The Academy's Evolution Site
Biological evolution is a central concept in biology. The Academies have long been involved in helping those interested in science comprehend the concept of evolution and how it affects all areas of scientific exploration.
This site provides students, teachers and general readers with a wide range of learning resources on evolution. It includes key video clip from NOVA and 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 religions and cultures as symbolizing unity and love. It can be used in many practical ways in addition to providing a framework for understanding the history of species and how they respond to changing environmental conditions.
The first attempts to depict the biological world were based on categorizing organisms based on their metabolic and physical characteristics. These methods depend on the collection of various parts of organisms, or fragments of DNA have significantly increased the diversity of a Tree of Life2. However the trees are mostly composed of eukaryotes; bacterial diversity is still largely unrepresented3,4.
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. Particularly, molecular techniques enable us to create trees using sequenced markers, such as the small subunit ribosomal gene.
Despite the rapid expansion of the Tree of Life through genome sequencing, a lot of biodiversity awaits discovery. This is particularly true for microorganisms that are difficult to cultivate, and are typically present in a single sample5. Recent analysis of all genomes resulted in a rough draft of the Tree of Life. This includes a large number 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 certain habitats require special protection. This information can be utilized in a variety of ways, including finding new drugs, fighting diseases and enhancing crops. It is also useful for conservation efforts. It can aid biologists in identifying the areas that are most likely to contain cryptic species with potentially significant metabolic functions that could be at risk from anthropogenic change. Although funding to protect biodiversity are essential, ultimately the best way to protect the world's biodiversity is for more people in developing countries to be equipped with the knowledge to take action locally to encourage conservation from within.
Phylogeny
A phylogeny is also known as an evolutionary tree, illustrates the connections between groups of organisms. Using molecular data similarities and differences in morphology, or ontogeny (the process of the development of an organism) scientists can construct a phylogenetic tree that illustrates the evolutionary relationships between taxonomic groups. Phylogeny is crucial in understanding evolution, biodiversity and genetics.
A basic phylogenetic Tree (see Figure PageIndex 10 Finds the connections between organisms with similar traits and have evolved from an ancestor with common traits. These shared traits can be analogous, or homologous. Homologous traits are similar in their evolutionary path. Analogous traits might appear like they are but they don't share the same origins. Scientists put similar traits into a grouping referred to as a clade. All organisms in a group share a characteristic, like amniotic egg production. They all evolved from an ancestor who had these eggs. The clades then join to form a phylogenetic branch to identify organisms that have the closest connection to each other.
For a more precise and accurate phylogenetic tree, scientists make use of molecular data from DNA or RNA to identify the relationships among organisms. This information is more precise and gives evidence of the evolution of an organism. Researchers can use Molecular Data to estimate the evolutionary age of organisms and determine the number of organisms that share a common ancestor.
The phylogenetic relationships between organisms are influenced by many factors, including phenotypic plasticity a kind of behavior that changes in response to unique environmental conditions. This can make a trait appear more resembling to one species than to another and obscure the phylogenetic signals. However, this problem can be reduced by the use of techniques like cladistics, which include a mix of analogous and homologous features into the tree.
In addition, phylogenetics can help predict the time and pace of speciation. This information will assist conservation biologists in making decisions about which species to save from the threat of extinction. In the end, it's the preservation of phylogenetic diversity that will result in an ecosystem that is complete and balanced.
에볼루션 카지노 사이트 Evolution KR of evolution is that organisms develop distinct characteristics over time due to their interactions with their environments. Many scientists have proposed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that a living thing would evolve according to its own requirements as well as 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 lead to changes that can be passed on to future generations.
In the 1930s & 1940s, theories from various areas, including genetics, natural selection, and particulate inheritance, merged to form a contemporary theorizing of evolution. This explains how evolution occurs by the variation in genes within the population, and how these variants change with time due to natural selection. This model, which includes genetic drift, mutations as well as gene flow and sexual selection, can be mathematically described.
Recent discoveries in the field of evolutionary developmental biology have demonstrated that variations can be introduced into a species by mutation, genetic drift, and reshuffling genes during sexual reproduction, and also through the movement of populations. These processes, along with other ones like directional selection and genetic erosion (changes in the frequency of a genotype over time), can lead to evolution, which is defined by change in the genome of the species over time, and also the change in phenotype over time (the expression of the genotype in an individual).
Students can better understand the concept of phylogeny through incorporating evolutionary thinking throughout all areas of biology. In a study by Grunspan and co., it was shown that teaching students about the evidence for evolution boosted their understanding of evolution during an undergraduate biology course. To find out more about how to teach about evolution, read The Evolutionary Potential of All Areas of Biology and Thinking Evolutionarily: A Framework for Infusing Evolution into Life Sciences Education.
Evolution in Action
Scientists have traditionally looked at evolution through 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 in the present. Bacteria transform and resist antibiotics, viruses reinvent themselves and are able to evade new medications and animals change their behavior in response to the changing environment. The changes that result are often easy to see.
But it wasn't until the late 1980s that biologists realized that natural selection could be observed in action as well. The key is that various traits confer different rates of survival and reproduction (differential fitness) and can be transferred from one generation to the next.
In the past, when one particular allele - the genetic sequence that determines coloration--appeared in a group of interbreeding organisms, it could quickly become more common than other alleles. In time, this could mean that the number of moths sporting black pigmentation in a group may 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, has tracked 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 shown that mutations can drastically alter the efficiency with which a population reproduces--and so, the rate at which it alters. It also shows evolution takes time, something that is hard for some to accept.
Another example of microevolution is how mosquito genes for resistance to pesticides appear more frequently in populations where insecticides are employed. This is because pesticides cause a selective pressure which favors those with resistant genotypes.
The rapid pace at which evolution takes place has led to an increasing awareness of its significance in a world that is shaped by human activity--including climate changes, pollution and the loss of habitats that prevent many species from adapting. Understanding evolution can help you make better decisions about the future of the planet and its inhabitants.