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

The Academy's Evolution Site

The concept of biological evolution is among the most fundamental concepts in biology. The Academies are involved in helping those who are interested in science learn about the theory of evolution and how it is incorporated across all areas of scientific research.

This site offers a variety of tools for teachers, students and general readers of evolution. It includes key video clip from NOVA and WGBH produced science programs on DVD.

Tree of Life

The Tree of Life, an ancient symbol, represents the interconnectedness of all life. It is a symbol of love and unity in many cultures. It has numerous practical applications as well, including providing a framework to understand the history of species, and 에볼루션 룰렛 how they respond to changing environmental conditions.

Early approaches to depicting the biological world focused on separating species into distinct categories that were identified by their physical and metabolic characteristics1. These methods, which rely on the sampling of different parts of living organisms or on sequences of short fragments of their DNA, significantly increased the variety that could be included in the tree of life2. However, these trees are largely made up of eukaryotes. Bacterial diversity is not represented in a large way3,4.

By avoiding the need for direct observation and experimentation, genetic techniques have made it possible to represent the Tree of Life in a more precise manner. In particular, molecular methods enable us to create trees by using sequenced markers like the small subunit ribosomal gene.

The Tree of Life has been significantly expanded by genome sequencing. However there is a lot of diversity to be discovered. This is especially true of microorganisms, which are difficult to cultivate and are typically only present in a single specimen5. A recent study of all genomes known to date has produced a rough draft of the Tree of Life, including many bacteria and archaea that are not isolated and whose diversity is poorly understood6.

This expanded Tree of Life can be used to determine the diversity of a particular area and determine if particular habitats require special protection. The information is useful in a variety of ways, such as finding new drugs, fighting diseases and improving the quality of crops. The information is also useful for conservation efforts. It can help biologists identify areas most likely to be home to cryptic species, which may have vital metabolic functions and are susceptible to changes caused by humans. Although funding to protect biodiversity are essential however, the most effective method to ensure the preservation of biodiversity around the world is for more people in developing countries to be empowered with the necessary knowledge to act locally to promote conservation from within.

Phylogeny

A phylogeny is also known as an evolutionary tree, reveals the relationships between various groups of organisms. Scientists can construct an phylogenetic chart which shows the evolutionary relationship of taxonomic groups using molecular data and morphological similarities or differences. The phylogeny of a tree plays an important role in understanding genetics, biodiversity and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 ) identifies the relationships between organisms that share similar traits that evolved from common ancestral. These shared traits can be analogous, or homologous. Homologous characteristics are identical in their evolutionary journey. Analogous traits might appear similar, but they do not share the same origins. Scientists arrange similar traits into a grouping called a clade. For example, all of the organisms that make up a clade share the trait of having amniotic eggs and evolved from a common ancestor which had eggs. A phylogenetic tree can be built by connecting the clades to determine the organisms that are most closely related to each other.

For a more detailed and accurate phylogenetic tree scientists make use of molecular data from DNA or RNA to determine the connections between organisms. This information is more precise than morphological information and provides evidence of the evolutionary background of an organism or group. Researchers can utilize Molecular Data to determine the evolutionary age of organisms and identify the number of organisms that share an ancestor common to all.

The phylogenetic relationships of a species can be affected by a number of factors such as the phenotypic plasticity. This is a kind of behavior that alters as a result of unique environmental conditions. This can make a trait appear more similar to one species than another, obscuring the phylogenetic signals. However, this issue can be cured by the use of methods such as cladistics that incorporate a combination of homologous and analogous features into the tree.

Furthermore, phylogenetics may help predict the time and pace of speciation. This information can assist conservation biologists decide which species they should protect from extinction. In the end, it is the preservation of phylogenetic diversity that will lead to an ecosystem that is complete and balanced.

Evolutionary Theory

The main idea behind evolution is that organisms change over time as a result of their interactions with their environment. Many scientists have proposed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism would evolve according to its individual requirements as well as the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical system of taxonomy and Jean-Baptiste Lamarck (1844-1829), who suggested that the usage or non-use of traits can lead to changes that are passed on to the

In the 1930s and 1940s, concepts from a variety of fields--including genetics, natural selection, and particulate inheritance -- came together to form the modern synthesis of evolutionary theory that explains how evolution occurs through the variations of genes within a population, and how those variations change in time due to natural selection. This model, which is known as genetic drift or mutation, gene flow and sexual selection, is a cornerstone of the current evolutionary biology and can be mathematically explained.

Recent developments in the field of evolutionary developmental biology have shown that genetic variation can be introduced into a species through mutation, genetic drift, and reshuffling of genes during sexual reproduction, and 에볼루션 바카라 체험 also by migration between populations. These processes, along with others, such as directional selection and gene erosion (changes in the frequency of genotypes over time) can lead to evolution. Evolution is defined as changes in the genome over time and changes in the phenotype (the expression of genotypes within individuals).

Students can gain a better understanding of the concept of phylogeny through incorporating evolutionary thinking throughout all aspects of biology. In a study by Grunspan and co. It was found that teaching students about the evidence for 무료 에볼루션 evolution boosted their acceptance of evolution during a college-level course in biology. To learn more about how to teach about evolution, see The Evolutionary Potential of All Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Scientists have studied evolution by looking in the past--analyzing fossils and comparing species. They also study living organisms. Evolution is not a past moment; it is an ongoing process that continues to be observed today. Viruses evolve to stay away from new drugs and bacteria evolve to resist antibiotics. Animals alter their behavior in the wake of a changing world. The results are often evident.

It wasn't until the 1980s that biologists began realize that natural selection was also at work. The reason is that different traits confer different rates of survival and 에볼루션 블랙잭 (just click the next post) reproduction (differential fitness) and can be transferred 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 could quickly become more common than other alleles. As time passes, this could mean that the number of moths that have black pigmentation in a population could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

Monitoring evolutionary changes in action is easier when a particular species has a rapid generation turnover such as bacteria. Since 1988 biologist Richard Lenski has been tracking twelve populations of E. coli that descended from a single strain; samples from each population are taken every day, and over fifty thousand generations have passed.

Lenski's work has demonstrated that a mutation can profoundly alter the rate at which a population reproduces--and so the rate at which it alters. It also proves that evolution is slow-moving, a fact that many are unable to accept.

Microevolution can be observed in the fact that mosquito genes for pesticide resistance are more prevalent in areas where insecticides have been used. This is due to the fact that the use of pesticides creates a selective pressure that favors those who have resistant genotypes.

The rapidity of evolution has led to a greater appreciation of its importance especially in a planet which is largely shaped by human activities. This includes pollution, climate change, and habitat loss that hinders many species from adapting. Understanding the evolution process can assist you in making better choices about the future of the planet and its inhabitants.