Tag: Complexity

How life begins

The gap has been closing little by little from both the astronomical and biological sides. But though it’s narrower now than ever before, it’s still a gap.

How did life begin? It seems possible, even very likely, that simple chemistry has the potential to generate life given the right conditions and plenty of time.

There’s always been a big puzzle over the origin of life here on Earth. Life is everywhere and in a vast array of forms. From the simplest archaea and bacteria, to the giant redwood and the humble grass in the field, the blue whale down to the smallest mite. So rich in variety, so wide in its presence from the deepest oceans to the highest mountains. Life is amazing!

The processes of evolution are well understood and impossible to deny; so puzzles over the many forms of life, its adaptability, and changes in the forms we see coming and going over deep time are clearly understood and well explained by biologists. (When did you last see a dinosaur?)

But how did it all start?

Ah! That has always been the unexplained mystery. Once we have a simple, replicating form of life on the planet we can see it might thrive, spread and grow in complexity.

There are various proposals. Perhaps it arrived in an asteroid kicked off Mars or somewhere else. But that does no more than move the origin to a different place in the Solar System. Maybe it all began at mid-ocean ridges where hot mineral-laden springs flow from hot rock layers below the surface. Perhaps, yes.

We know that many of the precursors for life exist out among the stars. Here in the Solar System, comets and asteroids are often richly endowed with amino acids, ribonucleotides, and all sorts of smaller precursors. These are the building blocks of proteins, RNA, DNA and so forth. We understand how these precursors can form spontaneously given simpler materials like water, methane, ammonia, compounds including atoms of phosphorus, sulphur and so forth. It just takes chance interactions, time, and a source of energy like ultraviolet light. The basic ingredients are there in the gas clouds that condense to form new stars and the material orbiting in disks around them.

All of these things are fairly well understood, but there’s a gap in our understanding between the presence of the components and the presence of life. The gap has been closing little by little from both the astronomical and biological sides. But though it’s narrower now than ever before, it’s still a gap.

Life in a computer?

Well, yes! And, no.

Some clever work by Blaise Agüera y Arcas, a Google vice-president of engineering, has uncovered an intriguing process. Setting a very simple ‘machine’ running random code (no meaningful program whatsoever) and waiting for something to happen, shows that eventually some very simple self-replicating code will appear in the system, and once it exists it replicates very quickly and then slowly increases in complexity. It’s not biological life of course, but it has all the qualities that we would recognise as lifelike. It replicates itself, different forms of replicating code compete with one another, they evolve, and they grow more and more complex. This doesn’t show us in any detail how biological forms got started, but it demonstrates that self-replication could happen in principle, and given enough time that it’s almost inevitable.

For the detail and background you should listen to Sean Carroll interviewing Blaise, the conversation is absolutely fascinating.

See also:

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Image of the day – 16

The stratus is semi-transparent near its fuzzy edge, you can see the higher layer through it.

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What’s in an image? Sometimes quite a lot, more than meets the eye.

I’m posting an image every day (or as often as I can). A photo, an image from the internet, a diagram or a map. Whatever takes my fancy.

Layer upon layer of clouds

I spotted this cloud scene in May 2024 and just had to capture it. As you can see, it’s a fine example of multiple horizontal levels of clouds of different kinds. At the bottom are small cumulus clouds, including one that looks higher than the others. That’s just perspective, they’re all at the same level, imagine them sitting on a transparent sheet stretched out from the horizon and passing overhead.

Above this is a grey layer with a fuzzy edge, it’s stratus cloud and again it’s a flat sheet at a higher level than the cumulus layer. The third layer is altocumulus, a third sheet at a higher level again. The stratus is semi-transparent near its fuzzy edge, you can see a higher layer through it.

The fourth layer is cirro-stratus, white and stretched out from side to side. And the final layer is cirrus, stretched fore and aft, at right angles to the cirrostratus below. So much going on at different levels in the atmosphere!

It’s very clear that things that seem really simple (the air above our heads) can show complex patterns of behaviour. That’s a good lesson to learn for life in general.

Themed image collections

The links below will take you to the first post in each collection

Cirencester, Favourites, Irish holiday 2024, Roman villa

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Emergence – an introduction

Emergence is everywhere, and you would not be here without it! … Emergence matters because it is one of the fundamental processes that we see in this universe at every imaginable scale.

