Wite a 3-5 paragraph answer : The beginning of life on Earth is characterized by

Question

Wite a 3-5 paragraph answer :

The beginning of life on Earth is characterized by a favorable suite of conditions. As the climate and environment changed, so did the types of organisms that developed. Describe the conditions on Earth that made life possible for different types of organisms. Think about geologic and evolutionary time scales in terms of how long it took for different organisms to development and become successful. Relate the history of life on Earth to how the climate and environment is changing today, especially in terms of rate of change. Please be specific with the types of changes that lead to different organisms.

Explanation / Answer

The conditions that made life possible for different types of organisms included the existence of the universal solvent i.e liquid water .As water possesed the abolity for H-bonding, tt played a vital role as it acted as a medium for reactivity, heterogeneous catalysis and self-organization.It was about during the 500 million years Earth's formation, i.e. approximately 4.0?Gyr ago that water became stable.Another important condition was the existence and availability of biotic raw materials such as the biotic elements such as C, H, N, O, P, S, Fe, Mg, etc., biotic molecules e.g. H2, H2O, NH3, CO, CO2, H2S, CH4, S and SO2 andminerals with Si, Fe, Ni, P and S.In this was was inlcuded the terrestrial sources of biotic raw material can be minerals that included the hydrothermal sources ,volcanic exhalations etc.

The availability of different sources of energy e.g solar energy, energy from lightening, cosmic rays and heat paved way for the formation of building blocks of biomolecules from simpler molecules and these biomolecules formed were aminoacids and nucleobases.Apart from all this,the prevalence of chemical conditions were very important for the existence of life and these included the thermal conditions and the photochemical condtions.

As the Earth was believed to be formed under heat and pressure,the first atmosphere was very hot and this was during the first billion years of formation i.e 4.5 to 3.8 billion years ago and this was called the Hadean Period or hellish period.It mostly included the helium and hydrogen that were so poisonous that nothing could survive.Gradually,the formation of the second atmosphere took place via volatile compounds such as water vapor, carbon monoxide, methane, ammonia, nitrogen, carbon dioxide, nitrogen, hydrochloric acid and sulfur that were produced by the constant volcanic eruptions on the Earth. The Earth now had had no free oxygen.

It was only about 4.1 billion years ago,that the Earth’s surface or crust began to cool and stabilize thereby resulting in the creation of the solid Earth surface with it rocks.Next,clouds formed as the Earth began to cool and this produced rainwater that formed the oceans. In the next 1.3 billion years i.e 3.8 to 2.5 billion years ago which is known as the Archean Period, the first life as well as landmasses began to form. Also,the initial life forms of life i.e were bacteria, that had the capability to survive under highly toxic atmosphere began to exist during this time.It was towards the end of the Archean Period and at the beginning of the Proterozoic Period which was approximately about 2.5 billion years ago that photosynthesis began to occur which produced oxygen and first fossils reveal that a type of blue-green algae were the first to perform photosynthesis.Next, with photosynthesis free oxygen began to build up and this happened around 1.8 billion years ago i.e around the middle of the Proterozoic Period and this paved the way for the emergence of life we see today. But again this increased oxygen created conditions did not support most of the existing life as these life forms demanded more oxygen.

The Proterozoic Period was followed by the Holocene Period or the Anthropocene Period which is also known as the Age of Man after which the Cambrian Period began. It was during this period that explosion of life took place and the major groups of plants and animals developed in a relatively very short time.I was about 498 million years later i,e 2.2 million years ago that emergence of the first modern human species took place.

In relation to history of Earth , we can say that the climate and environment is changing at a faster pace .This is due to an increased population that paves the way for pollution and increase in green house gases that lead to global warming which is responsible for making the Earth much hotter which eventually will lead to the melting of the glacier thereby resulting in increased sea level and a day will come when again there would be no life on earth as everthing would be submerged under the seas and oceans.

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