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 creation of new species and change in appearance of existing ones.
This has been proven by many examples such as the stickleback fish species that can thrive in fresh or saltwater and walking stick insect species that have a preference for particular host plants. These mostly reversible trait permutations however, are not able to explain fundamental changes in body plans.
Evolution by Natural Selection
Scientists have been fascinated by the development of all the living creatures that inhabit our planet for ages. The best-established explanation is Darwin's natural selection process, an evolutionary process that occurs when individuals that are better adapted survive and reproduce more effectively than those that are less well-adapted. Over time, a community of well adapted individuals grows and eventually becomes a new species.
Natural selection is an ongoing process and involves the interaction of three factors that are: reproduction, variation and inheritance. Mutation and sexual reproduction increase the genetic diversity of a species. Inheritance refers to the transmission of a person’s genetic traits, which include both dominant and recessive genes and their offspring. Reproduction is the process of producing fertile, viable offspring which includes both asexual and sexual methods.
All of these factors have to be in equilibrium to allow natural selection to take place. For example, if a dominant allele at one gene causes an organism to survive and reproduce more frequently than the recessive one, the dominant allele will become more common within the population. But if the allele confers a disadvantage in survival or decreases fertility, it will disappear from the population. This process is self-reinforcing meaning that a species with a beneficial characteristic can reproduce and survive longer than an individual with an inadaptive characteristic. The higher the level of fitness an organism has, measured by its ability reproduce and survive, is the greater number of offspring it can produce. People with desirable characteristics, like longer necks in giraffes or bright white patterns of color in male peacocks are more likely to be able to survive and create offspring, and thus will eventually make up the majority of the population over time.
Natural selection only acts on populations, not individuals. This is a major distinction from the Lamarckian theory of evolution which states that animals acquire characteristics through use or neglect. For instance, if the animal's neck is lengthened by stretching to reach for prey, its offspring will inherit a more long neck. The differences in neck length between generations will continue until the giraffe's neck gets too long that it can no longer breed with other giraffes.
Evolution through Genetic Drift
In genetic drift, the alleles at a gene may attain different frequencies within a population through random events. In the end, one will reach fixation (become so common that it cannot be eliminated by natural selection), while the other alleles drop to lower frequencies. In extreme cases, this leads to a single allele dominance. The other alleles are basically eliminated and heterozygosity has diminished to zero. In a small number of people, this could lead to the total elimination of recessive allele. This is known as the bottleneck effect and is typical of the evolutionary process that occurs when a large number individuals migrate to form a group.
A phenotypic bottleneck may also occur when the survivors of a catastrophe like an outbreak or mass hunt incident are concentrated in an area of a limited size. The survivors will have a dominant allele and thus will have the same phenotype. This may be the result of a war, an earthquake or even a cholera outbreak. The genetically distinct population, if it is left susceptible to genetic drift.
Walsh Lewens, Walsh, and Ariew define drift as a deviation from the expected value due to differences in fitness. They provide the famous case of twins who 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 can be very important in the evolution of an entire species. It is not the only method for evolution. 에볼루션 바카라 무료체험 is a process known as natural selection, in which phenotypic variation in the population is maintained through mutation and migration.
Stephens asserts that there is a significant distinction between treating drift as an actual cause or force, and considering other causes, such as migration and selection as causes and forces. He claims that a causal process explanation of drift permits us to differentiate it from other forces, and that this distinction is essential. He also argues that drift has a direction: that is it tends to reduce heterozygosity. extra resources has a magnitude, which is determined by the size of the population.
Evolution through Lamarckism
Students of biology in high school are often exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution is generally referred to as "Lamarckism" and it asserts that simple organisms evolve into more complex organisms by the inheritance of characteristics that are a result of the organism's natural actions, use and disuse. Lamarckism can be demonstrated by an giraffe's neck stretching to reach higher levels of leaves in the trees. This process would result in giraffes passing on their longer necks to their offspring, which then get taller.
Lamarck, a French zoologist, presented an innovative idea in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged previous thinking on organic transformation. According Lamarck, living organisms evolved from inanimate materials by a series of gradual steps. Lamarck wasn't the first to make this claim but he was thought of as the first to offer the subject a thorough and general explanation.
The prevailing story is that Lamarckism grew into a rival to Charles Darwin's theory of evolution through natural selection, and that the two theories fought each other in the 19th century. Darwinism eventually prevailed and led to the creation of what biologists today refer to as the Modern Synthesis. The theory argues the possibility that acquired traits can be inherited and instead suggests that organisms evolve through the action of environmental factors, like natural selection.
Lamarck and his contemporaries believed in the idea that acquired characters could be passed down to future generations. However, this concept was never a central part of any of their evolutionary theories. This is due in part to the fact that it was never validated scientifically.
But it is now more than 200 years since Lamarck was born and, in the age of genomics, there is a large amount of evidence that supports the heritability of acquired characteristics. This is referred to as "neo Lamarckism", or more commonly epigenetic inheritance. This is a model that is as valid as the popular neodarwinian model.
Evolution through adaptation
One of the most popular misconceptions about evolution is that it is a result of a kind of struggle for survival. This view is inaccurate and overlooks other forces that drive evolution. The struggle for survival is more precisely described as a fight to survive within a particular environment, which could be a struggle that involves not only other organisms, but also the physical environment itself.
Understanding how adaptation works is essential to understand evolution. The term "adaptation" refers to any specific characteristic that allows an organism to survive and reproduce within its environment. It can be a physical structure, like fur or feathers. Or it can be a behavior trait such as moving to the shade during hot weather, or moving out to avoid the cold at night.
An organism's survival depends on its ability to extract energy from the surrounding environment and interact with other organisms and their physical environments. The organism must have the right genes to create offspring, and it should be able to locate sufficient food and other resources. The organism should also be able to reproduce itself at an amount that is appropriate for its particular niche.
These elements, in conjunction with mutation and gene flow, lead to changes in the ratio of alleles (different types of a gene) in the gene pool of a population. This change in allele frequency can result in the emergence of novel traits and eventually, new species over time.
A lot of the traits 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 to hide. To understand the concept of adaptation it is crucial to discern between physiological and behavioral characteristics.
Physiological adaptations, such as the thick fur or gills are physical traits, whereas behavioral adaptations, such as the desire to find friends or to move to shade in hot weather, aren't. In addition it is important to understand that lack of planning does not make something an adaptation. In 에볼루션 바카라 무료 , failing to think about the implications of a choice can render it unadaptive despite the fact that it may appear to be logical or even necessary.