What is Free Evolution?
Free evolution is the idea that the natural processes that organisms go through can lead them to evolve over time. This includes the appearance and development of new species.
This has been proven by many examples such as the stickleback fish species that can live in salt or fresh water, and walking stick insect species that are apprehensive about particular host plants. These typically reversible traits cannot explain fundamental changes to basic body plans.
Evolution by Natural Selection
Scientists have been fascinated by the development of all living organisms that inhabit our planet for many centuries. The best-established explanation is that of Charles Darwin's natural selection, a process that is triggered when more well-adapted individuals live longer and reproduce more effectively than those less well-adapted. Over time, a population of well-adapted individuals increases and eventually forms a whole new species.
Natural selection is a cyclical process that involves the interaction of three factors: variation, inheritance and reproduction. Variation is caused by mutation and sexual reproduction, both of which increase the genetic diversity within the species. Inheritance is the term used to describe the transmission of a person’s genetic characteristics, which includes both dominant and recessive genes, to their offspring. Reproduction is the process of producing viable, fertile offspring, which includes both sexual and asexual methods.
Natural selection can only occur when all of these factors are in harmony. For example the case where a dominant allele at the gene allows an organism to live and reproduce more often than the recessive allele, the dominant allele will become more common in the population. However, if the gene confers a disadvantage in survival or reduces fertility, it will be eliminated from the population. This process is self-reinforcing meaning that a species with a beneficial trait can reproduce and survive longer than an individual with an unadaptive trait. The more offspring an organism produces, the greater its fitness, which is measured by its ability to reproduce and survive. People with good characteristics, such as a long neck in the giraffe, or bright white color patterns on male peacocks are more likely than others to reproduce and survive and eventually lead to them becoming the majority.
Natural selection is only a force for populations, not on individual organisms. This is a crucial distinction from the Lamarckian theory of evolution, which states that animals acquire traits due to the use or absence of use. If a giraffe stretches its neck to catch prey and the neck grows longer, then the children will inherit this characteristic. The difference in neck size between generations will increase until the giraffe is unable to reproduce with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when alleles of the same gene are randomly distributed in a population. Eventually, one of them will attain fixation (become so widespread that it cannot be eliminated by natural selection), while other alleles will fall to lower frequency. In extreme cases, this leads to dominance of a single allele. Other alleles have been essentially eliminated and heterozygosity has diminished to a minimum. In a small population it could lead to the complete elimination of recessive alleles. This is called a bottleneck effect, and it is typical of evolutionary process when a large number of individuals move to form a new group.
A phenotypic 'bottleneck' can also occur when the survivors of a catastrophe such as an outbreak or a mass hunting incident are concentrated in an area of a limited size. The remaining individuals will be mostly homozygous for the dominant allele which means they will all have the same phenotype and thus share the same fitness characteristics. This could be caused by war, earthquakes or even a plague. Whatever the reason the genetically distinct group that is left might be prone to genetic drift.
Walsh Lewens, Walsh and Ariew define drift as a deviation from the expected values due to differences in fitness. They provide a well-known example of twins that are genetically identical, have identical phenotypes, and yet one is struck by lightning and dies, while the other lives and reproduces.
This kind of drift could play a significant role in the evolution of an organism. It is not the only method for evolution. Natural selection is the primary alternative, where mutations and migration keep the phenotypic diversity in the population.
Stephens argues that there is a major difference between treating drift as a force or as an underlying cause, and considering other causes of evolution such as selection, mutation and migration as causes or causes. He argues that a causal mechanism account of drift allows us to distinguish it from these other forces, and that this distinction is crucial. He also argues that drift has a direction: that is, it tends to eliminate heterozygosity. It also has a specific magnitude which is determined by population size.
Evolution by Lamarckism
Biology students in high school are frequently introduced to Jean-Baptiste Lemarck's (1744-1829) work. His theory of evolution is commonly called "Lamarckism" and it states that simple organisms grow into more complex organisms via the inheritance of characteristics that are a result of the natural activities of an organism usage, use and disuse. Lamarckism is typically illustrated with an image of a giraffe stretching its neck further to reach higher up in the trees. 에볼루션 슬롯게임 causes giraffes' longer necks to be passed to their offspring, who would then become taller.
Lamarck, a French Zoologist, introduced 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 opinion, living things had evolved from inanimate matter via an escalating series of steps. Lamarck was not the first to suggest that this might be the case but his reputation is widely regarded as giving the subject its first broad and comprehensive analysis.
The predominant story is that Charles Darwin's theory of evolution by natural selection and Lamarckism fought in the 19th century. Darwinism eventually prevailed which led to what biologists refer to as the Modern Synthesis. The theory argues that acquired traits are passed down from generation to generation and instead argues 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 future generations. However, this notion was never a central part of any of their evolutionary theories. 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 also referred to as "neo Lamarckism", or more often epigenetic inheritance. This is a model that is just as valid as the popular neodarwinian model.
Evolution through adaptation
One of the most popular misconceptions about evolution is that it is driven by a type of struggle to survive. This is a false assumption and ignores other forces driving evolution. The struggle for survival is more effectively described as a struggle to survive within a specific environment, which could be a struggle that involves not only other organisms, but as well the physical environment.
To understand how evolution works it is important to think about what adaptation is. The term "adaptation" refers to any specific feature that allows an organism to survive and reproduce within its environment. It could be a physiological structure, like feathers or fur, or a behavioral trait, such as moving into shade in hot weather or stepping out at night to avoid cold.
The capacity of an organism to extract energy from its environment and interact with other organisms, as well as their physical environment, is crucial to its survival. The organism must have the right genes to produce offspring, and it must be able to locate enough food and other resources. In 에볼루션사이트 , the organism should be able to reproduce itself at an optimal rate within its environment.
These factors, along with mutation and gene flow can result in changes in the ratio of alleles (different varieties of a particular gene) in a population's gene pool. As time passes, this shift in allele frequencies can result in the emergence of new traits and ultimately new species.
Many of the characteristics we admire about animals and plants are adaptations, such as the lungs or gills that extract oxygen from the air, feathers or fur to provide insulation, long legs for running away from predators and camouflage for hiding. To understand the concept of adaptation it is crucial to differentiate between physiological and behavioral characteristics.
Physiological adaptations like thick fur or gills are physical traits, while behavioral adaptations, like the desire to find companions or to move to the shade during hot weather, aren't. Additionally, it is important to understand that a lack of forethought is not a reason to make something an adaptation. A failure to consider the consequences of a decision even if it seems to be rational, could make it unadaptive.