10 Best Books On Free Evolution
What is Free Evolution?
Free evolution is the notion that natural processes can cause organisms to develop over time. This includes the appearance and development of new species.
A variety of examples have been provided of this, such as different varieties of stickleback fish that can live in either fresh or salt water and walking stick insect varieties that prefer specific host plants. These are mostly reversible traits, however, cannot explain fundamental changes in body plans.
Evolution through Natural Selection
The development of the myriad living organisms on Earth is an enigma that has fascinated scientists for many centuries. The most well-known explanation is Darwin's natural selection process, which occurs when better-adapted individuals survive and reproduce more successfully than those who are less well adapted. Over time, a population of well adapted individuals grows and eventually creates a new species.
Natural selection is an ongoing process that involves the interaction of three factors: variation, inheritance and reproduction. Sexual reproduction and mutations increase genetic diversity in a species. Inheritance is the term used to describe the transmission of genetic traits, which include both dominant and recessive genes and their offspring. Reproduction is the generation of fertile, viable offspring which includes both sexual and asexual methods.
All of these elements have to be in equilibrium for natural selection to occur. If, for instance an allele of a dominant gene allows an organism to reproduce and live longer than the recessive allele, then the dominant allele will become more prevalent in a group. If the allele confers a negative survival advantage or reduces the fertility of the population, it will be eliminated. This process is self-reinforcing meaning that a species with a beneficial characteristic is more likely to survive and reproduce than an individual with an inadaptive characteristic. The more offspring an organism produces the more fit it is that is determined by its capacity to reproduce itself and survive. People with desirable traits, like a long neck in Giraffes, or the bright white patterns on male peacocks, are more likely than others to live and reproduce, which will eventually lead to them becoming the majority.
Natural selection is only a factor in populations and not on individuals. 에볼루션 사이트 is a crucial distinction from the Lamarckian evolution theory, which states that animals acquire traits through use or lack of use. For instance, if a animal's neck is lengthened by stretching to reach prey its offspring will inherit a larger neck. The difference in neck size between generations will continue to grow until the giraffe becomes unable to reproduce with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when the alleles of a gene are randomly distributed within a population. Eventually, only one will be fixed (become common enough that it can no longer be eliminated by natural selection), and the rest of the alleles will diminish in frequency. This can result in a dominant allele at the extreme. The other alleles are eliminated, and heterozygosity falls to zero. In a small group, this could lead to the total elimination of recessive alleles. This scenario is known as a bottleneck effect and it is typical of the kind of evolutionary process that occurs when a lot of people migrate to form a new group.
A phenotypic bottleneck may occur when survivors of a disaster such as an epidemic or mass hunt, are confined into a small area. The survivors will have an allele that is dominant and will share the same phenotype. This can be caused by earthquakes, war or even plagues. The genetically distinct population, if left susceptible to genetic drift.
Walsh, Lewens and Ariew define drift as a departure from expected values due to differences in fitness. They give a famous example of twins that are genetically identical, share identical phenotypes, and yet one is struck by lightening and dies while the other lives and reproduces.
This kind of drift could be very important in the evolution of an entire species. But, it's not the only way to progress. The primary alternative is a process called natural selection, where the phenotypic diversity of the population is maintained through mutation and migration.
Stephens asserts that there is a huge distinction between treating drift as an actual cause or force, and considering other causes, such as migration and selection mutation as causes and forces. He claims that a causal process account of drift allows us to distinguish it from these other forces, and that this distinction is essential. He argues further that drift has a direction, i.e., it tends towards eliminating heterozygosity. It also has a size which is determined based on population size.
Evolution through Lamarckism
In high school, students study biology they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution, commonly referred to as "Lamarckism is based on the idea that simple organisms develop into more complex organisms through inheriting characteristics that result from an organism's use and disuse. Lamarckism can be illustrated by a giraffe extending its neck to reach higher levels of leaves in the trees. This causes the longer necks of giraffes to be passed on to their offspring who would then grow even taller.
Lamarck the French zoologist, presented an innovative idea in his opening lecture at the Museum of Natural History of Paris. He challenged conventional wisdom on organic transformation. In his view living things evolved from inanimate matter via an escalating series of steps. Lamarck was not the first to make this claim however he was widely considered to be the first to provide the subject a thorough and general treatment.
The most popular story is that Lamarckism was an opponent to Charles Darwin's theory of evolutionary natural selection, and both theories battled out in the 19th century. Darwinism ultimately prevailed and led to what biologists refer to as the Modern Synthesis. The theory denies that acquired characteristics are passed down from generation to generation and instead argues organisms evolve by the selective influence of environmental factors, such as Natural Selection.
Lamarck and his contemporaries endorsed the idea that acquired characters could be passed on to future generations. However, this notion was never a major part of any of their theories about evolution. This is partly because it was never tested scientifically.
It has been more than 200 year since Lamarck's birth, and in the age genomics there is a growing evidence-based body of evidence to support the heritability of acquired traits. This is sometimes called "neo-Lamarckism" or, more commonly, epigenetic inheritance. It is a form of evolution that is just as relevant as the more popular Neo-Darwinian model.
Evolution by the process of adaptation
One of the most widespread misconceptions about evolution is that it is a result of a kind of struggle to survive. This view is inaccurate and overlooks the other forces that are driving evolution. The fight for survival is better described as a fight to survive in a specific environment. This may include not only other organisms but also the physical surroundings themselves.
To understand how evolution operates it is important to think about what adaptation is. Adaptation is any feature that allows living organisms to survive in its environment and reproduce. It could be a physical structure like feathers or fur. It could also be a behavior trait such as moving into the shade during hot weather, or moving out to avoid the cold at night.
The survival of an organism is dependent on its ability to extract energy from the environment and interact with other living organisms and their physical surroundings. The organism must possess the right genes to produce offspring, and it must be able to locate enough food and other resources. The organism must also be able to reproduce at a rate that is optimal for its niche.
These elements, in conjunction with mutation and gene flow result in a change in the proportion of alleles (different types of a gene) in the gene pool of a population. Over time, this change in allele frequencies could lead to the emergence of new traits and ultimately new species.
Many of the characteristics we find appealing in animals and plants are adaptations. For instance lung or gills that draw oxygen from air, fur and feathers as insulation, long legs to run away from predators and camouflage to conceal. However, a proper understanding of adaptation requires attention to the distinction between behavioral and physiological traits.
Physical traits such as the thick fur and gills are physical traits. The behavioral adaptations aren't, such as the tendency of animals to seek companionship or move into the shade during hot weather. It is also important to remember that a the absence of planning doesn't result in an adaptation. A failure to consider the implications of a choice even if it appears to be rational, may make it inflexible.