It might come as a shock to anyone who loves pandas, but these lumbering black and white creatures are not the most practical for the ecosystem. Nothing and nobody eats them, they barely interact with other species and have a hard time reproducing. On a more positive note, they help spread the seeds of the bamboo they spend many hours a day chewing, and have become a public face for conservation.

Another beloved bundle of fluff that falls into the same category has to be the koala. Australia's iconic marsupials spend more than 80 percent of their lives asleep, and the rest of the time eating eucalyptus. Like giant pandas, they don't feed on any other creatures and none seem to have acquired a taste for them. They don't even spread eucalyptus seeds. But they are pretty cute.

This fly might be welcome at the wasp's dinner of strawberry jam, but as a species they're not universally loved. On the contrary. We dislike their buzz, tasteless passion for feces, and ability to spread disease. That said, they can actually be useful. Apart from being spider food, some of the more than 110,000 fly species pollinate flowering plants.

Imagine a beautiful summer sunset — and now the swarm of mosquitoes ready to suck your blood. As with flies, we would all be happier living in a mosquito-free world, especially since they can transmit deadly diseases. But mosquitoes are a main source of food for birds, fish and mammals. And even if we did wipe out most of the mosquitoes, scientists believe new breeds would soon replace them.

We might like to think of wasps as the useless, often aggressive cousins of bees. But that's not the real story. Wasps are great pest fighters, preying on insects and parasites that wreak havoc on crops — sometimes by being particularly nasty and laying their eggs inside them, as they do with some caterpillars. They also pollinate plants and flowers as they feed on nectar.

OK, what about ticks and fleas? Apart from sucking blood, they're totally useless, right? In fact, some species of reptiles and birds feed on the insects, thereby benefiting from the blood they've sucked up from larger animals. And because they spread diseases, they help control wild animal populations. Their role might not sound pretty, but they do seem to have a purpose in life.

It's clear that most, if not all species on this planet have earned their place — even the annoying ones. But there's one species we're forgetting, and that's ourselves. If there were a prize for Earth's most useless species, humans should definitely be in the running. After all, there's one thing no other species does better than us: devastate nature.

Life and death are inseparable. The exhibition "A Brief History of Humankind" in Bonn's Bundeskunsthalle museum shows how, 13.8 billion years ago, molecules began to connect and turn into structured organisms. The above video still by US artist Bruce Conner shows what could spell the end of evolution: the nuclear bomb.

Remains of the oldest Eurasian hearth dating back 780,000 years were discovered on the banks of the river Jordan. The ability to control fire was a turning point in evolutionary history that moved mankind to the top of the food chain. Fire gave light, kept people warm; people cooked over a fire and used it to make stone tools. It was a gathering place - a Stone Age TV.

Homo sapiens had a fleeting chin, slanting forehead and a narrow brow ridge. The above skull is about 100,000 years old and was found in Israel, where Homo sapiens co-existed with Neanderthals for quite some time. All of the artifacts displayed in the Bonn exhibition are from Israel - and it's the first time they are on view in Europe.

This Neanderthal skull was unearthed in the Amud Cave in Galilee. Anatomically, it is nothing like the skull of Homo sapiens: the chin is even more fleeting, the back of the head shows an indentation. These early humans not only fulfilled their basic needs, archaeologists also found they held burial rituals and other forms of culture.

What makes us human? Family plays a huge role. Apart from historical objects, the exhibition also presents works by contemporary artists. US sculptor Charles Ray's 1993 "Family Romance" shows the fine line that connects family. In this sculpture, two parents hold their offspring's hands; however, the normalcy of a nuclear family is disrupted as both son and daughter are as tall as mom and dad.

Humans started forming figurines depicting gods about 8,000 years ago, at a time when people were settling, planting fields and forming communities. They created goddesses they could pray to for good harvests and fertility. The phallic shape in the above photo could also symbolize a male god. Lines and etchings indicate abstract portraits.

Unlike animals, humans can collect and write down knowledge. The Sumerians in southern Mesopotamia began to record information and numbers. This clay tablet was inscribed between 4,000 and 3,100 BC, paving the way for the complex memory systems needed to build cities and empires.

This coin made of electrum, a gold and silver alloy, is the oldest-known coin in the world. Embossed with the picture of a grazing stag, it is from the seventh century BC. Of course, other forms of payment already existed: sea shells, pearls and promissory notes.

In the third century BC, Arad was a flourishing business center at the crossroads of two trade routes in the Middle East. For 350 years, it was a magnificent city of palaces, temples and homes. The above model shows a typical square one-room dwelling with a flat roof, dating back to between 3,000 to 2,650 BC.

In 1912, Albert Einstein developed the theory of relativity, a sensation and a scientific revolution. The Israel Museum in Jerusalem owns the original manuscript to E=mc². The mathematical formula embodies the two sides of progress: With it, mankind gained important insight into physics, but it also enabled the creation of the first nuclear bomb.