- #1
johncena
- 131
- 1
organic evolution took place in the absence of oxygen...if so, how oxygen came on earth??
Oxygen first appeared on Earth approximately 2.4 billion years ago through a process called photosynthesis. Early photosynthetic organisms, such as cyanobacteria, used energy from the sun to convert carbon dioxide and water into oxygen and glucose.
The oxygen in Earth's atmosphere was primarily produced by photosynthetic organisms over billions of years. These organisms released oxygen as a byproduct of photosynthesis, gradually increasing the amount of oxygen in the atmosphere.
No, oxygen did not always exist on Earth. The early Earth had a very different atmosphere, mainly composed of gases such as methane, ammonia, and carbon dioxide. Oxygen became a significant component of the atmosphere only after photosynthetic organisms evolved.
Oxygen played a crucial role in the evolution of life on Earth. It allowed for the development of more complex and efficient organisms, as it is a vital component of cellular respiration. The increase of oxygen in the atmosphere also led to the formation of the ozone layer, protecting life on Earth from harmful UV radiation.
Scientists know about the history of oxygen on Earth through various sources of evidence, such as geological records, fossilized remains of ancient organisms, and chemical analysis of rocks. They can also study the composition of other planets and the processes of photosynthesis to understand how oxygen may have originated on Earth.