The Academy's Evolution Site

Biological evolution is a central concept in biology. The Academies have been active for a long time in helping people who are interested in science understand 에볼루션 코리아 the theory of evolution and how it influences all areas of scientific research.

This site provides students, teachers and general readers with a variety of learning 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, 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 react to changes in environmental conditions.

The first attempts to depict the biological world were founded on categorizing organisms on their metabolic and physical characteristics. These methods rely on the sampling of different parts of organisms or DNA fragments, have greatly increased the diversity of a tree of Life2. However these trees are mainly comprised of eukaryotes, and bacterial diversity is not represented in a large way3,4.

Genetic techniques have greatly expanded our ability to visualize the Tree of Life by circumventing the requirement for direct observation and experimentation. Trees can be constructed using molecular techniques such as the small subunit ribosomal gene.

Despite the rapid expansion of the Tree of Life through genome sequencing, much biodiversity still is waiting to be discovered. This is especially relevant to microorganisms that are difficult to cultivate, and are typically found in one sample5. A recent analysis of all known genomes has produced a rough draft version of the Tree of Life, including numerous bacteria and archaea that have not been isolated and which are not well understood.

The expanded Tree of Life can be used to evaluate the biodiversity of a specific area and determine if certain habitats need special protection. The information can be used in a range of ways, from identifying the most effective medicines to combating disease to enhancing crop yields. The information is also useful to conservation efforts. It can aid biologists in identifying areas most likely to have cryptic species, which could perform important metabolic functions and are susceptible to changes caused by humans. While funding to protect biodiversity are important, the most effective method to protect the world's biodiversity is to empower the people of developing nations with the knowledge they need to take action locally and encourage conservation.

Phylogeny

A phylogeny is also known as an evolutionary tree, reveals the relationships between groups of organisms. Utilizing molecular data as well as morphological similarities and distinctions or ontogeny (the course of development of an organism), scientists can build a phylogenetic tree that illustrates the evolutionary relationship between taxonomic groups. The role of phylogeny is crucial in understanding the relationship between genetics, biodiversity and evolution.

A basic phylogenetic tree (see Figure PageIndex 10 ) determines the relationship between organisms with similar traits that evolved from common ancestors. These shared traits can be either homologous or analogous. Homologous traits are the same in terms of their evolutionary path. Analogous traits could appear like they are, but they do not have the same ancestry. Scientists combine similar traits into a grouping referred to as a the clade. All members of a clade share a characteristic, for example, 에볼루션 amniotic egg production. They all derived from an ancestor with these eggs. The clades then join to create a phylogenetic tree to determine the organisms with the closest connection to each other.

For a more detailed and precise phylogenetic tree scientists rely on molecular information from DNA or RNA to identify the connections between organisms. This information is more precise than the morphological data and 에볼루션 gives evidence of the evolutionary history of an individual or group. Researchers can use Molecular Data to calculate the age of evolution of organisms and determine the number of organisms that share a common ancestor.

Phylogenetic relationships can be affected by a number of factors, 에볼루션 바카라 체험 including the phenotypic plasticity. This is a kind of behavior that alters due to particular environmental conditions. This can cause a particular trait to appear more like a species other species, which can obscure the phylogenetic signal. However, this issue can be solved through the use of techniques such as cladistics that combine homologous and analogous features into the tree.

Additionally, phylogenetics can help predict 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 lead to a complete and 에볼루션 balanced ecosystem.

Evolutionary Theory

The fundamental concept in evolution is that organisms change over time as a result of their interactions with their environment. Many scientists have developed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that a living thing would evolve according to its own needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern hierarchical system of taxonomy as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the usage or non-use of traits can cause changes that are passed on to the

In the 1930s and 1940s, ideas from different fields, including natural selection, genetics & particulate inheritance, merged to form a modern theorizing of evolution. This describes how evolution happens through the variation in genes within the population and 에볼루션 how these variants change with time due to natural selection. This model, which includes genetic drift, mutations, gene flow and sexual selection, can be mathematically described.

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

Students can gain a better understanding of the concept of phylogeny by using evolutionary thinking throughout all aspects of biology. A recent study conducted by Grunspan and colleagues, for example, showed that teaching about the evidence for evolution helped students accept the concept of evolution in a college-level biology course. For 에볼루션 슬롯 (bekker-Severinsen-2.Technetbloggers.de) more information on how to teach about evolution, read The Evolutionary Potential in 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 studying fossils, comparing species and studying living organisms. Evolution is not a distant event; it is an ongoing process that continues to be observed today. The virus reinvents itself to avoid new drugs and bacteria evolve to resist antibiotics. Animals adapt their behavior because of a changing world. The changes that result are often visible.

It wasn't until the late 1980s when biologists began to realize that natural selection was also in action. The reason is that different characteristics result in different rates of survival and reproduction (differential fitness) and are transferred from one generation to the next.

In the past, if one particular allele--the genetic sequence that determines coloration--appeared in a population of interbreeding organisms, it might rapidly become more common than other alleles. Over time, this would mean that the number of moths that have 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 much easier when a species has a rapid turnover of its generation such as bacteria. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that descend from one strain. The samples of each population were taken regularly and more than 500.000 generations of E.coli have passed.

Lenski's research has revealed that a mutation can dramatically alter the efficiency with the rate at which a population reproduces, and consequently the rate at which it alters. It also shows that evolution takes time, a fact that some people are unable to accept.

Another example of microevolution is the way mosquito genes that are resistant to pesticides are more prevalent in populations in which insecticides are utilized. This is due to the fact that the use of pesticides causes a selective pressure that favors those with resistant genotypes.

The rapid pace at which evolution can take place has led to an increasing recognition of its importance in a world shaped by human activity, including climate changes, pollution and the loss of habitats that prevent many species from adjusting. Understanding the evolution process can help us make better choices about the future of our planet and the lives of its inhabitants.