Life on Earth.
Life on Earth. 1. Analysis of the oldest sedimentary rocks provides evidence for the origin of life. * Identify the relationship between the conditions on early Earth and the origin of organic molecules. * Scientists estimate that the universe is 10-20 billion years old and arose as a big bang, which is still expanding the universe. * The early Earth was very different from the Earth today and no oxygen was present. This means that there was no ozone layer exposing the Earth’s surface to ultraviolet radiation. * There were large amounts of volcanic activity, heat, ash and dust and gases in the atmosphere. * Violent electric storms were common. * On our Earth, organic chemicals appear to have originated about 4 billion years ago. * Early Earth, with an atmosphere of water vapour, hydrogen, methane and ammonia, provided an environment in which the production of organic molecules would be most likely formed in the lower atmosphere or the Earth’s surface. * The organic compounds of water, carbohydrates, lipids, proteins and nucleic acids are composed of hydrogen (H), oxygen (O), carbon (C), nitrogen (N) and some other elements. * The elements needed to create these organic compounds were already present in the atmosphere in early Earth. * The lack of ozone layer, the frequent violent electric storms and the volcanic activity of early Earth could have provided the energy for molecules to be formed. * Discuss the implications of the existence of organic molecules in the cosmos for the origin of life on Earth. * The discovery of organic compounds on meteorites implies there are organic molecules in the cosmos. This means early Earth may have been ‘seeded’ with organic molecules from the cosmos and the first cells may have arrived from the cosmos. This has led to research in other areas (eg: radio spectroscopy to detect chemicals in outer space and the analysis of interstellar dust).
* Describe two scientific
* Describe two scientific