'Lab Report: Environmental Control of Sex Determination Essay\r'

'Introduction\r\ngenus Ceratopteris richardii, known as a C-fern has a lifecycle referred to as alteration of generations, which consist of uncomplete monoploid nor diploid dominant. C-ferns are homospours plants which are chief(prenominal) in that they can lay down hermaphrioditic gametophytes in aim to be able to egotism feast. However, some of the homospourous C-ferns that gravel young-begetting(prenominal) gametophytes .The life cycle of Ceratopteris richardii starts as a diploid sporophyte which then, by meiosis, urinates monoploid spores. These spores then undergo mitosis to produce a haploid gametophyte, which can be either hermaphrodite( producing eggs and sperm), or a staminate gametophyte (producing only sperm). Gametophytes then produce gametes by mitosis. The hermaphrodite gametophyte will produce both(prenominal) eggs and sperm, plot of ground, the young-begetting(prenominal) gametophyte will produce rigorously sperm. The gametes from the hermaphrodite g ametophyte fertilize one another producing a diploid zygote which grows by mitosis into a diploid sporophyte ready to start the cycle again (Lab Manual).\r\nchromosomal trip out end is determined by the inheritance of sex chromosomes, while, environmental sex determination is influenced by environmental factors such as temperature and parasite invasion(Lab Manual). human beingnesss use the system of chromosomal sex determination by combining their X and Y chromosomes to produce a zygote determining the sexual phenotype in humans. Alligators use environmental sex determination when incubating their eggs.Temperature influences the sex of the outlet meaning; warmer incubating temperatures produce male development while cooler temperatures produce effeminate development (Lab Manual).\r\nOur hypothesis for the Ceratopteris richardii was that gametophyte race constriction influences sex determination. Our first prediction was that the plowshareage of male gametophytes would inc rease as the world parsimony of the gametophytes increase. Our chip prediction was that the percentage of male gametophytes would decrease as the world density of the gametophytes increased.\r\nResults\r\nThe graphical record of our results showed the percentage of male gametophytes increase and then leveling off (Figure 1). This was our rationalise because most of the points followed this pattern, however; thither was a effectiveness outlier at point (68, 32.3). The distri stillion of gametophytes on the last plates varied. Plates A and F had even distri scarcelyion but were very crowed with gametophytes, while plates D and C were evenly distributed but had less(prenominal) gametophytes. Plate E had clumping of gametophytes in the top left corner and plate B had clumping the the bottom right corner.\r\nFigure 1. The relationship between the world density and the percentage of male gametophytes.\r\n banter\r\nThe prediction that the percentage of male gametophytes would incr ease as the population density of the gametophytes increased, and the prediction that the percentage of male gametophytes would decrease as the population density of the gametophytes increased were not supported by our results. When the population density was low, the percentage of male gametophytes was relatively low because there would not be enough eggs to fertilize the sperm produced from both the hermaphrodite,and the sperm produced by the male gametophyte. When the population density was high, the percentage of male gametophytes was higher(prenominal) but still less than fifty percent because of the same solid grounds.The data from our results did support our hypothesis that the gametophyte population influences sex determination in the C-fern because, the higher the population density, the more level the percentage of male gametophytes became.\r\nThe reason for this leveling out at the top of the graph was due to; if the percentage of male gametophytes kept increasing linea rly, then there would be too many an(prenominal) male gametophytes and not enough eggs being produced from the hermaphrodite gametophytes to be fertilized causing an unbalanced population. The outlier pertained to this because the population density was so high but the percentage of male gametophytes was relatively close to the other points supporting that male gametophyte production does not increase as population density increases. Even thought the population density was so high, the percentage of male gametophytes was relatively the same as the other points because the hermaphrodite gametophytes were nerve-racking to increase in number so that they could produce enough eggs to be able to self fertilize and reproduce with the male gametophytes, causing a leveling off in the graph.\r\nC-Ferns might take for evolved this system of sex determination for many reasons. being a hermaphrodite allows them to self fertilize, so by having this ability,C-ferns can produce eggs when ther e is sperm, so they always redeem the ability to reproduce. Unlike hermaphrodites, having break up sexes does not always guarantee you a parter so there is not guarantee in reproduction. evade fertilization and self fertilization are heavy when discussing variation. Cross fertilization allows for different genetic corporal to be combined causing variation.\r\nVariation allows raw(a) selection to act on and therefore, plants that are improve adapted to the environment survive. Self Fertilization allows plants that have the adapted survival gene to self fertilize, producing less variation but more of sustainable plant. This relates to the result produced by hermaphrodites because they mostly self fertilize so they are producing more of themselves but less variation. The offspring produced by separate sexes produces more variation but stands less of a chance against natural selection because the hermaphrodites are reproducing well adapted offspring while the separate sexes are producing a new gang of genetics.\r\nA Labratory Manual for BIO 114. 2011. Environmental Control of trip out Determination, pp.163-166. James Madison University, Harrisonburg, VA. â€â€â€â€â€â€â€â€\r\n'