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Biodiversity is defined as the richness of the living systems present at all the levels of
Answer to Problem 1TYK
Correct answer:
The greatest extinction in the history of life on the earth might be occurring now.
Explanation of Solution
Justification for the correct answer:
Option (e) states that ‘the greatest extinction on the earth may be occurring now.’ The biodiversity is now declining rapidly. It is occurring much faster than it might have occurred in the history of the earth. The reasons behind the greatest extinction are threats to the biodiversity. There are three major threats to biodiversity, namely deforestation, over-exploitation of fish population, and alteration of freshwater ecosystems. Hence, option (e) is correct.
Justification for the incorrect answers:
Option (a) states that ‘the greatest extinction on the earth occurred at the end of the Permian period.’ The Permian period ended with a Permian–Triassic extinction event, in which nearly 96% of the marine species and 70% of the terrestrial vertebrates became extinct. The present day extinction is going at a faster pace than the Permian period’s extinction. So, it is an incorrect option.
Option (b) states that ‘the greatest extinction on the earth occurred at the end of the Cretaceous period.’ The Cretaceous period ended with the event of Cretaceous–Paleogene extinction, which led to the non-avian dinosaurs, large marine reptiles, and pterosaurs extinction. It is still not the greatest extinction in the history of the earth. So, it is an incorrect option.
Option (c) states that ‘at the end of the Ordovician period, the greatest extinction occurred on the earth.’ The Ordovician period ended with the Ordovician–Silurian extinction event, which led to the extinction of invertebrates including mollusks and arthropods. This did not end with mass extinction. So, it is an incorrect option.
Option (d) states that ‘the greatest extinction took place at the end of the Cambrian era.’ The Cambrian era ended with the Cambrian–Ordovician extinction event, in which many brachiopods and conodonts got extinct. The greatest extinction did not take place at the end of this era. So, it is an incorrect option.
Hence, options (a), (b), (c), and (d) are incorrect.
Thus, it can be concluded that the greatest extinction might be occurring now and did not take place at the end of the Permian, Cretaceous, Ordovician, and Cambrian era. The current extinction is taking place due to human activities.
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Chapter 55 Solutions
Biology: The Dynamic Science
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- Which of the following do not provide evidence that a meteor strike was a partial cause of the Cretaceous-Paleogene mass extinction? a. A potential meteor crater off the coast of Mexico b. High layers of iridium in soil deposits in the geologic record at that time c. Shocked quartz was formed in large quantities at that time around the potential impact site d. An ozone hole appeared in the atmosphere at the time of the meteor strikearrow_forwardWe live in the Cenozoic era, and scientists know more about this era and the epochs it’s divided into than any other time period. Why is this? A. We know more about the Cenozoic era because this is the only era that has had a wide diversity of species living on Earth. B. We know more about the Cenozoic era because this is the most recent time period in the history of the Earth, and we have more information available to study. C. We know more about the Cenozoic era because the planet’s poles reversed magnetic fields at the beginning of this era. D. We know more about the Cenozoic era because fossils don’t exist to document previous eras.arrow_forwardDuring the ____ epoch, there were fewer ____ and more ____, a reversal in the relative representation of these forms during modern times. a. Eocene; omomyids; eosimiids b. Miocene; Old World monkeys; apes C. Miocene; apes; Old World monkeys d. Oligocene; apes; Old World monkeys e. Paleocene; New World monkeys; Old World monkeysarrow_forward
- According to "Our Earliest Ancestors", what time period is being discussed in this video? A.The Eocene B.The Miocene C.The Pleistocene D.The Paleocenearrow_forwardThere have been five main mass extinctions. Match each mass extinction event to its description. 1. Permian extinction 2. Cretaceous-Tertiary extinction 3. Triassic extinction 4. Devonian extinction 5. Ordovician extinction a. This extinction was most likely due to a change in sea level. During this event, about 60% of all marine species were eliminated. b. This is the best-known mass extinction. It eliminated most large animals, including the dinosaurs. c. This was the most severe extinction event. About 96% of life on Earth died during this event. d. This extinction was most likely caused by climate change. About 80% of land animals died during this event. e. This extinction was most likely due to a change in sea level. It especially affected coral reefs.arrow_forwardOne hypothesis for the Cambrian explosion was an increase in predator-prey relationships. It is thought that the resulting co-evolution of predator and prey may have been a factor in the rapid speciation of animals seen during this time. What findings in the fossil record would most support this? Group of answer choices a. increased incidence of larger-bodied animals b. increased incidence of sessile animals c. decreased incidence of animals with bilateral symmetry d. increased incidence of animals with radial symmetry e. increased incidence of shells, bony plates, spines, and/or clawsarrow_forward
- Martian meteorites found in Antarctica were determined to possibly contain life. Scientists looked skeptically at these meteorites because a. their results suggest unusual chemical signatures that do not indicate life. b. features thought to be Martian fossils could be nonbiochemical formations. c. it is impossible for a piece of the Martian surface to fall to Earth. d. both a and b are true.arrow_forwardThe eon comprising the Cambrian period up to the present is called the (1). It is divided into three eras: Paleozoic, Mesozoic, and Cenozoic. The Paleozoic era, first (2) appeared. Finally, the Cenozoic era is where (3), flourished, lasting up to this day.arrow_forwardSome epileptic conditions are due to neurons firing too often. This could be due to a lowering of the: Select one: a. threshold. b. set point. c. trigger point. d. cut off. The period of time during which an “explosion” of fossilized animals with bilateral symmetry are first found is the: Select one: a. Devonian. b. Jurassic. c. Cambrian. d. Ediacaran.arrow_forward
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