This website uses cookies to ensure you have the best experience. Learn more

Beginning Of Life Essay

2150 words - 9 pages

AST 309
part 2:
Extraterrestrial Life

The Origin and Evolution of Life on Earth

Overview
• The formation of Earth
• Pre-biotic chemistry (Miller-Urey exp.)
• First evidence for early life
• The evolution of life
• Extreme life on Earth: lessons for astrobiology

A timeline for the very early history of the Earth

The formation of Earth:

The Earth formed over ~50 Myr via planetesimal accretion

Earth differentiation:
The iron "drops" follow gravity and
accumulate towards the core. Lighter
materials, such as silicate minerals,
migrate upwards in exchange. These
silicate-rich materials may well have
risen to the surface in molten form,
giving rise to an initial magma ocean

Early Earth ...view middle of the document...

A timeline for the very early history of the Earth

In order to be able to find life outside our Earth, we have to
understand life in our own planet. The chemistry of life and the
different processes during the formation and evolution of the
Earth have played a crucial role.

Is life on Earth a very special thing ?
Can life spawn spontaneously elsewhere ?

Tiny zircons (zirconium silicate crystals) found in ancient stream deposits indicate that
Earth developed continents and water -- perhaps even oceans and environments in
which microbial life could emerge -- 4.3 billion to 4.4 billion years ago, remarkably soon
after our planet formed. The presence of water on the young Earth was confirmed when
the zircons were analyzed for oxygen isotopes and the telltale signature of rocks that
have been touched by water was found: an elevated ratio of oxygen-18 to oxygen-16.

A timeline for the very early history of the Earth

How to understand an astrobiologist (or any
microbiologist):
Monomer: usually a small molecule that can bind chemically to form a
polymer (amino acids are monomers)
Polymer: a macro-molecule composed of repeating structural units. Proteins
and nucleoacids (RNA & DNA) are polymers
Protein: a biochemical compound that facilitates a biological function
Encyme: are proteins that catalyze (e.g. increase rates) of chemical reactions
RNA: Ribonucleic acid, a macromolecule made of long chains of nucleotides (1
base, 1 sugar and a phosphate group). Single strand, can carry
genetic info.
DNA: Deoxyribonucleic acid, double-helix shaped macromolecule made of
nucleotides. Carries genetic information.

The Miller-Urey experiment
In the 1930s, Oparin and Haldane independently suggested
that ultraviolet radiation from the sun or lightning discharges
caused the molecules of the primordial atmosphere to react to
form simple organic (carbon-containing) compounds. This
process was replicated in 1953 by Stanley Miller and Harold
Urey, who subjected a mixture of H2O, CH4, NH3, and H2 to an
electric discharge for about a week. The resulting solution
contained water-soluble organic compounds, including several
amino acids (which are components of proteins) and other
biochemically significant compounds.

Problem: The assumed atmospheric composition

The experiments only give large yields of interesting
organics (amino acids, nucleic acids, sugars) if the gas is
H-rich (highly reducing). If the early atmosphere was CO2
+ N2 (mildly reducing), as many suspect, the yields are
tiny.

Atmosphere from
volcanic outgassing?

This would give atmosphere
rich in CO2, N2, and H2O.
Not the composition that
favors Miller-Urey synthesis.

Could the original atmosphere have been delivered to the Earth from
comets, asteroids, …? Perhaps then the composition would be H-rich.
What was the source of the early Earth’s atmosphere? Not necessarily “endogenous” (there from the
start). Outgassing from the crust due to volcanoes (top two), or planetesimal impact (lower left),...

Other assignments on Beginning Of Life

The Call Of Moses Essay

617 words - 3 pages -changing incident in the life of one man; however, it is a crucial turning point in the history of the nation of Israel. The burning bush marks the beginning of God’s direct intervention into the affairs of history. It is the basis for the call of Moses to return to Egypt as Israel’s deliverer. It is the beginning of the end of Egyptian oppression, the burning bush made not only an impact upon Moses and the people of Israel, but it also served as

Independent Reading Book Project Essay

1312 words - 6 pages  in many wedding receptions. The final stage  transpires in a river in the middle of a forest.   IV. Describe the mood (atmosphere) of your book:  The mood in this book changes as Eddie continues his journey through Heaven. In the  beginning is has a melancholy mood. We learn that he lives a sad, lonely life. Eddie had a terrible  relationship with his father, stayed in a career he didn't enjoy, got injured during the war, and was

Doctor

612 words - 3 pages ) Depr. Expense = Depreciation Rate * Book Value at Beginning of Year Book Value = Book Value at beginning of year - Depreciation Expense Sum-of-Years' Digits Method: Sum of digits = Useful Life + (Useful Life - 1) + (Useful Life - 2) + etc. Depr. rate = fraction of years left and sum of the digits (i.e. 4/15th) AC BAC BCR CBR CPI CV DUR EAC EF EMV ES ETC EV FV IRR LF LS NPV PERT PTA PV PV ROI SPI SV VAC σ ^ Actual Cost Budget at Completion