Part 1 of a series – Emergence

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One of my many interests is the way in which everything we’re familiar with in the universe developed out of a previous state, and how new features make further developments possible – over and over and over again.

I’d like to explain how this seems to be an underlying property of our universe. We are surrounded by astonishing levels of complexity and the earlier stages seem to be far simpler than later ones; at the beginning of the process (if there is a clear beginning) everything was simple. So how can the complex arise from the simple?

Ripples in the sand, an example of emergence (from Wikimedia Commons)

In its entirety this story will take us from the big bang, through particles and atoms, to chemistry, onwards to life, intelligence, and beyond. This is far, far too much for a single blog post, so I will choose topics one by one and write about them. I’m not planning to start at the beginning, and the posts won’t be in the order that events took place, but as I write additional articles, I plan to link them into a logical series.

How would I know anything about this topic?

I should explain something about my background and training – I’m not an expert on all of the topics we will be covering, perhaps not really an expert in any of them! I retired in 2010, but the first part of my career was in biology, specifically flower and fruit development in plums, so I do have a science background. My first degree was from Bath University in the UK, an honours degree in Horticulture; then during my research career I wrote an MSc thesis at Bristol University on the plum reproduction work; and later I completed an ordinary degree in mathematics and computing at the Open University as it seemed useful to have a background in methods that were becoming rather more frequently used by biologists. In the mid 90s my research career abruptly ended through unexpected personal circumstances.

But let’s go back to some thoughts on the complex arising from the simple. This is really quite counterintuitive for most people and, as it forms the basis for the story I want to tell, it’s important to think about it clearly at the start. At its heart, emergence is very simple. So simple we often take it for granted.

A few examples will help.

Example 1 – Cities

Where do cities come from? Obviously they’re built by people. Building towns and cities is something that people do, they provide places to live, places to work, shops, schools, hospitals, transport (ranging from footpaths to airports) and much more. Our societies could not exist without cities.

If we could take a few hundred people to a large, uninhabited island, what would they do? They would look for sources of food and water. They’d try to start a fire to keep warm. They’d explore the area. And they’d build shelters of some kind. Given time they might build a village.

Without people there would be no towns. But given a population, villages, towns and cities will eventually begin to appear. One person cannot build a village, let alone a city; it requires cooperation and a lot of resources.

It’s fair to say that cities emerge when large groups of people cooperate. A city and the life of a city are emergent properties of a cooperating group of people.

Example 2 – Murmurations

A murmuration is a flock of birds behaving in a particular way. I wrote about this some time ago in a different context. But take a look, especially at the video link in the article; it’s an amazing and beautiful thing to watch. Without the starlings there could be no murmuration. It’s another example of emergence. Murmuration becomes possible (though not inevitable) when there’s a large group of birds flying together.

Example 3 – The internet

For our final example, lets think about the internet. Something like the internet was bound to arise once computers became plentiful. It was useful to connect computers together so that all the computers in an office could share a single printer or some other resource. And then it became useful to connect up individual offices and companies for email, or file sharing. The details of the protocols that make it all possible don’t matter, it could have been done in a variety of ways; but the principle of world spanning connectivity was bound to develop, one way or another.

Predictability

Emergent behaviour is usually unpredictable. If you studied a single starling, or even a cage containing ten birds, you might learn a great deal about starlings, but nothing you learned would prepare you for the sight of a murmuration. Nor would it enable you to predict murmurations.

Why does emergence matter?

Emergence matters because it is one of the fundamental processes that we see in this universe at every imaginable scale. We see it in the behaviour of the wave functions that underlie elementary particles, and we see it in the formation of galaxies and even clusters of galaxies. We see it in everyday life (think about those cities mentioned above), we see it in the way collections of neurons give rise to complex behaviours in our brains, we see it in political life, in business, and in economics. Emergence is everywhere, and you would not be here without it!

Future articles

I’ll be writing on this topic again, but next time I’ll choose a particular example of emergence. This article acts as an introduction to the topic and will probably be accompanied by an index for this and other articles in the series. Along the way I’ll try to explain emergence in a bit more detail, and to provide links to material out there on the internet that will go far deeper than I plan to (or even could) take you, my readers.

See also:
Part 1 of a series – Emergence

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