advertisement

Ch02

67 %
33 %
advertisement
Information about Ch02
Entertainment

Published on October 15, 2007

Author: Heather

Source: authorstream.com

advertisement

Slide1:  Thurman and Trujillo Chapter 02 Origin of the Earth and Early Earth Slide2:  I. Introduction A. Universe and the Solar System Milky Way Big Bang Red Shift Solar System B. Origin of Earth and Solar System - read in text C. Composition of the Earth Minerals and Rocks D. Relative and Absolute Age Dating   Slide3:  Figure 2 - 01 Slide4:  Figure 2 - 02 Red Shift Note 1: “Red Shift” works the same way that the Doppler Effect works only instead of sound this is with light. The absorption feature most commonly used is that for hydrogen. Note 2: the Red Shift lead to the Big Bang hypothesis by Edwin Hubble. Slide5:  The Nebular Hypothesis Figure 2 – 05 Slide6:  Figure 2 – 03 Position of Earth in Solar System Inner 4 planets = terrestrial planets Outer 5 (now 4) planets = Jovian planets Slide7:  Internal Structure of Earth Figure 2 – 06 Note, the earth is density stratified. Why? Slide8:  II. Early Earth A. Early Atmosphere Evidence from Rock Record Evidence from Nobel Gases Likely Source of the Early Atmosphere B. Early Ocean Slide9:  Formation of the Oceans and Early Atmosphere Figure 2 – 07 Volcanic outgassing Recently some researchers have suggested that ice meteorites could have been an important source of water, although this view has been challenged. Slide10:  Evidence from Nobel Gases - additional evidence for the origin of the atmosphere comes from Nobel gases (at one time these were called inert gases and includes He, Ne, Ar, Kr) - since Ne is not reactive with other elements and has an atomic weight greater than either O or N, if an original atmosphere is present Ne should also be present at least at its cosmic abundance (cosmic abundance = abundance outside earth) however, in our atmosphere today Ne is 1/1,000,000 its cosmic abundance the low amount of Ne in the atmosphere suggests that either: 1. Earth formed without an atmosphere 2. early atmosphere escaped or was driven off by high temperatures, or 3. early atmosphere is still present but has since been highly modified Slide11:  Likely Source of the Early Atmosphere - as the planet was coalescing many of the lighter elements were lost to space before sufficient gravity developed (this may be what happened to the Ne) - after the planet became sufficiently solid the differentiation continued by outgassing - outgassing continues even today as light materials from within the earth are brought to the surface, especially in volcanoes -> volcanic outgassing - therefore by examining volcanic effluent we can get a good idea of what the original atmosphere was like Volcanic Effluent - common gases  CO2, H2O, N2, H2, CH4, NH3 - trace amounts of  Cl2, H2S, CO, SO2 - one gas that is a common component of our present atmosphere, O2, is missing from this list Slide12:  II. Early Earth C. Theories of the Origin of Life Possible Origins of Life: Scientific Method Slide13:  Possible Origins of Life Special creation Extraterrestrial From materials available on the early earth – that is, abiotic synthesis of Oparin (1922) Slide14:  SCIENTIFIC METHOD   The scientific method is the way that scientists formulate principles, hypotheses, theories, laws, and generalizations. Application of the scientific method requires following a number of steps including: 1. observation   2. form several hypotheses based on observation   3. test the hypothesis with many different sources of data   4. reject and/or modify hypotheses that don't work and retest 5. after numerous tests and verification by other workers a hypothesis may be called a theory   6. no theory is immune to question; theories may be discarded or refined as new data comes to light.   Slide15:  Notes about the Scientific Method Note 1, a theory must be tested with many different sources of data. A single source of data generally produces an untestable theory, that is, you either believe or don’t (= faith). Note 2, scientific theories are always open to modification as new data is discovered. That is, scientific theories are not absolute and are always open to being modified, refined or discarded. Note 3, just because an idea is untestable doesn’t mean it’s wrong. Note 4, there is a difference between testable and provable. Slide16:  II. Early Earth D . Tests of Abiotic Synthesis Urey/Miller Rubey/Abelson Significance of the Above Experiments Biochemical unity of life Slide17:  Figure 2 – 09 Urey/Miller Experiment Slide18:  Figure 2 – 09 Urey/Miller Experiment Slide19:  Experiments with abiotic synthesis Urey/Miller (1952/1953) Atmosphere – H2, CH4, NH3, H2O (vapor) Results – 2 amino acids, glycine and alanine formed Ruby/Abelson (1955/1956) Atmosphere – CO2, N2, CO, H2O (vapor) Results – when atmosphere was reducing (H2 added) many amino acids formed Slide20:  Significance of the Above Experiments 1. Abiotic synthesis is possible and amino acids could have formed from components in the early atmosphere. 2. The atmosphere clearly lacked oxygen and therefore was reducing. A highly reducing atmosphere containing H2 was even more favorable to the formation of organic compounds. 3. Experiments showed that an energy source was necessary to assemble organics. Later experiments showed the UV radiation was all the energy required. 4. Rubey's atmosphere is the clear winner because it is closer to average volcanic effluent and produced more amino acids. Slide21:  BIOCHEMICAL UNITY OF LIFE 1. only 23 common amino acids although a large number exist 2. only two common nucleic acids  RNA and DNA  both are found in all organisms except viruses 3. all nuclear and hereditary material is DNA except in viruses 4. the energy storing molecules in all organisms is ATP (adenosine triphosphate) So, what is the significance of forming a couple of amino acids? Slide22:  E. Fossil Record of Earliest Life First Fossils Characteristics of the first fossils Problems studying the earliest fossils Slide23:  Where did Life Begin? Slide24:  Where did Life Begin? Science News August 06, 2005 Slide25:  Figure 2 – 11 Diagram of a fossilized bacteria from Australia, ~3.465 Ga. Slide26:  Stromatolites Slide27:  Day/Night Growth of Stromatolites Slide28:  UV/IR resistance High Low Prokaryotes vs. Eukaryotes Slide29:  Characteristics of the first fossils 1. all prokaryotes - mainly cyanobacteria (blue-green algae) and other types of bacteria 2. all associated with chert and limestones - both these rock types usually form below MLW - may indicate the need for shielding from UV 3. often associated with "deep-water?" iron deposits - especially BIF's (Banded Iron Formation) - there is some speculation that iron may have been used as an electron carrier   Slide30:  Problems with studying earliest fossils 1. Many of the earliest proposed early forms of life have a structure that is very unremarkable and could have been formed by inorganic means. This is especially true for bacteria which are sphere, rod-shaped, or spiral-shaped. 2. Deformation could cause some structures to look like stromatolites that aren't. As a result of these problems many discoveries of Precambrian fossils have been questioned   Slide31:  F. The Atmosphere and Early Life G.Effect of O2 in the the ocean and atmosphere Banded Iron Formation (BIF) Red Beds Slide32:  Effect of O2 in the ocean Banded Iron Formations (BIF) - iron is one of the most common elements on the surface of the earth - today iron is locked up in its oxidized form - however, in a reducing environment iron could be transported in solution as ferrous iron - BIF's first appeared sometime between 3.7-4.0GY although their major development wasn't until later Slide33:  Effect of O2 in the ocean Banded Iron Formations (BIF) - banded iron formations look like just what their name suggests, alternating layers that are iron rich and iron poor - BIF's may represent seasonal blooms of blue-green algae with the iron precipitating when photosynthesis gives off a lot of oxygen BIF is a self-terminating process, because a point will be reached where more O2 is being produced than can be used to oxidize the ferrous iron in solution (in the ocean) and oxygen will escape to the atmosphere Slide34:  Effect of O2 in the atmosphere Red Beds - as O2 becomes common in the atmosphere iron can no longer be transported in solution and instead is oxidized at its source area on land - therefore, evidence for oxygen accumulating in the atmosphere comes from continental sedimentary deposits, red beds - prior to 2.0GY no continental deposits contain iron (or other easily oxidized material like uranium) - after 2.0GY red beds become increasingly common indicating the presence of oxygen in the atmosphere - red beds are most common from 1.8-1.2GY Slide35:  H. Importance of Oxygen in the Atmosphere Ozone layer Respiration I. Evolution of Eukaryotic Cell type Slide36:  Importance of Oxygen in the Atmosphere 1. ozone layer - as O2 builds up in the atmosphere an ozone layer begins to accumulate in the upper atmosphere - the ozone layer helps to shield the surface of the planet from radiation, especially UV 2. respiration - all early organisms depend on fermentative (anaerobic) respiration - in fact, oxygen may have been toxic to early organisms - as oxygen increased in the atmosphere, organisms had to develop defenses against it - one way to do that was to turn a liability into an asset by using oxidative (aerobic) respiration - one major advantage of oxidative respiration is that it is much more efficient, about 20 times more efficient, than anaerobic respiration   Slide37:  Atmospheric Oxygen Concentration through Time Figure 2 – 12 Slide38:  Figure 2-15 Slide39:  Figure 2 – 14 How are rocks dated? Relative and Absolute Age Dating Slide40:  Figure 2B Simplified Evolution of the Earth and Life

