Overview of human biological evolution

 
Perhaps while reading, many questions arise. In order to make understanding easier, selected facts are provided to aid in reasoning. Basic information has been chosen, as individuals can independently seek additional information on the topic.

108.    Brief history of earthly life

According to scientists, life on Earth began around 3.8 billion years ago with the first single-celled organisms lacking membranes, nuclei, or organelles. Following them, organisms with cell membranes, nuclei, and organelles appeared.

From the very beginning, single-celled organisms aimed to survive and replicate their RNA/DNA, reproducing by passing genetic information to the next generation. From a chemical standpoint, RNA/DNA are molecules like other molecules of non-living matter, yet with the ability to survive over time, replicate themselves, and evolve into more complex molecules.

From single-celled organisms, life on Earth began, and over many years, the entire tree of life gradually emerged as known from biology textbooks. Around 3.5 billion years ago, the first single-celled organisms appeared, relying on solar energy rather than chemical reactions using substances from their aggressive environment. They started producing oxygen, which then increased on Earth.

Thanks to oxygen, new types of single-celled organisms emerged. Multicellular organisms also arose, including those made of cells with different functions, not just colonies of identical cells.

The first nerve cells appeared around 600 million years ago, and in the tree of life, the human branch diverged from the chimpanzee branch only about 5 million years ago.

109.    Interesting facts about the human body

The human organism, or body, is composed of over 30 trillion cells, with more than 200 billion cells being reproduced and dying daily.

The cells in the human body come in around 200 different types, each type having a varying lifespan. For example, white blood cells live for 13 days, cells in the liver can live up to 18 months, and the lifespan of nerve cells matches our own lifespan.

All these cells exist in our body at this moment due to the fact that a sperm and egg cell from our parents fused, resulting in the miracle of mixing genetic information and gradual cell division to form all types of cells that make up our body, as we gradually reach biological and sexual maturity.

110.    The body as a living link to ancient life or the dawn of life

Throughout time, from the beginning of life on Earth to the present moment, there exists a “living link” to us, specifically to the cells that make up our bodies. Their ancestors are not just the cells of our parents and ancestors, but also those of all other organisms in the tree of life, tracing back from the human branch to its root. This includes organisms that have lived long ago and are ancestors to present-day ones. For instance, organisms with a backbone like monkeys, horses, frogs, rabbits, and fish, as well as ancestors to insects and even ancient mollusks (like ancestors to jellyfish). Scientists substantiate these claims through the percentage of gene (RNA/DNA) match between modern humans and genes of any other creature.

Let’s recall that from the very beginning of life, RNA/DNA molecules aim to survive over time by reproducing, creating new generations before they perish. They transmit the information encoded within their structures. RNA/DNA molecules themselves are so complexly structured that they can contain a vast amount of information within them.

This imparts an ancient quality to the human body, suggesting profound wisdom in the form of encoded information in RNA/DNA that has allowed life on Earth to survive until today and evolve multiple times over. This wisdom, or at least its most essential part, should have been passed from parent cells to the next generation’s cells throughout the entire evolution of life and now resides in the cells constructing our bodies.

111.    The human being as an individual

The biological goal of humanity, viewed as a collection of organisms with remarkably similar RNA/DNA, is continuously achieved through the birth of each newborn worldwide. If scientists study the RNA/DNA of any two individuals on Earth, they will always find a match of over 99.99%. In this line of reasoning, human RNA/DNA has existed on Earth for a considerable time and is expressed in the totality of all individuals. In this sense, all inhabitants of Earth are relatives. In other words, we are all closer or more distant cousins.

On the other hand, each of us possesses a unique individuality as a living representative of the human species. Even twins always have differences, both in their bodies and characters, albeit sometimes small.

What is individual life against the backdrop of the period during which life developed on Earth and even against the smaller period since the emergence of the human species?

Looking at joyful and somber statistics, it’s true that people die and are born every day, and life is structured in such a way that gradually takes away our loved ones and friends. A human life is like a drop in the ocean. However, this doesn’t make it less significant; quite the opposite. We face a challenge: to live the time we have in the best possible way!

112.    Moving wisely along our individual path!

If we draw a parallel between the biological life of the human species and an individual’s life, it becomes evident that our consciousness, particularly our rational mind, is like a temporary manager of an ancient biological specimen, containing all the wisdom of evolution in encoded form, housing the merged cells of all our ancestors.

Doesn’t this inspire wonder?

Each of us has an individual path and must use the time we have to discover and tread it. No one else can point it out for us, let alone walk it for us!

The fact that time is passing us and we fail to find a more suitable individual path doesn’t prevent us from causing harm to ourselves and thereby diminishing the time allocated to us here, sometimes even without realizing it.

Surely, it’s now clear that there’s no recipe for living the time we have in the best possible way because it’s a unique path, just as unique as our RNA/DNA. It’s over 99.99% identical to the RNA/DNA of other humans and still it’s unique. What we can do is preserve the time given to us on Earth and try to maintain or even improve our quality of life as much as possible.