Evolution through Natural Selection
Performance Assessment
Evolution is earth’s natural process to survive. Just like the latest technology, evolution makes the new organism better and stronger han the last model. The primary source of evolution is through natural selection. All living things can produce offspring but only a few off spring, the strongest, will live and reproduce. The offspring that survive are the organisms that have advantageous traits, traits that better suit their environment. Over a long period of time, organisms that have advantageous traits will dominate a population until the population has changed completely into something different. Darwin’s theory of natural selection is broken down into 4 simple steps: Overproduction, variation, selection, and adaptation. Without natural selection and evolution it would be almost impossible for organisms to survive with the ever changing environment.
The purpose of this lab was to see how natural selection effects organisms. It also showed the three different kinds of natural selection and illustrated examples of each.
In this lab I hypothesize that depending on the original population account and the extremity in which the different beads are fed upon different cases of natural selection will be illustrated. If the situation is extreme and the number of colored beads goes against the average, then the mode of natural selection will be disruptive selection. If the situation is controlled and the extreme numbers of colored beads balances out to an average, then the natural selection will be stabilizing selection. Finally if the situation causes one color to be more extreme than the others it is directional selection.
The Essay on Populations Natural Selection And Evolution
Outline how population size can be affected by natality, immigration, mortality and emigration. Natality = + Immigration = + Mortality = - Emigration = - Draw a graph showing the sigmoid shaped population curve. Explain reasons for the exponential growth phase, the plateau phase and the transitional phase between these two phases. Lag Phase o Only a few individuals to breed Exponential Growth ...
In order to complete this lab you need the following materials:
Data tables
Graph paper
Colored beads (6 different colors)
1 Plastic bag
1 Plastic cup
To find out more about natural selection I followed these steps:
1. First I counted all the colored beads and recorded their original numbers in data table 1.
2. Next I emptied all of the colored beads into their environment, which in this experiment is the plastic bag.
3. After that I continued my experiment starting with trial A. I picked up 25 beads in the following color order: yellow, green, and orange. I did not feed upon, pick up, any other colored beads.
4. After I had 25 beads in my stomach, the plastic cup, I counted the number of beads remaining in each color and recorded it in data table 1 under trial A.
5. Next, I returned all my beads back to their environment and continued with trial B. I picked up exactly 20 beads, one color at a time, beginning with black, then going to yellow, and finally moving onto blue.
6. 20 beads later, I counted the number of remaining beads in each color and recorded the information in data table 1 under trial B.
7. After returning all my beads to their environment I continued with the last trial-trail C. I picked up all of the red beads and all of the orange beads but no other color. I counted the remaining colored beads and recorded the individual number in data table 1 under trail C.
8. Finally, after my data table was filled in, I made a graph for trials A,B, and C consisting of the original numbers of beads and the number of beds remaining.
All of the numerical data I collected during this lab can be seen in my data table and graphs attached. In my graphs you can see that trial B was most closely related to the original population and trail C was the least similar to its original population. Trial A was in between both trials B and C.
The Essay on Bell Curve Populations Graph Leaves
Variation in peanut weight, leaf length, forearm length and Coquina shells Lab Purpose: The purpose is to investigate variation in four populations, peanuts (weight), leaves (length), forearms (length) and Coquina shells, to demonstrate whether the variation is a normal distribution (makes a bell curve). Another purpose of the investigation is to learn about the effects of variation on natural ...
In conclusion, there are three types of natural selection that all play a major factor in evolution. Evolution allows organisms to adapt to their changing environments and reproduce. The three types of natural selection are disruptive selection, stabilizing selection, and directional selection. My hypothesis was correct. The type of natural selection that took place depended on the extremity of the situation and the original population count. Trial C was the most unrelated to its original population count, which made the type of natural selection that took place disruptive selection. Trial B, on the other hand, was most closely related to its original population count making it stabilizing selection, and trial A was in-between both trials, with some major differences in numbers, making the case of natural selection, directional selection. This lab helped me to better understand not only evolution, but also the three varieties of natural selection and how they work in nature.
Questions:
1. For each of the graphs created, how does the histogram for each trial differ from the histogram of the original population?
Trial B was most closely related to its original population with only a few differences. Trial C resembled its original population graph least and had so many differences the two graphs seemed almost polar opposites. Trial A was in between both graphs in terms of similarities and differences. Graph A was quite a bit off for the first half of the color beads, but matched up exactly for the second half of the colored beads.
2. Which type of natural selection occurred in your bead population during Trial A and explain how you know this.
Trial A was in-between both trials, with some major differences in numbers, making the case of natural selection, directional selection. I know its directional selection because in the graph you see that it favors extremes on one side of a phenotypic range.
The Essay on Modeling Population Growth
Modeling Population Growth First of all, lets give definition to population growth. The term basically explains how the population changes with time (decreases or increases). It is controlled by the death and birth rates. According to the main ideas of modeling population growth, the rate at which a population changes depends on at least three factors (Modeling Population Growth: Main Ideas, ...
3. Which type of natural selection occurred in your bead population during Trial B and explain how you know this.
4. Stabilizing selection occurred during trial B. You can see this in the graph because the remaining population was very similar to the original population. There was no extreme number differences and they all came out balanced.
5. Give an example of each type of natural selection.
An example of stabilizing selection is the birth weight of humans Stabilizing selection would keep the babies at an intermediate weight, because babies that are too big or too small have less chance of being born healthy. An example of disruptive selection would be two types of seeds to eat for a population of birds, either of two different beak shapes might be selected for, but a beak that’s the average of the two shapes might not be particularly good at eating either seed, so it would be selected against. An example of directional selection could be in a population of plants, flowers with the brightest color might be selected for in order to attract the most pollinators.
6. Which type of natural selection occurred in your bead population during Trial C and explain how you know this.
In trial C disruptive selection took place and you can see this most clearly in my graph. The graphs are very different- almost opposite. The number of beads compared to the original population was extremely different. It favors the extremes on both ends of the phenotypic range.
7. In nature how long do you think it would take natural selection to occur and why?
I think it would take a long time for natural selection to take place and evolve a population because it happens very slowly and a tiny bit at a time. Natural selection needs hundreds if not thousands of years to occur.
7. Describe any sources of error that were present in the lab activity.
There are a number of things that could have gone wrong in this experiment. For example a simple math mistake such as counting beads wrong could have thrown off this experiment completely. Also if not all the beads were returned back to their environment each times the data would have been affected drastically.
The Essay on Natural Selection
Natural selection, according to Gulick, is the process through which heritable attributes that are beneficial or vital for survival and reproduction become a common thing in a population, whereas harmful characteristics become rare (p, 27). Natural selection occurs as a result of successful reproduction by persons who have advantageous traits (Darwin p, 39). This results in adoption of beneficial ...
8. Describe ways that the lab activity could be improved or extended.
This lab could be improved by having more trials, which would make our data more reliable.
