frogmarket9

User Name: You need to be a registered (and logged in) user to view username.

Total Articles : 0

https://trade-britanica.trade/wiki/Why_Evolution_Site_Is_The_Next_Big_Obsession

What is Free Evolution Free evolution is the notion that natural processes can cause organisms to evolve over time This includes the appearance and growth of new species This is evident in numerous examples of stickleback fish species that can live in saltwater or fresh water and walking stick insect types that are apprehensive about specific host plants These mostly reversible traits permutations cannot explain fundamental changes to the basic body plan Evolution through Natural Selection The development of the myriad living organisms on Earth is a mystery that has fascinated scientists for centuries The most wellknown explanation is Charles Darwins natural selection process which occurs when individuals that are better adapted survive and reproduce more effectively than those who are less welladapted Over time a community of well adapted individuals grows and eventually becomes a new species Natural selection is an ongoing process and involves the interaction of three factors including reproduction variation and inheritance Variation is caused by mutation and sexual reproduction both of which enhance the genetic diversity within an animal species Inheritance is the term used to describe the transmission of a persons genetic characteristics which includes both dominant and recessive genes to their offspring Reproduction is the process of producing viable fertile offspring This can be done by both asexual or sexual methods All of these factors must be in balance for natural selection to occur If for instance the dominant gene allele makes an organism reproduce and live longer than the recessive gene then the dominant allele becomes more prevalent in a population However if the gene confers an unfavorable survival advantage or reduces fertility it will disappear from the population This process is selfreinforcing meaning that the organism with an adaptive characteristic will live and reproduce more quickly than one with a maladaptive characteristic The more offspring an organism produces the more fit it is which is measured by its capacity to reproduce itself and live People with good characteristics such as the long neck of giraffes or bright white color patterns on male peacocks are more likely than others to live and reproduce which eventually leads to them becoming the majority Natural selection only acts on populations not individual organisms This is an important distinction from the Lamarckian theory of evolution which argues that animals acquire characteristics by use or inactivity If a giraffe stretches its neck to reach prey and its neck gets larger then its offspring will inherit this trait The length difference between generations will continue until the giraffes neck gets too long that it can no longer breed with other giraffes Evolution by Genetic Drift Genetic drift occurs when the alleles of a gene are randomly distributed within a population Eventually one of them will reach fixation become so common that it cannot be eliminated through natural selection and other alleles fall to lower frequencies This can lead to an allele that is dominant in the extreme The other alleles have been basically eliminated and heterozygosity has been reduced to zero In a small group this could result in the complete elimination of the recessive allele This scenario is called a bottleneck effect and it is typical of the kind of evolutionary process that takes place when a large amount of individuals move to form a new population A phenotypic bottleneck can also occur when the survivors of a disaster such as an outbreak or a mass hunting incident are concentrated in a small area The survivors will carry an allele that is dominant and will share the same phenotype This could be caused by conflict earthquake or even a plague Regardless of the cause the genetically distinct group that is left might be susceptible to genetic drift Walsh Lewens Walsh and Ariew define drift as a deviation from expected values due to differences in fitness They cite a famous instance of twins who are genetically identical and have identical phenotypes but one is struck by lightening and dies while the other lives and reproduces This type of drift is crucial in the evolution of a species It is not the only method of evolution The main alternative is a process known as natural selection in which the phenotypic variation of the population is maintained through mutation and migration Stephens asserts that there is a major distinction between treating drift as a force or a cause and considering other causes of evolution like mutation selection and migration as causes or causes 에볼루션게이밍 argues that a causalprocess explanation of drift lets us differentiate it from other forces and this differentiation is crucial He further argues that drift is both a direction ie it tends towards eliminating heterozygosity It also has a size which is determined based on population size Evolution by Lamarckism When high school students study biology they are often introduced to the work of JeanBaptiste Lamarck 1744 1829 His theory of evolution is often called Lamarckism and it states that simple organisms develop into more complex organisms via the inheritance of traits which result from the organisms natural actions usage use and disuse Lamarckism can be illustrated by a giraffe extending its neck to reach higher levels of leaves in the trees This would result in giraffes passing on their longer necks to offspring who then grow even taller Lamarck was a French zoologist and in his inaugural lecture for his course on invertebrate zoology held at the Museum of Natural History in Paris on 17 May 1802 he presented an innovative concept that completely challenged previous thinking about organic transformation According to him living things evolved from inanimate matter via the gradual progression of events Lamarck wasnt the only one to propose this but he was considered to be the first to provide the subject a thorough and general treatment The prevailing story is that Lamarckism was an opponent to Charles Darwins theory of evolution through natural selection and both theories battled it out in the 19th century Darwinism eventually triumphed and led to the creation of what biologists now call the Modern Synthesis The Modern Synthesis theory denies the possibility that acquired traits can be acquired through inheritance and instead it argues that organisms develop through the selective action of environmental factors including natural selection Although Lamarck endorsed the idea of inheritance through acquired characters and his contemporaries also spoke of this idea it was never a central element in any of their theories about evolution This is due to the fact that it was never scientifically validated Its been over 200 year since Lamarcks birth and in the age genomics there is a growing body of evidence that supports the heritability acquired characteristics This is referred to as neo Lamarckism or more generally epigenetic inheritance This is a version that is just as valid as the popular Neodarwinian model Evolution by adaptation One of the most popular misconceptions about evolution is being driven by a struggle to survive This view is inaccurate and ignores other forces driving evolution The fight for survival can be more accurately described as a struggle to survive in a specific environment This may include not only other organisms as well as the physical environment To understand how evolution works it is helpful to understand what is adaptation Adaptation refers to any particular feature that allows an organism to live and reproduce in its environment It can be a physical feature like fur or feathers Or it can be a trait of behavior such as moving to the shade during hot weather or moving out to avoid the cold at night The capacity of a living thing to extract energy from its environment and interact with other organisms and their physical environments is essential to its survival The organism should possess the right genes for producing offspring and to be able to access sufficient food and resources The organism should be able to reproduce at a rate that is optimal for its particular niche These elements along with mutations and gene flow can cause an alteration in the ratio of different alleles in the populations gene pool This change in allele frequency can lead to the emergence of new traits and eventually new species as time passes A lot of the traits we admire about animals and plants are adaptations like lung or gills for removing oxygen from the air feathers or fur to provide insulation long legs to run away from predators and camouflage for hiding However a proper understanding of adaptation requires paying attention to the distinction between the physiological and behavioral characteristics Physiological adaptations like the thick fur or gills are physical traits while behavioral adaptations like the tendency to seek out companions or to retreat to the shade during hot weather are not It is important to note that insufficient planning does not cause an adaptation A failure to consider the consequences of a decision even if it appears to be rational may make it unadaptive