What is Free Evolution?
Free evolution is the idea that the natural processes of organisms can lead to their development over time. This includes the development of new species and the alteration of the appearance of existing ones.
A variety of examples have been provided of this, such as different varieties of fish called sticklebacks that can be found in salt or fresh water, as well as walking stick insect varieties that are attracted to particular host plants. These are mostly reversible traits however, are not able to be the reason for fundamental changes in body plans.
Evolution by Natural Selection
The development of the myriad living creatures on Earth is an enigma that has fascinated scientists for centuries. The best-established explanation is Charles Darwin's natural selection process, which occurs when better-adapted individuals survive and reproduce more effectively than those who are less well adapted. As time passes, the number of individuals who are well-adapted grows and eventually develops into a new species.
Natural selection is a process that is cyclical and involves the interaction of 3 factors that are: reproduction, variation and inheritance. Sexual reproduction and mutation increase genetic diversity in the species. Inheritance refers the transmission of a person's genetic traits, which include recessive and dominant genes and their offspring. Reproduction is the process of producing viable, fertile offspring. This can be done via sexual or asexual methods.
에볼루션 바카라 무료체험 of these variables have to be in equilibrium for natural selection to occur. If, for instance, a dominant gene allele allows an organism to reproduce and live longer than the recessive gene, then the dominant allele is more prevalent in a group. However, if the allele confers a disadvantage in survival or decreases fertility, it will disappear from the population. The process is self-reinforcing, which means that an organism with a beneficial trait is more likely to survive and reproduce than an individual with a maladaptive trait. The more offspring an organism produces the more fit it is, which is measured by its ability to reproduce itself and survive. Individuals with favorable traits, such as having a longer neck in giraffes or bright white color patterns in male peacocks, are more likely to survive and produce offspring, and thus will become the majority of the population in the future.
Natural selection is only an aspect of populations and not on individuals. This is a crucial distinction from the Lamarckian theory of evolution that states that animals acquire traits either through use or lack of use. If a giraffe expands its neck in order to catch prey, and the neck becomes longer, then its offspring will inherit this characteristic. The difference in neck size between generations will continue to increase until the giraffe is no longer able to reproduce with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when alleles of the same gene are randomly distributed within a population. Eventually, one of them will reach fixation (become so widespread that it can no longer be removed by natural selection) and other alleles will fall to lower frequencies. This can result in dominance at the extreme. Other alleles have been essentially eliminated and heterozygosity has diminished to zero. In a small number of people this could lead to the complete elimination of recessive gene. This scenario is called a bottleneck effect, and it is typical of evolutionary process that takes place when a large amount of people migrate to form a new population.
A phenotypic bottleneck may occur when survivors of a disaster like an epidemic or mass hunting event, are concentrated in a limited area. The surviving individuals will be mostly homozygous for the dominant allele, meaning that they all share the same phenotype, and thus have the same fitness traits. This situation might be caused by a conflict, earthquake or even a disease. Regardless of the cause the genetically distinct group that remains could be susceptible to genetic drift.
Walsh Lewens, Lewens, and Ariew utilize a "purely outcome-oriented" definition of drift as any deviation from expected values for different fitness levels. They give the famous example of twins that are genetically identical and share the same phenotype. However one is struck by lightning and dies, while the other continues to reproduce.
This kind of drift could be very important in the evolution of an entire species. It is not the only method for evolution. Natural selection is the main alternative, in which mutations and migration keep the phenotypic diversity of the population.
Stephens argues that there is a big distinction between treating drift as a force or a cause and considering other causes of evolution such as selection, mutation and migration as forces or causes. He claims that a causal-process explanation of drift lets us distinguish it from other forces, and this distinction is essential. He further argues that drift has a direction, that is it tends to eliminate heterozygosity. It also has a size, that is determined by the size of the population.
Evolution through Lamarckism
When students in high school study biology they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution, commonly referred to as “Lamarckism” which means that simple organisms transform into more complex organisms inheriting characteristics that result from the organism's use and misuse. Lamarckism is typically illustrated by a picture of a giraffe stretching its neck longer to reach higher up in the trees. This process would result in giraffes passing on their longer necks to their offspring, who then get taller.
Lamarck Lamarck, a French Zoologist, introduced a revolutionary concept 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 through a series of gradual steps. Lamarck was not the first to suggest that this might be the case, but his reputation is widely regarded as being the one who gave the subject his first comprehensive and comprehensive analysis.
The most popular story is that Charles Darwin's theory of evolution by natural selection and Lamarckism fought during the 19th century. Darwinism ultimately won which led to what biologists call the Modern Synthesis. This theory denies acquired characteristics can be passed down through generations and instead, it claims that organisms evolve through the influence of environment factors, such as Natural Selection.
Lamarck and his contemporaries supported the idea that acquired characters could be passed down to the next generation. However, this notion was never a key element of any of their evolutionary theories. This is due in part to the fact that it was never tested scientifically.
It's been more than 200 years since Lamarck was born and, in the age of genomics there is a huge body of evidence supporting the possibility of inheritance of acquired traits. It is sometimes called "neo-Lamarckism" or, more often, epigenetic inheritance. It is a form of evolution that is as relevant as the more popular Neo-Darwinian theory.
Evolution by adaptation
One of the most common misconceptions about evolution is that it is being driven by a fight for survival. 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 certain environment. This can be a challenge for not just other living things as well as the physical surroundings themselves.
To understand how evolution works it is important to think about what adaptation is. It is a feature that allows a living organism to live in its environment and reproduce. It can be a physical structure like fur or feathers. Or it can be a trait of behavior that allows you to move into the shade during hot weather, or moving out to avoid the cold at night.
An organism's survival depends on its ability to obtain energy from the surrounding environment and interact with other living organisms and their physical surroundings. The organism must have the right genes to create offspring, and must be able to locate enough food and other resources. The organism should be able to reproduce at a rate that is optimal for its particular niche.
These factors, together with gene flow and mutations, can lead to a shift in the proportion of different alleles in a population’s gene pool. As time passes, this shift in allele frequency can result in the development of new traits and ultimately new species.
A lot of the traits we admire in animals and plants are adaptations. For instance the lungs or gills which extract oxygen from air feathers and fur for insulation and long legs to get away from predators, and camouflage to hide. However, a proper understanding of adaptation requires attention to the distinction between physiological and behavioral traits.
Physiological adaptations, like thick fur or gills, are physical traits, whereas behavioral adaptations, such as the desire to find companions or to retreat into the shade in hot weather, aren't. It is also important to remember that a lack of planning does not cause an adaptation. In fact, a failure to think about the implications of a behavior can make it unadaptive, despite the fact that it may appear to be sensible or even necessary.