Are You Getting The Most Of Your Evolution Site? > 자유게시판

The Academy's Evolution Site

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

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

Tree of Life

The Tree of Life, an ancient symbol, represents the interconnectedness of all life. It is an emblem of love and harmony in a variety of cultures. It also has practical applications, like providing a framework for understanding the evolution of species and how they respond to changes in the environment.

Early approaches to depicting the biological world focused on the classification of organisms into distinct categories which were identified by their physical and metabolic characteristics1. These methods, 바카라 에볼루션 based on sampling of different parts of living organisms or small fragments of their DNA, significantly increased the variety that could be included in a tree of life2. These trees are mostly populated of eukaryotes, 에볼루션코리아 while the diversity of bacterial species is greatly underrepresented3,4.

By avoiding the necessity for 에볼루션 바카라 사이트 direct experimentation and observation, genetic techniques have made it possible to represent the Tree of Life in a more precise way. We can construct trees using molecular methods, 에볼루션 룰렛 such as the small-subunit ribosomal gene.

Despite the rapid expansion of the Tree of Life through genome sequencing, a large amount of biodiversity awaits discovery. This is particularly true of microorganisms, which are difficult to cultivate and are typically only represented in a single specimen5. A recent analysis of all genomes that are known has created a rough draft of the Tree of Life, including many archaea and bacteria that have not been isolated, and whose diversity is poorly understood6.

This expanded Tree of Life can be used to assess the biodiversity of a particular area and determine if particular habitats need special protection. The information can be used in a variety of ways, from identifying the most effective treatments to fight disease to enhancing the quality of crops. This information is also useful to conservation efforts. It can aid biologists in identifying those areas that are most likely contain cryptic species with important metabolic functions that may be at risk of anthropogenic changes. While conservation funds are important, the best method to protect the world's biodiversity is to empower the people of developing nations with the information they require to act locally and support conservation.

Phylogeny

A phylogeny (also known as an evolutionary tree) shows the relationships between species. Using molecular data similarities and differences in morphology or ontogeny (the course of development of an organism) scientists can create a phylogenetic tree which illustrates the evolutionary relationships between taxonomic categories. Phylogeny is crucial in understanding biodiversity, evolution and genetics.

A basic phylogenetic tree (see Figure PageIndex 10 ) determines the relationship between organisms that share similar traits that evolved from common ancestors. These shared traits can be analogous or homologous. Homologous traits are the same in terms of their evolutionary path. Analogous traits could appear similar however they do not have the same ancestry. Scientists group similar traits into a grouping known as a the clade. For instance, all the species in a clade have the characteristic of having amniotic eggs and evolved from a common ancestor who had these eggs. A phylogenetic tree can be constructed by connecting clades to identify the species which are the closest to each other.

Scientists make use of molecular DNA or RNA data to construct a phylogenetic graph that is more accurate and precise. This data is more precise than morphological data and gives evidence of the evolutionary history of an individual or group. The analysis of molecular data can help researchers determine the number of organisms that have an ancestor common to them and estimate their evolutionary age.

The phylogenetic relationships of a species can be affected by a variety of factors, including phenotypicplasticity. This is a kind of behaviour that can change as a result of particular environmental conditions. This can cause a particular trait to appear more like a species other species, which can obscure the phylogenetic signal. This problem can be addressed by using cladistics. This is a method that incorporates a combination of analogous and homologous features in the tree.

Additionally, phylogenetics can aid in predicting the duration and rate of speciation. This information can aid conservation biologists to decide which species they should protect from extinction. Ultimately, it is the preservation of phylogenetic diversity which will result in an ecosystem that is complete and balanced.

Evolutionary Theory

The central theme in evolution is that organisms change over time as a result of their interactions with their environment. Many scientists have developed 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 as well as the Swedish taxonomist Carolus Linnaeus (1707-1778), who created 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, ideas from a variety of fields -- including natural selection, genetics, and particulate inheritance - came together to form the modern evolutionary theory synthesis, which defines how evolution occurs through the variations of genes within a population, and how those variations change in time as a result of natural selection. This model, called genetic drift or mutation, gene flow and sexual selection, is the foundation of current evolutionary biology, and can be mathematically explained.

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

Incorporating evolutionary thinking into all areas of biology education can increase students' understanding of phylogeny as well as evolution. In a recent study by Grunspan and co. It was found that teaching students about the evidence for evolution boosted their understanding of evolution in a college-level course in biology. For more information on how to teach about evolution, read The Evolutionary Potential of 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 studying fossils, comparing species, and observing living organisms. But evolution isn't just something that occurred in the past; it's an ongoing process happening today. The virus reinvents itself to avoid new drugs and bacteria evolve to resist antibiotics. Animals adapt their behavior in the wake of the changing environment. The resulting changes are often easy to see.

It wasn't until the late 1980s that biologists began realize that natural selection was also in play. The key is the fact that different traits result in a different rate of survival and reproduction, and can be passed down 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 prevalent than all other alleles. In time, 에볼루션 사이트 this could mean that the number of moths with black pigmentation in a group 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 easier when a particular species has a rapid turnover of its generation such as bacteria. Since 1988, biologist Richard Lenski has been tracking twelve populations of E. Coli that descended from a single strain; samples of each population are taken on a regular basis and more than fifty thousand generations have passed.

Lenski's work has shown that mutations can alter the rate of change and the effectiveness of a population's reproduction. It also proves that evolution takes time--a fact that many find difficult to accept.

Microevolution can be observed in the fact that mosquito genes for pesticide resistance are more common in populations where insecticides have been used. That's because the use of pesticides creates a selective pressure that favors individuals with resistant genotypes.

The speed of evolution taking place has led to an increasing appreciation of its importance in a world shaped by human activity--including climate change, pollution and the loss of habitats that prevent many species from adjusting. Understanding evolution can help us make better choices about the future of our planet and the lives of its inhabitants.