• 목록
• 답변
• 글쓰기
• 게시판 리스트 옵션
  • 수정
  • 삭제

The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies are committed to helping those who are interested in science to learn about the theory of evolution and how it is incorporated in all areas of scientific research.

This site provides a range of tools for teachers, students and general readers of evolution. It contains key video clips from NOVA and WGBH-produced science programs on DVD.

Tree of Life

The Tree of Life is an ancient symbol that symbolizes the interconnectedness of all life. It appears in many spiritual traditions and cultures as a symbol of unity and love. It has many practical applications as well, including providing a framework for understanding the history of species and how they respond to changes in environmental conditions.

Early attempts to describe the biological world were based on categorizing organisms based on their physical and metabolic characteristics. These methods, which rely on the sampling of different parts of organisms, or fragments of DNA, have significantly increased the diversity of a Tree of Life2. These trees are mostly populated by eukaryotes, and bacteria are largely underrepresented3,4.

Genetic techniques have greatly broadened our ability to depict the Tree of Life by circumventing the requirement for direct observation and 바카라 에볼루션 experimentation. Trees can be constructed using molecular techniques like the small-subunit ribosomal gene.

Despite the rapid growth of the Tree of Life through genome sequencing, much biodiversity still awaits discovery. This is especially relevant to microorganisms that are difficult to cultivate and which are usually only found in a single specimen5. A recent study of all genomes that are known has produced a rough draft version of the Tree of Life, including a large number of bacteria and archaea that have not been isolated, and their diversity is not fully understood6.

The expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, helping to determine if certain habitats require special protection. This information can be utilized in a variety of ways, including finding new drugs, battling diseases and 에볼루션 바카라 사이트바카라사이트 (cameradb.review) enhancing crops. It is also beneficial to conservation efforts. It can aid biologists in identifying areas most likely to have species that are cryptic, which could have important metabolic functions and are susceptible to the effects of human activity. While conservation funds are important, the best method to preserve the biodiversity of the world is to equip more people in developing nations with the information they require to act locally and promote conservation.

Phylogeny

A phylogeny is also known as an evolutionary tree, reveals the connections between groups of organisms. Scientists can construct an phylogenetic chart which shows the evolutionary relationships between taxonomic groups based on molecular data and morphological differences or similarities. Phylogeny is crucial in understanding biodiversity, evolution and genetics.

A basic phylogenetic Tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms with similar traits that evolved from common ancestral. These shared traits can be either homologous or analogous. Homologous traits share their underlying evolutionary path, while analogous traits look similar, but do not share the identical origins. Scientists arrange similar traits into a grouping called a clade. For instance, all of the organisms in a clade share the characteristic of having amniotic eggs and evolved from a common ancestor who had these eggs. A phylogenetic tree is built by connecting the clades to identify the species which are the closest to one another.

For a more detailed and accurate phylogenetic tree scientists use molecular data from DNA or RNA to establish the relationships between organisms. This data is more precise than morphological information and gives evidence of the evolutionary history of an organism or group. The use of molecular data lets researchers determine the number of species that share the same ancestor and estimate their evolutionary age.

The phylogenetic relationship can be affected by a number of factors, including phenotypicplasticity. This is a kind of behavior that changes in response to particular environmental conditions. This can cause a characteristic to appear more similar to one species than another which can obscure the phylogenetic signal. This problem can be addressed by using cladistics, which incorporates an amalgamation of homologous and analogous features in the tree.

Furthermore, phylogenetics may help predict the duration and rate of speciation. This information can aid conservation biologists in making decisions about which species to protect from extinction. In the end, it is the conservation of phylogenetic diversity that will lead to an ecosystem that is balanced and complete.

Evolutionary Theory

The central theme of evolution is that organisms develop various characteristics over time as a result of their interactions with their surroundings. Many theories of evolution have been developed by a variety of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who believed that an organism would evolve slowly according to its requirements and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed modern hierarchical taxonomy, and 에볼루션 바카라 체험 Jean-Baptiste Lamarck (1744-1829) who suggested that the use or misuse of traits cause changes that could be passed onto offspring.

In the 1930s & 1940s, theories from various fields, such as natural selection, genetics & particulate inheritance, came together to form a contemporary evolutionary theory. This defines how evolution is triggered by the variations in genes within the population and how these variations change with time due to natural selection. This model, which encompasses mutations, genetic drift as well as gene flow and sexual selection is mathematically described.

Recent developments in evolutionary developmental biology have revealed how variation can be introduced to a species by mutations, genetic drift or 에볼루션 룰렛 reshuffling of genes in sexual reproduction and the movement between populations. These processes, along with others such as directional selection or genetic erosion (changes in the frequency of an individual's genotype over time) can lead to evolution which is defined by change in the genome of the species over time and the change in phenotype over time (the expression of the genotype in the individual).

Students can gain a better understanding of the concept of phylogeny by using evolutionary thinking in all aspects of biology. In a recent study by Grunspan and co. It was demonstrated that teaching students about the evidence for evolution boosted their understanding of evolution in the course of a college biology. For more information on how to teach evolution look up The Evolutionary Power of Biology in All Areas of Biology or Thinking Evolutionarily: a Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Scientists have looked at evolution through the past, studying fossils, and comparing species. They also observe living organisms. Evolution is not a past event, but an ongoing process. The virus reinvents itself to avoid new drugs and 에볼루션 룰렛 bacteria evolve to resist antibiotics. Animals adapt their behavior because of a changing world. The changes that result are often evident.

It wasn't until late 1980s that biologists realized that natural selection could be observed in action as well. The key is the fact that different traits result in an individual rate of survival and reproduction, and can be passed on from one generation to the next.

In the past, when one particular allele--the genetic sequence that defines color in a group of interbreeding organisms, it might quickly become more common than the other alleles. Over time, this would mean that the number of moths with black pigmentation could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

It is easier to see evolutionary change when a species, such as bacteria, has a high generation turnover. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that are descended from a single strain. Samples of each population have been collected regularly, and more than 50,000 generations of E.coli have been observed to have passed.

Lenski's research has revealed that mutations can drastically alter the efficiency with which a population reproduces--and so, the rate at which it evolves. It also proves that evolution takes time, a fact that some are unable to accept.

Another example of microevolution is that mosquito genes that are resistant to pesticides are more prevalent in areas where insecticides are employed. This is due to pesticides causing an exclusive pressure that favors those with resistant genotypes.

The rapidity of evolution has led to a growing awareness of its significance especially in a planet shaped largely by human activity. This includes pollution, climate change, and habitat loss that hinders many species from adapting. Understanding evolution can help us make smarter decisions about the future of our planet as well as the life of its inhabitants.