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Explain the occurence of evolution
Explain the occurence of evolution
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One important topic about evolution is speciation and how species speciate, what this means is how some species diverge into a new and distinct species through the course of evolution. Speciation can happen because of various reasons, the most known are the following four, allopatric, peripatric, parapatric, and sympatric speciation. We are going to try and focus on a different aspect of speciation and that is chromosomes. We are going to look at how the mechanisms of evolution have aided with the evolution of sex chromosome in different species and how chromosomal rearrangements happen and how those can lead to the speciation of some species. The mechanisms of evolution include how genetic variability is passed on from generation to generation, …show more content…
Allopatric speciation arises when a species is separated into two separate groups that are then secluded from one another by a type of physical barrier. The physical barrier then makes it impossible for both species to breed and then each species develops differently because of the unique habitat and the characteristics that are inherited to the offspring. Peripatric speciation is when smaller groups isolate from a larger group to form a new species. Physical barriers then impede the interbreeding from both groups. In this type of speciation, the traits from the smaller groups become unique and are then inherited in each generation, distinguishing them from the larger groups. In parapatric speciation, the species are in a vast geographical area. In this larger area, only some species in certain closer geographic areas mate with one another. Those that are not in the same geographic region don’t mate and speciate by the differences in the same environment. Sympatric speciation happens when there are no physical barriers that avert mating between the species, in this case, all the members are adjacent to one another. The way that sympatric speciation occurs is spontaneous, when and the individual becomes dependent on a different food source that is unique to an area of the …show more content…
In most cases the only thing that is known is about the chromosomal rearrangements that happen, that can then be used to find which chromosomes are the ones responsible for speciation. We know too well that one chromosome is not the only one responsible, there are other factors that also affect speciation and in most cases, it is usually more than one chromosome and different chromosomes are identified in different species. There has been a study about how the chromosome X in humans is the one that controls speciation and
16. Describe two evolutionary consequences if the process of crossing over in meiosis ceased to occur. If crossing over in meiosis ceased to occur there would be less genetic variations and no diversity among a species. This would essentially mean that a species would not be able to adapt to an issue that could arise in the future, meaning that its species could potentially become extinct due to climate change or other arising events.
As for the maned wolf, the theorized cause of speciation would be because of mating. Most maned wolves are very solitary, and so the species might have different mating seasons, creating a different species. As for the approximate time of speciation, that would be depending on when the mating seasons would change, which would take hundreds of years, from 200 to
The DNA code, that forms our genes, was the missing key for Darwin to understand how things evolved. DNA does not stay the same, it can be changed by mutations. Mutations are needed to generate variations. Without the mutations things would stay the same generation after generation. Pieces of DNA called a switch can turn certain genes on or off. Genetic Switches helps to create mutations which are sometimes responsible for an entire new species spawning from another. This is how a snake can evolve from a four legged animal, and how a whale 's front flippers has bones inside that resembles
The third part of the evolution theory is speciation. Speciation means that different groups of creatures that cannot exchange genes with one another cannot interbreed with one another.
Charles Darwin’s theory of natural selection explains the general laws by which any given species transforms into other varieties and species. Darwin extends the application of his theory to the entire hierarchy of classification and states that all forms of life have descended from one incredibly remote ancestor. The process of natural selection entails the divergence of character of specific varieties and the subsequent classification of once-related living forms as distinct entities on one or many levels of classification. The process occurs as a species varies slightly over the course of numerous generations. Through inheritance, natural selection preserves each variation that proves advantageous to that species in its present circumstances of living, which include its interaction with closely related species in the “struggle for existence” (Darwin 62).
Natural and sexual selection are not random processes. If there is no difference between the individuals within the species there would be no selection. Sexual selection is related to mating, it acts on individual’s ability to obtain or successfully copulate with a partner. The idea of sexual selection was introduced by Charles Darwin in 1871; he revealed that there are organisms with traits which are not explained by the concept natural selection, for example the tail of a male peacock. His found two main ways in which sexual selection works, these are intra-sexual competition and inter-sexual selection. Intra sexual competition happens within species, usually between males. They compete against each other to be chosen as a mate by a member of opposite sex. Inter-sexual selection is choosing a mate among the members of opposite sex, usually done by females.
