Life is coeternal with matter and has no beginning; life arrived on Earth at the time of Earth's origin or shortly thereafter. Life arose on the early Earth by a series of progressive chemical reactions. Such reactions may have been likely or may have required one or more highly improbable chemical events.
Many scientists believe that RNA, or something similar to RNA, was the first molecule on Earth to self-replicate and begin the process of evolution that led to more advanced forms of life, including human beings.
Comets have this peculiar duality whereby they first brought the building blocks of life to Earth some 3.8 billion years ago and subsequent cometary collisions may have wiped out many of the developing life forms, allowing only the most adaptable species to evolve further.
Adam is the name given in Genesis 1-5 to the first human. Beyond its use as the name of the first man, adam is also used in the Bible as a pronoun, individually as "a human" and in a collective sense as "mankind".
Modern humans originated in Africa within the past 200,000 years and evolved from their most likely recent common ancestor, Homo erectus, which means 'upright man' in Latin. Homo erectus is an extinct species of human that lived between 1.9 million and 135,000 years ago.
Evidence shows that life probably began in the ocean at least 3.5 billion years ago. Photosynthesis began more than 2.5 billion years ago—the Great Oxidation Event. But it took hundreds of millions of years for enough oxygen to build up in the atmosphere and ocean to support complex life.
Russell argues that life began in vents on the seabed, where warm alkaline water seeps up from geological formations below. Interactions between warm water and rocks would provide chemical energy that would first drive simple metabolic cycles, which would later start making and using chemicals such as RNA.
IN 4.5 billion years of Earthly history, life as we know it arose just once. Every living thing on our planet shares the same chemistry, and can be traced back to “LUCA”, the last universal common ancestor.
So, however likely life might have been at the beginning, it's extremely unlikely that life could originate again on Earth today.
Half a billion years. That's how long the Earth existed as a barren world. Half a billion years of hell before the planet's molten seas of liquid rock cooled to give the world a solid surface. Only then did life appear.
Earth could continue to host life for at least another 1.75 billion years, as long as nuclear holocaust, an errant asteroid or some other disaster doesn't intervene, a new study calculates. But even without such dramatic doomsday scenarios, astronomical forces will eventually render the planet uninhabitable.
The earliest life forms we know of were microscopic organisms (microbes) that left signals of their presence in rocks about 3.7 billion years old. The signals consisted of a type of carbon molecule that is produced by living things.
While some evidence suggests that life may have originated from nonlife in hydrothermal vents on the ocean floor, it is possible that abiogenesis occurred elsewhere, such as deep below Earth's surface, where newly arisen protocells could have subsisted on methane or hydrogen, or even on ocean shores, where proteinoids ...
First cells likely arose in steamy mud pots, study suggests. Earth's first cellular life probably arose in vats of warm, slimy mud fed by volcanically heated steam—and not in primordial oceans, scientists say. (Also see "All Species Evolved From Single Cell, Study Finds.")
The discovery pushed back the time for the emergence of microbial life on land by 580 million years and also bolstered a paradigm-shifting hypothesis laid out by UC Santa Cruz astrobiologists David Deamer and Bruce Damer: that life began, not in the sea, but on land.
Currently, the most favored explanation for where the Earth got its water is that it acquired it from water-rich objects (planetesimals) that made up a few percent of its building blocks. These water-rich planetesimals would have been either comets or asteroids.
The first eon in Earth's history, the Hadean, begins with the Earth's formation and is followed by the Archean eon at 3.8 Ga. The oldest rocks found on Earth date to about 4.0 Ga, and the oldest detrital zircon crystals in rocks to about 4.4 Ga, soon after the formation of the Earth's crust and the Earth itself.
Even with the current advancements in science, we still cannot create life from scratch. However, scientists were able to create a strain of bacteria (E. coli) with a fully synthetic DNA code. It was created using the components of mycoplasma bacteria and a synthetically created genome.
Among the stunning variety of worlds in our solar system, only Earth is known to host life. But other moons and planets show signs of potential habitability.
We know that life began at least 3.5 billion years ago, because that is the age of the oldest rocks with fossil evidence of life on earth. These rocks are rare because subsequent geologic processes have reshaped the surface of our planet, often destroying older rocks while making new ones.
One arose from the consequences of cells accumulating substances from the environment, thus increasing their internal osmotic pressure. This resulted in two nearly simultaneous biological solutions: one (Bacteria) was the development of the external sacculus, i.e. the formation of a stress-bearing exoskeleton.
Earth is estimated to be 4.54 billion years old, plus or minus about 50 million years. Scientists have scoured the Earth searching for the oldest rocks to radiometrically date.
By 2050 , the world's population will exceed at least 9 billion and by 2050 the population of India will exceed that of China. By 2050, about 75% of the world population will be living in cities. Then there will be buildings touching the sky and cities will be settled from the ground up.
The world economy could more than double in size by 2050, far outstripping population growth, due to continued technology-driven productivity improvements. Emerging markets (E7) could grow around twice as fast as advanced economies (G7) on average.
Atmospheric oxygen levels are very slowly decreasing today due to the burning of fossil fuels, which consumes oxygen, and deforestation which reduces oxygen production, but not enough to alter biological processes.