Many of Earth's ecosystems still need to be explored

We know more than we ever have about our planet. But the more we explore, the more we realize there's a lot left to learn.

Earth's ice caps, oceans and other isolated places still have plenty of secrets — at least until we or our robots figure out how to get there.

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There are whole mountain ranges and lakes that have been sealed off from the rest of the world for millions of years in Antarctica. We have to drill or scan through thousands of feet of ice to learn about them.

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Year’s top 10 new species revealed
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Year’s top 10 new species revealed
Number 9. Drosera magnifica, Brazil. A member of the famed sundew genus, this rather large carnivorous plant lives in a very small and fragile region of the South American nation. Conservationists already fear for its survival. 
Number 7. Iuiuniscus iuiuensis, Brazil. It is definitely an isopod, but does something its land and water crustacean kin do not – build mud shelters. The structures are made for added protection during molting season. 
(Photo by Günter Peters/ullstein bild via Getty Images)
Number 6. Lasiognathus dinema, Gulf of Mexico. Anglerfish are largely known for two things – the pole-like extensions coming from their heads and their less than lovely appearances. This new one is no exception. 
Number 5. Phyllopteryx dewysea, Australia. The third known seadragon species is really rather stunning. Notable features include a bright red color overall and pink markings. 
Number 4. Phytotelmatrichis osopaddington, Peru. They are tiny enough to set up homes in the leaf bases of spikey plants, but what the itsy bitsy beetles rely upon for food remains a mystery.
Number 3. Pliobates cataloniae, Spain. About 11 million years ago, this primate wandered the area, scaling trees and grabbing fruit. The animal was only about 17-inches tall and weighed roughly 10 pounds. 
(REUTERS/Marta Palmero/Institut Catala de Paleontologia Miquel Crusafont (ICP)/Handout via Reuters)
Sirdavidia solannona. Monts de Cristal National Park, Gabon. Photo: Thomas Couvreur
Number 1. Umma gumma, Gabon. The damselfly is colorful and attention grabbing, inspiring scientists to name it after the Pink Floyd recording of the same name. 
(STR/AFP/Getty Images)

And then there are the ecosystems we don't even know about. Utility workers in Romania once found a cave that was cut off from the rest of the world for 5.5 million years. It had evolved a whole ecosystem of unique species that run on chemicals rather than sunlight.

We find some 18,000 new species every year. But scientists estimate we've only categorized about 14 percent of what's out there.

Only about 2,000 of those new species come from the oceans, but that could be because we haven't gotten around to looking closely yet. By volume, we've explored less than 5 percent of the ocean.

And our maps aren't very detailed. The water is so hard to look through, it's easier to map Mars than it is to get a detailed map of our own seafloor.

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