What are the explanation about the existence of life forms here on Earth?

We know that life on Earth is built around compounds that contain elements such as carbon, nitrogen, hydrogen and oxygen. Complex sequences of these elements bond together, forming the very building blocks of life. They form essential organic molecules, such as sugars, enzymes, proteins and DNA.

Which of the three planets is capable of sustaining life?

According to the panspermia hypothesis, microscopic life—distributed by meteoroids, asteroids and other small Solar System bodies—may exist throughout the Universe. Nonetheless, Earth is the only place in the Universe known to harbor life.

Which major processes were needed for the origin of life on Earth?

Here we discuss essential requirements for the first emergence of life on our planet and propose the following nine requirements: (1) an energy source (ionizing radiation and thermal energy); (2) a supply of nutrients (P, K, REE, etc.); (3) a supply of life-constituting major elements; (4) a high concentration of …

What do you understand by origin of life explain?

The origin of life means the emergence of heritable and evolvable self-reproduction. Thus, life originated from simple but already functional molecules, and its gradual evolution towards higher complexity was driven by cooperation and natural selection.

Which of these planets is known as the only habitable planet?

Understanding planetary habitability is partly an extrapolation of the conditions on Earth, as this is the only planet known to support life.

What are four major stages that are thought to be required for the origin of life?

In the first portion of section 22.1, four stages are ordered as follows: Stage 1: Organic molecules, like amino acids and nucleotides, were formed first and the precursors to all life, Stage 2: Simple organic molecules were synthesized into complex molecules such as nucleic acids and proteins, Stage 3: Complex …

What is a leading hypothesis for the formation of life on earth?

1. The formation of the earth according to the most widely held hypothesis, The Big Bang Theory, was that 4.6 billion years ago, a cloud of rocks and dust condensed due to gravitational pulls, and bombardments by ice and rocks caused intense heat that vaporized water on earth.

What is the history of life on Earth?

The history of life on Earth traces the processes by which living and fossil organisms evolved, from the earliest emergence of life to present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga.

What are the origins of life on Earth?

The origins of life cannot be dated as precisely, but there is evidence that bacteria-like organisms lived on Earth 3.5 billion years ago, and they may have existed even earlier, when the first solid crust formed, almost 4 billion years ago.

Is there only one kind of life on Earth?

If truly only one sort of life on Earth exists, then perspective is lacking in a most fundamental way. On the other hand, the historical continuity of all life-forms means that ancient life, perhaps even the origins of life, may be glimpsed by studying modern cells.

What is the first scientific theory on origin of life?

First scientific theory on origin of life came from Russian biochemist Alexander Oparin which stated that first life on earth appeared through chemical evolution .

How did life spread on Earth?

Over hundreds of millions of years, life spread through the seas and over Earth’s surface. The first life-forms were small and simple. Later forms were more complicated and diverse.