The Academy's Evolution Site

The concept of biological evolution is among the most fundamental concepts in biology. The Academies have long been involved in helping those interested in science comprehend the theory of evolution and how it affects all areas of scientific research.

This site provides a wide range of tools for teachers, students as well as general readers about evolution. It contains key video clips from NOVA and the 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 an emblem of love and unity across many cultures. It also has important practical applications, like providing a framework for understanding the evolution of species and how they respond to changing environmental conditions.

The earliest attempts to depict the world of biology focused on the classification of species into distinct categories that were distinguished by physical and metabolic characteristics1. These methods, which rely on the sampling of various parts of living organisms, or small fragments of their DNA, significantly expanded the diversity that could be represented in the tree of life2. However the trees are mostly comprised of eukaryotes, and bacterial diversity is not represented in a large way3,4.

In avoiding the necessity of direct experimentation and observation, genetic techniques have allowed us to depict the Tree of Life in a more precise way. Trees can be constructed by using molecular methods, such as the small-subunit ribosomal gene.

Despite the rapid expansion of the Tree of Life through genome sequencing, much biodiversity still remains to be discovered. This is particularly true for microorganisms that are difficult to cultivate and are often only represented in a single sample5. A recent analysis of all known genomes has created a rough draft of the Tree of Life, including numerous archaea and bacteria that have not been isolated and which are not well understood.

This expanded Tree of Life is particularly useful for assessing the biodiversity of an area, assisting to determine whether specific habitats require protection. This information can be used in a range of ways, from identifying new medicines to combating disease to enhancing the quality of crop yields. This information is also extremely useful in conservation efforts. It can aid biologists in identifying those areas that are most likely contain cryptic species with potentially important metabolic functions that could be at risk of anthropogenic changes. While funding to protect biodiversity are important, the best method to preserve the world's biodiversity is to equip more people in developing nations with the knowledge they need to act locally and support conservation.

Phylogeny

A phylogeny is also known as an evolutionary tree, reveals the connections between different groups of organisms. Scientists can create an phylogenetic chart which shows the evolutionary relationships between taxonomic categories using molecular information and morphological similarities or differences. Phylogeny plays a crucial role 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 and have evolved from a common ancestor. These shared traits can be either analogous or homologous. Homologous traits are the same in terms of their evolutionary path. Analogous traits may look similar but they don't have the same origins. Scientists put similar traits into a grouping called a the clade. For example, all of the organisms that make up a clade have the characteristic of having amniotic eggs. They evolved from a common ancestor who had these eggs. A phylogenetic tree can be constructed by connecting the clades to determine the organisms who are the closest to each other.

To create a more thorough and accurate phylogenetic tree, scientists rely on molecular information from DNA or RNA to identify the relationships between organisms. This information is more precise than morphological data and provides evidence of the evolution history of an individual or group. Researchers can utilize Molecular Data to estimate the age of evolution of organisms and determine how many organisms have the same ancestor.

Phylogenetic relationships can be affected by a variety of factors that include the phenotypic plasticity. This is a type of behaviour that can change in response to unique environmental conditions. This can cause a characteristic to appear more similar to one species than another, obscuring the phylogenetic signal. This problem can be addressed by using cladistics, which incorporates an amalgamation of homologous and analogous features in the tree.

Furthermore, phylogenetics may help predict the length and speed of speciation. This information can assist conservation biologists make decisions about which species they should protect from the threat of extinction. In the end, it's the preservation of phylogenetic diversity that will create a complete and balanced ecosystem.

Evolutionary Theory

The main idea behind 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 an organism would develop according to its own requirements as well as the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical system of taxonomy and Jean-Baptiste Lamarck (1844-1829), who believed that the use or absence of certain traits can result in changes that can be passed on to future generations.

In the 1930s & 1940s, ideas from different fields, such as natural selection, genetics & particulate inheritance, came together to create a modern evolutionary theory. This explains how evolution is triggered by the variation of genes in the population and how these variants alter over time due to natural selection. This model, which includes genetic drift, mutations, gene flow and sexual selection, can be mathematically described mathematically.

Recent discoveries in the field of evolutionary developmental biology have revealed that variations can be introduced into a species via mutation, genetic drift, and reshuffling of genes in sexual reproduction, and also through the movement of populations. These processes, as well as other ones like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time) can lead to evolution which is defined by change in the genome of the species over time and 에볼루션 바카라 무료 에볼루션 카지노 사이트; Gorizont.Org, also by changes 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. A recent study by Grunspan and colleagues, for instance revealed that teaching students about the evidence for evolution increased students' understanding of evolution in a college-level biology class. To learn more about how to teach about evolution, please see The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Scientists have studied evolution through looking back in the past, studying fossils, and comparing species. They also observe living organisms. But evolution isn't just something that occurred in the past, it's an ongoing process, that is taking place in the present. Bacteria transform and resist antibiotics, viruses reinvent themselves and escape new drugs, and 에볼루션 사이트 animals adapt their behavior in response to the changing climate. The changes that result are often apparent.

It wasn't until the 1980s when biologists began to realize that natural selection was in play. The reason is that different traits confer different rates of survival and reproduction (differential fitness) and can be transferred 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 quickly become more common than other alleles. In time, this could mean that the number of moths with black pigmentation in a group could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

It is easier to observe evolutionary change when an organism, like bacteria, has a rapid generation turnover. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. Coli that descended from a single strain; samples of each population are taken on a regular basis and more than fifty thousand generations have been observed.

Lenski's research has revealed that mutations can alter the rate at which change occurs and 에볼루션 사이트 the effectiveness at which a population reproduces. It also demonstrates that evolution takes time--a fact that some people are unable to accept.

Microevolution can be observed in the fact that mosquito genes for resistance to pesticides are more prevalent in areas where insecticides are used. This is because the use of pesticides creates a selective pressure that favors individuals with resistant genotypes.

The rapidity of evolution has led to a greater appreciation of its importance, especially in a world shaped largely by human activity. This includes the effects of climate change, pollution and habitat loss that prevents many species from adapting. Understanding the evolution process can help us make better choices about the future of our planet and the life of its inhabitants.