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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 to learn about the theory of evolution and how it is permeated in all areas of scientific research.

This site provides teachers, students and general readers with a range 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 a symbol of love and harmony in a variety of cultures. It has numerous practical applications as well, such as providing a framework for understanding the history of species, and how they respond to changing environmental conditions.

Early attempts to represent the world of biology were built on categorizing organisms based on their metabolic and physical characteristics. These methods depend on the collection of various parts of organisms or DNA fragments have greatly increased the diversity of a Tree of Life2. However, these trees are largely composed of eukaryotes; bacterial diversity is still largely unrepresented3,4.

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

The Tree of Life has been significantly expanded by genome sequencing. However there is a lot of biodiversity to be discovered. This is especially true of microorganisms, which can be difficult to cultivate and are often only found in a single specimen5. Recent analysis of all genomes resulted in an unfinished draft of a Tree of Life. This includes a large number of bacteria, archaea and other organisms that haven't yet been identified or the diversity of which is not thoroughly understood6.

The expanded Tree of Life can be used to evaluate the biodiversity of a specific region and determine if particular habitats require special protection. The information can be used in a variety of ways, from identifying the most effective remedies to fight diseases to improving crop yields. The information is also incredibly valuable for conservation efforts. It can aid biologists in identifying areas most likely to have cryptic species, which may have vital metabolic functions and be vulnerable to human-induced change. While funding to protect biodiversity are essential, the best way to conserve the world's biodiversity is to equip more people in developing nations with the knowledge they need to act locally and promote conservation.

Phylogeny

A phylogeny (also known as an evolutionary tree) depicts the relationships between species. Scientists can build a phylogenetic diagram that illustrates the evolutionary relationships between taxonomic groups based on molecular data and morphological differences or similarities. The phylogeny of a tree plays an important role in understanding genetics, biodiversity and evolution.

A basic phylogenetic tree (see Figure PageIndex 10 ) identifies the relationships between organisms with similar traits that have evolved from common ancestral. These shared traits can be either homologous or analogous. Homologous traits are the same in terms of their evolutionary journey. Analogous traits may look like they are but they don't have the same ancestry. Scientists group similar traits into a grouping known as a the clade. All members of a clade have a common characteristic, for example, amniotic egg production. They all derived from an ancestor who had these eggs. A phylogenetic tree can be built by connecting the clades to determine the organisms that are most closely related to each other.

To create a more thorough and accurate phylogenetic tree, scientists make use of molecular data from DNA or RNA to identify the relationships among organisms. This information is more precise and 에볼루션 코리아 provides evidence of the evolutionary history of an organism. Researchers can use Molecular Data to calculate the age of evolution of living organisms and discover how many organisms share a common ancestor.

The phylogenetic relationships of organisms can be influenced by several factors including phenotypic plasticity, a kind of behavior that alters in response to specific environmental conditions. This can cause a trait to appear more similar to one species than another, clouding the phylogenetic signal. This problem can be addressed by using cladistics, which incorporates a combination of homologous and analogous traits in the tree.

Additionally, phylogenetics aids determine the duration and speed at which speciation takes place. This information can assist conservation biologists in making choices about which species to safeguard from the threat of extinction. In the end, it's the preservation of phylogenetic diversity that will result in an ecosystem that is balanced and complete.

Evolutionary Theory

The main idea behind evolution is that organisms change over time due to their interactions with their environment. Many theories of evolution have been proposed by a wide range of scientists, including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing slowly in accordance with its requirements, the Swedish botanist Carolus Linnaeus (1707-1778) who developed the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1744-1829) who suggested that the use or non-use of traits cause changes that can be passed on to offspring.

In the 1930s and 1940s, theories from a variety of fields--including genetics, 에볼루션 카지노 사이트 natural selection and particulate inheritance -- came together to form the current evolutionary theory synthesis that explains how evolution is triggered by the variations of genes within a population and how those variants change over time due to natural selection. This model, known as genetic drift, mutation, gene flow, and sexual selection, is a key element of the current evolutionary biology and can be mathematically described.

Recent developments in the field of evolutionary developmental biology have revealed 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 like directional selection and genetic erosion (changes in the frequency of a genotype over time) can lead to evolution, which is defined by change in the genome of the species over time, 에볼루션 바카라 무료체험 and also by changes in phenotype over time (the expression of the genotype within the individual).

Students can better understand phylogeny by incorporating evolutionary thinking in all aspects of biology. A recent study conducted by Grunspan and colleagues, for example, showed that teaching about the evidence that supports evolution increased students' understanding of evolution in a college-level biology course. For more details about 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

Scientists have traditionally studied evolution by looking in the past, analyzing fossils and comparing species. They also observe living organisms. Evolution is not a past event, but a process that continues today. Bacteria mutate and 에볼루션 코리아 resist antibiotics, viruses evolve and escape new drugs and animals alter their behavior to the changing climate. The results are usually evident.

But it wasn't until the late-1980s that biologists realized that natural selection could be observed in action as well. The key to this is that different traits confer the ability to survive at different rates and reproduction, and they can be passed down from generation to generation.

In the past when one particular allele--the genetic sequence that controls coloration - was present in a population of interbreeding organisms, it could quickly become more prevalent than the other alleles. As time passes, that could mean the number of black moths in a population could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

It is easier to track evolutionary change when an organism, like bacteria, has a rapid generation turnover. 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 regularly and over 500.000 generations have been observed.

Lenski's work has shown that mutations can alter the rate at which change occurs and the rate of a population's reproduction. It also shows evolution takes time, something that is hard for some to accept.

Microevolution can also be seen in the fact that mosquito genes for 에볼루션 코리아 resistance to pesticides are more prevalent in areas that have used insecticides. That's because the use of pesticides causes a selective pressure that favors people with resistant genotypes.

The speed of evolution taking place has led to an increasing awareness of its significance 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 assist you in making better choices regarding the future of the planet and its inhabitants.