Never Give Up

526 words - 3 pages Never Give Up” There is no such thing as an ending Just a new beginning. I think this quote is awesome, and has a lot of meaning in my life. To me this quote literally mean, “never give up” when I say never I mean never God does everything for a reason. So I never complain neither do I ever give up. Basically everything good I do with

Abortion

571 words - 3 pages that abortion has been practiced since the beginning of time. They argue that choice must remain at the heart of the issue, that privacy should override all other concerns and somehow limit the outcome. They point out that control through contraception also and abortion on a belief in the importance of the individual’s responsibility for the economic and social conditions of his or her life.

Engineering

276 words - 2 pages developed and implemented. Thus through these different types of societies we have understood that the type of society in which man lived in the beginning is very different from the type of society in which he lives today. The story of human social life has undergone several forms and changes. Historically, societies have taken number of different forms and have changed in ways that are unique themselves.

Red Badge Of Courage

638 words - 3 pages through a character change that shows how people must get through their own fears, daily life, and struggles that hold us back from becoming the best. How Henry changes in this story, he shows that all people in the world have a sense of fear that we should overcome. In the beginning of the book, the first section, he is a young boy. He is inexperienced. He was selfish. He entered the war for the glory and not to serve his country. He wants to

Stolpestad

953 words - 4 pages Stolpestad By William Lychack Do you ever feel like you are going nowhere? Like your life is stuck in stagnation. Getting out of bed in the morning, going to work and returning home to bed just to rise and repeat the exact same routine the next day and the day after that. The routine becomes so familiar that it feels like the days goes by in a blur. It does not feel like you even exist in your body anymore. That feeling is the theme of the

Twentieth Century

316 words - 2 pages Standing at the turn of the new century, we observe the twentieth century as a great advance in technology. With those advances, human lives have changed dramatically. In some ways, life is worse, but mostly, it is better. So personaly speaking, I am, and probably will always be, one of those who agree with the idea that technology has made the world a better place to live. First of all, technology has brought with it a more comfortable life

Absjs

303 words - 2 pages onesia as the development country has to facing so many challenges and obstacles in order to achieve the goals of the country. From the very beginning the economic system in Indonesia is followed the Pancasila economic system. But, at the time before the new order, the economic system in Indonesia are liberal and statism that is not suitable for the citizen in the early of 50’s to 60’s. Before that time there are many program that

Word Art

315 words - 2 pages Topic: Inter-Caste & Inter-Religion Marriages. Marriages in India are fundamentally endogamous in nature. The influences of western education and socio-economic transformations have led to enormous change in the existing pattern of choosing one’s life partner and marriage practices in India. The trend analysed reveal that the proportion of inter-caste and inter-religious marriages has doubled in the last two and half decades. The study

Similar Documents

Beginning Of Durga Puja Essay

356 words - 2 pages The origin of celebrating Durga Pooja in Bengal dates back to 16th century AD. According to legends, the landlords of Malda and Dinajpur started Durga Puja for the first time in the state of Bengal. However, according to some sources it is said that Bhabananda Mazumdar of Nadiya or Raja Kangshanarayan of Taherpur first initiated autumn Durga Puja or Sharadiya, as it is called in Bengali. Over the years, the celebration has taken the form of mass

Hum115 R4 W1 Levels Steps Worksheet

649 words - 3 pages University of Phoenix Material Week 1 – Levels and Steps of Critical Thinking Worksheet Note. This is a three-part assignment. Please ensure you complete all three parts. Part 1: Critical Thinking Distribution Complete the following True/False questions about Beginning Critical Thinker, Average Critical Thinker, and Advanced Critical Thinker. Refer to pp. 13-15 in Ch. 1 of Critical Thinking in Everyday Life. 1. True

"O Me! O Life" Analysis

434 words - 2 pages format. At the beginning of his poem he introduces his final argument, “Oh me! Oh life! of the questions of these recurring,/ Of the endless trains of the faithless, of cities fill’d with the/ foolish”. Whitman conducts his question to the uselessness of life (the question) and hints his audience to his argument by comparing faithless and foolish. This conveys the idea that being faithless about life is “foolish.” This comparison also relates to

Society Essay

261 words - 2 pages and the society. So society is the place where a person in engaged from the beginning of his/her life. It is the society which plays a vital role in shaping an individual. A society is very important and essential thing for one’s living. No one can live a normal life in the absence of the society. Beside this it is an individual who makes a society complete. So there is indispensable relationship between a society and an individual. A