Difference Between Directional Selection And Disruptive Selection

The Chi square gave a statistical analysis comparison between the results of predation occurring because of selective pressure or predation occurring by chance alone. The result of the Chi square analysis showed a low probability of predation due to chance, showing again that the phenotypes of organisms affect their predation possibilities. Majority of the data proved that some organisms

Natural Selection is the concept that organisms better adapted to their environment tend to survive and produce more offspring. This leads to the creation of populations and diversity of life within them. In the Skittlefish Lab, many separate occurrences can be observed which detail and explain how Natural Selection works on a population over a period of time. Certain adaptations in a species in its entirety may display how individuals impact the whole population as they pass their traits onto their offspring, which do the same. This lab required students to observe the individual “Skittlefish” and “Sea M&Ms” in different environments as they camouflaged and hid from predators.

Natural selection is the process by which evolution occurs where organisms that are better suited to the environment (‘fittest’) survive and pass on favorable traits to the offspring. Organisms must adapt to the environment in order to survive. The stickleback fish adapted to the environment by keeping/removing the pelvic structures. For example, in Frog Lake, the all of the sticklebacks had complete pelvic structures because the lake was connected to a system of streams that allowed predators into the lake. The sticklebacks in Bear Paw Lake had reduced or absent pelvic structures because little/no predators are present in the lake.

Paragraph 1: Introduction - explain your lab. The lab that I chose to do was the “McGraw Hill Higher Education: Natural Selection - Virtual Lab.” I chose this lab because it was the one that most interested me, as I liked the format of the virtual lab. In this lab, I was able to manipulate both the environment and the allele frequency in order to record and investigate the generational breeding patterns of a group of organisms.

This meant that in the population there were already ten different color of prey that occurred naturally. However, when the environment was a blue background with colorful flowers and butterflies, many of the different colored prey had gone extinct and the red prey had the highest number of survivors. Also, environment two was pink, white, and black plaid and the prey that had the most number of survivors in that environment was white. This demonstrates that depending on the environment, different variations of a trait would be successful. It also demonstrates that the adaptations in this experiment depended on the environments.

The separation in gall characteristic in the two biomes is due to different selection systems exerted by natural enemies of the gall fly. Each natural enemy used similar coevolution patterns this predicts that geographic variation in species interactions will lead to opposing selective pressures on interacting species, producing geographic variation in the traits of interacting species (Craig et al. 2007). This study reinforces the idea that gall fly characteristics have many different factors effecting them such as habitat, geography and the predators that they are more likely to encounter in each different biome. Also this shows that natural selection has different roles on the galls depending on the

(Doc F). Another example of some of these horrendous situations was the spreading of diseases and plagues. These illnesses came from Asia and took the lives of the Romans living along the lines of the Mediterranean sea. (Doc F). This is because

For Natural Selection to occur there must be some level of variation among the population that is heritable.

To begin with, Wallace elaborates on why humans are immune to the effects of natural selection. While animals suffer from “individual isolation,” (Wallace 219) humans are “social and sympathetic.” (Wallace 219) Wallace gives the example that although animals

The dominant group came over from europe carrying multiple diseases that kill of huge portions of the

In a directional selection there is only one trait and it is always that dominant trait that dictates body of the population. The best example to show this is that in the area that giraffes live in the vegetation is in the higher trees so the giraffe has adapted a neck that is long enough to reach the vegetation that is crucial to its survival. It’s a lot like being graded on a curve where Directional selection is only going to have one peak to its curve but disruptive would have two peaks. 1. Many pathogenic bacteria

Directional selection means that natural selection is in favor of one extreme or another. An example of directional selection is that there is a green and red types of beetles. The predator in the area only likes green ones, this is a disadvantage for the green beetles. Another example, there are white rats and black rats. The predator, which is an eagle, the rats hide in mud; The eagle is able to see the white rats and eats them, that is an advantage to brown rats.

In a trophic system that is stable, most organisms are equally thriving, without any extreme stress or pressure to cause drastic population reduction as well as without limitless resources to allow unrestricted growth. A disturbance in the stability of a trophic system, or food web, could trigger a chain of reactions in which most, or sometimes all, of the trophic levels are affected. Some populations benefit from alterations in the system, but others suffer huge declines in numbers. Regarding consumer-driven effects, a change in consumer populations is often a product of immigration/emigration, development of prey adaptations against predators, as well as other biotic and abiotic factors, such as introduction of new species and weather (Evans 2011). In the case of an increase of a higher-leveled consumer, the trophic level directly below experiences intensified predation and rapid deterioration.

First, the evolution of HIV (human immunodeficiency virus), which has led to the resistance to some antiretroviral medications. Second, the H1N1 flu virus is a disease which was nicknamed the swine flu because the virus that causes the disease originated from live pigs, which is where it evolved. (DeNoon and Hitti). Lastly is the evolution of MRSA (Methicillin-resistant Staphylococcus aureus). MRSA is a bacterium that is responsible for various infections in humans that are difficult to treat due to its development of a resistance to common antibiotics.

a. What worm has natural selection selected AGAINST? diurnal worms FOR? nocturnal worms b. Darwin 's 5 points: Identify the 5 points in the scenario above. Population has variations.