If You've Just Purchased Evolution Site ... Now What?

The Academy's Evolution Site

Biology is a key concept in biology. The Academies have long been involved in helping those interested in science comprehend the concept of evolution and how it permeates every area of scientific inquiry.

This site provides students, teachers and general readers with a variety of learning resources about evolution. It also includes important 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 appears in many cultures and spiritual beliefs as an emblem of unity and love. It also has important practical applications, like providing a framework to understand the history of species and how they react to changes in the environment.

The earliest attempts to depict the world of biology focused on categorizing organisms into distinct categories that were distinguished by physical and metabolic characteristics1. These methods, based on the sampling of various parts of living organisms, or short fragments of their DNA significantly expanded the diversity that could be included in a tree of life2. The trees are mostly composed by eukaryotes and 에볼루션 바카라 the diversity of bacterial species is greatly underrepresented3,4.

In avoiding the necessity of direct experimentation and observation genetic techniques have made it possible to represent the Tree of Life in a much more accurate way. We can create trees by using molecular methods such as the small subunit ribosomal gene.

The Tree of Life has been greatly expanded thanks to genome sequencing. However there is a lot of diversity to be discovered. This is particularly true for microorganisms that are difficult to cultivate and which are usually only present in a single sample5. Recent analysis of all genomes has produced a rough draft of a Tree of Life. This includes a large number of archaea, bacteria and other organisms that haven't yet been isolated, or the diversity of which is not thoroughly understood6.

The expanded Tree of Life is particularly useful in assessing the diversity of an area, which can help to determine if specific habitats require special protection. The information can be used in a variety of ways, from identifying the most effective treatments to fight disease to enhancing crops. It is also valuable to conservation efforts. It can help biologists identify areas that are most likely to have cryptic species, which could have vital metabolic functions, and could be susceptible to the effects of human activity. Although funds to safeguard biodiversity are vital but the most effective way to preserve the world's biodiversity is for more people living in developing countries to be empowered with the knowledge to act locally in order to promote conservation from within.

Phylogeny

A phylogeny, also called an evolutionary tree, shows the connections between groups of organisms. Utilizing molecular data, morphological similarities and differences or ontogeny (the process of the development of an organism) scientists can create a phylogenetic tree which illustrates the evolutionary relationship between taxonomic categories. Phylogeny plays a crucial role in understanding biodiversity, genetics and evolution.

A basic phylogenetic tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms with similar traits that evolved from common ancestral. These shared traits are either homologous or analogous. Homologous traits are the same in their evolutionary paths. Analogous traits might appear similar however they do not have the same ancestry. Scientists arrange similar traits into a grouping called a the clade. All members of a clade have a common characteristic, for example, amniotic egg production. They all derived from an ancestor with these eggs. A phylogenetic tree can be built by connecting the clades to identify the organisms which are the closest to one another.

For a more precise and accurate phylogenetic tree, scientists use molecular data from DNA or RNA to identify the relationships between organisms. This information is more precise and gives evidence of the evolutionary history of an organism. Molecular data allows researchers to identify the number of species that share a common ancestor and to estimate their evolutionary age.

The phylogenetic relationships of organisms are influenced by many factors, 에볼루션 에볼루션 바카라 사이트 (look here) including phenotypic flexibility, a type of behavior that changes in response to unique environmental conditions. This can cause a trait to appear more like a species another, clouding the phylogenetic signal. This problem can be addressed by using cladistics. This is a method that incorporates a combination of homologous and analogous features in the tree.

Furthermore, phylogenetics may help predict the duration and rate of speciation. This information can aid conservation biologists in making choices about which species to save from disappearance. It is ultimately the preservation of phylogenetic diversity that will create an ecosystem that is complete and balanced.

Evolutionary Theory

The main idea behind evolution is that organisms change over time due to 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 a living thing would evolve according to its own needs, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical system of taxonomy and 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 next generation.

In the 1930s and 1940s, ideas from a variety of fields -- including natural selection, genetics, and particulate inheritance -- came together to create the modern evolutionary theory which explains how evolution happens through the variation of genes within a population and how these variants change in time as a result of natural selection. This model, which incorporates genetic drift, 에볼루션 mutations in gene flow, and sexual selection, can be mathematically described.

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

Incorporating evolutionary thinking into all areas of biology education could increase students' understanding of phylogeny as well as evolution. In a study by Grunspan et al. It was found that teaching students about the evidence for evolution increased their understanding of evolution during a college-level course in biology. To find out more about how to teach about evolution, please see The Evolutionary Potential of All Areas of Biology and Thinking Evolutionarily: A Framework for Infusing Evolution in Life Sciences Education.

Evolution in Action

Traditionally scientists have studied evolution through studying fossils, comparing species and studying living organisms. But evolution isn't a thing that happened in the past; it's an ongoing process, taking place today. Bacteria evolve and resist antibiotics, viruses evolve and are able to evade new medications, and animals adapt their behavior in response to the changing environment. The changes that result are often evident.

It wasn't until late 1980s when biologists began to realize that natural selection was also in play. The key is that various traits confer different rates of survival and reproduction (differential fitness), and can be passed down from one generation to the next.

In the past, when one particular allele, the genetic sequence that defines color in a group of interbreeding organisms, it might quickly become more prevalent than all other alleles. In time, this could mean that the number of black moths within a particular population could rise. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

Monitoring evolutionary changes in action is easier when a species has a fast generation turnover, as with bacteria. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that are descended from one strain. Samples from each population have been taken regularly and more than 500.000 generations of E.coli have passed.

Lenski's research has shown that mutations can drastically alter the efficiency with which a population reproduces--and so, the rate at which it changes. It also demonstrates that evolution takes time, which is hard for some to accept.

Another example of microevolution is the way mosquito genes that confer resistance to pesticides appear more frequently in areas where insecticides are employed. This is because the use of pesticides creates a pressure that favors individuals with resistant genotypes.

The rapid pace at which evolution takes place has led to a growing recognition of its importance in a world shaped by human activities, including climate changes, pollution and the loss of habitats which prevent the species from adapting. Understanding evolution can help us make smarter choices about the future of our planet as well as the life of its inhabitants.