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https://elearnportal.science/wiki/Its_History_Of_Evolution_Baccarat

What is Free Evolution Free evolution is the idea that the natural processes of living organisms can lead to their development over time This includes the appearance and development of new species Many examples have been given of this such as different varieties of fish called sticklebacks that can be found in fresh or salt water and walking stick insect varieties that favor particular host plants These mostly reversible traits permutations cannot explain fundamental changes to the basic body plan Evolution through Natural Selection Scientists have been fascinated by the development of all the living creatures that live on our planet for ages Charles Darwins natural selection is the most wellknown explanation This process occurs when those who are better adapted have more success in reproduction and survival than those who are less welladapted Over time a community of well adapted individuals grows and eventually creates a new species Natural selection is a process that is cyclical and involves the interaction of 3 factors including reproduction variation and inheritance Variation is caused by mutation and sexual reproduction both of which enhance the genetic diversity of an animal species Inheritance is the transfer of a persons genetic traits to his or her offspring which includes both recessive and dominant alleles Reproduction is the production of fertile viable offspring which includes both sexual and asexual methods All of these factors must be in harmony to allow natural selection to take place For instance the case where a dominant allele at one gene can cause an organism to live and reproduce more frequently than the recessive allele the dominant allele will be more prevalent in the population However if the allele confers an unfavorable survival advantage or reduces fertility it will be eliminated from the population The process is selfreinforcing meaning that an organism with an adaptive trait will live and reproduce more quickly than those with a maladaptive feature The more offspring that an organism has the more fit it is which is measured by its capacity to reproduce itself and survive People with good traits like a longer neck in giraffes and bright white patterns of color in male peacocks are more likely to be able to survive and create offspring and thus will eventually make up the majority of the population in the future Natural selection is only a force for populations not on individuals This is a significant distinction from the Lamarckian theory of evolution which states that animals acquire characteristics through use or disuse If a giraffe extends its neck to reach prey and its neck gets longer then its offspring will inherit this characteristic The differences in neck size between generations will continue to increase until the giraffe becomes unable to breed with other giraffes Evolution through Genetic Drift Genetic drift occurs when alleles from a gene are randomly distributed in a population In the end only one will be fixed become common enough that it can no more be eliminated through natural selection and the other alleles will decrease in frequency In the extreme this it leads to a single allele dominance The other alleles are eliminated and heterozygosity is reduced to zero In a small number of people this could result in the complete elimination the recessive gene This scenario is called the bottleneck effect It is typical of an evolutionary process that occurs whenever the number of individuals migrate to form a group A phenotypic bottleneck may also occur when the survivors of a catastrophe like an outbreak or a mass hunting incident are concentrated in the same area The surviving individuals will be largely homozygous for the dominant allele which means that they will all have the same phenotype and therefore share the same fitness characteristics This could be caused by a war an earthquake or even a disease The genetically distinct population if left vulnerable to genetic drift Walsh Lewens Walsh and Ariew define drift as a departure from the expected values due to differences in fitness They cite a famous example of twins that are genetically identical and have identical phenotypes and yet one is struck by lightening and dies while the other lives and reproduces This kind of drift can play a significant part in the evolution of an organism It is not the only method of evolution Natural selection is the most common alternative where mutations and migrations maintain the phenotypic diversity in the population Stephens asserts that there is a significant difference between treating the phenomenon of drift as a force or cause and treating other causes such as selection mutation and migration as forces and causes He claims that a causal process account of drift allows us to distinguish it from other forces and this distinction is essential He also argues that drift has a direction that is it tends to reduce heterozygosity He also claims that it also has a magnitude that is determined by population size Evolution by Lamarckism In high school students study biology they are often introduced to the work of JeanBaptiste Lamarck 1744 1829 His theory of evolution also referred to as Lamarckism states that simple organisms evolve into more complex organisms adopting traits that result from the organisms use and misuse Lamarckism is typically illustrated by a picture of a giraffe extending its neck to reach leaves higher up in the trees Discover More Here would result in giraffes passing on their longer necks to their offspring which then get taller Lamarck was a French Zoologist In his inaugural lecture for his course on invertebrate Zoology at the Museum of Natural History in Paris on 17 May 1802 he introduced an innovative concept that completely challenged previous thinking about organic transformation According to Lamarck living creatures evolved from inanimate materials through a series of gradual steps Lamarck was not the first to suggest that this could be the case but he is widely seen as giving the subject its first general and thorough treatment The predominant story is that Charles Darwins theory of natural selection and Lamarckism fought in the 19th Century Darwinism eventually triumphed and led to the creation of what biologists call the Modern Synthesis This theory denies acquired characteristics can be passed down through generations and instead argues organisms evolve by the selective influence of environmental factors including Natural Selection While Lamarck supported the notion of inheritance through acquired characters and his contemporaries also spoke of this idea however it was not an integral part of any of their evolutionary theorizing This is partly because it was never scientifically validated Its been more than 200 year since Lamarcks birth and in the field of age genomics there is a growing evidence base that supports the heritabilityacquired characteristics This is often called neoLamarckism or more often epigenetic inheritance It is a variant of evolution that is just as valid as the more popular NeoDarwinian theory Evolution through the process of adaptation One of the most common misconceptions about evolution is being driven by a fight for survival This view is a misrepresentation of natural selection and ignores the other forces that drive evolution The fight for survival is more accurately described as a struggle to survive in a specific environment This can include not just other organisms as well as the physical environment itself Understanding adaptation is important to comprehend evolution Adaptation refers to any particular characteristic that allows an organism to live and reproduce in its environment It could be a physiological structure such as fur or feathers or a behavioral trait like moving to the shade during the heat or leaving at night to avoid the cold The capacity of an organism to draw energy from its surroundings and interact with other organisms as well as their physical environment is crucial to its survival The organism must possess the right genes to generate offspring and it must be able to locate sufficient food and other resources Moreover the organism must be able to reproduce itself in a way that is optimally within its environment These factors in conjunction with gene flow and mutations can lead to an alteration in the ratio of different alleles in a populations gene pool Over time this change in allele frequencies can result in the development of new traits and ultimately new species Many of the characteristics we admire in animals and plants are adaptations For instance lung or gills that extract oxygen from the air fur and feathers as insulation and long legs to get away from predators and camouflage to hide However a complete understanding of adaptation requires attention to the distinction between physiological and behavioral traits Physical characteristics like thick fur and gills are physical characteristics Behavioral adaptations are not an exception for instance the tendency of animals to seek out companionship or move into the shade during hot weather It is also important to keep in mind that the absence of planning doesnt cause an adaptation Inability to think about the implications of a choice even if it appears to be rational may make it unadaptive