In order for a species to survive, its population has to evolve. Evolution is the process of gradual change driven by natural selection to improve survival. Evolution is the explanation of how life got to its current state. Before the idea of evolution, the Bible gave the explanation of how things came to be, the Theory of Creation. Charles Darwin is credited for developing the theory of evolution. Scientist such as Georges Cuiver, James Hutton and Charles Lyell, and Jean-Baptiste Lamarck heavily influenced Darwin. It is because of Darwin’s voyage aboard the Beagle that we now have a scientific explanation of how species came to be. Canines have evolved and have been domesticated by artificial selection into our household pets. Unlike natural
With the studies that Charles Darwin obtained he published his first work, “The Origin of Species.” In this book he explained how for millions of years animals, and plants have evolved to better help their existence. Darwin reasoned that these living things had gradually changed over time to help themselves. The changes that he found seemed to have been during the process of reproduction. The traits which would help them survive became a dominant trait, while the weaker traits became recessive. A good example of what Darwin was trying to explain is shown in giraffes. Long-necked giraffes could reach the food on the trees, while the short-necked giraffes couldn’t. Since long necks helped the giraffes eat, short-necked giraffes died off from hunger. Because of this long-necks became a dominant trait in giraffes. This is what Charles Darwin would later call natural selection.
What is evolution and how does it work? Evolution is the theory of how one form of life changes into another form. Evolution also is the change of a population’s inherited traits from generation to generation. Evolution helps to explain why an animal, human, and plant looks the way it does and acts the way it does; it gives an explanation of the history of life. Genes come in many varieties and the evolution helps to make it happen. Mutation, natural selection, genetic drift, and gene flow: the four forces that make the evolution work.
Inside the cells that produce sperm and eggs, chromosomes become paired. While they are pressed together, the chromosomes may break, and each may swap a portion of its genetic material for the matching portion from its mate. This form of recombination is called crossing-over. When the chromosomes glue themselves back together and separate, each has picked up new genetic material from the other. The constellation of physical characteristics it determines is now different than before crossing-over.
Many scientists in the past, such as Aristotle and Plato, believed that there were no changes in populations; however, other scientists, such as Darwin and Wallace, arose and argued that species inherit heritable traits from common ancestors and environmental forces drives out certain heritable traits that makes the species better suited to survive or be more “fit” for that environment. Therefore, species do change over a period of time and they were able to support their theory by showing that evolution does occur. There were four basic mechanisms of evolution in their theory: mutation, migration, genetic drift, and natural selection. Natural selection is the gradual process by which heritable traits that makes it more likely for an organism to survive and successfully reproduce increases, whereas there is a decline in those who do have those beneficial heritable traits (Natural Selection). For example, there is a decrease in rain which causes a drought in the finches’ environment. The seeds in the finches’ environment would not be soft enough for the smaller and weaker beak finches to break; therefore, they cannot compete with the larger and stronger beak finches for food. The larger and stronger beak finches has a heritable trait that helps them survive and reproduce better than others for that particular environment which makes them categorized under natural selection (Freeman, 2002).
Darwin explain that, excepting for two reasons, variability cannot be distinguish from species. The first is by the discovery of intermedate ways of linking, and the other explains that by certain indefinite amount of differences between them; this mean that if the differences are few, are considerated and classified variabilities inside the same
Evolution is not something that happened over night, it happened over millions of years. A species evolves by the process of natural selection, or survival of the fittest. Whichever organism is better fitted to its environment and way of life, will survive and pass on the genes necessary to survive. Many researchers and scientists have seen this happen, such as Charles Darwin.
Over a long period of time organisms on an island change so they can no longer interbreed with organisms on different islands, the inability to interbreed in known as reproductive isolation. Reproductive isolation is due to Geographical isolation. A population can be geographically split in many ways which include Rivers form, Sea levels rise and fall, walls getting build, continents drift, climate isolation etc. If the environment conditions change for these populations they would then adapt to that environment, hence as long as they is no Gene flow between the two populations, they would genetically become different that they could no longer interbreed. An example of this includes a species of birds that once lived together, however now live on separate nearby
The process of evolution comprises of many complex of mechanisms. These mechanisms fundamentally allow the progression of speciation and adaptation to occur. There are 4 common kinds of evolutionary mechanism of change: Natural Selection, Genetic Drift, Mutation and Migration.