전체검색

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

The Academy's Evolution Site

Biological evolution is one of the most important concepts in biology. The Academies are committed to helping those who are interested in science learn about the theory of evolution and how it can be applied in all areas of scientific research.

This site provides students, teachers and general readers with a variety of educational resources on evolution. It contains key video clips from NOVA and WGBH produced science programs on DVD.

Tree of Life

The Tree of Life, an ancient symbol, symbolizes the interconnectedness of all life. It is used in many religions and cultures as a symbol of unity and love. It also has many practical applications, such as providing a framework to understand the evolution of species and how they react to changes in the environment.

Early approaches to depicting the biological world focused on categorizing species into distinct categories that had been distinguished by physical and metabolic characteristics1. These methods, based on sampling of different parts of living organisms or sequences of small fragments of their DNA greatly increased the variety of organisms that could be represented in the tree of life2. However these trees are mainly comprised of eukaryotes, and bacterial diversity remains vastly underrepresented3,4.

By avoiding the need for direct observation and experimentation genetic techniques have enabled us to represent the Tree of Life in a more precise way. Particularly, molecular methods allow us to build trees by using sequenced markers like the small subunit ribosomal RNA gene.

Despite the massive expansion of the Tree of Life through genome sequencing, much biodiversity still awaits discovery. This is especially true of microorganisms that are difficult to cultivate and are typically only represented in a single specimen5. Recent analysis of all genomes resulted in an unfinished draft of a Tree of Life. This includes a wide range of archaea, bacteria, and other organisms that haven't yet been identified or whose diversity has not been fully understood6.

The expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, helping to determine whether specific habitats require special protection. This information can be utilized in a variety of ways, from identifying the most effective remedies to fight diseases to enhancing the quality of the quality of crops. The information is also incredibly valuable in conservation efforts. It can aid biologists in identifying the areas most likely to contain cryptic species with potentially significant metabolic functions that could be vulnerable to anthropogenic change. While funds to protect biodiversity are essential, the best method to protect the world's biodiversity is to empower more people in developing countries with the necessary knowledge to take action locally and encourage conservation.

Phylogeny

A phylogeny, also called an evolutionary tree, 에볼루션바카라사이트 shows the relationships between various groups of organisms. By using molecular information, morphological similarities and differences, or ontogeny (the process of the development of an organism) scientists can construct a phylogenetic tree that illustrates the evolution of taxonomic groups. Phylogeny is essential in understanding the evolution of biodiversity, evolution and genetics.

A basic phylogenetic tree (see Figure PageIndex 10 Determines the relationship between organisms that have similar traits and evolved from an ancestor 에볼루션카지노사이트 (look here) that shared traits. These shared traits can be analogous, or homologous. Homologous traits are identical in their evolutionary origins and analogous traits appear similar, but do not share the same ancestors. Scientists put similar traits into a grouping called a clade. For instance, all the organisms in a clade have the characteristic of having amniotic eggs and evolved from a common ancestor that had these eggs. A phylogenetic tree is then constructed by connecting clades to identify the species that are most closely related to each other.

Scientists utilize DNA or RNA molecular information to build a phylogenetic chart that is more precise and detailed. This information is more precise than morphological information and provides evidence of the evolution history of an organism or group. Researchers can use Molecular Data to estimate the evolutionary age of living organisms and discover how many organisms have a common ancestor.

The phylogenetic relationships of a species can be affected by a variety of factors, including the phenomenon of phenotypicplasticity. This is a kind of behavior that alters due to particular environmental conditions. This can cause a trait to appear more similar to a species than to another, obscuring the phylogenetic signals. This problem can be addressed by using cladistics, which is a an amalgamation of analogous and homologous features in the tree.

In addition, phylogenetics can help predict the time and [Redirect-302] pace of speciation. This information will assist conservation biologists in making choices about which species to save from the threat of extinction. In the end, it's the conservation of phylogenetic diversity which will create an ecosystem that is balanced and complete.

Evolutionary Theory

The central theme of evolution is that organisms develop different features over time based on their interactions with their surroundings. Many theories of evolution have been developed by a variety of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop slowly according to its needs as well as the Swedish botanist Carolus Linnaeus (1707-1778) who designed modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits cause changes that can be passed on to the offspring.

In the 1930s and 1940s, ideas from a variety of fields -- including genetics, natural selection and particulate inheritance - came together to create the modern synthesis of evolutionary theory that explains how evolution happens through the variation of genes within a population, and how these variants change in time as a result of natural selection. This model, which incorporates genetic drift, mutations in gene flow, and sexual selection is mathematically described.

Recent advances in evolutionary developmental biology have shown how variation can be introduced to a species through mutations, genetic drift, reshuffling genes during sexual reproduction, and even migration between populations. These processes, as well as others, such as directional selection and gene erosion (changes in frequency of genotypes over time), can lead towards evolution. Evolution is defined as changes in the genome over time and changes in the phenotype (the expression of genotypes in individuals).

Students can gain a better understanding of the concept of phylogeny by using evolutionary thinking in all aspects of biology. A recent study by Grunspan and colleagues, 무료 에볼루션 for example demonstrated that teaching about the evidence that supports evolution helped students accept the concept of evolution in a college biology course. For 에볼루션 코리아 more information on how to teach about evolution, please read The Evolutionary Potential of all Areas of Biology and Thinking Evolutionarily: A Framework for Infusing the Concept of Evolution into Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution by looking back--analyzing fossils, comparing species and studying living organisms. But evolution isn't just something that happened in the past, it's an ongoing process taking place today. Bacteria evolve and resist antibiotics, viruses evolve and are able to evade new medications, 에볼루션 무료 바카라 and animals adapt their behavior in response to a changing planet. The results are often visible.

It wasn't until the late 1980s that biologists began to realize that natural selection was also at work. The key is that different characteristics result in different rates of survival and reproduction (differential fitness) and can be passed down from one generation to the next.

In the past, if a certain allele - the genetic sequence that determines colour was found in a group of organisms that interbred, it might become more prevalent than any other allele. Over time, this would mean that the number of moths with black pigmentation may 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 much easier when a species has a rapid generation turnover like bacteria. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. coli that descended from a single strain. samples of each population are taken every day and over 500.000 generations have passed.

Lenski's research has demonstrated that mutations can alter the rate at which change occurs and the rate at which a population reproduces. It also demonstrates that evolution takes time, which is difficult for some to accept.

Another example of microevolution is the way mosquito genes that are resistant to pesticides show up more often in areas in which insecticides are utilized. This is due to pesticides causing an exclusive pressure that favors individuals who have resistant genotypes.

The rapidity of evolution has led to a greater recognition of its importance particularly in a world shaped largely by human activity. This includes pollution, climate change, and habitat loss that hinders many species from adapting. Understanding the evolution process will help us make better decisions regarding the future of our planet as well as the life of its inhabitants.