What is Free Evolution?
Free evolution is the concept that the natural processes of living organisms can cause them to develop over time. This includes the development of new species and transformation of the appearance of existing species.
A variety of examples have been provided of this, including different kinds of stickleback fish that can live in fresh or salt water and walking stick insect varieties that prefer particular host plants. These reversible traits are not able to explain fundamental changes to the basic body plan.
Evolution through Natural Selection
The development of the myriad of living organisms on Earth is an enigma that has fascinated scientists for centuries. Charles Darwin's natural selection theory is the best-established explanation. This process occurs when those who are better adapted are able to reproduce faster and longer than those who are less well-adapted. As time passes, the number of individuals who are well-adapted grows and eventually develops into an entirely new species.
Natural selection is a process that is cyclical and involves the interaction of three factors that are: reproduction, variation and inheritance. Variation is caused by mutations and sexual reproduction, both of which increase the genetic diversity of an animal species. Inheritance refers to the transmission of a person’s genetic characteristics, which includes both dominant and recessive genes and their offspring. Reproduction is the process of creating viable, fertile offspring. This can be achieved through sexual or asexual methods.
Natural selection only occurs when all of these factors are in balance. If, for example the dominant gene allele makes an organism reproduce and last longer than the recessive gene, then the dominant allele becomes more prevalent in a population. If the allele confers a negative advantage to survival or decreases the fertility of the population, it will be eliminated. The process is self reinforcing which means that the organism with an adaptive trait will live and reproduce far more effectively than those with a maladaptive feature. The higher the level of fitness an organism has as measured by its capacity to reproduce and survive, is the more offspring it produces. Individuals with favorable traits, like having a longer neck in giraffes, or bright white colors in male peacocks are more likely be able to survive and create offspring, and thus will eventually make up the majority of the population in the future.
Natural selection only affects populations, not individual organisms. This is a significant distinction from the Lamarckian theory of evolution which argues that animals acquire traits through use or neglect. For instance, if a Giraffe's neck grows longer due to stretching to reach prey its offspring will inherit a more long neck. The difference in neck length between generations will persist until the giraffe's neck gets too long that it can no longer breed with other giraffes.
Evolution through Genetic Drift
In genetic drift, alleles within a gene can attain different frequencies in a population due to random events. 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 diminish in frequency. In the extreme this, it leads to one allele dominance. Other alleles have been essentially eliminated and heterozygosity has been reduced to zero. In a small group, this could lead to the total elimination of recessive alleles. This is known as the bottleneck effect and is typical of an evolutionary process that occurs when an enormous number of individuals move to form a group.
A phenotypic bottleneck can also occur when the survivors of a catastrophe such as an outbreak or mass hunting event are concentrated in a small area. The survivors will share a dominant allele and thus will share the same phenotype. This may be caused by conflict, earthquake, or even a plague. Regardless of the cause, the genetically distinct population that remains is prone to genetic drift.
Walsh Lewens, Lewens, and Ariew employ Lewens, Walsh and Ariew employ a "purely outcome-oriented" definition of drift as any departure from expected values for differences in fitness. They provide the famous case of twins that are genetically identical and share the same phenotype, but one is struck by lightning and dies, but the other continues to reproduce.
This kind of drift can be very important in the evolution of the species. However, it's not the only way to evolve. Natural selection is the primary alternative, where mutations and migration maintain phenotypic diversity within a population.
Stephens asserts that there is a significant distinction between treating drift as a force or as a cause and treating other causes of evolution such as selection, mutation and migration as causes or causes. He claims that a causal-process account of drift allows us separate it from other forces and that this differentiation is crucial. He also argues that drift has an orientation, i.e., it tends towards eliminating heterozygosity. It also has a size, which is determined based on the size of the population.
Evolution by Lamarckism
When high school students take biology classes, they are frequently introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution, commonly referred to as “Lamarckism”, states that simple organisms evolve into more complex organisms inheriting characteristics that are a product of an organism's use and disuse. Read the Full Article can be demonstrated by an giraffe's neck stretching to reach higher branches in the trees. This causes giraffes' longer necks to be passed to their offspring, who would then grow even taller.
Lamarck was a French zoologist and, in his opening 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. In his opinion, living things had evolved from inanimate matter through an escalating series of steps. Lamarck was not the first to suggest that this might be the case, but he is widely seen as being the one who gave the subject his first comprehensive and thorough treatment.
The popular narrative is that Lamarckism became an opponent to Charles Darwin's theory of evolution by natural selection, and both theories battled it out in the 19th century. Darwinism ultimately won, leading to what biologists refer to as 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 action of environmental factors, including natural selection.
Lamarck and his contemporaries endorsed the notion that acquired characters could be passed down to the next generation. However, this idea was never a central part of any of their theories on evolution. This is due to the fact that it was never scientifically tested.
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 acquired characteristics. This is often referred to as "neo-Lamarckism" or, more frequently, epigenetic inheritance. This is a model that is as valid as the popular Neodarwinian model.
Evolution by adaptation
One of the most commonly-held misconceptions about evolution is its being driven by a struggle for survival. This view is inaccurate and ignores other forces driving evolution. The fight for survival can be more precisely described as a fight to survive in a specific environment, which could be a struggle that involves not only other organisms but also the physical environment.
Understanding how adaptation works is essential to understand evolution. It refers to a specific characteristic that allows an organism to survive and reproduce within its environment. It can be a physiological structure such as fur or feathers or a behavioral characteristic, such as moving into the shade in hot weather or stepping out at night to avoid the cold.
The survival of an organism is dependent on its ability to obtain energy from the environment and to interact with other organisms and their physical environments. The organism needs to have the right genes to create offspring, and it should be able to access enough food and other resources. The organism must also be able reproduce at an amount that is appropriate for its specific niche.
These factors, together with mutations and gene flow, can lead to a shift in the proportion of different alleles within the population's gene pool. The change in frequency of alleles could lead to the development of new traits and eventually, new species as time passes.
Many of the features we admire in animals and plants are adaptations. For instance lung or gills that draw oxygen from air feathers and fur as insulation and long legs to get away from predators and camouflage to conceal. To understand adaptation it is crucial to differentiate between physiological and behavioral characteristics.
Physiological traits like thick fur and gills are physical characteristics. Behavior adaptations aren't like the tendency of animals to seek out companionship or move into the shade in hot weather. In addition it is important to note that a lack of forethought does not mean that something is an adaptation. In fact, failure to consider the consequences of a behavior can make it unadaptive even though it may appear to be sensible or even necessary.