuels and help reduce global warming.
·         Endemic- Both of them are endemic species to the western coast of India. So, their cultivation is not going to cause any environmental harm and reduces the risk of bio invasion in this region.
·         Bloom forming- Both species being bloom forming they have spontaneous growth. So there is no need for any expensive cultivation systems such as photo bioreactors or extensive use of fertilizers/pesticides. They can grow sporadically at shorelines and can sequester CO.
·         Medicinal values- Both species have similar characteristic like other algal species which have Kahalalide-F, used in clinical trials against prostate and breast cancers. So they can be used in Pharmaceutical products.
It should be noted that, this discovery was the first molecular study on Indian algae, and first algal species discoveed in past 40 years.

65. Major greenhouse gases are CO2, Methane, Nitrous Oxide [N2O], Ground level Ozone, and Hydro chlorofluorocarbons (HCFCs). Luckily, Nitrogen, N2 which makes up 78% of air is not a greenhouse gas. [Oxygen makes up 21 % of air].  Now the major part of climate talks is replacement of chlorofluorocarbons with Hydro chlorofluorocarbons (HCFCs) which would not affect atmospheric ozone. It is to be noted that chlorofluorocarbons are major ozone depleting substances. [See Kyoto protocol]. But the problem with HDFCs is that they are greenhouse gases which will aid in global warming.

68. The correct question would be “Which of the following statements is NOT true about Carbon Monoxide”?
Carbon monoxide [CO] is a colorless, odorless, and tasteless gas that is slightly less dense than air. It is toxic to humans when encountered in concentrations above about 35 ppm [parts per million] although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal biological functions.  In the atmosphere, it is spatially variable and short lived, having a role in the formation of ground-level ozone. It acts as neurotransmitter and along with nitric oxide and hydrogen sulfide acts as anti-inflammatories, vasodilators and promotes neo-vascular growth. In concentrations above 35 ppm, it couples with hemoglobin in the red blood corpuscles of the blood and paralyses the oxygen transport to the cells, thus long exposure kills the person due to asphyxia or non-availability of oxygen to the body.  Interestingly, it is NOT a greenhouse gas. Hence, answer is “b”.

69. India started adopting European emission and fuel regulations for four-wheeled light-duty and for heavy-duty vehicles since 2000. India’s own emission regulations still apply to two- and three-wheeled vehicles. At present Bharath III fuel emission norms are under implementation throughout India and Bharath IV stage fuel emission norms in 13 cities of India.  
[Additional information: The National Auto Fuel Policy, announced on October 6, 2003, envisioned a phased program for introducing Euro 2 - 4 emission and fuel regulations by 2010. For 2-and 3-wheelers, Bharat Stage II applied from April 1, 2005 and Stage III standards came into force in April 1, 2010. The roll out of Bharat Stage IV limits nationwide was delayed by the challenge of convincing fuel producers to make the necessary investments required to supply 50 ppm sulfur fuel nationwide. Potential solutions that have been suggested include deregulation of diesel prices, an environment compensation charge on diesel vehicles and an additional levy on diesel fuel. Even in cities with Bharat Stage IV limits, there have been challenges ensuring the dominance of compliant vehicles. Some of these challenges include: exemptions granted to some specialty vehicle (e.g., taxis) manufacturers, registration of Bharat Stage III vehicles by vehicle owners outside of their place residence due to loopholes in residential proof, registration of commercial vehicles outside of the Bharat Stage IV zones and insufficient availability of some specialty vehicles (e.g., garbage trucks) in Bharat Stage IV configurations.
In order to establish limits beyond Bharat Stage IV, the Indian Planning Commission established a Committee in 2013 to draft an updated Auto Fuel Policy. The panel recommended that Bharat Stage IV fuel be required nationwide from April 2017 followed by a further step up to the Bharat Stage V in April 2020. Draft recommendations discussed prior to the report’s release included a national Bharat Phase IV+ stage (40 ppm sulfur) starting in 2017 and a national Bharat Stage V fuel standard staring in 2021.
Attempts to set fuel economy standards started in 2007, but it were delayed due to inter-ministerial conflicts and pressure from the automobile industry. In January 2014, India notified minimum fuel efficiency norms for passenger vehicles that are sold in India. Two sets of standards were announced: one set for fiscal years 2016-17 to 2020-21 and another for fiscal year 2021-22 onwards.]

72. There are several types of plant bio-monitors, including Mosses, Lichens, tree bark, bark pockets, tree rings, leaves and fungi.
·         Lichens are organisms comprising both Fungi and Algae. They are found on rocks and tree trunks, and they respond to environmental changes in forests, including changes in forest structure –conservation biology, air quality and climate. The disappearance of lichens in a forest may indicate environmental stresses, such as high levels of sulfur dioxide, sulfur-based pollutants, and nitrogen oxides.
·         The composition and total biomass of algal species in aquatic systems serves as an important metric for organic water pollution and nutrient loading such as nitrogen and phosphorus.
There are genetically engineered organisms, that help us indicate toxicity levels in the environment; e.g., a type of genetically engineered grass that grows a different colour if there are toxins in the so

73. The oxygen exists in dissolved state in the water and is the lifeline for the aquatic life. Let see the factors which determine its content in water.
              1. Photosynthetic activity, releases O2 into water as a by-product.  
              2. O2 consumption by the plants and animals for their respiration decreases O2
                  content in water.  
             3. De-composition of the organic matter into inorganic components require oxygen 
                 as oxidizer and therefore this activity lowers the O2 levels in water. [BOD].
              4. Size of the water body has no relevance to the O2 levels in the water body.
              5. Temperature of the water has great effect on the O2 levels. The quantum of O2
                   levels would decrease with increasing temperature.  In other words, cold water
                   contain higher levels of O2 than warm water.
Hence, correct option is “b”.
[Additional information: Temperature promotes the activity of decomposers in the water and they break down more and more organic matter and depletes the liquid oxygen in the water]

74. Bioremediation is a waste management technique that involves the use of organisms such as bacteria and fungus to remove or neutralize pollutants from a contaminated site. In simple words, it is a “treatment that uses naturally occurring organisms to break down hazardous substances into less toxic or non toxic substances”.

75. Taj Mahal, one of the wonders of the world is under threat due to acid rain which is otherwise described as “Marble cancer”. The acid rain is due to release of high concentrations of SO2 and NOx, causing acid rain.

80. The succession that starts on the bare rock or for the first time in any nude area is called as “Primary Succession”. The succession which starts on a deserted farmland or on a burnt forest is called “Secondary succession”.


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