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.
A variety of examples have been provided of this, including various varieties of stickleback fish that can live in either salt or fresh water, as well as walking stick insect varieties that prefer specific host plants. These typically reversible traits are not able to explain fundamental changes to the basic body plan.
Evolution by Natural Selection
Scientists have been fascinated by the development of all the living organisms that inhabit our planet for centuries. The most well-known explanation is Charles Darwin's natural selection, a process that occurs when individuals that are better adapted survive and reproduce more successfully than those that are less well-adapted. As time passes, the number of well-adapted individuals grows and eventually forms an entirely new species.
Natural selection is an ongoing process that involves the interaction of three factors including inheritance, variation, and reproduction. Sexual reproduction and mutations increase the genetic diversity of an animal species. Inheritance is the transfer of a person's genetic characteristics to the offspring of that person that includes dominant and recessive alleles. Reproduction is the generation of viable, fertile offspring, which includes both sexual and asexual methods.
All of these variables must be in harmony to allow natural selection to take place. If, for example an allele of a dominant gene allows an organism to reproduce and last longer than the recessive gene The dominant allele is more prevalent in a group. If the allele confers a negative advantage to survival or decreases the fertility of the population, it will be eliminated. The process is self-reinforced, which means that an organism with a beneficial characteristic is more likely to survive and reproduce than one with an unadaptive trait. The greater an organism's fitness which is measured by its ability to reproduce and survive, is the greater number of offspring it can produce. People with good characteristics, such as the long neck of giraffes, or bright white patterns on male peacocks are more likely to others to reproduce and survive which eventually leads to them becoming the majority.
Natural selection is an aspect of populations and not on individuals. This is a significant distinction from the Lamarckian theory of evolution which argues that animals acquire characteristics through use or neglect. If a giraffe stretches its neck to reach prey, and the neck becomes longer, then the offspring will inherit this characteristic. The differences in neck length between generations will continue until the giraffe's neck gets so long that it can not breed with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when alleles of one gene are distributed randomly in a population. Eventually, one of them will reach fixation (become so widespread that it can no longer be removed through natural selection) and the other alleles drop to lower frequencies. news can result in an allele that is dominant in extreme. The other alleles are essentially eliminated, and heterozygosity falls to zero. In a small population, this could result in the complete elimination of recessive gene. This is known as the bottleneck effect. It is typical of an evolution process that occurs when an enormous number of individuals move to form a population.
A phenotypic 'bottleneck' can also occur when the survivors of a catastrophe such as an outbreak or mass hunt incident are concentrated in a small area. The surviving individuals are likely to be homozygous for the dominant allele, meaning that they all share the same phenotype, and therefore share the same fitness characteristics. This could be caused by war, earthquakes or even plagues. Regardless of the cause, the genetically distinct population that is left might be susceptible to genetic drift.
Walsh Lewens and Ariew utilize Lewens, Walsh and Ariew employ a "purely outcome-oriented" definition of drift as any deviation from the expected values for differences in fitness. They give a famous example of twins that are genetically identical, have identical phenotypes, and yet one is struck by lightning and dies, whereas 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. The main alternative is a process known as natural selection, in which phenotypic variation in the population is maintained through mutation and migration.
Stephens argues that there is a significant difference between treating drift as a force or as an underlying cause, and treating other causes of evolution, such as selection, mutation and migration as forces or causes. He claims that a causal process explanation of drift allows us to distinguish it from these other forces, and that this distinction is essential. He further argues that drift has a direction, that is, it tends to eliminate heterozygosity, and that it also has a magnitude, that is determined by population size.
Evolution through Lamarckism
Biology students in high school are frequently exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution is often known as "Lamarckism" and it states that simple organisms develop into more complex organisms by the inheritance of traits which result from the natural activities of an organism, use and disuse. Lamarckism can be demonstrated by an giraffe's neck stretching to reach higher leaves in the trees. This could cause giraffes' longer necks to be passed on to their offspring who would then grow even taller.
Lamarck Lamarck, a French Zoologist from France, presented an idea that was revolutionary in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged previous thinking on organic transformation. In his view living things had evolved from inanimate matter via an escalating series of steps. Lamarck was not the first to suggest that this could be the case, but he is widely seen as having given the subject its first general and thorough treatment.
The dominant story is that Charles Darwin's theory of natural selection and Lamarckism were competing 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 and instead, it claims that organisms evolve through the influence of environment factors, such as Natural Selection.
Lamarck and his contemporaries believed in the notion that acquired characters could be passed down to the next generation. However, this notion was never a key element of any of their theories on evolution. This is partly because it was never scientifically validated.
It's been over 200 years since the birth of Lamarck, and in the age genomics, there is an increasing body of evidence that supports the heritability acquired characteristics. This is also known as "neo Lamarckism", or more generally epigenetic inheritance. It is a variant of evolution that is as valid as the more well-known Neo-Darwinian theory.
Evolution through adaptation
One of the most common misconceptions about evolution is that it is driven by a sort of struggle to survive. In reality, this notion is a misrepresentation of natural selection and ignores the other forces that drive evolution. The fight for survival can be more effectively described as a struggle to survive within a particular environment, which can involve not only other organisms but also the physical environment.
Understanding the concept of adaptation is crucial to comprehend evolution. Adaptation refers to any particular feature that allows an organism to survive and reproduce within its environment. It can be a physiological structure, like feathers or fur, or a behavioral trait like moving into the shade in hot weather or stepping out at night to avoid cold.
The ability of an organism to draw energy from its environment and interact with other organisms as well as their physical environment, is crucial to its survival. The organism needs to have the right genes to produce offspring, and it should be able to locate enough food and other resources. In addition, the organism should be capable of reproducing itself in a way that is optimally within its niche.
These factors, together with mutations and gene flow can cause changes in the proportion of different alleles in the population's gene pool. The change in frequency of alleles can result in the emergence of new traits and eventually new species in the course of time.
Many of the features that we admire in animals and plants are adaptations, such as lungs or gills to extract oxygen from the air, feathers or fur for insulation, long legs for running away from predators and camouflage for hiding. To comprehend adaptation it is essential to differentiate between physiological and behavioral characteristics.
Physiological adaptations like thick fur or gills are physical traits, whereas behavioral adaptations, like the tendency to search for companions or to move to shade in hot weather, are not. Additionally it is important to remember that a lack of thought is not a reason to make something an adaptation. In fact, failing to consider the consequences of a decision can render it unadaptive even though it might appear logical or even necessary.