【推荐1】During the 20th century, an estimated 3 million great whales were hunted to provide humans with oil, meat and rose fertiliser. Roger Payne, a biologist and environmentalist, spurred (推动) a worldwide environmental conservation movement with his discovery that whales could sing.

This discovery was made in 1967 during his research trip to Bermuda (百慕大) when a navy engineer provided him with a recording of curious underwater sounds documented. Payne identified the tones as songs whales sing to one another and he was conscious from the start that whale song was to get the public interested in protecting an animal previously considered little more than a resource, curiosity or nuisance.

Payne saw the discovery of whale song as a chance to spur interest in saving the giant animals, who were disappearing from the planet. In 1970, Payne released the album Songs of the Humpback Whale. The record, a surprise hit, fueled a global movement to end the practice of commercial whale hunting and save the whales from extinction. It remains the bestselling environmental album in history.

The impact of the whale song discovery on the early environmental movement was immense. Many antiwar protesters of the day took on saving animals and the environment as a new cause. The humpback whale became the icon of a new environmental awareness. And the whales entered pop culture, no longer the fearsome beasts. In 1977, the whale calls were loaded on to the Voyager probes and sent into outer space.

Payne, graduating from Harvard University and Cornell University with a doctor’s degree, authored or co authored dozens of scientific papers, gave hundreds of lectures, made countless television programmes and films, and led 100 oceanic expeditions. Payne had started an ambitious new project: CETI, a combination of scientists using new technology to interpret what whales might be “saying”.

【推荐2】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.