Charles Darwin's Theory Of Natural Selection
Natural selection is Charles Darwin’s most famous theory; it states that evolutionary change comes from genetic variation in each generation and the survival of individuals with different combinations of these variable traits. Organisms with such characteristics that increase their probability of survival in their environment will endure and possess more opportunities to reproduce. Over time these traits are passed on to their offspring and proliferate through the population. Darwin’s innovative ideas and evidence captivated and introduced the world to evolution. Our experiment In lab emphasized Darwin’s principles by simulating the process of natural selection and observing one species of different colored lizards in two different habitats.
The first habitat consisted of a dense stand of sunflowers( mostly dark green and black with hints of yellow and orange) where a population of 52 ( 1st generation),different colored lizards, 12 dark green, 18 black, 18 orange, one brown, one yellow, one dark green, and one grey, made their home. The population of lizards were preyed upon by two hawks, therefore decreasing the population size to a total of 8 lizards, three dark green and five black. The hawks act as a selective pressure to the population of lizards by preying on the least qualified, stimulating differential reproductive success. According to Darwin, these 8 lizards had an advantage over the rest by blending with the environment (mostly green, black and yellow), which enabled them to survive and pass on those traits to their offspring. These mostly black and dark green lizards reproduced up until their population reached 52(2nd generation), 18 dark green, 32 black and a mutation, an orange lizard. The traits passed on to the 2nd generation show a propensity for black and dark green. The last trial (3 generation) for the sunflower habitat provides evidence for the mechanism of natural selection because the 52 lizards were mostly black and green (42 black, 8 green and two orange), since they inherited the traits of those best adapted. The color of the lizards slowly shifted from seven different colors, to the two best fitted (dark green and black) for in the sunflower habitat.
The 3rd generation of lizards experienced an environmental change. The new habitat for the lizards became a grassland, which included mostly dark green and brown tones. After the hawks came down and preyed on the lizards, 8 of them were left, seven black, and a mutant, an orange lizard. These lizards had the right traits for surviving in the grassland environment and got to reproduce until the population reached 52(4th generation) again, 42 black, 8 orange, a yellow and one gray. After the hawks came down once again the population was reduced to 8 black lizards, which reproduced to 50 black and 2 orange. We repeated this up until the last generation which ended up being 49 brown, 2 dark green and 1 orange. The colors that dominated and kept coming back were mostly brown, dark green and black. This showed evidence for the gradual evolution of the population of lizards since it changed from being mostly black, which worked for the sunflower habitat, to mostly brown, more suitable for the grassland habitat.
This experiment enabled us to understand all the factors that come together for evolution to happen. These factors are evolution, diversification, common descent, gradualism and natural selection. The last generation of lizards was completely different from the 1st generation. We had a wide range of color within the species, but with time, the 10th generation was mostly brown. This means the population of lizards evolved to increase their chances of survival according to their environment and selective pressures. This experiment provided evidence for Darwin’s theory of natural selection in the evolutionary framework.
Bibliography
Montgomery, Stephen. http://darwin200.christs.cam.ac.uk/pages/index.php?page_id=d3. 2009. Article. 27 January 2014.
The first habitat consisted of a dense stand of sunflowers( mostly dark green and black with hints of yellow and orange) where a population of 52 ( 1st generation),different colored lizards, 12 dark green, 18 black, 18 orange, one brown, one yellow, one dark green, and one grey, made their home. The population of lizards were preyed upon by two hawks, therefore decreasing the population size to a total of 8 lizards, three dark green and five black. The hawks act as a selective pressure to the population of lizards by preying on the least qualified, stimulating differential reproductive success. According to Darwin, these 8 lizards had an advantage over the rest by blending with the environment (mostly green, black and yellow), which enabled them to survive and pass on those traits to their offspring. These mostly black and dark green lizards reproduced up until their population reached 52(2nd generation), 18 dark green, 32 black and a mutation, an orange lizard. The traits passed on to the 2nd generation show a propensity for black and dark green. The last trial (3 generation) for the sunflower habitat provides evidence for the mechanism of natural selection because the 52 lizards were mostly black and green (42 black, 8 green and two orange), since they inherited the traits of those best adapted. The color of the lizards slowly shifted from seven different colors, to the two best fitted (dark green and black) for in the sunflower habitat.
The 3rd generation of lizards experienced an environmental change. The new habitat for the lizards became a grassland, which included mostly dark green and brown tones. After the hawks came down and preyed on the lizards, 8 of them were left, seven black, and a mutant, an orange lizard. These lizards had the right traits for surviving in the grassland environment and got to reproduce until the population reached 52(4th generation) again, 42 black, 8 orange, a yellow and one gray. After the hawks came down once again the population was reduced to 8 black lizards, which reproduced to 50 black and 2 orange. We repeated this up until the last generation which ended up being 49 brown, 2 dark green and 1 orange. The colors that dominated and kept coming back were mostly brown, dark green and black. This showed evidence for the gradual evolution of the population of lizards since it changed from being mostly black, which worked for the sunflower habitat, to mostly brown, more suitable for the grassland habitat.
This experiment enabled us to understand all the factors that come together for evolution to happen. These factors are evolution, diversification, common descent, gradualism and natural selection. The last generation of lizards was completely different from the 1st generation. We had a wide range of color within the species, but with time, the 10th generation was mostly brown. This means the population of lizards evolved to increase their chances of survival according to their environment and selective pressures. This experiment provided evidence for Darwin’s theory of natural selection in the evolutionary framework.
Bibliography
Montgomery, Stephen. http://darwin200.christs.cam.ac.uk/pages/index.php?page_id=d3. 2009. Article. 27 January 2014.