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This 7 page Class Notes was uploaded by Alexa Rosenfeld on Monday November 30, 2015. The Class Notes belongs to BIOL 1030-003 at Clemson University taught by Kristi J. Whitehead in Fall 2015. Since its upload, it has received 48 views. For similar materials see General Biology I in Biology at Clemson University.
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Date Created: 11/30/15
Chapter 15 Tracing Evolutionary History Sections 1511519 Looks at how the earth began macroevolution big changes How did wings evolve Sections 151153 Early Earth and the Origin of Life Early Earth 0 Evidence suggests that 46 billion years ago the earth was formed 0 Earth in the early times 39 billion years ago 0 Water vapor o Volcanic eruptions 0 UV radiation 0 Intense lightning 0 Figure 151 Page 294 artist rendition The Beginning of Life 0 1 Synthesis of small organic molecules 0 Monomers o How did this happen How did we get the ones we got I Stanley Miller experiment 0 In a lab he simulated the conditions that were thought to be on early earth water vapor atmosphere methane ammonia hydrogen lightening and then it was cooled down to settle out a solution into the ocean that he formed and see what he ended up with amino acids and hydrocarbons 0 Figure 152 Page 29 o 2 Formation of polymers 0 0 Proteins and nucleic acids Once we have amino acids how did we get to peptides I Hot surfaces clay sand water water with biological compounds washed up onto the hot surfaces The water then evaporated and the monomers were concentrated and then made polymers 0 3 Packaging of molecules into protocells O 0 Life begins at the cellular level Precells I Formation of membranes I If you put phospholipids into an aqueous solution they form a membrane with the heads and tails o 4 Origin of selfreplicating molecules 0 Ability to reproduce 0 Can make more of themselves without any other type of machinery I DNA molecules aren t that known for selfassembling it is reliant on other enzymes to replicate I RNA is known to selfassemble so if it is put into a solution with nucleotides it can selfassemble into strands of RNA 0 Can act as enzymes 0 Probable had RNA in the first forming molecules Figure 153 B Page 296 Theories in this order in order for life to begin Sections 154156 Major Events in the History of Life Maj or eventsmacroevolution How did patterns change Figure 154 Page 297 Origin of Prokaryotes Were the only things on Earth for about 15 billion years but there are fossils that could be 35 billion years old Transformed the atmosphere 0 Produced tremendous amounts of oxygen Over time some prokaryotes have been able to become photosynthetic The presence of oxygen has provided pathways for aerobic respiration There is evidence of anaerobic respiration and fermentation Origin of Eukaryotes Development of single celled eukaryotes was about 2 billion years ago Endosymbiont theory either a eukaryote engulfed a photosynthetic prokaryote and created a chloroplast or an aerobic respiration prokaryote was engulfed to create a mitochondrion Radiometric Dating 0 Let s us estimate the age of something that is very very old 0 As long as you are living you are taking up a large amount of stable C12 and a decaying C14 ratio amounts should stay stable as long as you are living 0 HALF LIFE C14 gt5000 years I What is left you can determine how long ago something has died 0 Figure 155 Page 298 Fossil Record 0 Gives relative ages of things 0 Geologic Record I Order and how old rocks are 0 3 eons I Archaean I Proterozoic I Phanerozoic o Paleozoic era 0 Mesozoic era 0 Cenozoic era 0 Table 156 Page 299 o Span of earth 60 minuteshumans are in the last 02 seconds Sections 1571513 Mechanisms of Macroevolution 0 BIG THINGS 0 Dinosaurs 0 Have to go back to the levels of the Earth 0 Figure 157 A Page 300 o Crustouter most I Sea oor continents o Mantle I What crust sits on top of I Movement of the earth s plates I Deep sea hydrothermal vents 0 Outer core I Liquid 0 Inner core I Solid Continental Drift 0 Plate tectonics o Earth s crust is divided into pieces that oat on top of the mantle 0 Some kind of disturbance that moves the mantle and the plates 0 Mantle moves plates move 0 Impact 0 250 million years ago pangea I Super continent was formed with this drift I Others have happened but this was most recent 0 Figure 157 B Page 300 0 San Andreas Fault 0 Figure 158 Page 302 o Pangea and its breakdown o Caused huge environmental changes Ocean deepened and pulled water away from the shores when continents were formed Shore lines increased greatly Huge impact on marine life 0 o o 0 Figure 157 C Page 301 Mass Extinctions 0 5 mass extinctions within the last 500 million years 0 At least 50 of all species on earth have to be eliminated o Permian mass extinction 0 Huge amounts of Volcanic eruptions o 96 of all marine organisms 0 Severe took over 100 million years to recover 0 Cretaceous mass extinction o Asteroid hit the earth 0 Took out the dinosaurs and left birds 0 Figure 159 Page 303 0 Why do we care 0 Recovery time is huge o Takes millions of years to replace biological diversity 0 In the middle of the 6th mass extinction right now rate 1001000x greater than normal extinction rate Importance of adaptive