It's no secret that bees are vital — in fact, they were even declared the most important species on Earth by the Royal Geographical Society. As the world's foremost pollinators, they play a major role in the life cycle of many plant species and help maintain healthy ecosystems. They are also responsible for pollinating many of the crops we eat.

We might consider them a pest at times, but ants are another common insect we should never take for granted. They can be found on every continent except Antarctica and fulfill a variety of roles, from circulating nutrients in the soil, to dispersing seeds and eating other insects. Scientists are currently studying the possible impact of climate change on ant colonies around the world.

Neither plant nor animal, microbe or protozoa, fungi are sometimes described as the "fifth kingdom of life on Earth." They can be found in the water, in the soil and in the air. They essentially act as the world's natural nutrient recyclers and some species can even absorb harmful metals like mercury and digest polyurethane plastics.

It's hard to understate just how important these micro-organisms are to life on Earth. For one thing, they produce more than 50 percent of the planet's atmospheric oxygen — without them, the amount of free oxygen in the atmosphere would be much lower, making for a very uncomfortable environment. They are also the foundation of the food chain in marine ecosystems.

What do bananas, baobab trees and tequila have in common? They all depend on bats for pollination and insect regulation. All over the world, different species of bats fill a vital ecological niche to ensure certain crops continue to thrive. A healthy population of bats can save millions of dollars worth of pesticides and they are an important sign of a robust ecosystem.

The humble earthworm is so important to Earth's biosphere that it is sometimes referred to as an "ecosystem engineer." They lead busy lives aerating and enriching the soil and recycling organic material — and, of course, occupying an indispensable place in the food chain. Despite their status as a stalwart of many ecosystems, certain species are under threat from such things as land clearance.

As our closest living biological relatives, primates offer a great deal of insight into human biology. They are also a keystone species in many tropical forests, serving as "gardeners" by dispersing seeds and creating places where new plants can grow. In order for such forests to survive and thrive, we need to ensure the survival of the primates who inhabit them.

Often called the rainforests of the sea, coral reefs fill a diverse range of roles, from serving as a foundation for intricate food webs, to protecting coastlines. Researchers also estimate coral reefs support as much as a quarter of all marine life, making them one of the most diverse ecosystems on Earth. The loss of coral reefs would imply the loss of countless marine species.