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Scientists prove carnivore extinction theory Why we forget to remember Prof Yash
Pal THIS UNIVERSE |
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Scientists prove carnivore extinction theory THE extinction of a carnivore could lead to other predatory species dying out, according to new research. Scientists have previously put forward this theory, but a University of Exeter team has now carried out the first experiment to prove it. The study shows how the demise of one carnivore species can indirectly cause another to become extinct. Researchers believe any extinction can create a ripple effect across a food web, with far-reaching consequences for many other animals. The research adds weight to growing evidence that a ‘single species’ approach to conservation, for example in fisheries management, is misguided. Instead the focus needs to be holistic, encompassing species across an entire ecosystem. The researchers bred two species of parasitic wasps, along with the two types of aphids on which each wasp exclusively feeds. They set up tanks with different combinations of the species and observed them for eight weeks. In tanks that did not include the first species of wasp, the second went extinct within a few generations. In tanks in which they co-existed, both wasp species thrived. In the absence of the first wasp species, its prey grew in numbers. This threatened the other aphid, which the second wasp species attacks, eventually leading to its extinction. Both types of aphids feed on the same plants and there was not enough food for one to survive when the other thrived in the absence of its wasp predator. Lead researcher Dr Frank van Veen said: “Our experiment provides the first proof of something that biologists have argued for a long time. “That predators can have indirect effects on each other, to the extent that when one species is lost, the loss of these indirect effects can lead to further extinctions. “Although our study focused on insects, the principle would be the same for predators in any ecosystem, ranging from big cats on the African plains to fish in our seas. “Our research highlights the fact that a ‘single species’ approach to conservation can be ineffective and even counter-productive. “For example, protecting cod could lead to increased fishing pressure on other predatory fish which then, by the mechanism we have demonstrated here, could lead to further
negative effects on the cod.” A team of university scientists and second-year undergraduate students designed the experiment. The idea came about during a seminar, in which students were challenged to design an experiment that could prove the theory that predators have indirect effects on each other. The students were so inspired by the idea of proving a long-held theory that more than 30 of them volunteered to conduct the experiment with their lecturers. — The Independent
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Sometimes even skilled professionals forget to perform a simple task they have executed without difficulty thousands of times before, leading to disastrous consequences. These kinds of oversights occur in professions as diverse as aviation and computer programming, but research from psychological science reveals that these lapses may not reflect carelessness or lack of skill but failures of prospective memory. R. Key Dismukes, a scientist at the NASA Ames Research Center, reviews the rapidly growing field of research on prospective memory, highlighting the various ways in which characteristics of everyday tasks interact with normal cognitive processes to produce memory failures that sometimes have disastrous consequences. Failures of prospective memory typically occur when we form an intention to do something later, become engaged with various other tasks, and lose focus on the thing we originally intended to do. Despite the name, prospective memory actually depends on several cognitive processes, including planning, attention, and task management. Common in everyday life, these memory lapses are mostly annoying, but can have tragic consequences. “Every summer several infants die in hot cars when parents leave the car, forgetting the child is sleeping quietly in the back seat,” Dismukes pointed out. For all the negative attention that multitasking has received in recent years, it is perhaps no surprise that multitasking is also a major cause of prospective memory failures. We seem to have adapted fairly well to juggling several tasks simultaneously. But research shows that when a problem arises with whatever task we’re currently focused on, we become vulnerable to cognitive tunneling, forgetting to switch our attention back to the other tasks at hand. Research also reveals that implementation intentions, identifying when and where a specific intention will be carried out, can help guard against such failures in everyday life. Dismukes points out that having this kind of concrete plan has been shown to improve prospective memory performance by as much as two to four times in tasks such as exercising, medication adherence, breast self-examination, and homework completion. The study was published in the Current Directions in Psychological Science, a journal of the Association for Psychological Science. — ANI
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THIS UNIVERSE The Sun is constantly converting its mass into energy, and in the process it is losing mass at the rate of 4 million tonnes per second. This means that year after year, it is losing its gravitational pull towards all the nine planets encircling it. So the orbits of all planets, from Mercury to Pluto, should be gradually increasing and all of them should gradually be getting farther away from the Sun. If this is true, all of them will cease to be the planets of the Sun and may become freely floating bodies in space. This certainly is in contradiction to another theory which suggests that the Sun will eventually become a ‘Red Giant’; its size will increase many times and the Earth is likely to be swallowed by it. Which one of these two is more likely to occur? Your concern about the future of the Sun and its family is touching and justified. There can be other scenarios also. You have yourself indicated that active life of the Sun also depends on the rate at which it is consuming fuel; it is losing its mass but it is also getting hotter. This is taken into account when it is said that the end of the Sun’s active life will go through a 'Red Giant' faze. Somehow the suggestion that in future the Sun will become old and a physically weak entity, incapable of keeping its family together does not seem probable to me. This mode of decay of planetary systems does not look too appealing, scientifically or aesthetically. Readers can e-mail questions to Prof Yash Pal at palyash.pal@gmail.com
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US hypersonic aircraft crashes seconds into military test flight LOS ANGELES: An unmanned experimental aircraft designed to fly six times the speed of sound broke apart over the Pacific Ocean seconds into a military test flight due to a faulty control fin, the US Air Force said on Wednesday. The problem with the fin on the craft known as the Waverider or X-51A was identified in a test flight, 16 seconds after a rocket booster on the remotely monitored craft was ignited to propel it forward, the Air Force said in a statement. Astronomers find record-breaking galaxy cluster Massachusetts: A massive so-called galaxy cluster, one of the largest structures in the universe, has been discovered about 5.7 billion light years from Earth and credited with setting several important new cosmic records, US-based researchers said. The Harvard-Smithsonian Center for Astrophysics said that observations of the cluster, which has shown a prodigious rate of star formation, may force astronomers to rethink how such colossal structures and galaxies that inhabit them evolve over time.
— Reuters |
Rod Minchin
