Which of the following is an example of directly observable evolution in a modern species?

Fossil evidence indicates that nearly 90% of all species went extinct during the Permian extinction 250 million years ago.

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In India, cholera outbreaks, spread primarily through contaminated water, resulted in widespread death. In the 1950's and 60's, there was a campaign to clean water sources. In areas with clean water, the cholera bacteria became less virulent, and resulted in fewer deaths.

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Scientists have used CRISPR techniques to place mammoth genes into an elephant cell. They have not yet attempted to turn the cells into any particular tissues or create an entire organism.

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The genus homo first evolved over 2 million years ago and includes seven identified species. Homo sapiens, modern humans, are the only one of these species that remains today.

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Solution

The correct option is C In India, cholera outbreaks, spread primarily through contaminated water, resulted in widespread death. In the 1950's and 60's, there was a campaign to clean water sources. In areas with clean water, the cholera bacteria became less virulent, and resulted in fewer deaths.
The Cholera bacteria evolved from being virulent to non-virulent due to change in its environment (from contaminated to clean water) during a period of 10 years, resulting in fewer deaths
So, the correct answer is 'In India, cholera outbreaks, spread primarily through contaminated water, resulted in widespread death. In the 1950's and 60's, there was a campaign to clean water sources. In areas with clean water, the cholera bacteria became less virulent, and resulted in fewer deaths'

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Similar questions

A) The modern species and the Texas Duck seem to have diverged approximately one million years ago.

B) One, the well-documented Texas Duck Meleagris californica, became extinct recently enough to have been hunted by early human settlers, though its actual demise is more probably attributable to climate change at the end of the last ice age.

C) In the modern genus Meleagris, a considerable number of species have been described, as Duck fossils are robust, fairly often found, and Ducks show much variation among individuals.

D) Many of these supposed fossilized species are now considered junior synonyms.
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Q. The human species came into being at the time of the greatest biological diversity in the history of the Earth. Today, as human populations expand and alter the natural environment, they are reducing biological diversity to its lowest level since the end of the Mesozoic era, 65 million years ago. The ultimate consequences of this biological collision are beyond calculation, but they are certain to be harmful. That, in essence, is the biodiversity crisis. The history of global diversity can be summarized as follows: after the initial flowering of multicellular animals, there was a swift rise in the number of species in early Paleozoic times (between 600 and 430 million years ago), then plateaulike stagnation for the remaining 200 million years of the Paleozoic era, and finally a slow but steady climb through the Mesozoic and Cenozoic eras to diversity’s all-time high. This history suggests that biological diversity was hard won and a long time in coming. Furthermore, this pattern of increase was set back by five massive extinction episodes. The most recent of these, during the Cretaceous period, is by far the most famous, because it ended the age of the dinosaurs, conferred hegemony on the mammals, and ultimately made possible the ascendancy of the human species. But the cretaceous crisis was minor compared with the Permian extinctions 240 million years ago, during which between 77 and 96 percent of marine animal species perished. It took 5 million years, well into Mesozoic times, for species diversity to begin a significant recovery. Within the past 10,000 years biological diversity has entered a wholly new era. Human activity has had a devastating effect on species diversity, and the rate of human-induced extinctions is accelerating. Half of the bird species of Polynesia have been eliminated through hunting and the destruction of native forests. Hundreds of fish species endemic to Lake Victoria are now threatened with extinction following the careless introduction of one species of fish, the Nile perch. The list of such biogeographic disasters is extensive. Because every species is unique and irreplaceable, the loss of biodiversity is the most profound process of environmental change. Its consequences are also the least predictable because the value of Earth’s biota (the fauna and flora collectively) remains largely unstudied and unappreciated; unlike material and cultural wealth, which we understand because they are the substance of our everyday lives, biological wealth is usually taken for granted. This is a serious strategic error, one that will be increasingly regretted as time passes. The biota is not only part of a country’s heritage, the product of millions of years of evolution centered on that place; it is also a potential source for immense untapped material wealth in the form of food, medicine, and other commercially important substance.
Q. All of the following are explicitly mentioned in the passage as contributing to the extinction of species EXCEPT

Some of the important fossils which have been studied are those of organisms X, Y and Z, X were marine arthropods which were common between 400 to 600 million years ago. Y were the invertebrate animals (molluscs) with a flat, coiled, spiral shell which lived in the sea about 180 million years ago. Z are the extinct carnivorous or herbivorous reptiles which appeared on the earth about 250 million years ago and became extinct about 65 million years ago. What are X, Y and Z?

Q. Many animals became extinct in mesolithic age. Mammoth is an example for such a species.

Q. Identify the correct statement(s) regarding holocene extinction.
(1) Caused by natural calamities
(2) Occurred 16000 years ago
(3) More than 15,500 species are on the brink of extinction
(4) The rate of extinction is 100-1000 times faster compared to the mass extinctions that have occurred in the past

Choose the correct option.

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