Historical Geology Week 4
Historical Geology Week 4 GEOL1005
Popular in Historical Geology
verified elite notetaker
Popular in Geology
This 5 page Class Notes was uploaded by Kate Notetaker on Thursday February 4, 2016. The Class Notes belongs to GEOL1005 at George Washington University taught by Catherine A. Forster in Winter 2016. Since its upload, it has received 28 views. For similar materials see Historical Geology in Geology at George Washington University.
Reviews for Historical Geology Week 4
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 02/04/16
February 2, 2016 Evolution Charles Darwin o Studied at Cambridge o First wanted to become a doctor but found a real love for geology and natural history o After he got out of Cambridge Went on the HMS Beagle to South America Studied for 5 years Would send specimen and data he collected back to London o When he got back, he was well known because of all the things he wrote o He found that: living organisms are very variable extinct organisms were very closely related to the living organisms he found o Settled down and became a gentleman farmer for the rest of his life Married rich and didn’t have to work o Expert of barnacles Wrote a lot of papers on this topic o Really interested with worms and compost (especially as a farmer) o Did a lot of pigeon breeding Found that he could start with one kind of pigeon and get a new breed o Start with one basic form and through selective breeding you can come up with many different forms o During his voyage he had seen these finches Galapagos island Different kinds of beaks depending on the environment they lived in Each island had different kinds of fauna Birds had different beak shapes to eat what was available Robert Malthus o You have to control human population otherwise you will have too many people to feed o Darwin used Malthus ideas This became the foundation for what we call “survival of the fittest” Transmutation of species o How species change evolution o Natural selection as the mechanism for this transmutation 1858 Darwin got a letter from Alfred Wallace o He almost came up with the same ideas as Darwin about evolution o Darwin and Wallace present a paper on evolution 1859 Darwin publishes his book on the origin of species Darwin saw evolution as descent with modification Gregor Mendel o Bred peas o Mendelian genetics o Found that inheritance followed very strict rules Unchanging, not random o Basic unit of inheritance: genes Figured out how these are passed down from generation to generation Mechanism for evolution to work on o 1865 Mendel publishes his findings Pretty much ignored o 1890 Mendel’s findings were rediscovered and figured out how it all worked (especially with Darwin’s findings) o Genes were all linked together in a chain like strand: DNA Tells the organism what its going to look like, how its going to behave, etc. At first, we did not know what DNA looked like (structure) Because of this we could not know how it reproduced 1952 Rosalind Franklin and her students worked with X-ray diffraction o Photo 51 found that DNA was a double helix 1953 James Watson and Francis Crick published how everything was arranged with this double helix Double Helix of DNA o Linked together through “base pairs” of amino acids o Gave the clue of how DNA replicated Caveats to DNA being passed down o Mutations or “mistakes” happen all the time Natural or by external factors DNA doesn’t stay the same, it changes Some of these mutations are helpful, some are the opposite o Horizontal gene transfer One species to another Study published last year that says there are around 145 foreign genes in the human genome From bacteria, virus, plant material, etc. Hox Genes regulatory genes o Regulate what the other genes do o Tells you where everything is supposed to be (where your eyes/legs/other trait is supposed to be on your body) Species evolve not the family or an individual o Have a Genus name and a Species name For humans, genus is Homo and species is sapiens Genus name is always capitalized, species is not o A lot of species are very variable Variation between a species could be large or small Variation can also be partitioned Vary among segments of species o Change from one species to another is “speciation” Difficult to observe in the world today Can happen quickly, can be slow all depends on the natural pressures Can be effected by geology Ex. Lesser Antilles anole lizards o 3 different groups of lizards o lava flows that separated group 1 and 2 and another that separated two from three o Two of the groups were closely related and the other was less similar o The lava flow between group 2 and 3 was more recent You can look at the order of events to make sense of evolution of species o Geology can drive the variation/evolution of some species February 4, 2016 Fossilization o Long term process that preserves organic remains o First thing preserved is the organism itself Body fossil o Evidence of organism Trace fossils Can take a number of forms Footprints (tracks) Burrows Nests and eggs Coprolites fossilized feces o Learn a lot of the diet of the organism Chemical traces or chemical fossils o Sedimentary rocks where we usually find fossils Mudrocks Sandstones Volcanic ash deposits Precipitated sedimentary rocks limestones o Fossils need to be buried and remain buried In one of these sediments Don’t have to be buried rapidly Just before it is completely disintegrated Some places where burial doesn’t occur everywhere Sedimentary rock not accumulating in some places Pre-burial conditions? Scavenging Decomposition o Place it gets buried has to be conducive to preservation Burial environment If the burial environment is too dry, too acidic, or too coarse grained Won’t be preserved Post-burial conditions Effects of sediment type, pH, bone size and other factors in a lab setting o Lagerstatten Places of exceptional preservation Archaeopteryx Even the feathers are preserved o Molds and casts No original material Just an impression Footprints The impression/negative is the mold o Compression (carbon film) Distilled organic molecules o Permineralization (petrefaction) Mineralization of the “hard parts” Two of the minerals that water will carry to the bones are Silica and Calcium carbonate In slightly acidic environments silica is preferred Preserve incredibly fine detail o Preservation in amber Preservation in fossilized tree resin o Ice / freezing as preservation Complete organisms are very rare o Peat bogs Sphagnum moss Preserves organic material very well Highly anaerobic o Asphalt/tar as preservation Petroleum Animals became mired in the sticky asphalt seeps Predators and scavengers came in to eat them and got stuck themselves What we see that is preserved best is the hard parts of material Soft tissues o Mold and cast o Permineralization o Compressions Behavior Taphonomy o Study of pre-burial conditions By looking at the preserved melanosomes, they could figure out the color of the animal Inherent bias in the fossil record o Due to requirements for fossilization Both hard and soft parts can be preserved o Often down to microscopic detail o Because of detail, we can find out more about the biology of the animal than what lies on the surface
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'