• 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 involved in helping those interested in science learn about the theory of evolution and how it is incorporated throughout all fields of scientific research.

This site provides teachers, students and general readers with a variety of learning resources about evolution. It includes important 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 is used in many spiritual traditions and cultures as symbolizing unity and love. It has many practical applications as well, such as providing a framework to understand the evolution of species and how they respond to changing environmental conditions.

The first attempts to depict the biological world were based on categorizing organisms based on their physical and metabolic characteristics. These methods, based on the sampling of various parts of living organisms or on short fragments of their DNA greatly increased the variety of organisms that could be included in a tree of life2. However, these trees are largely made up of eukaryotes. Bacterial diversity remains vastly underrepresented3,4.

By avoiding the need for direct observation and experimentation, genetic techniques have allowed us to represent the Tree of Life in a much more accurate way. Particularly, molecular techniques allow us to build trees by using sequenced markers such as the small subunit ribosomal gene.

The Tree of Life has been dramatically expanded through genome sequencing. However there is still a lot of diversity to be discovered. This is particularly true of microorganisms, which can be difficult to cultivate and are usually only found in a single sample5. A 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 isolated or whose diversity has not been thoroughly understood6.

This expanded Tree of Life can be used to evaluate the biodiversity of a particular area and determine if particular habitats require special protection. The information can be used in a variety of ways, 에볼루션 바카라 사이트 (Click4r.com) from identifying new treatments to fight disease to enhancing the quality of crops. It is also beneficial in conservation efforts. It helps biologists determine the areas that are most likely to contain cryptic species with potentially important metabolic functions that could be at risk from anthropogenic change. Although funds to safeguard biodiversity are vital, ultimately the best way 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 in order to promote conservation from within.

Phylogeny

A phylogeny, also called an evolutionary tree, illustrates the connections between groups of organisms. By using molecular information, morphological similarities and differences or ontogeny (the process of the development of an organism) scientists can create an phylogenetic tree that demonstrates the evolutionary relationship between taxonomic categories. The phylogeny of a tree plays an important role in understanding the relationship between genetics, biodiversity and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms with similar traits that have evolved from common ancestral. These shared traits may be analogous or homologous. Homologous traits are identical in their underlying evolutionary path and analogous traits appear similar, but do not share the same origins. Scientists put similar traits into a grouping referred to as a Clade. For example, all of the organisms that make up a clade share the characteristic of having amniotic eggs. They evolved from a common ancestor that had these eggs. The clades are then linked to form a phylogenetic branch to identify organisms that have the closest relationship to.

Scientists make use of molecular DNA or 에볼루션 바카라사이트 RNA data to construct a phylogenetic graph which is more precise and precise. This information is more precise and provides evidence of the evolution history of an organism. Molecular data allows researchers to determine the number of species that have a common ancestor and to estimate their evolutionary age.

The phylogenetic relationships of a species can be affected by a variety of factors that include the phenotypic plasticity. This is a type of behavior that alters due to particular environmental conditions. This can cause a characteristic to appear more similar to a species than to the other which can obscure the phylogenetic signal. This issue can be cured by using cladistics. This is a method that incorporates a combination of homologous and analogous traits in the tree.

In addition, phylogenetics can help predict the length and speed of speciation. This information will assist conservation biologists in deciding which species to save from the threat of extinction. Ultimately, it is the preservation of phylogenetic diversity which will lead to an ecologically balanced and complete ecosystem.

Evolutionary Theory

The fundamental concept in evolution is that organisms alter over time because of their interactions with their environment. Many scientists have come up with theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism could develop according to its own requirements, the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern hierarchical system of taxonomy as well as Jean-Baptiste Lamarck (1844-1829), who believed that the use or absence of traits can cause 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 create the modern synthesis of evolutionary theory, which defines how evolution happens through the variations of genes within a population, and how these variants change in time due to natural selection. This model, known as genetic drift or mutation, gene flow and sexual selection, is the foundation of the current evolutionary biology and can be mathematically described.

Recent discoveries in the field of evolutionary developmental biology have revealed that variations can be introduced into a species through mutation, genetic drift, and reshuffling of genes during sexual reproduction, 에볼루션사이트 and also through the movement of populations. These processes, in conjunction with others such as the directional selection process and the erosion of genes (changes to the frequency of genotypes over time) can result in evolution. Evolution is defined by changes in the genome over time, as well as changes in phenotype (the expression of genotypes in individuals).

Incorporating evolutionary thinking into all aspects of biology education can improve student understanding of the concepts of phylogeny and evolution. A recent study conducted by Grunspan and 에볼루션 바카라 colleagues, for example, showed that teaching about the evidence supporting evolution increased students' acceptance of evolution in a college-level biology course. To find out more about how to teach about evolution, please read The Evolutionary Potential in all Areas of Biology and Thinking Evolutionarily: A Framework for Infusing Evolution in Life Sciences Education.

Evolution in Action

Traditionally scientists have studied evolution through looking back, studying fossils, comparing species and observing living organisms. Evolution is not a distant event, but an ongoing process that continues to be observed today. Bacteria mutate and resist antibiotics, viruses reinvent themselves and escape new drugs and animals change their behavior in response to a changing planet. The results are usually visible.

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

In the past, if one particular allele, 에볼루션 카지노 the genetic sequence that determines coloration--appeared in a population of interbreeding species, it could rapidly become more common than the other alleles. Over time, this would mean that the number of moths that have black pigmentation may increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

It is easier to see evolution when the species, 에볼루션 바카라 사이트 like bacteria, has a high generation turnover. Since 1988 biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain; samples of each population are taken every day, and over 500.000 generations have passed.

Lenski's research has revealed that mutations can alter the rate of change and the effectiveness of a population's reproduction. It also shows evolution takes time, something that is difficult for some to accept.

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

The rapid pace at which evolution can take place has led to a growing recognition of its importance in a world shaped by human activity--including climate change, pollution and the loss of habitats that prevent the species from adapting. Understanding evolution will aid you in making better decisions about the future of the planet and its inhabitants.