radiation 0 Many new species evolve from a common ancestor during periods of change 0 May follow extinction events 0 Ancestor usually colonizes new areas 0 Success of mammals and diversity on earth is believed to occur from adaptive radiation after the extinction of the dinosaurs 0 Figure 1510 Page 304 Evolution and Development 0 Fossil records cannot tell us the mechanisms 0 The control of development is by genes with rate timing and spatial patterns 0 What was going on at the DNA level 0 Homeotic genes genes that have a lot to do with basic processes and structure where the wings on a fruit y should be 0 A lot of what we see with these control genes when we have different events from evolution these genes can be altered where when how they are expressed regulation of the genes mutations lead to the differences we see resulting from mass extinctions o Poedomorphosis 0 Genes as a juvenile stage disappears when it moves to an adult stage timing I Figure 1511 A Page 304 0 Rate in which things change 0 Differences in terms of the development of the jaw bone and the skull in a chimpanzee result is that skulls look different I Figure 1511 B Page 305 0 Top is found in the ocean and bottom is in the fresh water 0 Differences is that in fresh water there is predators in fresh water that would grab the pelvic spine and eat them so then the trait was lost I Figure 1511 C Page 305 Evolution of Structures Gradual adaptations of existing structures See an existing structure and over time there will be gradual changes that will lead to a complex structure because of some selective pressures Complex from simple Exaptations can complicate 0 Where something evolved for some reason but over time the purpose of the thing changed Eye structures in mollusks complexity 0 Figure 1512 Page 306 Evolution is not goal directed Nothing more than pressures from the environment are allowing somethings to grow at a greater rate If the environment changes all of what was made can become a detriment instead of having advantages all bets are off Be careful interpreting the fossil records 0 There are missing fossils and problems with it o If you look at a subset you can get a clearer picture of what happened over time but if you look at a bigger picture the trend disappears and it gets more complicated 0 Figure 1513 Page 307 Sections 15141519 Phylogeny and the Tree of Life Taxonomy Names species and classify Doesn t necessarily tell you about how organisms are related Carolus Linnaeus came up with it Binomial name 0 Genus and species 39 Escherichia coli 1 Always written in italics Genus is capitalized and species is lowercase 2 3 In a lab report when writing multiple times you can abbreviate to E coli 4 Figure 1515 A Page 309 Phylogeny Looks at how things are related from an evolutionary standpoint o What was the last common ancestor 0 Most has been based on the fossil records or homologies o Homologies presence or absence of homologous structures 0 Morphological I Shape similarities 0 Molecular I Sequence of the DNA 0 Complicated by analogies o It is not impossible that organisms from common environments could have similarities but not have the same common ancestors 0 Similar structures that come from similar selective pressures NOT common ancestry o Phylogenetic tree image of hypotheses can change with new techniques and information o Goes from broad to specific 0 When they are branched into two you are looking at a more recent common ancestor I Coyote and wolf instead of cat 0 Figure 1515 B Page 309 0 Construction of phylogenetic trees 0 Cladistics field where you create phylogenetic trees I Method creating Cladesmonophyletic groups ancestral species and everything that came from it I Created by comparing what is the same and what is different between the species I Shared ancestral characters 0 Put organisms into a clade 0 Doesn t allow us to differentiate between them cannot separate 0 EX having a backbone vertebrates I Shared Derived characters 0 Mammals make up own branch within the clade of vertebrates 0 Model of constructing the tree 0 In groups relationship between the ones you are studying 0 Out groups at least one member has to make this up you know no matter how the in groups are related to each other the out group is NOT RELATED AT ALL 0 Look at shared characteristics more shared more related kangaroo and beaver in this case 0 Figure 1516 A Page 310 o More closely the branch point the more closely related to a common ancestor I Figure 1516 B Page 311 o How do you rank what is most important Molecular Systematics o More similar DNA sequences are the more related the organisms are 0 Similarity of differences can be used to determine relatedness 0 Molecular clocks o All DNA has the possibility to randomly mutate 0 There are some genes that we know has a predictable rate of change so we can look at the number of differences to say that the organisms diverged from each other about this long ago 0 Most reliable molecular clock today rRNA gene is now in the small subunit of the ribosome ssrRNA Constantly Changing 0 Biology is constantly changingeven the most basic things 0 Phylogenetic trees are only a hypothesis 0 Can constantly change 0 Currently a 3 domain system
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