The Academy's Evolution Site

The concept of biological evolution is among the most central concepts in biology. The Academies have been active for a long time in helping those interested in science understand the concept of evolution and how it influences all areas of scientific exploration.

This site offers a variety of resources for teachers, students as well as general readers about evolution. It also 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 represents the interconnectedness of life. It is a symbol of love and unity across many cultures. It has numerous practical applications as well, including providing a framework for understanding the evolution of species and how they respond to changing environmental conditions.

The first attempts at depicting the biological world focused on categorizing species into distinct categories that were distinguished by their physical and metabolic characteristics1. These methods are based on the sampling of different parts of organisms, or DNA fragments have significantly increased the diversity of a tree of Life2. However the trees are mostly comprised of eukaryotes, and bacterial diversity is still largely unrepresented3,4.

By avoiding the necessity for direct experimentation and observation genetic techniques have made it possible 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 biodiversity to be discovered. This is particularly the case for microorganisms which are difficult to cultivate, and 에볼루션 바카라사이트 which are usually only found in a single specimen5. A recent analysis of all genomes has produced an unfinished draft of the Tree of Life. This includes a wide range of archaea, bacteria, and 에볼루션 코리아 other organisms that haven't yet been identified or whose diversity has not been fully understood6.

The expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, 에볼루션 바카라사이트 assisting to determine whether specific habitats require special protection. This information can be used in a range of ways, from identifying the most effective treatments to fight disease to enhancing crop yields. The information is also useful in conservation efforts. It helps biologists determine the areas that are most likely to contain cryptic species with important metabolic functions that may be vulnerable to anthropogenic change. Although funds to protect biodiversity are crucial but the most effective way to protect the world's biodiversity is for more people living in developing countries to be empowered with the knowledge to take action locally to encourage conservation from within.

Phylogeny

A phylogeny (also called an evolutionary tree) shows the relationships between different organisms. Scientists can create a phylogenetic chart that shows the evolution of taxonomic categories using molecular information and morphological differences or similarities. Phylogeny plays a crucial role in understanding genetics, biodiversity and evolution.

A basic phylogenetic tree (see Figure PageIndex 10 Identifies the relationships between organisms that have similar traits and 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 identical origins. Scientists arrange similar traits into a grouping known as a the clade. For example, all of the organisms that make up a clade share the characteristic of having amniotic eggs and evolved from a common ancestor who had these eggs. The clades are then linked to form a phylogenetic branch to determine which organisms have the closest connection to each other.

Scientists use DNA or RNA molecular information to create a phylogenetic chart that is more precise and detailed. This information is more precise and provides evidence of the evolutionary history of an organism. Researchers can utilize Molecular Data to determine the evolutionary age of organisms and determine the number of organisms that have a common ancestor.

Phylogenetic relationships can be affected by a number of factors, including phenotypicplasticity. This is a type of behaviour that can change due to specific environmental conditions. This can cause a characteristic to appear more similar to one species than another, obscuring the phylogenetic signals. This issue can be cured by using cladistics, which is a a combination of analogous and homologous features in the tree.

Additionally, phylogenetics aids predict the duration and rate at which speciation takes place. This information can aid 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 lead to a complete and balanced ecosystem.

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 proposed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism would evolve according to its individual requirements and needs, 에볼루션 카지노 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 certain traits can result in changes that are passed on to the

In the 1930s and 1940s, ideas from a variety of fields -- including genetics, 에볼루션 바카라사이트 natural selection, and particulate inheritance -- came together to create the modern synthesis of evolutionary theory, which defines how evolution is triggered by the variation of genes within a population, 에볼루션카지노 and how those variations change over time as a result of natural selection. This model, called genetic drift, mutation, gene flow, and sexual selection, is a key element of modern evolutionary biology and is mathematically described.

Recent discoveries in the field of evolutionary developmental biology have demonstrated how variation can be introduced to a species through genetic drift, 에볼루션 카지노 mutations, reshuffling genes during sexual reproduction and the movement between populations. These processes, in conjunction with others, such as directionally-selected selection and erosion of genes (changes in 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 within individuals).

Students can gain a better understanding of the concept of phylogeny through incorporating evolutionary thinking in all aspects of biology. A recent study by Grunspan and colleagues, for instance, showed that teaching about the evidence for evolution helped students accept the concept of evolution in a college-level biology class. For more information on how to teach about evolution read The Evolutionary Power of Biology 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. Evolution isn't a flims event; it is an ongoing process. Viruses evolve to stay away from new medications and bacteria mutate to resist antibiotics. Animals adapt their behavior because of a changing world. The results are often evident.

It wasn't until late 1980s that biologists understood that natural selection can be observed in action as well. The reason is that different traits have different rates of survival and reproduction (differential fitness), and can be passed from one generation to the next.

In the past when one particular allele, the genetic sequence that determines coloration--appeared in a population of interbreeding species, it could rapidly become more common than all other alleles. As time passes, this could mean that the number of moths that have black pigmentation 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 evolution when the species, like bacteria, has a rapid generation turnover. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that are descended from a single strain. The samples of each population have been taken regularly and more than 50,000 generations of E.coli have been observed to have passed.

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

Another example of microevolution is the way mosquito genes that are resistant to pesticides appear more frequently in populations where insecticides are employed. This is due to pesticides causing a selective pressure which favors individuals who have resistant genotypes.

The speed at which evolution takes place has led to an increasing recognition of its importance in a world shaped by human activity, including climate change, pollution and the loss of habitats that hinder many species from adapting. Understanding evolution will aid you in making better decisions about the future of our planet and its inhabitants.