How did life on earth come about? The first clues came millions of years ago

How did life on earth come about?  The first clues came millions of years ago

The invention of thousands of exoplanets led to a renaissance in interest in the origin of life. Virtually all of them Other planetary systems are quite different from ours. Does this mean that there is something special about the solar system that allowed life on earth to flourish? We need to consider what we really know about the origin of all of us.

What was it like in the beginning?

We live in a diverse natural world. Our habitat is regulated by food networks – polar bears eat the urchins that eat the cormorants. These and other animals need oxygen to get energy from food. But the earth was not so friendly here during adolescence.

The methane-rich and oxygen-deficient atmosphere has made the earth unsuitable for life for a long time. The earliest manifestations of life were microorganisms that left their presence in rocks about 3.7 billion years old.

Photo: Paul Harrison / Wikipedia / Creative Commons

Contemporary stromatolites in Australia

Evidence of the presence of microorganisms has also been preserved in so-called slightly younger stromatolites that formed about 3.5 billion years ago. Stromatolites are formed when sticky clusters of microorganisms settle and bind deposits in layers. Scientists are studying today’s rare living stromatolite rocks to better understand the earliest living things on Earth.

If the earth were once uninhabitable, what would the oxygen atmosphere look like? This happened about 2.4 billion years ago, when they evolved Cyanobacteria – the first organisms on our planet to synthesize lightIt produces food using water and solar energy and releases oxygen at the same time. This led to a rapid, dramatic increase in oxygen levels, making it less environmentally friendly to other microorganisms that are intolerant to gas.

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Photo: NASA Earth Observatory

Evidence of the so-called event Oxygen disaster The beach is hidden in the rocks. When oxygen is nearby, iron reacts chemically (oxidizes) and is removed from the system. The rocks before this event were cut with iron stripes. Obsolete rocks after this event have no iron bands and show that oxygen was already present. After the initial explosion of oxygen, the level of oxygen stabilized at low levels, which lasted for billions of years. As the cyanobacteria die and flow down, their decomposition is likely to reduce the amount of oxygen.

Cell life and first animals

Microorganisms, although capable of processing many chemicals, did not have the specialized cells needed to build complex bodies. Something revolutionary happened when microbes began to live inside other microbes, Acting as their organs, e.g., creating mitochondria. First, genetic material was packed into a specific structure – the cell nucleus – which offered some evolutionary properties. The cells began to connect to each other because it could eat more efficiently or protect itself from the harmful environment.

The grouping of cells and the variation in their function eventually led to the development of tissues. About 800 million years ago, the first animals appeared – Perhaps they are creatures similar to modern sponges. Although the level of oxygen in the oceans is still low (compared to current levels), the amount of this element was sufficient for the sponges to survive. This is due to the sedentary life of these creatures and the simple structure of their bodies. Sponges became the first reef makers on earth.

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About 580 million years ago (the Edicaran period), other organisms appeared with sponges. These diverse marine creatures – with bodies like leaves, ribbons and sheets – have lived with sponges for about 80 million years. Fossil evidence for this can be found in fossil rocks around the world. The body shape of most Edicaran animals is not similar to that of modern groups. By the end of the Ediacar, as oxygen levels rose, more “familiar” organisms emerged. The sponges that ate the bacteria also caused the oceans to saturate with oxygen. The remains of the creature Dickinsonia costata indicate that it was moving along the coast, May be eating microbial waste. Some say this is our oldest relative.

The end and the beginning

Photo: Pixabay

About 541 million years ago, most Edicaran species became extinct Great weather disasterWhich scientists always discuss. They did their part Bodybuilding plans for growing animals, Nutrition Relations and Environmental Engineering.

The ditches found in the fossil record, up to the end of the Ediacar, indicate that roundworm-like animals began to dig into the ocean floor. These early environmental engineers intercepted the debris, possibly ventilating it, interfering with the living conditions of other Edicar animals. While the environmental conditions of some animals have deteriorated, they have improved for others, stimulating species change.

And so on Cambrian eruption (542-510 million years ago)That is, the rapid formation of a large number of different organisms. In the new, rumming lifestyle, tough body parts like shells and spines emerged. They allowed the animals to shape their environment more intensely, like digging trenches. There has also been a shift to more active animals, with different heads and tails allowing directional movement to follow the prey. Active feeding of well-armed animals such as trilobites will further destroy the beach where the “survivors” lived to become soft ediacs.

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Photo: Doomna publiczna / Flickr / RobinGoodfellow_ (m)


Unique diets have divided the environment and allowed for more diversification of life. Many of these strange-looking creatures were evolutionary experiments, such as the five-eyed opossumIn addition, other groups, such as the Trilobites, flourished and dominated the earth for hundreds of millions of years, but eventually perished. Reef-building stromatolite bacteria also became extinct, and rocks formed by organisms called brachiopods evolved from the constant changes in the earth. Today’s dominant reef-building organism – hard corals – appeared only a billion years later.

By the end of the Cambrian, all existing species – mollusks, arthropods, and invertebrates – had already developed. More food nets were created, which became the basis of the earth’s modern habitat.

>> See also: What if the moon were twice as close to the earth? Scientists answer

>> See also: The age of the meteorite from the origin of the solar system has been confirmed. “The Key to the Puzzle of Life on Earth”

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