Species are dropping like flies - so much so that the World Wildlife Fund estimates that anything between 200 - 100,000 animals go extinct every year.

Many of these extinctions are triggered by human activity, from the iconic passenger pigeon to black rhinos to Tasmanian tigers. We now have the technology to breed extinct species, but what role should we be playing in bringing animals back from the dead? Do we have a moral responsibility to fix the damage we caused? And what about animals that went extinct hundreds or millions of years ago?

These were the questions raised at a recent discussion session at the American Museum of Natural History in New York. Speakers Harry W. Greene, from Cornell University and Ben Minteer, chair of the Arizona Zoological Society presented arguments for and against de-extinction. They demonstrated that the de-extinction debate is much more complex than building a real-life version of Jurassic Park. Not only are the causes of extinction different, the time frame and the role that extinct creatures played in their ecosystem varies greatly. How do we decide what makes one animal more important than another?

"De-extinction is driven by the same values that brought about extinction in the first place; the inability to stop tinkering," said Ben Minteer, a bio-ethicist.

For Minteer, if we start bringing back extinct animals, we won't learn our lesson - it will give us an excuse to keep plowing through the world's natural resources. "De-extinction does not address the root of the problem," he said. "Do we demonstrate our power through controlling nature or by showing restraint?"

Minteer added that bringing back species takes them out of their ecological context and natural timescale.

But Harry W. Greene was in a different camp. He argued that we've already restored species on the brink of extinction, so is bringing back species all that different? Take the peregrine falcon, for example. Peregrine falcons almost disappeared in the United States because of DDT in fertilizers. Captive breeding programs brought these birds back - but four of the species that now populate North America are actually Eurasian.

Greene also sited the California Condor, which became extinct in the wild in 1987 and has since been rewilded in Arizona and Utah. Every year, California Condors have to be caught and tested for toxic metal contamination - which then has to be removed via dialysis. But the price is high - 5 million dollars per year. If we're willing to dish out huge sums of money for the condor, what's stopping us from going further?

For Greene, bringing back crucial species that played an important historical role in their ecosystems could be an effective way of rehabilitating landscapes. This raises another part of the de-extinction spectrum: animals that humans had no role in eliminating.

The idea of bringing back the woolly mammoth has captivated the public for many years. Every once in a while a new headline suggests that scientists are "closer than ever" to bringing these mighty majestic creatures to life. Animals like mammoths could play an important role in seed dispersal or even fire suppression - a task which often overwhelms firefighters in areas where wild fires are frequent. We already drastically alter the landscapes around us, where do we draw the line? Should we leave things as they are?

"Doing nothing is not risk free," said Greene. "The debate about de-extinction is about values; what we decide to do and not to do."

What do you think?

Should we bring animals back from extinction?