8 minute read
A Quick Narrative of What Life is About
A simple scientific explanation
by Iryna Stryha
Have you ever stopped to wonder how life actually works? Exploring the complexities of life and existence involves connecting knowledge from various fields, as everything is closely interconnected. By studying one thing, you can uncover connections to many other areas, expanding your understanding of the world. Today, let’s explore some aspects of how life works, hoping to spark new connections in your mind, enriching your perception of existence.
One of the most fascinating phenomena in our universe is the force of entropy. It refers to the tendency of systems to move from a state of greater organization to a state of lesser organization. In the context of life, entropy is the force that ultimately leads to the decay and death of living things. The universe doesn’t really like complexity — it wants things to get simple. However, living organisms constantly work against entropy to maintain their complex structures.
All life is based on cells, which are considered the smallest living systems. Cells are alive, but they emerge from non-living components, forming a separated system within the universe. When this separation breaks, the cell dies and becomes a part of the non-living universe again. To stay alive, every second, a huge number of processes occur in the cell to ensure its separation from the rest of the universe and prevent it from achieving entropy.
For example, cell membrane regulates the flow of ions in and out of a cell. If the balance is disrupted, the cell will die. To perform processes like this, a cell needs energy, which is the ability of things in the universe to create change. Constant change is required to maintain life. The total amount of energy in our universe is always the same. It can change form, but the amount remains constant.
One of the main challenges early life on Earth faced was finding a source of energy and a way to use it. The earliest cells obtained energy from simple chemical reactions. Over time, they discovered a mechanism for energy transfer — using a molecule called ATP (adenosine triphosphate). Its structure is good for accepting and releasing energy. When a cell needs energy, it can break down ATP and use the released chemical energy to do work and create change. Every living thing on Earth uses ATP or something very similar to keep life’s crucial processes going. The first living systems didn’t have much energy to create and maintain bigger complexity, so life on Earth stayed pretty simple for a while.
All life is based on cells, which are considered the smallest living systems.
Eventually, life on Earth figured out how to harness an amazing energy source — the sun. Sun fuses atoms and emits photons — a source of energy that spreads across the solar system. Some cells learned to convert this electromagnetic energy (photons) into chemical energy stored in ATP — we call this process photosynthesis. Over time, some cells figured out how to store a lot of chemical energy using glucose, which is also easy to break down. Some other cells decided to just eat other hard-working cells that produced energy, with all their ATP and glucose, instead of doing the work of converting the energy. So now, some cells produced sugar, others ate them. The processes of both types of cells produced a limited amount of energy and made their evolutionary possibilities somewhat constrained. Evolution was happening, but there were no significant changes.
This continued until two cells figured out a way to work together — one cell ate another and did not kill it. This cell became the ancestor of all animals on our planet, including you. We can trace back our existence to this moment when the history of life changed forever — when the two cells became one, they became way more powerful. This phenomenon occurs everywhere in the universe — and is called emergence. Emergence describes how small things gather to become something better together — complexity arising from simplicity. From then on, the inner cell, which evolved into what we now call mitochondria, could focus on producing ATP and delegate survival to the outer cell. The outer cell focused on protection from the dangerous external world. It provided the mitochondria with food, not having to worry about energy production. Mitochondria take glucose that the cell gets from eating other things and combust it with oxygen and prototype molecules to make new, energy-rich ATP. This division of labor meant that the new cell had much more energy available, leading to more possibilities for more complex structures to develop and evolution to unfold.
These cells began forming communities, creating multicellular life. These communities adopted different philosophies and ways of existence, which they stored in DNA that changed over time and generations, resulting in diverse organisms. Emergence continued to shape life, and eventually evolution led to humans.
As humans, we are composed of trillions of cells. They cooperate, specialize, and interact using an incredibly complex language of proteins, developing higher organization. Our organs and body parts are extremely complex systems. The more complex the system, the more resistant it is to entropy. Individual cells are far more vulnerable to entropy than humans overall.
We can trace back our existence to this moment when the history of life changed forever — when the two cells became one, they became way more powerful.
So still, human life is quite fragile as it requires a constant supply of materials used to sustain the lives of many individual cells that make up our bodies. Every human cell is filled with little machines that provide you with energy to stay alive. If this process is interrupted, even for a few minutes, you will die.
Our bodies have figured out some mechanisms to be less prone to lack of supplies — for example, we store glucose in fat cells so that if we don’t eat for a while, we still have the energy to sustain life. However, we can’t store enough oxygen to survive for more than a few minutes. Why wouldn’t we store ATP directly to prevent death after a few minutes without air? Well, in one day, to sustain itself, your body produces an amount of ATP somewhat equal to your weight. The molecule is constantly produced and used up fairly quickly. ATP is good for quick energy spread but terrible for storing, as it only contains 1% of glucose’s energy and is three times bigger. Blood system constantly transports the nutrients (like glucose) and oxygen to cells around the body. Without it, cells can’t provide themselves with energy. That’s why, for example, if a person’s heart stops beating, immediate actions like a heart massage are needed to do the heart’s job externally. If the heart stops pumping blood, it means many cells simultaneously would not be able to produce energy to stay alive. The more time would pass without restoring the system — the more cells would die — meaning a human as a whole might eventually die as well.
Our existence is so simple yet so complex. Atoms form molecules — molecules form proteins — proteins make up cells — cells create organs — organs form individuals — and individuals build societies.
Our existence is so simple yet so complex. Atoms form molecules — molecules form proteins — proteins make up cells — cells create organs — organs form individuals — and individuals build societies. But how do individual cells know what to do? There is no higher authority dictating their actions, just single units communicating with their neighbors and acting according to the feedback. Similarly, human societies, nations, and humanity as a whole exist just because many humans interact with one other.
A single human without humanity and its accumulated knowledge is just an animal. But together we form something way more powerful and truly fascinating. A lot of processes occurring in humanity are pretty similar to what happens on smaller scales. We evolve as individuals, we communicate using our own languages, we create connections and share love that contributes to mutual growth and evolution, we store information and pass it on to next generations, we specialize, create communities with different ideologies – so that something bigger than us can evolve.
I hope this narrative evoked new ideas and links in you and added puzzle pieces to your understanding of the world. Life is an adventure waiting to be explored, and your curiosity is the compass that guides the way.
