The Academy's Evolution Site

Biology is a key concept in biology. The Academies have been active for 에볼루션 룰렛 a long time in helping those interested in science comprehend the theory of evolution and how it influences every area of scientific inquiry.

This site provides students, teachers and general readers with a range of learning resources on evolution. It includes 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 seen in a variety of cultures and spiritual beliefs as symbolizing unity and love. It also has practical applications, like providing a framework for understanding the history of species and how they react to changing environmental conditions.

The first attempts at depicting the biological world focused on categorizing species into distinct categories that were distinguished by their physical and 무료 에볼루션 metabolic characteristics1. These methods, which are based on the collection of various parts of organisms or DNA fragments have significantly increased the diversity of a tree of Life2. These trees are mostly populated by eukaryotes and the diversity of bacterial species is greatly underrepresented3,4.

In avoiding the necessity of direct observation and experimentation genetic techniques have allowed us to represent the Tree of Life in a more precise way. We can construct trees using molecular techniques, such as the small-subunit ribosomal gene.

The Tree of Life has been greatly expanded thanks to genome sequencing. However, there is still much diversity to be discovered. This is especially true of microorganisms, which can be difficult to cultivate and are usually only found in a single sample5. A recent analysis of all known genomes has produced a rough draft version of the Tree of Life, including a large number of bacteria and archaea that are not isolated and which are not well understood.

The expanded Tree of Life can be used to assess the biodiversity of a specific region and determine if specific habitats require special protection. The information can be used in a range of ways, from identifying the most effective treatments to fight disease to enhancing crop yields. This information is also useful for conservation efforts. It helps biologists discover areas that are most likely to have species that are cryptic, which could have important metabolic functions and be vulnerable to the effects of human activity. While funding to protect biodiversity are essential, 에볼루션 the best way to conserve the biodiversity of the world is to equip more people in developing countries with the information they require to take action locally and encourage conservation.

Phylogeny

A phylogeny (also known as an evolutionary tree) depicts the relationships between different organisms. Using molecular data, morphological similarities and differences, or ontogeny (the course of development of an organism), scientists can build a phylogenetic tree that illustrates the evolutionary relationships between taxonomic groups. The concept of phylogeny is fundamental to understanding evolution, biodiversity and genetics.

A basic phylogenetic Tree (see Figure PageIndex 10 Determines the relationship between organisms with similar traits and evolved from an ancestor with common traits. These shared traits can be either analogous or 에볼루션 바카라사이트 homologous. Homologous traits are similar in terms of their evolutionary paths. Analogous traits might appear similar but they don't share the same origins. Scientists group similar traits together into a grouping known as a clade. All members of a clade share a characteristic, for example, amniotic egg production. They all came from an ancestor 에볼루션 바카라 무료 with these eggs. A phylogenetic tree is constructed by connecting clades to determine the organisms who are the closest to one another.

Scientists utilize molecular DNA or RNA data to create a phylogenetic chart that is more precise and precise. This information is more precise and provides evidence of the evolution history of an organism. Researchers can utilize Molecular Data to estimate the age of evolution of organisms and identify how many organisms have a common ancestor.

The phylogenetic relationships between species can be affected by a variety of factors, including phenotypic plasticity an aspect of behavior that changes in response to specific environmental conditions. This can cause a trait to appear more like a species another, clouding the phylogenetic signal. However, this issue can be reduced by the use of techniques like cladistics, which include a mix of homologous and analogous features into the tree.

In addition, phylogenetics can aid in predicting the duration and rate of speciation. This information will assist conservation biologists in making choices about which species to save from extinction. Ultimately, it is the preservation of phylogenetic diversity that will result in an ecologically balanced and complete ecosystem.

Evolutionary Theory

The fundamental concept in evolution is that organisms change over time due to their interactions with their environment. Many scientists have proposed theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism would develop according to its own requirements and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern taxonomy system that is hierarchical as well as Jean-Baptiste Lamarck (1844-1829), who believed that the use or absence of certain traits can result in changes that are passed on to the next generation.

In the 1930s and 1940s, theories from a variety of fields -- including genetics, natural selection, and particulate inheritance -- came together to create the modern evolutionary theory, which defines 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, mutations, gene flow and sexual selection is mathematically described mathematically.

Recent advances in the field of evolutionary developmental biology have revealed how variation can be introduced to a species by genetic drift, mutations and reshuffling of genes during sexual reproduction and the movement between populations. These processes, in conjunction with others, such as directionally-selected selection and erosion of genes (changes to the frequency of genotypes over time), can lead towards evolution. Evolution is defined by changes in the genome over time and changes in phenotype (the expression of genotypes in an individual).

Students can better understand phylogeny by incorporating evolutionary thinking in all areas of biology. A recent study by Grunspan and colleagues, for example demonstrated that teaching about the evidence for evolution increased students' acceptance of evolution in a college biology course. 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 Infusing Evolution in Life Sciences Education.

Evolution in Action

Traditionally scientists have studied evolution by looking back--analyzing fossils, comparing species and observing living organisms. Evolution is not a past event, but an ongoing process that continues to be observed today. Viruses evolve to stay away from new antibiotics and bacteria transform to resist antibiotics. Animals adapt their behavior as a result of a changing world. The results are usually evident.

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

In the past, if one particular allele, the genetic sequence that controls coloration - was present in a group of interbreeding organisms, 에볼루션 바카라 무료 it could rapidly become more common than other alleles. In time, this 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.

Observing evolutionary change in action is much easier when a species has a rapid generation turnover such as bacteria. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that are descended from one strain. The samples of each population have been collected regularly and more than 500.000 generations of E.coli have passed.

Lenski's research has shown that mutations can drastically alter the rate at which a population reproduces--and so, the rate at which it evolves. It also proves that evolution takes time--a fact that some find hard to accept.

Microevolution can also be seen in the fact that mosquito genes for pesticide resistance are more common in populations where insecticides have been used. That's because the use of pesticides creates a pressure that favors those with resistant genotypes.

The rapidity of evolution has led to an increasing appreciation of its importance, especially in a world which is largely shaped by human activities. This includes climate change, pollution, and habitat loss that prevents many species from adapting. Understanding evolution can help us make better decisions regarding the future of our planet and the life of its inhabitants.