Natural Selection - Lab Report Example

Biology 1108: Natural Selection Lab Homework Assignment Introduction The definition of natural selection is; differential reproduction and survival of living things due to their existing physical conditions/attributes. The theory of selection is attributed to Charles Darwin evolution theory. In His theory, Charles Darwin defines selection as the process of the functional relationship that exists between phenotypes and fitness. The fitness in this context is defined by three different kinds of curve which include; directional selection whereby the traits of a given organism are related to fitness linearly, stabilizing whereby the trait of interest has an optimum value, and finally, Disruptive curve in which organisms that have the largest and the smallest values of any given trait boots of highest fitness value and conversely, organism that have intermediate values are disadvantaged.

Considering the above stated facts, it is seen that in the long term, Directional selection results to generation of the new type of species from the existing species. This is unlike stabilizing in which the given specie maintains its existing type without any variation over the long period of time. It has been found that stabilizing selection results in the refinement of the existing specie type. On the other hand, disruptive selection facilitates favouritisms of given individuals of a given phenotype (Williams).

ResultsThis experiment’s main objective is the comparison on how the population size varies in different generations depending on different environmental conditions, determination of the effect of different predator types on the population of prey, and the gaining of graphing and interpretation knowledge.Hypothesis1. If the environmental conditions favour a given specie, the population size of the said specie increases in the next generation as compared to the preceding population size, and vice versa. 2. Increase in the number of predators on given specie results in the decrease in the population size of the preyResultsPREDATOR POPULATION HABITAT 1Group dataGeneration 1# prey captured    Total #Predator typeGroup 1Group 2Group 3Group 4Group 5 Knives201003Forks4873325Spoons55831233Clothespin76811840Generation 2# prey captured    Total #Predator typeGroup 1Group 2Group 3Group 4Group 5 Knives000000Forks1648221Spoons4484929Clothespin111317221881Generation 3 # prey captured    Total #Predator typeGroup 1Group 2Group 3Group 4Group 5 Knives000000Forks000000Spoons5413101345Clothespin2416343319126   PREY POPULATION HABITAT 1Group dataGeneration 1 # Eaten Group 1Group 2Group 3Group 4Group 5Total EatenPrey Type Pinto5132415Garbanzo34791235White5886431S.

pea5660320Generation 2 # Eaten Group 1Group 2Group 3Group 4Group 5Total EatenPrey Type Pinto22210218Garbanzo101017171670White4686832S.pea0521311Generation 3 # Eaten Group 1Group 2Group 3Group 4Group 5Total EatenPrey Type Pinto662018858Garbanzo911711947White1422015960S.pea011068PREY POPULATION HABITAT 2Group dataGeneration 1 # EatenGroup 1Group 2Group 3Group 4Group 5Total EatenPrey Type Pinto91086841Garbanzo9111110849White121110121358S.pea4400311Generation 2 # EatenGroup 1Group 2Group 3Group 4Group 5Total EatenPrey Type Pinto151017121367Garbanzo6810131350White161314141471S.

pea5666932Generation 3 # EatenGroup 1Group 2Group 3Group 4Group 5Total EatenPrey Type Pinto181519121882Garbanzo141418181983White87981042S.pea9437427PREDATOR POPULATION HABITAT 2Group dataGeneration 1# prey captured    Total #Predator typeGroup 1Group 2Group 3Group 4Group 5 Knives5643422Forks910771043Spoons1010981249Clothespin1010910645Generation 2# prey captured    Total #Predator typeGroup 1Group 2Group 3Group 4Group 5 Knives000000Forks98810944Spoons2521272433130Clothespin881211746Generation 3 # prey captured    Total #Predator typeGroup 1Group 2Group 3Group 4Group 5 Knives000000Forks10101010747Spoons2722272435135Clothespin1281210951   Figure 1A scatter plot of predator versus generation for habitat 1.

In this habitat, the number of Clothespin is increasing linearly while knives and spoons are decreasing as the generation changes. However, number of spoons decreases from first generation to second generation, then it starts increasing. Figure 2: A scatter plot of prey versus generation for habitat 1.In this habitat, the number of S. pea preys decreases tremendously in all the generation. The number of White and pinto decreases from first generation to second generation and starts increasing from generation 2 to generation 3Figure 3: A scatter plot of predator versus generation for habitat 2.

The number of Forks and clothespin in this habitat is almost constant. The change in the number of spoons increases tremendously from generation 1 to generation 2 and decreases from generation 2 to generation 3Figure 2: A scatter plot of prey versus generation for habitat 1.In this habitat, all the preys increases from generation 1 to generation 2. Also, the trend is the same in generation 2 to generation 3 save White only.ConclusionsAs the Number of predators increases, the number of preys decreases.

This is due to the fact that an increase in the number of predators results into more preys being eaten and as a result, their (prey) number decreases. Also, as the number of predators decreases, the number of preys increases. This is attributed to the fact that the decrease in the number of predators’ results into less preys being killed thus their increase in number.ReferencesWilliams, George. Adaptation and Natural Selection. West Sussex: Princeton University press, 1992. print.