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The Academy's Evolution Site

Biology is a key concept in biology. The Academies are involved in helping those interested in science comprehend the evolution theory and how it is incorporated in all areas of scientific research.

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

Tree of Life

The Tree of Life is an ancient symbol of the interconnectedness of life. It is seen in a variety of religions and cultures as symbolizing unity and love. It has many practical applications as well, such as 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 organisms into distinct categories which had been distinguished by their physical and metabolic characteristics1. These methods, which are based on the sampling of different parts of organisms or short fragments of DNA have greatly increased the diversity of a tree of Life2. These trees are largely composed by eukaryotes and bacterial diversity is vastly underrepresented3,4.

In avoiding the necessity of direct observation and experimentation, genetic techniques have enabled us to depict the Tree of Life in a more precise manner. Particularly, molecular methods enable us to create trees by using sequenced markers like the small subunit ribosomal RNA gene.

The Tree of Life has been greatly expanded thanks to genome sequencing. However, there is still much biodiversity to be discovered. This is particularly relevant to microorganisms that are difficult to cultivate and are typically found in one sample5. A recent study of all genomes known to date has created a rough draft of the Tree of Life, including numerous archaea and bacteria that have not been isolated and 에볼루션 바카라 무료체험 which are not well understood.

The expanded Tree of Life can be used to assess the biodiversity of a particular area and determine if particular habitats require special protection. The information can be used in a range of ways, from identifying the most effective medicines to combating disease to enhancing crop yields. This information is also extremely useful in conservation efforts. It can aid biologists in identifying the areas that are most likely to contain cryptic species that could have significant metabolic functions that could be vulnerable to anthropogenic change. While funds to protect biodiversity are important, the most effective method to protect the world's biodiversity is to equip more people in developing nations with the necessary knowledge to act locally and support conservation.

Phylogeny

A phylogeny, also known as an evolutionary tree, reveals the relationships between different groups of organisms. By using molecular information, morphological similarities and differences or ontogeny (the course of development of an organism) scientists can create a phylogenetic tree which illustrates the evolutionary relationship between taxonomic categories. The role of phylogeny is crucial in understanding genetics, biodiversity and evolution.

A basic phylogenetic tree (see Figure PageIndex 10 ) identifies the relationships between organisms with similar traits that evolved from common ancestral. These shared traits may be analogous, or homologous. Homologous traits are the same in their evolutionary paths. Analogous traits may look like they are however they do not have the same origins. Scientists combine similar traits into a grouping called a the clade. Every organism in a group share a trait, such as amniotic egg production. They all derived from an ancestor that had these eggs. A phylogenetic tree can be constructed by connecting the clades to identify the organisms which are the closest to one another.

For a more precise and accurate phylogenetic tree scientists make use of molecular data from DNA or RNA to establish the relationships among organisms. This information is more precise and gives evidence of the evolution history of an organism. Researchers can use Molecular Data to calculate the evolutionary age of organisms and identify the number of organisms that share the same ancestor.

The phylogenetic relationships of a species can be affected by a number of factors such as the phenomenon of phenotypicplasticity. This is a type of behavior that changes due to particular environmental conditions. This can cause a characteristic to appear more similar to one species than to the other and obscure the phylogenetic signals. This issue can be cured by using cladistics, which is a an amalgamation of homologous and analogous features in the tree.

In addition, phylogenetics can aid in predicting the duration and rate of speciation. This information can aid conservation biologists to decide which species they should protect from extinction. It is ultimately the preservation of phylogenetic diversity that will create 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 scientists have proposed theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism could 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 traits can cause changes that can be passed on to future generations.

In the 1930s and 1940s, concepts from a variety of fields -- including natural selection, genetics, and particulate inheritance - came together to form the current synthesis of evolutionary theory which explains how evolution happens through the variations of genes within a population and how those variants change in time as a result of natural selection. This model, known as genetic drift, mutation, gene flow and sexual selection, 에볼루션 바카라 무료체험 is a key element of current evolutionary biology, and can be mathematically described.

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

Students can better understand phylogeny by incorporating evolutionary thinking into all aspects of biology. In a recent study conducted by Grunspan and colleagues., it was shown that teaching students about the evidence for evolution increased their understanding of evolution in the course of a college biology. To find out 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 traditionally studied evolution by looking in the past--analyzing 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 taking place today. Viruses evolve to stay away from new medications and bacteria mutate to resist antibiotics. Animals alter their behavior because of the changing environment. The results are usually evident.

But it wasn't until the late 1980s that biologists realized that natural selection could be seen in action, as well. The key is that various characteristics result in different rates of survival and reproduction (differential fitness) and can be passed from one generation to the next.

In the past when one particular allele, the genetic sequence that controls coloration - was present in a population of interbreeding organisms, it might rapidly become more common than other alleles. As time passes, this could mean that the number of moths sporting black pigmentation 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 turnover of its generation such as bacteria. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that are descended from a single strain. Samples of each population were taken regularly and more than 500.000 generations of E.coli have been observed to have passed.

Lenski's research has revealed that a mutation can dramatically alter the efficiency with the rate at which a population reproduces, and consequently the rate at which it evolves. It also demonstrates that evolution takes time, which is difficult for some to accept.

Another example of microevolution is the way mosquito genes that are resistant to pesticides are more prevalent in populations where insecticides are used. Pesticides create a selective pressure which favors those 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 climate change, 바카라 에볼루션 바카라 에볼루션 무료체험 (Https://Offercereal99.Bravejournal.Net/15-Gifts-For-The-Evolution-Baccarat-Free-Experience-Lover-In-Your-Life) pollution, and habitat loss that hinders many species from adapting. Understanding the evolution process can help you make better decisions about the future of our planet and its inhabitants.