Earth’s natural resources include air, minerals, plants, soil, water, and wildlife. Conservation is the care and protection of these resources so that they can survive for future generations. It includes maintaining diversity of species, genes, and ecosystems, as well as functions of the environment, such as nutrient cycling.
Continued human population growth has led to unsustainable rates of consumption of our natural resources, resulting in a loss of Earth’s biodiversity. The main factors driving biodiversity loss include habitat destruction, climate change, invasive (入侵的) species and pollution.
Declining biodiversity is closely intertwined with species extinction. While extinction is a normal process of nature, the rate at which it is happening today is not. Scientists estimate that current extinction rates are about a thousand times higher now than would be expected based on the fossil record, and that we may be experiencing a mass extinction event, which is when 75 percent or more species are lost at a time.
The extinction of the passenger pigeon is a famous example of an extinction caused by human activity. It was once the most richest land bird in North America, with a population of approximately three to five billion when Europeans arrived. Despite its vast numbers, this pigeon became extinct in the wild by the 1900s because of overhunting. The last individual bird, named Martha, died in captivity in 1941 at the Cincinnati Zoo.
Conservation practices and policies—ranging from the removal of invasive species, to setting aside protected land for wildlife and plants, to establishing the U. S. Endangered Species Act (ESA)—have been put in place to deal with these extinction pressures. Currently, more than 26,500 species are estimated to be at risk of extinction, though the exact number is difficult to calculate.
8. How does the author illustrate “conservation” in the text?
A.By giving a definition. |
B.By offering an example. |
C.By listing some facts. |
D.By making comparisons. |
9. What does the underlined part “intertwined with” mean in paragraph 3?
A.Caused by. |
B.Connected to. |
C.Disturbed by. |
D.Similar to. |
10. Why does the author take the passenger pigeon as an example?
A.To show that animals die out quickly. |
B.To tell North America is perfect for animals. |
C.To explain how species die out in a short time. |
D.To state that man is to blame for extinction. |
11. What’s the suitable title for the text?
A.Conservation, Necessary and Urgent. |
B.The Extinction of the Passenger Pigeon. |
C.Effective Ways Done to the Environment. |
D.Protection, More Than the Care for Animals. |