The Academy's Evolution Site

The concept of biological evolution is among the most central concepts in biology. The Academies are involved in helping those who are interested in science comprehend the evolution theory and how it is permeated across all areas of scientific research.

This site provides students, teachers and general readers with a wide range of learning resources about evolution. It has the most important video clips from NOVA and the WGBH-produced science programs on DVD.

Tree of Life

The Tree of Life, an ancient symbol, represents the interconnectedness of all life. It is used in many cultures and spiritual beliefs as a symbol of unity and love. It also has practical applications, such as providing a framework to understand the history of species and how they react to changes in the environment.

Early approaches to depicting the biological world focused on the classification of organisms into distinct categories which had been identified by their physical and metabolic characteristics1. These methods, 에볼루션 바카라 사이트 which rely on sampling of different parts of living organisms or sequences of small DNA fragments, significantly expanded the diversity that could be included in a tree of life2. However the trees are mostly comprised of eukaryotes, and bacterial diversity remains vastly underrepresented3,4.

By avoiding the need for direct observation and experimentation, genetic techniques have enabled us to depict the Tree of Life in a much more accurate way. We can create trees using molecular techniques like the small-subunit ribosomal gene.

Despite the dramatic expansion of the Tree of Life through genome sequencing, a lot of biodiversity is waiting to be discovered. This is especially relevant to microorganisms that are difficult to cultivate and which are usually only present in a single sample5. Recent analysis of all genomes resulted in a rough draft of a Tree of Life. This includes a wide range of bacteria, archaea and other organisms that have not yet been isolated or their diversity is not well understood6.

The expanded Tree of Life is particularly useful in assessing the diversity of an area, assisting to determine if specific habitats require protection. This information can be used in many ways, including finding new drugs, fighting diseases and improving the quality of crops. This information is also beneficial for conservation efforts. It can help biologists identify those areas that are most likely contain cryptic species that could have important metabolic functions that could be at risk of anthropogenic changes. Although funds to protect biodiversity are crucial but the most effective way to protect 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) depicts the relationships between different organisms. By using molecular information, morphological similarities and differences or ontogeny (the process of the development of an organism) scientists can construct a phylogenetic tree that illustrates the evolution of taxonomic categories. The concept of phylogeny is fundamental to understanding the evolution of biodiversity, evolution and genetics.

A basic phylogenetic tree (see Figure PageIndex 10 Finds the connections between organisms with similar characteristics and have evolved from an ancestor with common traits. These shared traits could be homologous, or analogous. Homologous traits share their evolutionary roots and analogous traits appear similar, but do not share the same ancestors. Scientists arrange similar traits into a grouping called a the clade. For example, all of the species in a clade share the characteristic of having amniotic egg and 에볼루션 바카라 evolved from a common ancestor who had eggs. A phylogenetic tree is constructed by connecting clades to identify the organisms who are the closest to each other.

For a more detailed and accurate phylogenetic tree, scientists use molecular data from DNA or RNA to establish the relationships among organisms. This data is more precise than morphological information and provides evidence of the evolution background of an organism or group. The use of molecular data lets researchers identify the number of organisms that have a common ancestor and to estimate their evolutionary age.

Phylogenetic relationships can be affected by a variety of factors that include the phenotypic plasticity. This is a kind of behavior that changes due to particular environmental conditions. This can make a trait appear more resembling to one species than to another which can obscure the phylogenetic signal. However, this issue can be cured by the use of techniques such as cladistics that combine analogous and homologous features into the tree.

In addition, phylogenetics can aid in predicting the time and pace of speciation. This information can assist conservation biologists in making decisions about which species to protect from extinction. Ultimately, it is the preservation of phylogenetic diversity that will lead to an ecologically balanced and complete ecosystem.

Evolutionary Theory

The fundamental concept in evolution is that organisms change over time as a result of their interactions with their environment. Many theories of evolution have been developed by a wide variety of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing gradually according to its requirements as well as the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits cause changes that can be passed on to offspring.

In the 1930s and 1940s, 에볼루션 바카라 사이트 theories from a variety of fields -- including genetics, natural selection, and particulate inheritance--came together to form the modern evolutionary theory which explains how evolution is triggered by the variation of genes within a population and how those variants change over time as a result of natural selection. This model, which incorporates genetic drift, mutations as well as gene flow and sexual selection can be mathematically described mathematically.

Recent discoveries in the field of evolutionary developmental biology have shown that variations can be introduced into a species by mutation, genetic drift, and reshuffling of genes during sexual reproduction, as well as by migration between populations. These processes, in conjunction with others such as directionally-selected selection and erosion of genes (changes in 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 in individuals).

Students can gain a better understanding of the concept of phylogeny through incorporating evolutionary thinking throughout all aspects of biology. In a recent study by Grunspan et al., it was shown that teaching students about the evidence for evolution increased their understanding of evolution in the course of a college biology. For more information on how to teach about evolution, please see The Evolutionary Potential of All Areas of Biology and Thinking Evolutionarily: A Framework for 에볼루션 사이트 Infusing Evolution into Life Sciences Education.

Evolution in Action

Scientists have looked at evolution through the past, analyzing fossils and comparing species. They also study living organisms. Evolution is not a past event, but an ongoing process that continues to be observed today. Bacteria evolve and resist antibiotics, viruses re-invent themselves and elude new medications, and animals adapt their behavior in response to the changing climate. The changes that result are often easy to see.

However, it wasn't until late-1980s that biologists realized that natural selection could be observed in action as well. The key is that different traits confer different rates of survival and reproduction (differential fitness) and are passed from one generation to the next.

In the past, if one allele - the genetic sequence that determines colour was present in a population of organisms that interbred, it might become more common than other allele. In time, this could mean 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.

Observing evolutionary change in action is much easier when a species has a fast generation turnover like bacteria. Since 1988, biologist Richard Lenski has been tracking twelve populations of E. Coli that descended from a single strain. samples from each population are taken regularly and 에볼루션바카라사이트 - https://Lovewiki.faith - over 50,000 generations have now been observed.

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

Another example of microevolution is how mosquito genes that are resistant to pesticides show up more often in populations where insecticides are used. Pesticides create a selective pressure which favors those who have resistant genotypes.

The rapidity of evolution has led to an increasing recognition of its importance, especially in a world shaped largely by human activity. This includes pollution, climate change, and habitat loss, which prevents many species from adapting. Understanding the evolution process will assist you in making better choices about the future of the planet and its inhabitants.