They are smaller than a grain of sand, shaped like a pancake and live in the ocean munching on microbesVery small living things, also known as microorganisms. all day. On the surface, you may not find it too flattering to be compared to them.

After all, we are the species that created the internet, built rockets and learned how to do complex heart surgery. What do we have in common with an amorphousWithout a clearly defined shape. miniature sea blob just three cell layers thick?

More than you might think. Scientists believe that these animals, called placozoans, may be the blueprintDesign plans or drawing. for our nervous systems - and therefore also for all of our most complex emotions, experiences, wishes and fears.

They are the "simplest animals on Earth", without any body parts or organs (including a brain). They reproduce by fissionSplitting into two or more parts. and are commonly mistaken for amoebasSingle-celled animals. , not animals. We have spent years underestimating them.

But researchers have now found evidence that placozoans have "neuron-like" cells which could have led to the development of neurons in other animal lineages, including ourselves. They developed the theory after noticing that some of the behaviours of placozoan bodies are reminiscent of nervous systems in their earliest stages of development.

These "neuron-like" cells are called peptidergicNeurons that secrete peptide hormones. cells, which activate the cells around them using amino acidsOrganic compounds which form the basic constituents of proteins.. The researchers believe that nervous systems originally consisted of these peptidergic cells, before evolving into neuronsNeurons, also known as nerve cells, are cells in the nervous system that use chemical or electrical signals to transmit information throughout the body. , which send electrical signals to carry information across the body.

We are often tempted to take our brains for granted. More often than not we are using them for menialJobs that do not require much skill. tasks like deciding what we want for dinner or navigating our way through an awkward social encounter. We rarely remember that our minds were billions of years in the making.

Many scientists think that the first two main groups of life - single-celled bacteriaA large group of single-cell microorganisms. Some cause disease in animals and humans. and archaeaA group of micro-organisms that are similar to but very evolutionarily different from bacteria. , formed 3.9 billion years ago. In turn, placozoans are thought to have formed around 800 million years ago, along with the first animals. Whilst the single-celled organisms that first crawled in our ancient oceans did not have brains, scientists think that early animals had electrical pulses and chemical signals which allowed them to communicate with each other.

It was when neurons started to appear that the stage was set for the human race. Neurons allowed animals to process information as well as relaying it, which meant that more sophisticated species could develop and become responsive to their environment.

There we have it. A mere few hundred million years later, we start to develop language, culture, art. And it could all come down to these tiny clusters of cells drifting around the sea.

We understand remarkably little about the human mind. But its possibilities are endless, and its roots stretch back almost to the beginning of life on Earth - and maybe even life elsewhere too, if there are extraterrestrialAnything from outside Earth. placozoans bumbling about on another planet somewhere. After all, they are one of the simplest animal lineages known to us. If intelligent alien life exists, it may have started with the same steps as us.

Yes: We have been searching for the origins of human intelligence, and every added piece of information helps us to get closer to that goal. Neuroscience is one of our most urgent fields.

No: Understanding where something came from does not equal understanding it. Finding out that placozoans may hold the key to the earliest form of the nervous system does not really help us to understand how our brains work and why we experience things the way we do.

Or... The secrets of the human mind are more philosophical than scientific. Science can only help us to conceive of human emotions and psychological processes to a certain extent.