Fruit Fly Essay

According to Darwin and his theory on evolution, organisms are presented with nature’s challenge of environmental change. Those that possess the characteristics of adapting to such challenges are successful in leaving their genes behind and ensuring that their lineage will continue. It is natural selection, where nature can perform tiny to mass sporadic experiments on its organisms, and the results can be interesting from extinction to significant changes within a species.

The four forces of evolution are: gene flow, natural selection, mutation, and genetic drift. Gene flow is when two populations change genetic material. This exchange in genetic material often results from having an allele drift to fixation. Natural selection is when certain organism survive certain situations based off the traits that they have that make them better equipped to do so. Mutation is a the change in a gene or chromosome in DNA sequences in many forms that happen randomly. This change and mutation can be from substitutions, additions or deletions.

The basis of genetics were established by Gregor Mendel, an Augustinian monk in the mid to late 1800’s. Through the observations from cross-pollinating pea plants, Mendel was able to discover the basic laws of inheritance. Years later genetics would be studied on a multitude of organisms, some more than others. Drosophila melanogaster or the common fruit fly has been studied in depth for its great advantages, such as size, reproduction rate, ease of care and inexpensive room and board.

Throughout this experiment a number of random and procedural errors were apparent; these errors could have affected the results of the experiment in a number of ways. One experimental error that occurred during the experiment was that some flies became stuck in the food source and died. The main cause of this was the fact that the fly vials were stood up (vertically) before the flies had fully recovered from the anaesthetic. This could be overcome in future experiments by ensuring that the vials are kept horizontal until all of the flies fully recover from the anaesthetic.

Drosophila melanogaster is a small, common fly found near unripe and rotted fruit. It has been in use for over a century to study genetics. Thomas Hunt Morgan was the best biologist studying Drosophila early in the 1900’s. Morgan was the first to discover sex-linkage and genetic recombination, which placed the small fly in the forefront of genetic research. Scientists have used Drosophila for many reasons. For one they are very easy to maintain, breed, anesthetize, and kill with little equipment. They are also very small and it is easy to distinguish males vs females and sexually mature flies and virgins. At lastly, the flies have a very short two week life span. On days 2-7 of their life

To set up this experiment, two twenty-five gallon aquariums, 3 petri-dishes, 200 flies, rotten bananas, and yeast were used. The bananas chosen to be an accelerant for the growth of the yeast and were frozen so they would be easier to cut. The yeast was used because the drosophila melanogaster prefer this as a food source.  The vestigial and wild type flies were sexed (to determine their sex), sorted, and counted.  An initial population size of 100 total flies was decided so that it would be easier to determine the phenotypic percentage of the total population. Fly paper was placed in one of the sets of cages to impose a method of natural selection as well as the sexual selection which is being solely tested by the other set of cages.

Introduction: The intention of this lab was to gain a better understanding of Mendelian genetics and inheritance patterns of the drosophila fruit fly. This was tasked through inspecting phenotypes present in the dihybrid crosses performed on the flies. An experimental virtual fly lab assignment was also used to analyze the inheritance patterns. Specifically, the purpose of our drosophila crosses is to establish which phenotypes are dominant/recessive, if the traits are inherited through autosome or sex chromosomes and whether independent assortment or linkage is responsible for the expressed traits.

melanogaster, leaving B and D to be our mutants. Before crossing our populations, we made not of each one’s phenotype in order to see how crossing them would affect their phenotypes: Population B flies had no wings and red eyes, population D had full wings and black eyes and population G had full wings and red eyes. We expected the resulting phenotypes to be some sort of combination, revealing which traits were dominant. However, what we did not expect was the abnormal mutant that arose in a couple of our populations.

Describe the sex and phenotype of the mutant fly. Describe the phenotype as it compares to the wild type.

The Drosophila melanogaster is a fruit fly with a very short life cycle. They can be winged or wingless, and have red eyes or white eyes. The different options are called alleles. Alleles are the variants of a specific gene, and one is received from each parent on each chromosome. (“What Are Dominant and Recessive?”). It was chosen to use winged females and wingless males to predict the offspring in this experiment. The winged allele is dominant, meaning it only needs one allele to physically appear. The wingless allele is recessive, which gets covered up by the dominant allele (“Fruit Fly Genetics”). Each trait has two alleles in the flies’

Introduction Gregor Mendel, the father of genetics, established the basic principles of heredity by crossing different varieties of pea plants and observing the succession of traits in the resulting generations. In order to studying the trends of heredity, model organisms are crossed and observed for the resulting traits. Drosophilia melanogaster, the fruit fly, has been a useful species in the study and practice of genetics. The fruit fly is an excellent model organism due to its short generation time, large offspring numbers, simply and cheap care, easy handling in a lab setting, and large and varied stocks available with minimum cost. It was among the first organisms to be used for genetic analysis (Pierce, 2005).

we said goodbye and placed them in the fly morgue. We allowed the F2 larval

Of the five conditions that have to be met for Hardy-Weinberg Equilibrium, we assumed that there would be random mating, no natural selection, and no gene flow. Based on our results we don’t have sufficient evidence to reject the null hypothesis. However, 2 conditions that were possibly not met would be that a large enough population was not used, and that there could have been mutations. To improve the experiment, we can calculate the minimum population size to be studied through statistical calculations, be more aware of the difference in shade of ebony and wildtype flies since that may have caused some confusion at times, and be more careful to not let flies escape or die before observing them. Nevertheless, even with slight variations, it is highly possible to obtain Hardy-Weinberg Equilibrium in populations monitored under specific laboratory

The two species concepts that are used in this case are the biological and morphological species concepts. The biological species concept defines a species as a population or group of populations whose members have the potential to interbreed with one another in nature to produce fertile offspring, but cannot successfully interbreed with members of other species. The morphological species concept states that a species is defined by measurable anatomical standards. No the apple maggot flies are not distinct as a species from hawthorn maggot flies. The apple and hawthorn maggot flies cannot be distinguished from each other physically but they differ genetically. These two organisms are not geographically or physically but they differ genetically.

The four forces of evolution are natural selection, mutation, genetic drift and gene flow. Natural selection occurs when organisms with better traits reproduce and pass their traits to their children. Mutations are when genes are altered in the DNA whether it would occur through the deleting, rearranging or inserting genes. Genetic drift is a random instance that can potentially remove variation from a population’s genes and cause changes in allele frequencies. The two types of genetic drift are the bottleneck effect, when a population’s size decreases drastically and the founder effect, when a small group from a population move and reproduce in a different location from the original. Gene flow is when genes exchange between two very different