Bio 105 1st Edition Lecture 18Past lecture (17)Redshift – 1920’sCMB – 1960COBE – 1992WMAP – 2003Why is the universe story important?Shows us…- That the unfolding of the universe is a continuum of which we are a part of.- Our history is the same (single-beginning – same development)- The incredible nature of our intelligence.Omnia exeunt in mysterium – no matter how much we study, we find more and more mystery.Our solar system1. Nebula-gaseous collection of matter that started creation of universe.2. Starts to spin (gravity comes into play)3. Sun lights up, and dust comes together.4. Plants are createdSun (5 billion)Proto-sun = early sunPeriod of Great Bombardment (earliest phase of history of Solar System)- We know the age of the solar system because of the rocks on Earth.- Asteroids that enter Earth because Earth is so technically active. (Earthquakes, etc.)1. Formation of Moon (giant impact hypothesis) – widely accepted, but still controversial. Oblique collision between Earth and Thea.How long do start live for?-Not forever, they eventually use up all their hydrogen (fuel)Complex LifePrinciple of Mediocrity – Earth is a typical planet Universe likely teams with complex life elsewhere (COMMON)Rare Earth Hypothesis – emergence of complex life is highly improbably. (RARE)Life arising during the period of great bombardment (“outgassing”, there was no ozone layer)- Through pre-biotic chemical evolutiono Abiogenesis - No stratosphere – the protective layer (no ozone)- Very low level of gaseous (Hydrogen) in troposphere.Early Earth – Abundant ultraviolet light, lighting, and radiation. Conditions in which life is born.Current Lecture (18)Early Earth - Not enough oxygen in atmosphere for the living.- There was strong radiation, no ozone. - No aspects for living, and no promise.Two theories of origin of life on Earth1. Life building molecules arose outside of Earth through pre-biotic chemical evolution – exogenesis- Supporting evidence o Organic matter (building blocks) throughout galaxies and Universe.o Some meteorites carry molecules of life.- Challenges o It is a long inter-planetary/galactic trip by living organism possibleo No known life outside Earth- There are possibility primitive meteorites and comets brought water to early Earth.(Through impact)- Life building compounds on early Earth may have had cosmic origins.2. Life arose on early Earth through pre-biotic chemical evolution – abiogenesis- Organic soup/primordial soup-No one knows where the origin of life began.-“Degassing” brought a lot of energy, and the Earth need energy for molecules to form. Miller-Urey Experiment (1950’s)- Formed molecules in experiment by mimicking early Earth.- Found building blocks of life- Multitudes of organic molecules form readily.- Re-evaluated many times since early atmosphere was different that what was firstthought.- Chemical evolution still supported by abundance. Complex macromolecules form protocells (first cell) more complex cells- Conditions on early Earth were suitable for formations of carbon rich molecules –from which life evolved.- Very primitive life by 3.8 billion years ago.Protocells – early formation of cells- No one has synthesized a living cell.- The earliest life consists of prokaryotes, which lived in an oxygen-free environment, 3.8billion years ago.- Infant life and early Earth began to evolve together.Eukaryotic –all need oxygen- All multicellular life.- Varies in size- DNA strandProkaryotic (bacteria)- Much smaller- No nucleus - Circular DNA- No-membrane bound organelles- Abundant todayPhotosynthesis (2.8 billion years ago) evolved. (Some cells develop capacity to deal with Ozone)- Oxygen later increases in the atmosphere.- IT IS IMPORTANT – greatest pollution in early history of the Earth. 6CO2 + 6H2O ------> C6H12O6 + 6O2- Life formed intimate relationships with sun.- Superpower creates food from sunlight within its own body.*Photosynthesis develops in prokaryotes (3.5 -3 billion years ago)- Prototroph = eat light - Sustains all eukaryotes life, a keystone moment.Oxygen Revolution begins… very slowlyGreat oxygen event (GEO) -2.4 billion years ago- Atmospheric and ocean shifts from abiotic to biotic regulationo Regulation by life on earth.Origin of Eukaryotes - In Endsymbiotic Hypothesis (beneficial) for origin of mitochondria (powerhousegenerators of cell) and Chloroplasts (energy suppliers)- It states that some of the organelles in today’s eukaryotic cells were once prokaryoticmicrobes. - Chloroplasts are descendants of photosynthetic prokaryotes.- Giant leap in evolution, it makes complex life possible. - Cooperation, not competition- Eukaryotes merged 2 billion years ago.Universal tree of life- Not all unicellular life is prokaryotic- All evidence supports the single origin.- Atmospheric oxygen increases- Stratospheric ozone forms, and has protected life for 450 million years.Present Level of Gas in TroposphereNitrogen – 75%Oxygen – 21%Argon - .93%Carbon Dioxide -.03%Traces of water, methane,
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