(Original post by Jayk Bakner)
The thing is, extinction is part of the natural order of things. Do you see any megalodon's cruising about the Atlantic? Nope...and we're probably better off because of it. If they were about, they probably would've hunted one species or another to extinction too. So I agree with the OP...it's no biggie really. Humanity only really cares about extinction if the creatures in question are cute, anyways.
Yes extinction is natural, but 75 species going extinct every day is not. Megalodon went extinct through natural causes. Whilst they were about I sincerely doubt they drove any species to extinction themselves. If they were still about today they would probably be endangered anyway because of the extreme pressure man puts on our seas.
Edit: Actualy posted this at the same time as John.
1. I'm not saying that this dolphin was prey for any species. Such extinctions can have both top down and bottum up reprocusions. That is to say that the dolphin may have preyed on another species- with the dolphin now 'gone' that species may thrive. This is purly hypothetical however, I don't know the exact role the river dolphins played in this ecosystem. Its just people's thinking in this matter that scares me. You can't take a slack attitude towards extinction just because of one species you don't care about. In this instance, the dolphin disappearing may have no significant effect, but there are plenty of other cases where a keystone species may be lost and the effects may be much worse.
A better example of such a case my be coral reef ecosystems, mainly because I understand coral reefs better than I do river ecosystems in China. Sea turtles are an endangered species, and one of their primary food sources on coral reefs are sea urchins. If sea turtles go extinct then the predation pressure on urchins is released significantly. This may cause a population boom in urchins meaning that they out compete grazing fish (sea urchins are grazers also). The fish, already under pressure from over fishing, will disappear. Fishing communities built up around this will collapse. Likewise, if the sea urchins then suddenly die out (they would become susceptible to a mass mortality event caused by disease, as had happened in the Caribbean) then there will be nothing to graze on the algae. This will overgrow the coral and an entire reef can be destroyed.
2. A mass extinction is a scientific term. There have been 6 so far and each is a totally natural occurrence (the dinosaurs wiped out being the most recent). One species going extinct will not cause a mass extinction. However, 75 species going extinct every day, for 100 years, will. I'll just quote wikipedia on this bit.
"Present day — the Holocene extinction event. 70% of biologists view the present era as part of a mass extinction event, possibly one of the fastest ever, according to a 1998 survey by the American Museum of Natural History. Some, such as E. O. Wilson of Harvard University, predict that man's destruction of the biosphere could cause the extinction of one-half of all species in the next 100 years. Research and conservation efforts, such as the IUCN's annual "Red List" of threatened species, all point to an ongoing period of enhanced extinction, though some offer much lower rates and hence longer time scales before the onset of catastrophic damage. The extinction of many megafauna near the end of the most recent ice age is also sometimes considered part of the Holocene extinction event. Some paleontologists, however, question whether the available data support a comparison with mass extinctions in the past."