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Nadia 1-8, 21 Evolution questions 21. The sequence of nucleotides are inherited and are passed on through a species and a species diverges when the sequence of nucleotides changes. The sequence of nucleotides are the coding for the production of proteins. DNA sequences can be compared with other organisms. The structures of proteins are generally determined and can be compared between species. By comparing amino acids sequences in proteins from different species, the degree of similarity indicates that the genes from the protein evolved from a common gene and the degree of similarity between the 2 species. Comparing DNA uses DNA-DNA hybridization measures the extent of hydrogen bonding between single-stranded DNA strands together. Restriction maps which use the same restriction enzymes in the recombinant DNA technology and each restriction enzyme recognizes a specific sequence of a few nucleotides and cuts the DNA wherever the shorter sequence is formed in the larger sequence. DNA sequence analysis is when the actual nucleotide sequences of DNA are compared
 * 1) The 4 processes needed for the spontaneous origin of life on earth are the synthesis of polymers from monomers which formed when amino acids came in contact with hot sand, clay or rock, self –replicating molecules known as protobionts. These were aggregates of abiotically produced molecules surrounded by a membrane or membrane like structures. They exhibited some properties associated with life including simple reproduction metabolism and the maintenance of an internal chemical environment different from the exterior environment. The third process was the synthesis of organic molecules and the fourth is the formation of water which tends to depolymerize (make it difficult for molecules to polymerize) but which is still necessary for life.
 * 2) The experiments of Miller and Urey simulated conditions thought to have existed on early Earth. A warm flask of water simulated the primeval sea. The “atmosphere” consisted of H2, CH4, NH3 and H2Ovapor. Sparks were discharged in the simulated atmosphere to mimic lightning and a condenser cooled the atmosphere by raining water and any dissolved compounds into the sea. As material circulated through the apparatus Miller & Urey collected samples. They found a variety of organic compounds: amino acids like alanine & glutamic acid (common in the proteins of organisms) and other amino acids and oily hydrocarbons. They concluded that organic molecules the first step in the origin of life, can form in a strongly reduced atmosphere.
 * 3) Comets can carry organic compounds so when earth was bombarded with asteroids and comets 4 billion years ago, these compounds were brought to earth.
 * 4) One location where an organic compound could have been synthesized in space. Scientists recreated the environment in space (low pressure & temperature) and were able to synthesize amino acids. This supports the hypothesis that molecules needed for life could have originated in space. Organic compounds could also have been synthesized in alternating wet and dry conditions such as the seashore or floor plains of a river. The drying of clay particles could have catalyzed reactions to form organic molecules. They could also have formed near volcanoes. Volcanic eruptions spit out water vapor, gasses & minerals which could have formed organic compounds. These new minerals plus the heat from the volcano would have created conditions to form amino acids & sugars. Finally organic compounds could have formed in deep oceans. Near the thermal vents, hot water rises and picks up minerals along the way. This process could have resulted in the formation of organic compounds.
 * 5)  RNA can replicate itself. It is autocatalytic which aids in replication. RNA can make the dimensional shapes & comes in different varieties.
 * 6) Coacervates are almost like living organisms. Lining cells may have been preceded by coacervates. They rend to self-assemble when a suspension of polypeptides/nucleic acids etc is shaken. Microspheres self-assemble, form a membrane store energy etc.
 * 7) About 3.5 billion years ago some bacteria developed the ability to photosynthesize. This helped convert iron dissolved in sea water into precipitates of iron oxide, or most colored layers of rock. Photosynthesis produces oxygen as waste. The photosynthetic bacteria rapidly reproduced, thus creating more oxygen.
 * 8) In addition to the existence of a nuclear envelope and cytoskeleton, eukaryotic cells differ from prokaryotic cells that they contain mitochondria and/or chloroplasts. The endosymbiotic theory proposes that these organelles were originally smaller prokaryotic cells that had entered larger cells via endocytocis which overtime evolved into the organelles of the chloroplast and mitochondria.

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Harper Hill's = = Amaya Bayne question 13~ Allopartric speciation is the mode of speciation induced when the ancestral population becomes segregated by a geographical barrier and Sympatric speciation occurs as a result of radical change in the genome that produces a reproductively isolated subpopulation in the midst of its parent population.

Christie Collins question 22.) Species diverge as changes occur in nucleotide bases with each species acquiring its own set of genetic mutations. A close match in the amino acid sequences of two proteins from different species indicates that the genes fro those proteins evolved from a common gene. Differences in amino acid sequences of the blood protein hemoglobin and cytochrome c, an old protein found in aerobic organisms were shown to be greater the more phylogenetically distant the species. In DNA-DNA hybridization, how tightly the DNA of one species can bind to the DNA of the other depends on the degree of similarity. Comparing nucleotide sequences between corresponding DNA segments from different species has the potential of telling us how much divergence there has been in the evolution of the genes derived from the same ancestral gene.

Deja Stewart (Question 19) Evan Webber Q's 1-8 Jane Culkin question 20
 * Homologous structures:** Structures such as the arms, forelegs, flippers, and wings, that are similar across species because of a structural theme that was present in a common ancestor.
 * Vestigial Organs:** Vestigial organs are homologous structures that are of little to no importance to the organism. The organs are usually fully developed.

Sara Park (Question 16) - Another idea on the pace of evolution that challenges gradualism is Cuvier's theory of catastrophism which refers to the boundaries between strata to indicate that past species had become extinct due to a catastophe.
 * Gradualism**: Theory proposed by Hutton that states that changes are due to //slow//, continuous processes; organisms //gradually// adapt and evolve.
 * Punctuated Equilibrium**: //Nongradual// appearance of new species; new species arise //rapidly// after it buds from a parent species.

Trevor Cassidy- Origin of Life 5) RNA can replicate itself. It’s autocatalytic which aids in replication. RNA can make 3D shapes. Essentially, natural selection occurred with RNA. RNA came in a variety of shapes and sizes. This allowed for variety in organisms.

7) Photosynthetic bacteria, the first cyanobacteria are capable of making organic compounds from water and CO2, releasing O2 as a biproduct. They flourished and changed the world.

Donte (18) Sickle cell anemia is an example of balanced polymorphism because of the heterozygote advantage that is has. This involves the locus in humans for one chain of hemoglobin, the protein of red blood cells that transports oxygen. A specific recessive allele at that locus causes sickle-cell disease in homozygous individuals. Heterozygotes are resistant to maleria which is an advantage in tropical regions where sickel-cell disease is a major cause of death.