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 creation of new species and alteration of the appearance of existing species.
This is evident in numerous examples of stickleback fish species that can be found in fresh or saltwater and walking stick insect varieties that prefer specific host plants. These are mostly reversible traits can't, however, explain fundamental changes in basic body plans.
Evolution through Natural Selection
The development of the myriad living creatures on Earth is a mystery that has fascinated scientists for many centuries. Charles Darwin's natural selection theory is the best-established explanation. This process occurs when people who are more well-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 forms an entirely new species.
Natural selection is an ongoing process and involves the interaction of 3 factors that are: reproduction, variation and inheritance. Sexual reproduction and mutation increase the genetic diversity of a species. Inheritance is the transfer of a person's genetic characteristics to the offspring of that person which includes both dominant and recessive alleles. Reproduction is the process of creating fertile, viable offspring. This can be achieved by both asexual or sexual methods.
Natural selection is only possible when all these elements are in balance. For instance the case where a dominant allele at the gene can cause an organism to live and reproduce more frequently than the recessive one, the dominant allele will be more prevalent in the population. If the allele confers a negative survival advantage or decreases the fertility of the population, it will disappear. This process is self-reinforcing meaning that an organism that has a beneficial trait can reproduce and survive longer than one with an inadaptive trait. The more fit an organism is as measured by its capacity to reproduce and endure, is the higher number of offspring it can produce. People with desirable characteristics, such as 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 an aspect of populations and not on individuals. This is a major distinction from the Lamarckian evolution theory, which states that animals acquire traits either through usage or inaction. If a giraffe extends its neck to catch prey and its neck gets longer, then the offspring will inherit this characteristic. The differences in neck length between generations will persist until the giraffe's neck becomes too long to no longer breed with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when alleles of a gene are randomly distributed in a group. At some point, only one of them will be fixed (become common enough to no longer be eliminated by natural selection) and the other alleles will drop in frequency. This can result in a dominant allele in extreme. The other alleles are essentially eliminated, and heterozygosity decreases to zero. In a small population it could lead to the total elimination of recessive alleles. This is known as the bottleneck effect. It is typical of an evolutionary process that occurs when a large number individuals migrate to form a population.
A phenotypic bottleneck may also occur when the survivors of a disaster like an outbreak or mass hunt event are confined to a small area. The survivors will be mostly homozygous for the dominant allele which means that they will all have the same phenotype and will therefore have the same fitness traits. This can be caused by earthquakes, war, or even plagues. Regardless of the cause the genetically distinct group that remains could be prone to genetic drift.
Walsh Lewens, Walsh, and Ariew define drift as a departure from the expected value due to differences in fitness. They cite a famous example of twins that are genetically identical, have identical phenotypes but one is struck by lightning and dies, whereas the other lives and reproduces.
This kind of drift can be vital to the evolution of the species. But, mouse click the following article 's not the only method to develop. Natural selection is the primary alternative, where mutations and migration keep the phenotypic diversity in the population.
Stephens claims that there is a significant distinction between treating drift as an actual cause or force, and treating other causes like selection mutation and migration as forces and causes. He claims that a causal-process account of drift allows us differentiate it from other forces, and this differentiation is crucial. He argues further that drift has a direction, i.e., it tends to eliminate heterozygosity. It also has a size that is determined by the size of the population.
Evolution by Lamarckism
When high school students study biology, they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution is commonly referred to as "Lamarckism" and it asserts that simple organisms evolve into more complex organisms via the inheritance of traits that are a result of an organism's natural activities use and misuse. Lamarckism is illustrated through an giraffe's neck stretching to reach higher levels of leaves in the trees. This could cause giraffes to give their longer necks to offspring, who then get taller.
Lamarck was a French zoologist and, in his lecture to begin his course on invertebrate Zoology at the Museum of Natural History in Paris on the 17th of May in 1802, he presented a groundbreaking concept that radically challenged the previous understanding of 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 his reputation is widely regarded as having given the subject its first broad and comprehensive treatment.
The predominant story is that Charles Darwin's theory of evolution by natural selection and Lamarckism were rivals in the 19th Century. Darwinism eventually prevailed and led to what biologists call the Modern Synthesis. The theory argues that acquired traits are passed down from generation to generation and instead argues organisms evolve by the influence of environment factors, such as Natural Selection.
Lamarck and his contemporaries endorsed the notion that acquired characters could be passed on to future generations. However, this notion was never a major part of any of their evolutionary theories. This is partly because it was never scientifically validated.
But it is now more than 200 years since Lamarck was born and in the age of genomics, there is a large body of evidence supporting the heritability of acquired characteristics. This is also known as "neo Lamarckism", or more often epigenetic inheritance. This is a version that is as reliable as the popular neodarwinian model.
Evolution through adaptation
One of the most widespread misconceptions about evolution is that it is a result of a kind of struggle for survival. This notion is not true and ignores other forces driving evolution. The fight for survival can be better described as a fight to survive in a specific environment. This can be a challenge for not just other living things but also the physical environment itself.
To understand how evolution functions, it is helpful to think about what adaptation is. It is a feature that allows a living thing to survive in its environment and reproduce. It could be a physical structure such as feathers or fur. Or it can be a characteristic of behavior such as moving to the shade during hot weather, or coming out to avoid the cold at night.
The capacity 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 must have the right genes to generate offspring, and it must be able to find sufficient food and other resources. Moreover, the organism must be able to reproduce itself in a way that is optimally within its environment.
These factors, together with gene flow and mutations can cause a shift in the proportion of different alleles within a population’s gene pool. This shift in the frequency of alleles can result in the emergence of new traits and eventually, new species as time passes.
Many of the characteristics we admire about animals and plants are adaptations, like the lungs or gills that extract oxygen from the air, fur or feathers to protect themselves, long legs for running away from predators and camouflage to hide. However, a proper understanding of adaptation requires a keen eye to the distinction between the physiological and behavioral characteristics.
Physiological adaptations like thick fur or gills are physical characteristics, whereas behavioral adaptations, such as the tendency to seek out companions or to move into the shade in hot weather, aren't. In addition it is important to understand that a lack of forethought does not make something an adaptation. In fact, failing to think about the consequences of a behavior can make it unadaptable, despite the fact that it appears to be logical or even necessary.