When was bacteria created

And both organelles use their DNA to produce many proteins and enzymes required for their function. A double membrane surrounding both mitochondria and chloroplasts is further evidence that each was ingested by a primitive host.

The two organelles also reproduce like bacteria, replicating their own DNA and directing their own division. It is passed down directly from mother to child, and it accumulates changes much more slowly than other types of DNA. Because of its unique characteristics, mtDNA has provided important clues about evolutionary history.

For example, differences in mtDNA are examined to estimate how closely related one species is to another. Conditions on Earth 4 billion years ago were very different than they are today. The atmosphere lacked oxygen, and an ozone layer did not yet protect Earth from harmful radiation.

Heavy rains, lightning, and volcanic activity were common. Yet the earliest cells originated in this extreme environment. And then, through two extraordinary events, bacteria changed the face of the Earth. And shortly after that — on planetary timescales at least — bacteria created the complex cells required for all plant and animal life to evolve.

Bacteria built the world we live in today. Tiny organisms once ruled the whole world. Up until two billion years ago, all life on Earth fell into two great domains — bacteria and archaea. Since that time, a third domain of life, eukaryotes, has thrived alongside the other two.

It consists of plants, fungi, and animals, including us. Bacteria are incredibly diverse, and can specialise to live nearly anywhere and eat almost anything. Together with the archaea, they represent the dominant form of life on Earth. There are more species of bacteria than any other life form. The most recent estimate predicts that bacteria account for over three quarters of all species of life on Earth.

This diversity is a mark of how bacteria have evolved to thrive in nearly all environments on this planet. Scientists once thought of archaea and bacteria as a single group of organisms. Then in , genetic analysis revealed that archaea had a separate evolutionary history to bacteria and therefore represent an independent branch of life altogether. Fewer than species of bacteria can do you any damage by causing infectious disease.

The vast majority of species either live in you harmlessly, or actively keep bad at bay, like microscopic superheroes. Bacterial cells are filled with a substance called cytoplasm, a concentrated mixture of proteins and nutrients needed for life. A single twisted and compacted loop of DNA carries their genetic code, but they may also have supplementary useful genes in tiny rings called plasmids. Some bacteria have hair-like flagella that they rotate, or tiny retractable pili which they use like grappling hooks.

Bacteria come in many shapes and sizes. You could fit 2, of the smallest into a millimetre, while the largest are more than half a millimetre long and visible to the naked eye. The Earth was a sizzling-hot, barren lump of rock when it formed, 4. In the fertile warmth of hydrothermal vents on the ocean floor, microorganisms began to grow. The earliest evidence of this — still under debate — may be in rock samples from an ancient seafloor vent in Canada. The rocks contain strands and tubes made of iron oxide - similar to structures built today by bacteria that live around deep-sea vents.

Hydrothermal vents were the habitat that hosted the last universal common ancestor shared by all life forms, according to recent research. It contained microbes whose DNA was like a missing link in understanding how complex cells — and thus all animals — evolved.

But without any sunlight, it is bacteria that power the habitat by harnessing a cocktail of chemicals. Hot, mineral-rich water wells up from fissures where new ocean crust is formed at mid-ocean ridges. Bacteria harvest chemicals to release energy, forming thick mats that other species feed on, setting up a food web. Some bacteria thrive in extreme environments such as hydrothermal vents and hot springs like Octopus Springs, in Yellowstone National Park.

We call these bacteria extremophiles because they can live in temperatures up to 80 degrees Celsius and can survive in high concentrations of chemicals usually harmful to life. EARTH: 3. The land was black and lava-encrusted, and the seas were green with dissolved iron. Yet life was evolving in shallow waters. They identified fossilised remains of possible stromatolites, structures built by bacteria, in a rocky outcrop in western Greenland.

These were accompanied by distinctive chemical signatures that suggest the processes of life. It is rare to discover rock from this early period of time that has not been altered beyond recognition. If you look closely at these stromatolites in Shark Bay, Australia today, you will occasionally spot bubbles emerging from them as bacteria break the water down and release oxygen.

This is the process that began when the atmosphere contained only 1 per cent oxygen, and resulted, two billion years later, in an atmosphere with 20 per cent oxygen. Around 2. Cyanobacteria living in the oceans evolved the ability to split water using energy from the Sun. Through this process, called photosynthesis, they began producing oxygen as a by-product. This was the start of the Great Oxygenation Event. This set the scene for complex life to develop. We owe our evolution, and our existence, to bacteria.

Traces of iron rusted on contact with the oxygen being pumped out by cyanobacteria. The rusty sediments fell to the bottom of shallow oceans, taking with them their red hue. Today, scientists can compare sedimentary rocks from before and after the rise in oxygen levels, and see the telltale sign of red rust.

Red layers of iron in this rock have been rusted by oxygen. They provide evidence of the timescale on which bacteria began producing oxygen in the oceans — although there is a chance the reddening happened after the rock formed. Perhaps there are more questions to ask, more possibilities to consider. Cyanobacteria, also known as blue-green algae, started out on Earth quite a while ago. Possible fossil examples have been found in rocks that are around million years old, in Western Australia.

Although commonly referred to as blue-green algae, cyanobacteria are not actually algae. Cyanobacteria, and bacteria in general, are prokaryotic life forms. This characteristic is distinctive of bacteria and archaea; all other life forms on Earth, including real algae, consist of eukaryotic cells with organelles and with genetic material contained in one place the nucleus. Bacteria and archaea are hardy creatures. They must have split from the other two after the bulk of the development of biochemistry and cell biology had taken place.

This is to say that as advances took place the older forms were eliminated and diversity was only temporary.

Two kinds of events could, in principle, permit stable diversity to arise. One kind occurs when two nearly simultaneous, different advances occur, both of which overcome the same problem.