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Evolution and Biogenesis
Evolution: changes in one or more characteristics in a population over a period of time. All living thing come from other living things Evolution, by definition, means the changes in one or more characteristics in a population over a period of time.
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Spontaneous Generation and Experiments
From nonliving to living Fish Maggots Redi’s Expirments SG does not occur Spallanzani’s Experiment Microscope Louis Pasteur’s Experiment Swan-neck flask Biogenesis Contest
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< Spallanzani ^Pasteur
Broth in flask > Kept open > boiled > Microorganisms found in neck of flask ^Pasteur
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Earth 4 Billion The First Organic Compounds
Ammonia, hydrogen gas, water vapor, and methane Simple organic compounds
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Fossils Remnant of an organism of a past geologic age.
Molds or outlines Carbon Dating Fossils, by definition, are a remnant or trace of an organism of a past geologic age, such as a skeleton or leaf imprint, embedded and preserved in the earth's crust. Fossils are molds or outlines that create a visual for pre-existing creature and plants. They can be imprints in rocks, or they can create a model by filling molds with minerals. The age of a fossil can be determined by Carbon Dating. The half life, used to figure the age of a fossile, of Carbon-14 is 5,715.
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Carbon Dating Based of the half life of Carbon-14, a fossil bone was found to posses mg of C-14. Compared to an identical fossil bone found today, which contains 20 mg of C-14. What is the age of the bone? Bone = .625 mg C-14 Current Bone = 20 mg C-14 20 mg = 0 10 mg = 5,715 5 mg = 11,430 2.5 mg = 17,145 1.25 mg = 22,860 0.625 mg = 28,575 Answer: Approximately 28,575 years old Given this word problem, we can used obtained information to date the fossil. (Have the class do along with us) Based of the half life of Carbon-14, a fossil bone was found to posses mg of C-14. Compared to an identical fossil bone found today, which contains 20 mg of C-14. What is the age of the bone? (Explain each step and uncover the answer at the end)
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Created the concept of the “Ladder of Life”
Aristotle Created the concept of the “Ladder of Life” Church members disbelieved and did not want to accept the theory Little changes were possible Aristotle created the concept of “the ladder of life”, which is a progression of life forms from lower to higher, humans being on the top. This explains survival of the fittest, because if certain qualities were not present, the life form would cease to exists. Church members wanted to believe that the creation of the earth was ll God’s work, and not that of science. Rather then having sudden changes, little changes over a longer period of time were very possible.
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Jean Baptiste de Lamarck
Species from the same family, have traits from a common ancestor Believed that traits developed in one’s life, would be passed to their offspring. The used traits, would be more developed and passed on. If species came from a same family, they would come from a common ancestor. If a trait was acquired in one’s life, it would be passed on to the next generation. For example, if muscles were developed over their life, the amount of muscle would be passed on to their offspring, yet it is the just the ability to acquire the amount of muscle desired. The traits used more often would be the ones developed and passed on to further generations. While if a trait was not used, such as a tail in humans, it would be lessened with each new generation. Most of his theories were very easily disproved.
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Darwin, Malthus, Wallace
Charles Darwin Took observations while exploring the Galapagos Islands The Origin of Species in 1859 Thomas Malthus Introduced survival of the fittest. Alfred Wallace Similar ideas to that of Darwin’s Darwin recorded all of his findings while he visited South America and the Galapagos Islands. He noticed that the beaks of birds were different due to the foods they needed to catch and eat. He published his book The Origin of Species in 1859 which included many of his ideas and findings from Malthus. Malthus introduced, and wrote about, his theory on how the competition for recourses explained the survival of some animals and the death of others. Wallace believed animals developed certain traits in order to adapt to their environment. He and Darwin worked independently, while each of them basically had the same idea for evolution.
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A Closer Look: Darwin Descent with Modification
“The newer forms appearing in the fossil record are actually the modified descendents of older species.” Modification by Natural Selection States how evolution occurs and how survival of the fittest takes place Survival of the Fittest The idea of Descent with Modification explains how species change over time, yet come from the basis of an older form. The idea of Modification by Natural Selection is how the growth of populations by bringing up the rate of death or lowering the rate of reproduction. The Survival of the Fittest states how the environment is the deciding factor to which species survive and which die off.
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Evidence of Evolution Evidence includes: Fossils and Molds
Comparative Anatomy Homologous Structures- Similarities of bone structure in different species, shared from one ancestor Analogous Structures- Serve identical functions, look some what alike Vestigial Structures- Features that were useful to ancestors, but are now not of use Embryological Evidence Evidence includes the finding of fossils and molds to support theories. The Comparative Anatomy consists of homologous structures which states that the bone structure is similar in different species, and is shared from one ancestor. For example the fact that there is, in the arm, one large bone, two bones, and smaller bones at the end is the same with humans, birds, cats, bats, and propoises. Analogous structures states that the bones that are similar serve the same functions and also look alike. Vestigial structures talk about how any thing that wasn’t used slowly disappeared, while if it was used numerous amounts of times it continued to get stronger. An example would be a human tail bone. Embryological evidence is that an embryo looked the same at one point in the early stages of development for a gorilla, fish, and a rabbit.
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Patterns of Evolution Coevolution Convergent Evolution
Two species related to each other will coevolve. Convergent Evolution Have similar phenotypes; ancestral types are different Divergent Evolution When the beginning species is completely different from the resulting species. Artificial selection and adaptive radiation Coevolution is the change of two or more species in close association with each other. For example, plants, and the animals that pollinate them. Convergent evolution is when the environment selects similar phenotypes even though the ancestral types were quite different. For example, sharks and porpoises look similar but have different ancestors. Divergent evolution is when two or more related populations or species become more and more dissimilar. For example, the artificial selection of dogs. Adaptive radiation many related species evolve from a single ancestral species. The Galapagos Finches are an example of adaptive radiation because their need for food changes their appearance.
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Genetic Equilibrium Variations Cause Mutation Evironmet Hereditary
Random fusion of gametes
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Gene Pool Total in population Dominant allele = p Recessive allele = q
p + q = 1 Hardy-Weinberg Genetic Equilibrium p2 +2pq + q2 = 1
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