The Academy's Evolution Site

Biological evolution is one of the most important concepts in biology. The Academies have been for a long time involved in helping people who are interested in science understand the concept of evolution and how it affects every area of scientific inquiry.

This site provides a range of resources for teachers, students and general readers of 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, symbolizes the interconnectedness of all life. It is a symbol of love and harmony in a variety of cultures. It also has practical uses, like providing a framework for understanding the history of species and how they react to changes in the environment.

Early approaches to depicting the biological world focused on categorizing organisms into distinct categories which had been distinguished by physical and metabolic characteristics1. These methods are based on the collection of various parts of organisms or short DNA fragments, 에볼루션 바카라사이트 have greatly increased the diversity of a Tree of Life2. The trees are mostly composed by eukaryotes, and the diversity of bacterial species is greatly underrepresented3,4.

In avoiding the necessity of direct experimentation and observation genetic techniques have allowed us to depict the Tree of Life in a more precise manner. Particularly, molecular techniques allow us to build trees by using sequenced markers like the small subunit of ribosomal RNA gene.

The Tree of Life has been greatly expanded thanks to genome sequencing. However there is still a lot of biodiversity to be discovered. This is particularly true for microorganisms that are difficult to cultivate, and are usually found in a single specimen5. A recent analysis of all known genomes has produced a rough draft version of the Tree of Life, including a large number of archaea and bacteria that have not been isolated, and which are not well understood.

This expanded Tree of Life is particularly useful in assessing the diversity of an area, helping to determine if specific habitats require special protection. This information can be utilized in a variety of ways, including finding new drugs, battling diseases and improving crops. The information is also incredibly useful in conservation efforts. It can help biologists identify areas that are likely to have species that are cryptic, which could have vital metabolic functions and are susceptible to human-induced change. While funds to protect biodiversity are crucial, ultimately the best way to protect the world's biodiversity is for more people living in developing countries to be equipped with the knowledge to act locally in order to promote conservation from within.

Phylogeny

A phylogeny, also known as an evolutionary tree, reveals the connections between groups of organisms. Scientists can construct a phylogenetic diagram that illustrates the evolutionary relationships between taxonomic categories using molecular information and morphological diff.pdc.edu/?URL=https://2ch-ranking.net/redirect.php?url=https://evolutionkr.kr/">에볼루션사이트 phylogenetics may help predict the length and speed of speciation. This information can aid conservation biologists to make decisions about which species to protect from the threat of extinction. It is ultimately the preservation of phylogenetic diversity which will result in an ecosystem that is complete and balanced.

Evolutionary Theory

The central theme of evolution is that organisms develop various characteristics over time due to their interactions with their surroundings. Many scientists have proposed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism could evolve according to its own requirements and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical system of taxonomy as well as Jean-Baptiste Lamarck (1844-1829), who believed that the usage or non-use of traits can cause changes that are passed on to the

In the 1930s and 1940s, concepts from a variety of fields -- including natural selection, genetics, 에볼루션 바카라 사이트 (atavi.Com) and particulate inheritance - came together to create the modern evolutionary theory that explains how evolution happens through the variation of genes within a population and how those variants change in time as a result of natural selection. This model, called genetic drift, mutation, gene flow and sexual selection, is a key element of the current evolutionary biology and is mathematically described.

Recent discoveries in the field of evolutionary developmental biology have revealed how variation can be introduced to a species through genetic drift, mutations, reshuffling genes during sexual reproduction and migration between populations. These processes, in conjunction with others, such as the directional selection process and the erosion of genes (changes to the frequency of genotypes over time) can lead to evolution. Evolution is defined by changes in the genome over time, as well as changes in phenotype (the expression of genotypes within individuals).

Incorporating evolutionary thinking into all areas of biology education could increase students' understanding of phylogeny and evolutionary. A recent study by Grunspan and colleagues, for instance, showed that teaching about the evidence supporting evolution helped students accept the concept of evolution in a college-level biology course. For more information on how to teach evolution read The Evolutionary Potential in all Areas of Biology or Thinking Evolutionarily: a Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Traditionally scientists have studied evolution through looking back--analyzing fossils, comparing species, and studying living organisms. But evolution isn't a thing that happened in the past; it's an ongoing process, that is taking place in the present. Viruses evolve to stay away from new antibiotics and bacteria transform to resist antibiotics. Animals adapt their behavior as a result of the changing environment. The results are often evident.

However, it wasn't until late-1980s that biologists realized that natural selection could be seen in action, as well. The main reason is that different traits result in a different rate of survival and reproduction, and can be passed on from generation to generation.

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

It is easier to see evolutionary change when a species, such as bacteria, has a high generation turnover. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that descend from one strain. The samples of each population have been taken regularly and more than 500.000 generations of E.coli have passed.

Lenski's work has demonstrated that a mutation can profoundly alter the speed at which a population reproduces--and so the rate at which it changes. It also shows evolution takes time, something that is difficult for some to accept.

Microevolution can also be seen in the fact that mosquito genes for pesticide resistance are more prevalent in areas where insecticides are used. Pesticides create an exclusive pressure that favors individuals who have resistant genotypes.

The speed at which evolution takes place has led to an increasing appreciation of its importance in a world that is shaped by human activity--including climate changes, 에볼루션 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 as well as the lives of its inhabitants.