The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies are involved in helping those who are interested in the sciences comprehend the evolution theory and how it can be applied throughout all fields of scientific research.

This site provides a range of sources for teachers, students as well as general readers about evolution. It contains key video clips from NOVA and WGBH produced science programs on DVD.

Tree of Life

The Tree of Life is an ancient symbol that symbolizes the interconnectedness of life. It is a symbol of love and harmony in a variety of cultures. It also has practical applications, such as providing a framework to understand the evolution of species and how they respond to changing environmental conditions.

Early approaches to depicting the world of biology focused on separating organisms into distinct categories which had been distinguished by their physical and metabolic characteristics1. These methods, which rely on the sampling of different parts of organisms or fragments of DNA, have greatly increased the diversity of a tree of Life2. However the trees are mostly comprised of eukaryotes, and bacterial diversity is not represented in a large way3,4.

By avoiding the need for direct experimentation and observation, 에볼루션 무료체험 genetic techniques have allowed us to depict the Tree of Life in a more precise manner. Particularly, molecular methods enable us to create trees using sequenced markers, such as the small subunit ribosomal 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 especially the case for microorganisms which are difficult to cultivate and which are usually only present in a single sample5. A recent study of all genomes that are known has created a rough draft of the Tree of Life, including many bacteria and archaea that have not been isolated and which are not well understood.

This expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, 에볼루션 블랙잭사이트 (http://www.fluencycheck.com/User/voyagestreet3) assisting to determine if certain habitats require protection. This information can be used in a range of ways, from identifying new remedies to fight diseases to enhancing the quality of crops. It is also beneficial for conservation efforts. It can help biologists identify the areas most likely to contain cryptic species that could have important metabolic functions that could be at risk from anthropogenic change. Although funding to safeguard biodiversity are vital but the most effective way to preserve the world's biodiversity is for more people in developing countries to be empowered with the necessary knowledge to act locally in order to promote conservation from within.

Phylogeny

A phylogeny, also known as an evolutionary tree, reveals the connections between various groups of organisms. Scientists can construct an phylogenetic chart which shows the evolution of taxonomic groups using molecular data and morphological similarities or differences. Phylogeny plays a crucial role in understanding biodiversity, genetics and evolution.

A basic phylogenetic tree (see Figure PageIndex 10 Finds the connections between organisms that have similar characteristics and have evolved from a common ancestor. These shared traits may be analogous or homologous. Homologous traits share their evolutionary roots and analogous traits appear similar but do not have the identical origins. Scientists organize 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. The clades are then connected to create a phylogenetic tree to determine which organisms have the closest relationship.

Scientists utilize DNA or RNA molecular data to construct a phylogenetic graph that is more precise and precise. This information is more precise and gives evidence of the evolutionary history of an organism. The use of molecular data lets researchers identify the number of organisms that share an ancestor common to them and 에볼루션 무료체험 estimate their evolutionary age.

The phylogenetic relationships between organisms are influenced by many factors including phenotypic plasticity, an aspect of behavior that alters in response to specific environmental conditions. This can make a trait appear more resembling to one species than to another, obscuring the phylogenetic signals. This problem can be addressed by using cladistics, which is a the combination of homologous and analogous features in the tree.

Furthermore, phylogenetics may aid in predicting the time and pace of speciation. This information can help conservation biologists decide which species to protect from extinction. In the end, it is the preservation of phylogenetic diversity that will lead to an ecosystem that is balanced and complete.

Evolutionary Theory

The central theme in evolution is that organisms alter over time because of 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 proposed that a living organism develop gradually according to its requirements and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits cause changes that could be passed on to offspring.

In the 1930s and 1940s, theories from various areas, including genetics, natural selection and particulate inheritance, merged to form a contemporary synthesis of evolution theory. This explains how evolution happens through the variations in genes within the population, and how these variations change with time due to natural selection. This model, which incorporates mutations, genetic drift, gene flow and sexual selection, can be mathematically described mathematically.

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

Students can better understand phylogeny by incorporating evolutionary thinking in all areas of biology. A recent study by Grunspan and colleagues, for example revealed that teaching students about the evidence that supports evolution helped students accept the concept of evolution in a college biology class. For more information about how to teach evolution look up The Evolutionary Power of Biology in All Areas of Biology or Thinking Evolutionarily as a Framework for Integrating Evolution into Life Sciences Education.

Evolution in Action

Traditionally, 에볼루션 무료체험 scientists have studied evolution by looking back--analyzing fossils, comparing species, and studying living organisms. Evolution isn't a flims event, but an ongoing process. The virus reinvents itself to avoid new medications and bacteria mutate to resist antibiotics. Animals alter their behavior as a result of the changing environment. The changes that result are often evident.

It wasn't until the late 1980s that biologists began realize that natural selection was also in play. The key is the fact that different traits result in the ability to survive at different rates as well as reproduction, and may be passed down from one generation to another.

In the past, if an allele - the genetic sequence that determines colour - was found in a group of organisms that interbred, it might become more common than other allele. As time passes, that could mean the number of black moths within 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 see evolutionary change when the species, like bacteria, has a high generation turnover. Since 1988, Richard Lenski, a biologist, 에볼루션카지노 has been tracking twelve populations of E.coli that descend from one strain. Samples from each population have been collected regularly and more than 500.000 generations of E.coli have been observed to have passed.

Lenski's work has demonstrated that mutations can drastically alter the speed at the rate at which a population reproduces, and consequently, the rate at which it alters. It also demonstrates that evolution takes time, a fact that is difficult for some to accept.

Another example of microevolution is how mosquito genes that are resistant to pesticides show up more often in areas where insecticides are employed. This is because the use of pesticides creates a selective pressure that favors individuals who have resistant genotypes.

The rapidity of evolution has led to a greater recognition of its importance particularly in a world which is largely shaped by human activities. This includes the effects of climate change, pollution and habitat loss that hinders many species from adapting. Understanding the evolution process will help us make better choices about the future of our planet, as well as the life of its inhabitants.