Jessica Northey Exam Number 250104
1.Compare and contrast directional selection and disruptive selection, Provide and example of each.
Directional selection and disruptive selection differ because instead of the subject only going in one direction it will split off and go two different ways for example if some flowers and their colors. The main colors may be red, pink and white primarily, and the more dominate color being a pink flower. But if we remove the pink flower completely from the equation then the flowers will shift toward the dominant white color over the red. 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
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Vertebrates are known to be animals with backbones. Tooth reduction is one of the major evolutionary trends that developed among major vertebrate groups that allowed for the transition from aquatic to terrestrial life. Evolution of limbs and being able to breath air are other evolutionary trends that took placeThese trends include improved respiration and protective and insulating body coverings. More over the transition from water to land also included changing to more efficient reproductive methods like having a placenta for some animals or egg layers for other animals. Lastly, the morphology of organisms evolved such that for land they would have paired, muscular appendages used for crawling and
From this, we can see that our early ancestor mainly ate plants with a plenty of insects for food. In addition, the author mentioned that our hands have evolved for grasping things like flatter nails instead of claws as we do not have to climb up to tress to look for food or catch any insects. Human traits also have forward-facing eyes and larger brains than most of the
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.
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
2: Tiktaalik had a flat head with two eyes on it, fins, and a flexible neck. It was the missing link of life evolving from water to land. It filled in the
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.
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. The theories of early primate evolution appeared about 60 million years ago after most of the early living species had already become extinct. New discoveries have supported one theory over another as more research is done.
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.
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. The plesiadaptiforms, which are not considered real primates because of the lack of key primate features, went extinct at the end of the Paleocene epoch. At the beginning of the Eocene epoch came the euprimates, considered the first real primates, whose features made them well-adapted to arboreal life. Euprimates had convergent eye orbits, opposable digits, nails, and larger brains than plesiadaptiforms. This coincides with a period of global warming which made for a more tropical and forested habitat.
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.
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.
Here, both extremes (traits) are selected. This indicates that most of the individuals in a population exhibit either of the two extremes, with no preference over which extreme is better, while very few individuals show intermediate traits. If shown on a graph, the population bell curve has two peaks with a “valley” in the middle of them. This type of natural selection can lead to speciation, and form two or more different species in areas that go through harsh environmental changes (i.e. pollution). The best example for disruptive selection is the evolution of peppered moth in London at the beginning of the Industrial Revolution.
Introduction 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.
BIOLOGY RESEARCH ESSAY 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.
Charles Darwin was born on February 12, 1809, and died on April 19, 1882. His death is a mystery sort of because he had a disease that no one knew was and therefor there wasn’t a cure for it. It all started after the time Charles Darwin had finally returned to his hometown in England from the famous voyage he sailed called The Beagle. He spent almost 5 years working as a naturalist on the Beagle.