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    the eggs of aquatic birds are not hatched due to presence of a _____chemical in their food ?


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    Shell of egg in bird becomes thin (not properly formed) due to the pollution of pesticides. This is due to interference in the activity of

    Click here👆to get an answer to your question ✍️ Shell of egg in bird becomes thin (not properly formed) due to the pollution of pesticides. This is due to interference in the activity of


    Shell of egg in bird becomes thin (not properly formed) due to the pollution of pesticides. This is due to interference in the activity of


    Ca ATPase


    Mg ATPase




    None of the above

    Medium Open in App

    Updated on : 2022-09-05

    Solution Verified by Toppr

    Correct option is A)

    Due to chronic injection of pesticides like DDT in birds resulted in thinner and weaker shell. The Ca-ATPase pump responsible for transporting Ca which is inhibited by the pesticide and results in less Ca in the shell. Thus , the correct answer is option A.

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    स्रोत : www.toppr.com

    Environmental Issues MCQ

    Environmental Issues MCQ - Questions with answer keys are updated regularly. Explore exhaustive multiple-choice questions only at BYJU'S

    BiologyMCQ'sEnvironmental Issues Mcq

    Environmental Issues MCQ

    1. Which of the following facts is incorrect?

    Global warming is the rise in the average temperature of the earth’s climate system

    Eutrophication is observed in water bodies

    The greenhouse effect is a natural phenomenon

    Ozone is harmless to breathe

    2. Areas that are under the influence of DDT may observe a decline in the population of birds. This is due to the fact that

    Birds stopped laying eggs altogether

    The eggs did not hatch

    Predation of the eggs increased

    None of the above.

    3. Measuring BOD (biological oxygen demand) is primarily used for

    Estimating the types of microbes

    Determine the level of dissolved oxygen

    Estimating the quantity of organic matter in sewage water

    None of the above

    4. Cosmic rays, such as gamma rays are a source of

    Soil Pollution Noise Pollution Thermal Pollution Radiation pollution

    5. The primary agenda of the Kyoto protocol is 

    Regulation of hazardous wastes

    Regulate the production of nuclear energy

    Control anthropogenic sources of greenhouse gases

    None of the above

    6. The presence of _________ in a water body is an indicator of water pollution.

    Zygosporangium E.Coli

    Deinococcus radiodurans

    None of the above

    7. Eggshells of birds become unusually thin when exposed to the pesticides in their environment. The protein that gets affected is ________

    Calmodulin Cysteine Serine None of the above

    8. Lichens are good bioindicators for 

    Environmental radiation

    Soil pollution

    Water and air pollution

    None of the above

    9. A moth having a speckled wing, able to blend into its background due to its dark colouration is called

    Industrial melanism Adaptation Predation Evolution

    10. Carbon dioxide is primarily called a greenhouse gas because

    Traps heat Traps light Traps warm currents None of the above

    11. Trichoderma harzianum is a ________ that is predominantly used as a fungicide

    Virus Fungus Bacteria Protozoa

    12. Greenhouse gases are those that absorb and emit infrared radiation. Examples inlude__________

    Nitrogen Ozone Argon None of the above

    13. Depletion of the ozone layer is damaging to human health. Negative effects include

    Skin cancers Osteoporosis Dyspepsia None of the above

    14. __________ is an organism used to gauge the quality of an ecosystem. 

    Decomposers Predator Bio-remediator Bioindicator

    15. _________ is a waste disposal method where solid organic wastes are converted to the residue and gaseous products through combustion.

    Incarnation Incineration Incarceration Incubation

    Answer Keys for Environmental Issues MCQs

    1- 4 2- 2 3- 3 4- 4 5- 3

    6- 2 7- 1 8-3 9- 1 10- 1

    11- 2 12- 2 13- 1 14- 4 15- 2

    Explore more MCQs on Environmental issues or other related topics by registering at BYJU’S Biology.

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    स्रोत : byjus.com

    DDT and Birds

    DDT and Birds

    Birds played a major role in creating awareness of pollution problems. Indeed, many people consider the modern environmental movement to have started with the publication in 1962 of Rachel Carson's classic Silent Spring, which described the results of the misuse of DDT and other pesticides. In the fable that began that volume, she wrote: "It was a spring without voices. On the mornings that had once throbbed with the dawn chorus of robins, catbirds, doves, jays, wrens, and scores of other bird voices there was now no sound; only silence lay over the fields and woods and marsh." Silent Spring was heavily attacked by the pesticide industry and by narrowly trained entomologists, but its scientific foundation has stood the test of time. Misuse of pesticides is now widely recognized to threaten not only bird communities but human communities as well.

