9 Signs That You re The Evolution Site Expert

The Academy's Evolution Site

Biological evolution is one of the most fundamental concepts in biology. The Academies have been active for a long time in helping people who are interested in science understand the concept of evolution and how it permeates all areas of scientific exploration.

This site provides a range of tools for students, teachers and general readers of evolution. It contains the most important video clips from NOVA and WGBH's science programs on DVD.

Tree of Life

The Tree of Life, 에볼루션 바카라 an ancient symbol, represents the interconnectedness of all life. It is seen in a variety of religions and cultures as an emblem of unity and love. It has numerous practical applications as well, including providing a framework for understanding the history of species, and how they react to changes in environmental conditions.

Early approaches to depicting the world of biology focused on separating organisms into distinct categories that were identified by their physical and metabolic characteristics1. These methods, which are based on the sampling of different parts of organisms or short DNA fragments have significantly 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 represent the Tree of Life in a much more accurate way. We can construct trees using molecular techniques such as the small subunit ribosomal gene.

Despite the dramatic expansion of the Tree of Life through genome sequencing, a large amount of biodiversity awaits discovery. This is especially true of microorganisms that are difficult to cultivate and are often only represented in a single specimen5. A recent study of all genomes that are known has produced a rough draft version of the Tree of Life, including a large number of archaea and bacteria that have not been isolated, and 에볼루션 룰렛에볼루션 바카라 무료체험 (shenasname.Ir) whose diversity is poorly understood6.

The expanded Tree of Life can be used to evaluate the biodiversity of a particular area and determine if specific habitats require special protection. The information is useful in a variety of ways, such as finding new drugs, battling diseases and enhancing crops. This information is also extremely beneficial to conservation efforts. It can aid biologists in identifying areas that are likely to have cryptic species, which may have vital metabolic functions, and could be susceptible to the effects of human activity. While conservation funds are essential, the best method to preserve the world's biodiversity 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. Scientists can construct a phylogenetic diagram that illustrates the evolutionary relationships between taxonomic categories using molecular information and morphological differences or similarities. The role of phylogeny is crucial in understanding genetics, biodiversity and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms that share similar traits that evolved from common ancestral. These shared traits could be either analogous or homologous. Homologous traits are identical in their evolutionary origins, while analogous traits look like they do, but don't have the same ancestors. Scientists group similar traits into a grouping called a Clade. All members of a clade share a trait, such as amniotic egg production. They all came from an ancestor who had these eggs. The clades are then linked to form a phylogenetic branch that can identify organisms that have the closest connection to each other.

Scientists make use of molecular DNA or RNA data to construct a phylogenetic graph that is more precise and detailed. This information is more precise than morphological information and provides evidence of the evolutionary history of an organism or group. The analysis of molecular data can help researchers identify the number of species that share a common ancestor and to estimate their evolutionary age.

The phylogenetic relationship can be affected by a number of factors such as the phenomenon of phenotypicplasticity. This is a kind of behavior that alters as a result of particular environmental conditions. This can make a trait appear more similar to a species than another and obscure the phylogenetic signals. This problem can be mitigated by using cladistics, which is a the combination of analogous and homologous features in the tree.

In addition, phylogenetics helps determine the duration and speed of speciation. This information will assist conservation biologists in making decisions about which species to protect from the threat of extinction. In the end, it's the preservation of phylogenetic diversity that will lead to an ecosystem that is complete and balanced.

Evolutionary Theory

The main idea behind 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 such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who believed that an organism would evolve slowly according to its needs as well as the Swedish botanist Carolus Linnaeus (1707-1778) who conceived modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that the use or misuse of traits can cause changes that can be passed on to offspring.

In the 1930s and 1940s, ideas from a variety of fields--including natural selection, genetics, and particulate inheritance -- came together to create the modern evolutionary theory synthesis which explains how evolution is triggered by the variations of genes within a population, and how those variants change over time as a result of natural selection. This model, which encompasses genetic drift, mutations in gene flow, and sexual selection, can be mathematically described.

Recent discoveries in the field of evolutionary developmental biology have shown that variations can be introduced into a species via genetic drift, mutation, and reshuffling of genes in sexual reproduction, and also through the movement of populations. These processes, as well as others like directional selection and 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 also by changes in phenotype over time (the expression of the genotype in the individual).

Incorporating evolutionary thinking into all aspects of biology education could increase student understanding of the concepts of phylogeny and evolutionary. A recent study by Grunspan and colleagues, for instance demonstrated that teaching about the evidence that supports evolution increased students' understanding of evolution in a college-level biology class. To find out more about how to teach about evolution, look up The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily A Framework for Infusing the Concept of 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 study living organisms. But evolution isn't a thing that occurred in the past, it's an ongoing process that is taking place right now. Viruses evolve to stay away from new antibiotics and bacteria transform to resist antibiotics. Animals adapt their behavior in the wake of a changing environment. The changes that result are often apparent.

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

In the past, if one particular allele, the genetic sequence that defines color in a population of interbreeding species, it could quickly become more common than the other alleles. As time passes, that could mean the number of black moths in the 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 a species, such as bacteria, has a rapid generation turnover. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain. samples of each are taken regularly and more than 50,000 generations have now been observed.

Lenski's work has demonstrated that a mutation can dramatically alter the efficiency with which a population reproduces and, consequently the rate at which it alters. It also shows evolution takes time, something that is difficult for some to accept.

Another example of microevolution is that mosquito genes for resistance to pesticides appear more frequently in areas where insecticides are used. This is due to pesticides causing a selective pressure which favors those with resistant genotypes.

The speed at which evolution takes place has led to an increasing recognition of its importance in a world that is shaped by human activities, including climate change, pollution and the loss of habitats which prevent many species from adjusting. Understanding evolution can help us make better decisions about the future of our planet, and the life of its inhabitants.