According to Jon Erickson in “Dying planet, the extinction of species”(published in 1991 by TAB Books), this article gives the definition of endangered species. An endangered species is a population of an organism which is at risk of becoming extinct because it has few in number or threatened by changing environmental or predation. The writer indicates that The World Conservation Union (IUCN) has calculated that endangered species have taken 40 percent of all organisms. Fortunately, he describes that many nations have laws to protect endangered animals. However, only a few of them have obtained legal protection as well as most of them do not gain public notice.
In addition, he explains that each organism plays a key role in our food chains. Population increases or declines often result in secondary species. Moreover, he points out that the whole ecosystem structure may be changed even destroyed irreversibly.
On the other hand, the writer states that some scientists think extinction is a natural effect of the process of natural selection. “Extinct animals should be extinct”, they argue that.
Critique
According to this text, I get much knowledge about endangered animals. The writer uses numbers to state that animals are in danger because recent rates of extinction are 100 to 1000 times higher than the typical or average extinction rates. Humans are disrupting the ecological balance by hunting, habitat destruction etc. I agree with this point that loss of a species may lead to destroy of whole food chain. However, I also think that extinction must exist because it is the process of natural selection. Species with strong traits that can adapt and suit to environment is easier to survive through the process of natural selection.
This acticle is logical, well organized and provides many explanations and definitions to help me understand some concepts. He uses lots of examples and picture which make his article more attractive.
Monday, August 6, 2007
Sunday, July 29, 2007
Summary of Reading Task #3
According to David Watson in “Empire of Extinction” (Earth Island Journal, vol.19, Autumn 2004), he indicates that the prevailing human attitude that people are the “lords and possessors of nature” and he thinks that’s the cause of species endangerment and extinction. He mentions that daily life in the North countries contributes far more to ecological destruction that population growth in the south.
Watson disagrees with the idea that extinctions are a natural and unavoidable result of human expansion. He states that in many instances humans have ignorantly slaughtered species when such extinction was preventable. Plus, he mentions that some believe we can provide a decent life for twice the number of people now living. However, Watson insists that human beings should learn to live in a way that leaves the planet in a state of ecological harmony for all species. Making this decision will require humans to limit their own numbers, alter their consumption patterns, and agree to live a more simplified existence. He stressed that healthy ecosystems are key to the survival of all species, including humans.
Critique
In this text, the writer comes up with a logical argument that people should limit their own numbers, alter their consumption patterns, and live a more simplified existence in order to prevent species extinction. He prevents lots of examples to support his arguments. Also, he mentions that others opposing opinions about human’s attitude towards to extinction.
This text is organized. However, his intended audiences might be experts and scientists in the same field as him. Therefore, the text is not easy for me to read. Moreover, this text provides further information which I think are very useful for my research topic.
Watson disagrees with the idea that extinctions are a natural and unavoidable result of human expansion. He states that in many instances humans have ignorantly slaughtered species when such extinction was preventable. Plus, he mentions that some believe we can provide a decent life for twice the number of people now living. However, Watson insists that human beings should learn to live in a way that leaves the planet in a state of ecological harmony for all species. Making this decision will require humans to limit their own numbers, alter their consumption patterns, and agree to live a more simplified existence. He stressed that healthy ecosystems are key to the survival of all species, including humans.
Critique
In this text, the writer comes up with a logical argument that people should limit their own numbers, alter their consumption patterns, and live a more simplified existence in order to prevent species extinction. He prevents lots of examples to support his arguments. Also, he mentions that others opposing opinions about human’s attitude towards to extinction.
This text is organized. However, his intended audiences might be experts and scientists in the same field as him. Therefore, the text is not easy for me to read. Moreover, this text provides further information which I think are very useful for my research topic.
Sunday, July 22, 2007
Summary of Reading Task #2
According to Deborah Barnes in “Research in the News: Creating a Cloned Sheep Named Dolly” (2003), the writer states that, “in biology, a clone is a cell or an organism that is genetically identical to another cell or organism”. In her article, She explains the process of creating clone is, when scientists decide to clone an animal, they take the nucleus of a cell and place it into an egg cell. The egg cell then divides to produce an embryo that develops into an animal. However, she describes the cloned sheep Dolly, the first mammal to have been successfully cloned, was different and remarkable because of she was generated from a specialized adult cell, not from an unspecialized embryonic cell.
After Dolly, more and more other animals have been cloned, the writer mentions that, cloning is now considered a promising tool for preserving endangered species from being extinct. Also, she thinks that extinct species may be “brought back to life”. However, she suggests that the cloning of an extinct species has not yet been attempted, due to technological limitations, though bioethical and philosophical objections have also been raised.
Furthermore, in her article, she states that many biologists and environmentalists oppose cloning endangered species — not because they think it won't work but because they think “it may deter donations to help preserve natural habitat and wild animal populations”.
After Dolly, more and more other animals have been cloned, the writer mentions that, cloning is now considered a promising tool for preserving endangered species from being extinct. Also, she thinks that extinct species may be “brought back to life”. However, she suggests that the cloning of an extinct species has not yet been attempted, due to technological limitations, though bioethical and philosophical objections have also been raised.
Furthermore, in her article, she states that many biologists and environmentalists oppose cloning endangered species — not because they think it won't work but because they think “it may deter donations to help preserve natural habitat and wild animal populations”.
Sunday, July 15, 2007
Summary of Reading Task #1
According to Janet Larsen in “The Sixth Great Extinction ”(November 2004), she indicates that there have been at least five mass extinctions in the history of life. She mentions that first known extinction on earth was about half a billion years ago. Most experts believe that a change in sea level dramatically destroyed many plants and animals' habitats. Also, she describes that, at the end of the Permian period, the single largest extinction event happened, up to 96 percent of all ocean species died out as well as three-quarters of vertebrates on land disappeared. Finally, she states 85 percent of the planet's species, including all of the dinosaurs, at 65 million years ago, were eliminated. Researchers suggest that this event was most likely caused by a large meteorite striking Earth.
“The average extinction rate today is up to 10,000 times faster than the rate that has prevailed over the past 60 million years,” she suggests that, human beings are facing the "Sixth Extinction". However, she presents this extinction is the result of human activities.
In contrast, not all experts believe that human activities are responsible for the endangered species threat. Jane S. Shaw, points out in her February 2004 article published in the Backgrounder, that population growth means that people will create habitats for wildlife. She stresses that “They will create ponds, establish gardens, plant trees, and set up bird nesting-boxes.”
In a word, Larsen implies that healthy ecosystems are key to the survival of all species and people should act together to stop the progress of this newest mass extinction.
“The average extinction rate today is up to 10,000 times faster than the rate that has prevailed over the past 60 million years,” she suggests that, human beings are facing the "Sixth Extinction". However, she presents this extinction is the result of human activities.
In contrast, not all experts believe that human activities are responsible for the endangered species threat. Jane S. Shaw, points out in her February 2004 article published in the Backgrounder, that population growth means that people will create habitats for wildlife. She stresses that “They will create ponds, establish gardens, plant trees, and set up bird nesting-boxes.”
In a word, Larsen implies that healthy ecosystems are key to the survival of all species and people should act together to stop the progress of this newest mass extinction.
Subscribe to:
Posts (Atom)