Life in a nutshell

Through the centuries, artists from Shakespeare to Monty Python have offered their interpretations on the nature and meaning of life. But researchers in the biosciences and medicine surely have a more exact definition of what life is. Or do they?

Professor Hannu Sariola is a doctor, pathologist and researcher in developmental biology, so you would be forgiven for assuming he is a man with a clear understanding of both life and death. However, when asked “what is life”, he answers: I don’t know.

One can of course try to sketch the rough outlines of life. Take the following example:  According to the laws of physics, all clouds move with the wind. If a cloud is moving against the wind, it may be alive, because it at least appears to be moving independently. Or: All living things consume energy.

We only know life as it exists on our planet. The Universe may harbour life-forms that we would not recognise as being alive. As Sariola points out:

– We do not understand how the only form of life we know got started, but we do know that at some point on the evolutionary continuum humans appeared. In the chain of life, the death of an individual, or even a species, is insignificant, since new individuals and species will still be created– until some disaster breaks the chain. That would mean the end of life as we know it.

The soul in the brain

Sariola is a paediatric pathologist whose duties include autopsies on dead foetuses. When does a person’s life begin, and when does it end?

– Conception marks the beginning of the potential for an individual life, but not the beginning of the person. Up to 80% of fertilised eggs are spontaneously aborted without the woman ever realising conception has occurred. Development into a person happens gradually, and it is guided by both genetic and environmental factors, says Sariola.

– The point at which a human is considered to be a person actually varies between cultures. In some indigenous cultures, children are not named until they turn three. It is only then when they are thought likely enough to survive that personhood is granted.

The end of a person’s life is easier to define than the beginning: the consumption of energy ends and cells begin to die. It may, however, be difficult to pinpoint the exact moment of death, as different tissue types need different amounts of oxygen, resulting in different rates of cell death.

Finland was among the first countries in the world to consider brain death one of the definitions of medical death. Sariola agrees with this decision – once the brain is dead, the individual is no longer alive as a person. This is the case even if the heart continues to pump blood and maintain the other basic functions of the body.

Could we say he is talking about the soul?

– We could indeed, says Sariola. – The best definition of a soul I have heard of is that it is an internal sense which enables us to experience ourselves. Once the brain is dead, the soul is gone.

Drawing the lines of life

According to Sariola, the great division of biological life runs between plant and animal: these two kingdoms diverged long ago, even though they still share certain basic characteristics. Fungi are between the two kingdoms, although Sariola would locate them closer to animals than plants, based on their biology. 

In the microbiological realm, Sariola draws the line of biological life at viruses. According to him, the nature of viruses is a philosophical question:

– Viruses do not have independent life. If a virus which exists as a parasite of a cell were considered to be alive, would that not mean that a computer virus would also be alive? It can also be transmitted to other computers, replicate itself and spread.

Sariola points out that interesting things are happening on the borderlines of biological life and machines. With strides in robotics, artificial intelligence and biological materials, the border is becoming increasing nebulous. 

Sarah Butcher, professor of microbiology, studies the areas between the animate and inanimate. Microbiology is a perfect example of how the discussion about the nature of life becomes increasingly complicated the smaller the units under discussion are.  

The scientific community does not always agree, even on the basics. For example, whether viruses are alive is a controversial topic.

– From the perspective of biology, life involves certain processes, such as respiration and energy metabolism. In this sense, viruses are not alive, Butcher states.

Not alive but efficient

However, even if viruses are not alive, they are very efficient at what they do.

– Their job is to be a parasite and to make others do their work for them. They exploit the resources of others, guide events and seize the benefits.  In that sense they are like dictators, despite their tiny size, says Butcher.

Viruses carry genetic material such as DNA or RNA. Therefore, the existence of genetic material and the ability to reproduce are not enough for something to be considered alive. – All living things are selfish genetic units, but not all selfish genetic units are living things. This brings us to the concept of the ‘selfish gene’, introduced 40 years ago by Richard Dawkins, which is very compatible with evolution, says Butcher.

Moving borders

In addition to viruses, a host of other non-living parasites hitch rides on the smallest living units, and they are masters of reproduction. The simplest units are viroids, which are just bits of DNA or RNA, or prions, which are misfolded proteins. As Butcher continues:

–  These tiny bits must have an important role to play, because there are so many of them. They may be microscopic in size, but their impact is unmissable.

According to Butcher, the current classifications of life may well change in the future. For example, synthetic biology, which combines biology with technology, is only getting started. Researchers are now able to build completely new molecules which can reproduce either independently or through parasitism. In the future, we may be able to create entire living organisms for research or biotechnology.

– I think the current definitions of life are too narrow to encompass everything we see around us. And what we do not see because it is too minute for the naked eye, Butcher points out.

Does old life matter?

Professor Ilkka Hanski, who studies ecology and evolutionary biology, calls the current life-forms on Earth “old life”, and self-replicating artificial intelligence “new life”.

– Personally, I consider the development of artificial intelligence and robotics a threat to old life, Hanski says, but points out that he is not an expert in this field.

If a sophisticated artificial intelligence were combined with state-of-the art synthetic biology, the result could be a completely new type of life somewhere between old life and robotic life. Researchers are already capable of producing synthetic bacteria in the laboratory.

According to Hanski, some synthetic biology researchers think that the disappearance of “old life” is not a problem, as new life can always be created.

– This is an incredibly naïve idea which reveals a lack of understanding of ecological interactions and the complexity of their evolution. Some think that we can just build new ecosystems. They do not understand that an interactive relationship involving just three different organism generates highly complex dynamics, Hanski snaps, visibly annoyed.

The requirements of life

The question of what should be studied to ensure life on our planet is a serious one for the professor.

– To maintain life on Earth, we should find solutions to huge unsolved issues. Personally, I consider global capitalism based on constant growth to be one of the most difficult challenges. It is the foundation upon which everything else rests.

According to Hanski, no feasible alternative to a global market economy currently exists, but we should try to find one quickly. He proposes this as a topic for researchers in economics, social sciences and the humanities. He believes we must find a path to a stable economy which would not rely on continuous growth.

– At the moment, we are trying to solve the problems through international financial control which seeks to guide the global markets. I don’t know if this is sufficient, or whether the control mechanisms are perpetually one step behind. I don’t know what kind of a revolution we need or what we should seek to achieve through one. However, a stable economy is a necessity for seriously embarking on the work to find the solutions to environmental problems, Hanski muses.

Untapped information

We have enormous amounts of information. The problem is that we aren’t using it. As Hanski points out, this raises a whole group of new questions. In terms of society, there is little benefit to producing information if it is not put to use.

How could we take advantage of existing information? – Perhaps researchers in political science could find a solution.

Hanski sees our current government as a perfect illustration of the problem. It shortsightedly sees basic research as pointless busywork and instead wants carefully targeted research which would serve to boost economic growth and enhance our competitive edge. At the same time, the government is not making use of the information that already exists.

Hanski believes this is the result of a common but misguided way of making political decisions, in which the decisions are made first and research information to justify them is sought afterwards.

The production of new information would only be the third step in this process.

Professor Hanski thinks that the potential for major scientific breakthroughs could lie in global climate change feedback mechanisms and large-scale interactions relating to matter and energy cycles.

Hanski is amused to note that only one of the important issues he mentions is related to the production of biological information, and two relate to something completely different. – New information is by definition something about which we know nothing. This is why it is crucial that we put existing information to use.