Compare And Contrast Directional Selection And Disruptive Selection

Directional selection and disruptive selection are two of the three types of natural selection. Although both of them result in a population adapting to biotic and abiotic environments, they differ in many ways. Directional selection occurs when one extreme phenotype is favored over the other phenotypes, whereas disruptive selection occurs when two or more phenotypes are favored over the others. Another difference is that disruptive selection favors polymorphism and directional selection causes species to evolve over time and leads to the extinction of those lacking the phenotypes causing the distribution curve to shift.

Environmental change plays an important role in evolution. When an environmental change occurs, it can be a physical or chemical change. It can also be a gradual process such as the formation of mountains, or it can be a rapid and unexpected change, such as a natural disaster. When changes in organism’s environments occur, they must adapt to their new environment, this can cause ample amounts of selective stress and pressure on organisms, causing some species to eventually die out, while other organisms strive and evolve to be better adapted to this change.

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. The lab starts with me being able to choose from four different environments that I want to put my organisms in. I also get to choose one of the four different allele frequencies that are allowed. I can mix and match the environment and frequencies however I want to. After picking an environment and a frequency, I then am able to move one generation forward. When I move a generation forward, the allele frequency will change. The reason for this is because the organisms with the least helpful phenotypes will be eaten by predators while the organisms with the better phenotypes will live on to breed, thus shifting the gene pool to go in a certain direction. I am able to move a total of 5 generations forward and each and every time I move the allele frequency will change to favor the superior phenotype, thus representing the

In directional selection, one extreme trait is favored over the mean trait or other extreme trait; and this occurs in environments that have undergone changes over time. Changes in terms of climate, weather and food availability are the driving forces for this type of natural selection. If shown on a graph, the population bell curve shifts either farther left or farther right, indicating that one trait, is favored over another for a species. An example of this type of natural selection is the beak length of the Galapagos finches, which changed through time due to changes in food availability. Those with larger and deeper beaks survived the scarcity of insects since they were able to crack seeds. When insects became abundant, finches have developed smaller and longer beaks.

The article I have chosen was written by Helen Pilcher and is about evolution of creatures, especially for primates. However, until now, what do our very first primates were like still remain mysterious as we do not have sufficient information and evidences which are 60 million years ago. Yet, we still cannot deny that evolution occurs in creatures. No matter for humans, animals or plants, all of them will make changes because of their living habits and environment in order to survive. In this article, the author explains everything clearly about the primate evolution was taken around million years ago and ancestors are a small and nocturnal creature. Also, she explained several specific features of primate evolution with detail examples throughout the article.

The Earth's climate went through several major changes throughout the Tertiary period that led to the flourishing of primate species and the extinction of other primate species.

climate change influenced nonhuman primate evolution because with the changes, nonhuman primates were forced to evolve in order to survive. As the climate change progressed and several species started to die out, nonhuman primates evolved through time and thus they were able to survive and climate change that occurred and were able to evolve into creatures that we see during present times.

If a lake is cut from the ocean and has no large fish as predators (only dragonflies), then the sticklebacks will have a better chance at surviving and reproducing because the sticklebacks will be better adapted to the environment (presence/absence of a pelvic bone) and have little to no predators. The hypothesis was supported.

Adaptations allow deep-sea creatures to survive in extreme environments. There are many different adaptations that allow an animal to survive. The three common adaptations consist of habitat, appearance, and diet. The Giant Squid, Zombie Worm, and the Yeti Crab utilized these adaptations to survive, and without them it would be difficult to nearly impossible to keep their species alive and flourishing. Each one of theses species is suited for its environment and survival tasks through its adaptations.

We have probably all heard of natural selection but do we really know what it means? There are some statements that could lead people to misunderstand different scientific concepts or any concepts or issues in general.The term natural selection might seem like a simple term but it holds complexities within its two syllables and in order to have a clear understanding of it one must be able to differentiate between an individual and a whole species. As defined in the textbook, a species consist of a diverse population of individual while an individual is a single entity within the species. A person who is currently taking Anthropology 1 can identify at least three misconceptions and provide a thorough explanation to rectify these errors.

Natural selection can however be limited by several factors These factors include, the variation gene not being available, history not allowing the variation to develop or the trade-off of a variation creating a different problem for the animal.

Darwin during those 5 years, spent time researching and getting specimens of animals. After his exploration he observed the specimens with professionals, and soon found out that certain animals were the same but different in look wise, or that from the beginning of time, the creatures he saw then weren’t the same as the creatures before his era. He then makes an idea called transformism. Transformism is when an animal or creature changed or became different through time.

Evolution is the process of change over time. It can be split in two questions, how did something living come from something that was not alive? And, how did things that were already living turn into other living things? Natural selection is when the “breeder: is the environment. This belief of natural selection came from Charles Darwin. Many ideas led him to believe what he believed. One of them was, James Hutton’s ideas about geological change. His theory consisted that sediments, rocks, soil, etc were made after the great flood and new species “rose” from that disaster and that it’s a cycle. Charles Lyell’s theory also shaped his thinking. Lyell wrote the book of “Principles of Geology”, where Hutton became famous. He believed that the earth

Approximately 530 million years ago, there was a rapid diversification of animal species. In this relatively short evolutionary event, most major phyla appeared. The term Cambrian Explosion describes the geologically sudden appearance of multi-cellular animals in the fossil record. Pre-Cambrian organisms consisted of prokaryotes, eukaryotes, bacteria and ediacaran life forms. In less than 5 million years, most of the basic body plans that we observe in modern groups appeared; cnidarians, molluscs, arthropods, echinoderms and the chordates all came on to the scene. This explosion directly conflicts Darwin’s theory of natural selection acting on random variation, the Cambrian fossil record contradicts the empirical expectations of

There is great speculation around evolution. As we are continually in the process of discovering the history of human beings, there are many questions surrounding this topic. One very interesting question is why ancient ancestors of homo-sapiens evolved to walk upright like we do today. An apes’ DNA is astonishingly similar to that of a humans, (97% the same) and yet, our bones’ shapes and structure are very different. (Own knowledge, Source D) Bipedalism is unique to humans and it is known to be one of the earliest developments in hominids. (Source G, C) This phenomenon has intrigued researchers and historians for a number of years. There are many answers to this involved question; this essay will look at a few of them.