Add a comment

Related presentations

Related pages

CH02 - gov.uk

CHFP000 06/16 Version 5.0 CH02 Change of corporate director’s details Where to send You may return this form to any Companies House address, however for ...
Read more

Change the details of a corporate director (CH02 ...

Use this form to change the details of a corporate entity that is a director.
Read more

ch02 - Scribd

Package Title: Assessment Questions Course Title: Intro IS 4e Chapter Number: 2 Question Type: True/False 1) A business process. has inputs and outputs ...
Read more

ch02 - Scribd

Welcome to Scribd! Start your free trial and access books, documents and more. Find out more
Read more

Ch02 - Food and Agriculture Organization

Chapter 1 Honeybees of the Genus apis. Contents - Previous - Next. A. The dwarf honeybee Apis florea B. The giant honeybee Apis dorsata C. The oriental ...
Read more

Ch02 - UNESCO

Introduction. Purpose of the study Perspectives on pest management in libraries and archives Hazards of pests in libraries and archives Health concerns ...
Read more

Auna AMP-CH02 2-Kanal-Verstärker | | auna

Auna AMP-CH02 2-Kanal-Verstärker - Leistungsfreudiger 2-Kanal-Verstärker mit 1400W Leistungsspitze, Hoch- und Niedrigpegel-Eingängen sowie regelbarem ...
Read more

TranzX CH02 36V E-Bike Batterie Akku Ladegerät online ...

TranzX CH02 36V E-Bike Batterie Akku Ladegerät bei BadBikes Wernigerode online preiswert günstig Fahrräder kaufen
Read more

Breezy CH02

Edy Schuetz, Pilot, Eigenbauer, Flugzeugkonstrukteur, Masch. Ing. ... Der fliegende «Kranausleger» HB-YLX. Es brauchte viele Motivatoren und Helfer um ...
Read more

Ch02 - Food and Agriculture Organization

1. How soil is destroyed. Contents - Previous - Next. Soil is a complex mixture Soil teems with life Only a fraction of land is arable Erosion destroyed ...
Read more