Transcript Document

The Marine
Environment
Ocea 101
Raphael Kudela
Beginnings of the Universe, Earth, and Life
 The Universe and Solar System
 Dimensions and distances
 Our planets
 Earth’s Composition
 Structure of the Earth
 Types of rocks
 Relative versus Absolute Dating
 Geological History
 Where did the water and salts come from?
 Origins of Life
 Cold versus Hot
 autotrophic, heterotrophic, chemotrophic
The Universe and Galaxies
Still expanding…
Universe Contains
~1020 stars
Milky Way is about
15 billion years old
(byp), and is a Spiral
galaxy
Our galaxy contains
about 100 billion stars
~100,000 light years
across
Structure of the Early
Universe
Turquoise or
Beige?
Glazebrook and
Baldry (2002)
calculated that the
universe was
Turquoise….
But it turns out it’s
really Beige.
The Solar System
~ 5 byp old
Condensed from a stellar supernova--it
started as a hot, rotating cloud of gases
The Solar System
As the solar system condensed,
it formed planets…those that
are close to the sun lost their
atmospheres
Proto-Earth formed ~4.8 byp
100,000x larger, and 500x heavier
Moon formed by an impact with
something the size of Mars
Earth is far enough away from the
sun to keep its atmosphere, close
enough not to freeze
The Earth’s Composition
3 Layers:
Core (Fe, Ni)
Mantle (Fe, Mg, Si, O)
Crust (aluminosilicates)
3 Types of Rock:
Igneous
Sedimentary
Metamorphic
Oceanic Basins are
formed of basalts,
continents are mostly
granitic
Dating Rocks
Relative Dating
Early 19th Century
Correlate rock strata
with fossils
Absolute Dating
Curies discovered
radiation
Almost all rocks have
radio-isotopes
If you know t1/2, can
calculate exact date
Radioisotope
Radon-222
Strontium-90
Radium-226
Plutonium-239
Uranium-235
Half-life
4 days
28 years
1602 years
24 400 years
700 000 000 years
Carbon-14
Phosphorous-32
Tritium (H-3)
Americium-241
Nitrogen-13
5730 years
14.3 days
12.3 years
432 years
9.96 minutes
Radioactive Decay Functions
Pt=P0
-lt
e
P= Parent Isotope
D= Daughter Isotope
t= Time
l= Radioactive decay function
t1/2= half-life
Geological History
Initially ,there was no
atmosphere, no ocean (too hot),
no oxygen!
~4byp, oceans formed
Outgassing of volcanoes, or
“snow-balls”?
Water allows chemical
weathering of rocks
Heavy elements (Na, Ca, K, Si,
Mg, Fe) appear to have come from
rocks (dissolution)
Excess volatiles (Cl, S, C, N) had
to come from volcanoes!
Hydrologic Cycle
Scientific Hypotheses (post-Beagle)
Edward Forbes--The “azoic hypothesis”
Ross Brothers--Deep sea life at the poles, and
the “emergence hypothesis”
Darwin: Natural selection and evolution
1857: T.H. Huxley describes “Bathybius
haeckllii”
Origins of Life
Development of amino and
nucleic acids
1st organisms were probably
simply “heterotrophs” ~3.85
byp
~3.5 byp, first autotrophs, bluegreen algae (or cyanobacteria)
arose…adapted to an oxygen
rich atmosphere
Endosymbiosis Hypothesis
First proposed by Lynne Margulis (1974)
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
We are symbionts on a symbiotic planet and if we care
to, we will find symbiosis everywhere” -- Lynne Margulis
Evolution of Photosynthesis
• Photosynthesis evolved in the
absence of oxygen (a very
reducing atmosphere)
• It evolved independently in a
number of bacterial organisms
• It is responsible for all
present-day oxygen in the
atmosphere