Technology Is Making Evolution Site Better Or Worse? > 자유게시판

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

The Academy's Evolution Site

Biological evolution is a central concept in biology. The Academies have long been involved in helping people who are interested in science comprehend the theory of evolution and how it influences every area of scientific inquiry.

This site provides students, teachers and general readers with a wide range of educational resources on evolution. It contains key video clips from NOVA and the 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 an emblem of love and unity across many cultures. It has numerous practical applications as well, including providing a framework to understand the evolution of species and how they react to changes in environmental conditions.

Early attempts to represent the biological world were built on categorizing organisms based on their physical and metabolic characteristics. These methods, which rely on sampling of different parts of living organisms or on small DNA fragments, greatly increased the variety of organisms that could be included in the tree of life2. However the trees are mostly comprised of eukaryotes, and bacterial diversity remains vastly underrepresented3,4.

Genetic techniques have significantly expanded our ability to represent the Tree of Life by circumventing the requirement for direct observation and experimentation. Particularly, molecular methods allow us to construct trees using sequenced markers such as the small subunit ribosomal RNA gene.

The Tree of Life has been significantly expanded by genome sequencing. However there is a lot of biodiversity to be discovered. This is particularly relevant to microorganisms that are difficult to cultivate, and are usually found in one sample5. A recent analysis of all genomes produced an initial draft of the Tree of Life. This includes a variety of bacteria, archaea and other organisms that have not yet been isolated or the diversity of which is not fully understood6.

The expanded Tree of Life is particularly useful for assessing the biodiversity of an area, assisting to determine if specific habitats require protection. The information is useful in a variety of ways, including finding new drugs, fighting diseases and improving crops. It is also useful in conservation efforts. It can help biologists identify areas that are likely to have cryptic species, which could have important metabolic functions, and could be susceptible to changes caused by humans. While funds to protect biodiversity are essential but the most effective way to protect the world's biodiversity is for more people in developing countries to be empowered with the knowledge to act locally to promote conservation from within.

Phylogeny

A phylogeny (also called an evolutionary tree) illustrates the relationship between different organisms. Scientists can build a phylogenetic chart that shows the evolutionary relationships between taxonomic categories using molecular information and morphological similarities or differences. Phylogeny is essential in understanding evolution, biodiversity and genetics.

A basic phylogenetic Tree (see Figure PageIndex 10 Determines the relationship between organisms that have similar traits and have evolved from a common ancestor. These shared traits can be analogous, or homologous. Homologous traits share their underlying evolutionary path, while analogous traits look like they do, but don't have the same ancestors. Scientists group similar traits into a grouping called a clade. All members of a clade have a common characteristic, 에볼루션 for example, amniotic egg production. They all evolved from an ancestor that had these eggs. The clades are then connected to form a phylogenetic branch that can determine the organisms with the closest relationship.

Scientists use molecular DNA or RNA data to create a phylogenetic chart that is more precise and detailed. This data is more precise than the morphological data and provides evidence of the evolution history of an individual or 에볼루션 group. Molecular data allows researchers to determine the number of organisms that have an ancestor common to them and estimate their evolutionary age.

The phylogenetic relationships of organisms can be influenced by several factors, including phenotypic flexibility, a type of behavior that alters in response to specific environmental conditions. This can cause a trait to 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 combine similar and homologous traits into the tree.

Furthermore, phylogenetics may help predict the duration and rate of speciation. This information can aid conservation biologists to decide which species they should protect from extinction. In the end, it's the conservation of phylogenetic variety that will lead to an ecosystem that is complete and balanced.

Evolutionary Theory

The main idea behind evolution is that organisms develop various characteristics over time due to their interactions with their environment. Several theories of evolutionary change have been proposed by a wide 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, the Swedish botanist Carolus Linnaeus (1707-1778) who developed modern hierarchical taxonomy, and 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 and 1940s, ideas from a variety of fields--including genetics, natural selection, and particulate inheritance - came together to form the modern evolutionary theory synthesis, which defines how evolution happens through the variation of genes within a population, and how those variations change over time as a result of natural selection. This model, 에볼루션바카라사이트 known as genetic drift, mutation, gene flow and sexual selection, is a cornerstone of modern evolutionary biology and is mathematically described.

Recent discoveries in the field of evolutionary developmental biology have revealed that variations can be introduced into a species via genetic drift, 에볼루션 코리아 mutation, and reshuffling of genes in sexual reproduction, as well as through migration between populations. These processes, along with others like directional selection and genetic erosion (changes in the frequency of a genotype over time), can lead to evolution that is defined as changes in the genome of the species over time, and also by changes in phenotype as time passes (the expression of that genotype within the individual).

Students can gain a better understanding of phylogeny by incorporating evolutionary thinking into all aspects of biology. In a study by Grunspan et al. It was demonstrated that teaching students about the evidence for evolution boosted their acceptance of evolution during an undergraduate biology course. For more details on how to teach evolution look up The Evolutionary Potential in All Areas of Biology or Thinking Evolutionarily A Framework for Integrating Evolution into Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution through looking back, studying fossils, comparing species, and observing living organisms. However, evolution isn't something that occurred in the past. It's an ongoing process, that is taking place today. Bacteria mutate and resist antibiotics, viruses evolve and elude new medications and animals change their behavior 에볼루션 바카라사이트 to the changing climate. The changes that result are often visible.

It wasn't until late 1980s that biologists began realize that natural selection was in action. The main reason is that different traits result in a different rate of survival as well as reproduction, and may be passed down from generation to generation.

In the past, if an allele - the genetic sequence that determines colour was found in a group of organisms that interbred, it could be more common than any other allele. As time passes, this could mean that the number of moths sporting black pigmentation in a population may increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

Observing evolutionary change in action is easier when a particular species has a rapid turnover of its generation such as bacteria. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that are descended from a single strain. Samples of each population have been taken regularly and more than 500.000 generations of E.coli have passed.

Lenski's research has revealed that a mutation can profoundly alter the speed at the rate at which a population reproduces, and consequently, the rate at which it changes. It also shows that evolution takes time, which is hard for some to accept.

Another example of microevolution is how mosquito genes that are resistant to pesticides show up more often in areas where insecticides are employed. This is due to the fact that the use of pesticides creates a pressure that favors individuals who have resistant genotypes.

The rapidity of evolution has led to an increasing recognition of its importance especially in a planet that is largely shaped by human activity. This includes climate change, pollution, and habitat loss that prevents many species from adapting. Understanding the evolution process will help us make better choices about the future of our planet, as well as the lives of its inhabitants.