What is Free Evolution?

Free evolution is the idea that natural processes can cause organisms to evolve over time. This includes the appearance and growth of new species.

This has been demonstrated by many examples of stickleback fish species that can be found in salt or fresh water, and walking stick insect varieties that prefer particular host plants. These reversible traits, however, cannot explain fundamental changes in body plans.

Evolution by Natural Selection

Scientists have been fascinated by the evolution of all living creatures that inhabit our planet for centuries. The most widely accepted explanation is Charles Darwin's natural selection process, an evolutionary process that is triggered when more well-adapted individuals live longer and reproduce more successfully than those less well adapted. Over time, a community of well-adapted individuals increases and eventually becomes a new species.

Natural selection is an ongoing process and involves the interaction of 3 factors including reproduction, variation and inheritance. Variation is caused by mutations and sexual reproduction both of which enhance the genetic diversity of the species. Inheritance is the passing of a person's genetic traits to their offspring that includes dominant and recessive alleles. Reproduction is the process of producing fertile, viable offspring which includes both asexual and sexual methods.

All of these variables have to be in equilibrium to allow natural selection to take place. For instance the case where an allele that is dominant at a gene causes an organism to survive and reproduce more often than the recessive allele the dominant allele will be more prominent within the population. If the allele confers a negative advantage to survival or lowers the fertility of the population, it will go away. The process is self-reinforcing which means that an organism with an adaptive trait will survive and reproduce much more than those with a maladaptive feature. The greater an organism's fitness as measured by its capacity to reproduce and survive, is the greater number of offspring it produces. Individuals with favorable characteristics, such as the long neck of giraffes, or bright white color patterns on male peacocks are more likely to others to reproduce and survive and eventually lead to them becoming the majority.

Natural selection is only an element in the population and not on individuals. This is a major distinction from the Lamarckian theory of evolution which holds that animals acquire traits either through use or lack of use. For instance, if a animal's neck is lengthened by stretching to reach for prey and its offspring will inherit a larger neck. The difference in neck length between generations will persist until the neck of the giraffe becomes too long to no longer breed with other giraffes.

Evolution through Genetic Drift

Genetic drift occurs when alleles from the same gene are randomly distributed in a population. Eventually, only one will be fixed (become common enough to no longer be eliminated by natural selection), and the rest of the alleles will diminish in frequency. In extreme cases it can lead to a single allele dominance. The other alleles are eliminated, and 에볼루션 게이밍 heterozygosity falls to zero. In a small group this could result in the complete elimination of the recessive allele. This is known as a bottleneck effect and it is typical of the kind of evolutionary process that takes place when a lot of people migrate to form a new group.

A phenotypic bottleneck may also occur when the survivors of a disaster such as an outbreak or a mass hunting event are concentrated in an area of a limited size. The survivors will carry a dominant allele and thus will share the same phenotype. This situation might be caused by conflict, earthquake or even a cholera outbreak. The genetically distinct population, if it is left susceptible to genetic drift.

Walsh, Lewens and Ariew define drift as a departure from the expected values due to differences in fitness. They provide a well-known example of twins that are genetically identical, share identical phenotypes, but one is struck by lightening and dies while the other lives and reproduces.

This kind of drift can be vital to the evolution of a species. But, it's not the only method to progress. The main alternative is a process called natural selection, where the phenotypic diversity of the population is maintained through mutation and migration.

Stephens claims that there is a major difference between treating drift as a force, or a cause and treating other causes of evolution like selection, mutation and migration as forces or causes. Stephens claims that a causal process explanation of drift lets us distinguish it from other forces and this distinction is crucial. He further argues that drift has a direction, that is, it tends to eliminate heterozygosity. He also claims that it also has a magnitude, 에볼루션바카라사이트 that is determined by population size.

Evolution by Lamarckism

In high school, students study biology, they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution, 에볼루션 바카라 (Read the Full Write-up) commonly referred to as "Lamarckism" which means that simple organisms develop into more complex organisms through inheriting characteristics that result from the use and abuse of an organism. Lamarckism is illustrated through an giraffe's neck stretching to reach higher branches in the trees. This causes giraffes' longer necks to be passed onto their offspring who would grow taller.

Lamarck, a French zoologist, presented a revolutionary concept in his opening lecture at the Museum of Natural History of Paris. He challenged the previous thinking on organic transformation. According Lamarck, living organisms evolved from inanimate materials by a series of gradual steps. Lamarck wasn't the first to make this claim, but he was widely thought of as the first to provide the subject a thorough and 에볼루션 general treatment.

The predominant story is that Charles Darwin's theory of natural selection and Lamarckism were competing during the 19th century. Darwinism eventually prevailed and led to what biologists call the Modern Synthesis. The theory argues that acquired characteristics can be inherited and instead, it argues that organisms develop through the action of environmental factors, such as natural selection.

Lamarck and his contemporaries believed in the idea that acquired characters could be passed down to the next generation. However, this notion was never a central part of any of their theories about evolution. This is partly due to the fact that it was never validated scientifically.

However, it has been more than 200 years since Lamarck was born and in the age genomics there is a vast amount of evidence to support the heritability of acquired characteristics. This is referred to as "neo Lamarckism", or more generally epigenetic inheritance. This is a model that is as reliable as the popular neodarwinian model.

Evolution through Adaptation

One of the most popular misconceptions about evolution is that it is being driven by a struggle to survive. This view misrepresents natural selection and ignores the other forces that drive evolution. The fight for survival can be more accurately described as a struggle to survive in a particular environment. This can include not only other organisms, but also the physical surroundings themselves.

To understand how evolution operates, it is helpful to consider what adaptation is. Adaptation refers to any particular feature that allows an organism to live and reproduce within its environment. It could be a physiological structure, such as fur or feathers or a behavior like moving into the shade in hot weather or stepping out at night to avoid the cold.

The capacity of a living thing to extract energy from its surroundings and 에볼루션 interact with other organisms and their physical environments is essential to its survival. The organism should possess the right genes to produce offspring and to be able to access sufficient food and resources. The organism must also be able to reproduce itself at a rate that is optimal for its niche.

These elements, in conjunction with gene flow and mutation result in a change in the proportion of alleles (different forms of a gene) in the population's gene pool. This shift in the frequency of alleles could lead to the development of novel traits and eventually new species as time passes.

Many of the characteristics we admire in animals and plants are adaptations. For instance, lungs or gills that extract oxygen from the air, fur and feathers as insulation and long legs to get away from predators and camouflage for hiding. To understand adaptation it is crucial to discern between physiological and behavioral characteristics.

Physiological adaptations, such as the thick fur or gills are physical traits, whereas behavioral adaptations, such as the desire to find companions or to retreat to the shade during hot weather, are not. In addition it is important to note that a lack of thought does not make something an adaptation. A failure to consider the implications of a choice even if it appears to be logical, can make it unadaptive.