    The potentially lethal impact of DDT on birds was first noted in the late 1950s when spraying to control the beetles that carry Dutch elm disease led to a slaughter of robins in Michigan and elsewhere. Researchers discovered that earthworms were accumulating the persistent pesticide and that the robins eating them were being poisoned. Other birds fell victim, too. Gradually, thanks in no small part to Carson's book, gigantic "broadcast spray" programs were brought under control.

    But DDT, its breakdown products, and the other chlorinated hydrocarbon pesticides (and nonpesticide chlorinated hydrocarbons such as PCBs) posed a more insidious threat to birds. Because these poisons are persistent they tend to concentrate as they move through the feeding sequences in communities that ecologists call "food chains." For example, in most marine communities, the living weight (biomass) of fish-eating birds is less than that of the fishes they eat. However, because chlorinated hydrocarbons accumulate in fatty tissues, when a ton of contaminated fishes is turned into 200 pounds of seabirds, most of the DDT from the numerous fishes ends up in a relatively few birds. As a result, the birds have a higher level of contamination per pound than the fishes. If Peregrine Falcons feed on the seabirds, the concentration becomes higher still. With several concentrating steps in the food chain below the level of fishes (for instance, tiny aquatic plants crustacea small fishes), very slight environmental contamination can be turned into a heavy pesticide load in birds at the top of the food chain. In one Long Island estuary, concentrations of less than a tenth of a part per million (PPM) of DDT in aquatic plants and plankton resulted in concentrations of 3-25 PPM in gulls, terns, cormorants, mergansers, herons, and ospreys.

    "Bioconcentration" of pesticides in birds high on food chains occurs not only because there is usually reduced biomass at each step in those chains, but also because predatory birds tend to live a long time. They may take in only a little DDT per day, but they keep most of what they get, and they live many days.

    The insidious aspect of this phenomenon is that large concentrations of chlorinated hydrocarbons do not usually kill the bird outright. Rather, DDT and its relatives alter the bird's calcium metabolism in a way that results in thin eggshells. Instead of eggs, heavily DDT-infested Brown Pelicans and Bald Eagles tend to find omelets in their nests, since the eggshells are unable to support the weight of the incubating bird.

    Shell-thinning resulted in the decimation of the Brown Pelican populations in much of North America and the extermination the Peregrine Falcon in the eastern United States and southeastern Canada. Shell-thinning caused lesser declines in populations of Golden and Bald Eagles and White Pelicans, among others. Similar declines took place in the British Isles. Fortunately, the cause of the breeding failures was identified in time, and the use of DDT was banned almost totally in the United States in 1972.

    The reduced bird populations started to recover quickly thereafter, with species as different as ospreys and robins returning to the pre-DDT levels of breeding success in a decade or less. Furthermore, attempts to reestablish the peregrine in the eastern United States using captive-reared birds show considerable signs of success. Brown Pelican populations have now recovered to the extent that the species no longer warrants endangered status except in California. The banning of DDT has helped to create other pesticide problems, however. The newer organophosphate pesticides that to a degree have replaced organochlorines, such as parathion and TEPP (tetraethyl pyrophosphate), are less persistent so they do not accumulate in food chains. They are, nonetheless, highly toxic. Parathion applied to winter wheat, for instance, killed some 1,600 waterfowl, mostly Canada Geese, in the Texas panhandle in 1981.

    Unfortunately, however, DDT has recently started to become more common in the environment again; its concentration in the tissues of starlings in Arizona and New Mexico, for example, has been increasing. While the source of that DDT is disputed, what is certain is that DDT has been shown to be present as a contaminant in the widely used toxin dicofol (a key ingredient in, among others, the pesticide Kelthane). Dicofol is a chemical formed by adding single oxygen atoms to DDT molecules. Unhappily, not all the DDT gets oxygenated, so that sometimes dicofol is contaminated with as much as 15 percent DDT

    स्रोत : web.stanford.edu

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