Biology II week 1 notes
Biology II week 1 notes BIOL1082
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This 3 page Class Notes was uploaded by Emmanuel Notetaker on Monday January 18, 2016. The Class Notes belongs to BIOL1082 at University of Cincinnati taught by Dr. Beyette in Summer 2015. Since its upload, it has received 47 views. For similar materials see Biology II: Evolution, Physiology, and Ecology in Biology at University of Cincinnati.
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Date Created: 01/18/16
GENERAL BIOLOGY NOTES WEEK 1 CHAPTER 22 Evolution is defined as descent with modification, a phrase used by Darwin in proposing that Earth’s many species are descendants of ancestral species that were different from present day species. Some factors that affect evolution are natural selection and artificial selection. Natural Selection is the process by whereby organisms better adapted to their environment tend to survive and produce more offspring. The theory of its action was first fully expounded by Charles Darwin and is now believed to be the main process that brings about evolution. On the other hand, Artificial Selection is the intentional breeding of plants or animals. It means the same thing as selective breeding. Selective breeding is a technique used when breeding domesticated animals, such as dogs, pigeons, or cattle. Some of these animals will have traits that a breeder will want to preserve. The following are some main differences in Natural Selection and Artificial Selection; Natural Selection Artificial Selection 1. Organisms do not choose Organisms choose individuals Individuals with desired traits with the desired traits. 2. Offspring inherits traits from Offspring bear little resemblance Its parents i.e. making them to its wild ancestors resemble their ancestors more 3. Tendance to be able to survive Less tendance to survive and reproduce and reproduce is high Evolutionary change as it name may imply is the change in the characteristics of a population of organisms over successive generations. Evolutionary change is mostly caused by migration of certain species to a different environment, however, theses organisms live in various habitats, and the gradually accumulate diverse modifications, or adaptations, that fit them to a specific way of life. Biological evolution is defined as any genetic change in a population that is inherited over several generations. These changes may be small or large, noticeable or not so noticeable. Evolution is not a theory but a fact, evolution is proven to be very true and indisputable. Actually, Evolution is happening everywhere in every day of our lives. A study of Soapberry bugs, in particular, regions show rapid evolutionary change. The soapberry bugs in Southern Florida and Central Florida have different beak size due to the seeds they feed on, their beaks correspond to the depth at which seeds are found with the fruits. In Sothern Florida, the seed-eating bugs feed on the Balloon Vine seeds which are close to reaching than the Goldenrain Seeds in Central Florida, therefore, the beaks of the soapberry bugs in Southern Florida are shorter than the beaks of the same type of bugs in Central Florida. This study proves that evolution through natural selection can happen rapidly since the Goldenrain tree reached Central Florida only 35years before the study. A study of drug-resistant bacteria shows that natural selection can even be way faster than some people thought. Bacteria in many years have developed enzymes that help them resist certain forms of antibiotics. This is so because antibiotics work by deactivating proteins that bacteria use to synthesize their cell walls. However, most bacteria populations have variations that alter how they are affected by antibiotics. Some of these bacteria are able to synthesize their cell walls using different proteins that were not affected by the antibiotics, therefore, they produce more and form enzymes that help them to resist more forms of antibiotics. Homology is the similarity resulting from a common ancestry. Homology can be very evident by analyzing similarities among different organisms. However, characteristics present in an ancestral organism is altered by natural selection in its descendants over time as they face different environmental conditions. As a result, related species can have characteristics that have an underlying similarity yet function differently. Homologous structures are structures that were present in the ancestry organisms but have undergone modification over time as the descendants get exposed to different environmental conditions. Vestigial structures are structures that served a function in an organism’s ancestor and is still present in the organism. These structures can serve same purposes the organism share with its ancestor. Analogous structures are similar structures organisms from different ancestry obtain due to the adaptation of the environment they share. CHAPTER 23 (23.1-23.2) This chapter briefly talks about evolution in populations. A study of finches in Galapagos help explain the whole idea better. Finches in Galapagos had a greater change in beak size after the drought in 1977, these finches were eating hard large seed during the drought so only those with long enough beaks survived the drought. Moreover, the beaks of these finches changed to a longer ones in the next generation due to natural selection. Microevolution is the change in allele frequencies in a population over generations. Genetic variation refers to the diversity in gene frequencies. Genetic variation is important because it cause evolution to occur. Genetic variation can cause the deletion and insertions of some nucleotides and this can help make new species evolve. Genetic variations can be measured in the phenotype, blood group and even at the molecular level of DNA. Causes of variations might be from mutations, gene duplications, or other processes producing new alleles and new genes. Hardy-Weinberg Equilibrium is said to be obtained when the allele and genotype frequencies expected in a generation is equal to the observed. This is important because it helps to determine whether evolution is occurring in a population. Equations in Hardy-Weinberg : (p^2) + 2pq + (q^2) = 1 or p + q = 1
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