The Academy's Evolution Site
Biological evolution is one of the most central concepts in biology. The Academies are involved in helping those who are interested in the sciences comprehend the evolution theory and how it can be applied across all areas of scientific research.
This site provides teachers, students and general readers with a range of learning resources on evolution. It also includes important video clips 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 a symbol of love and unity in many cultures. It can be used in many practical ways as well, including providing a framework to understand the evolution of species and how they react to changes in environmental conditions.
The earliest attempts to depict the biological world focused on categorizing organisms into distinct categories which had been distinguished by their physical and metabolic characteristics1. These methods, which rely on the sampling of various parts of living organisms, or sequences of short fragments of their DNA significantly increased the variety that could be represented in a tree of life2. These trees are largely composed by eukaryotes, and bacteria are largely underrepresented3,4.
Genetic techniques have greatly broadened our ability to represent the Tree of Life by circumventing the requirement for direct observation and experimentation. Trees can be constructed by using molecular methods like the small-subunit ribosomal gene.
The Tree of Life has been dramatically expanded through genome sequencing. However there is a lot of diversity to be discovered. This is especially true for microorganisms that are difficult to cultivate, and are usually found in a single specimen5. A recent analysis of all genomes produced an unfinished draft of the Tree of Life. This includes a large number of archaea, bacteria, and other organisms that have not yet been isolated, or whose diversity has not been thoroughly understood6.
에볼루션 룰렛 expanded Tree of Life is particularly useful for assessing the biodiversity of an area, which can help to determine whether specific habitats require protection. This information can be utilized in a variety of ways, from identifying the most effective medicines to combating disease to enhancing the quality of the quality of crops. This information is also beneficial for conservation efforts. It can help biologists identify the areas most likely to contain cryptic species that could have important metabolic functions that may be at risk of anthropogenic changes. While conservation funds are essential, the best way to conserve the world's biodiversity is to equip the people of developing nations with the information they require to act locally and support conservation.
Phylogeny
A phylogeny, also called an evolutionary tree, illustrates the connections between various groups of organisms. Scientists can create a phylogenetic chart that shows the evolutionary relationships between taxonomic groups using molecular data and morphological differences or similarities. Phylogeny is crucial in understanding evolution, biodiversity and genetics.
A basic phylogenetic tree (see Figure PageIndex 10 ) determines the relationship between organisms that share similar traits that evolved from common ancestors. These shared traits may be homologous, or analogous. Homologous traits are the same in terms of their evolutionary journey. Analogous traits could appear like they are, but they do not share the same origins. Scientists put similar traits into a grouping called a Clade. For example, all of the organisms in a clade share the characteristic of having amniotic egg and evolved from a common ancestor who had eggs. The clades are then linked to form a phylogenetic branch to identify organisms that have the closest relationship to.
Scientists utilize molecular DNA or RNA data to build a phylogenetic chart that is more accurate and precise. This information is more precise and provides evidence of the evolutionary history of an organism. Researchers can use Molecular Data to determine the age of evolution of organisms and identify how many organisms have an ancestor common to all.
The phylogenetic relationships between organisms 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 make a trait appear more similar to a species than to another and obscure the phylogenetic signals. However, this problem can be cured by the use of methods like cladistics, which combine analogous and homologous features into the tree.
In addition, phylogenetics can aid in predicting the time and pace of speciation. This information will assist conservation biologists in making decisions about which species to protect from disappearance. In the end, it's the preservation of phylogenetic diversity which will create an ecosystem that is complete and balanced.
Evolutionary Theory
The fundamental concept of evolution is that organisms develop different features over time due to their interactions with their environment. Many scientists have come up with theories of evolution, including 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 suggested 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 explains how evolution is triggered by the variations of genes within a population, and how these variants change in time due to natural selection. This model, which encompasses mutations, genetic drift in gene flow, and sexual selection is 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 during sexual reproduction, as well as through migration between populations. These processes, along with others such as directional selection or genetic erosion (changes in the frequency of an individual's genotype over time), can lead to evolution which is defined by change in the genome of the species over time and also by changes in phenotype over time (the expression of the genotype in an individual).
에볼루션 게이밍 can gain a better understanding of the concept of phylogeny by using evolutionary thinking throughout all aspects of biology. In a recent study by Grunspan et al. It was found that teaching students about the evidence for evolution boosted their understanding of evolution during the course of a college biology. For more information on how to teach evolution read The Evolutionary Potential in All Areas of Biology or Thinking Evolutionarily: a Framework for Integrating Evolution into Life Sciences Education.
Evolution in Action
Scientists have traditionally studied evolution through looking back in the past, analyzing fossils and comparing species. They also study living organisms. But evolution isn't a thing that happened in the past; it's an ongoing process, happening today. Bacteria transform and resist antibiotics, viruses re-invent themselves and elude new medications and animals alter their behavior in response to the changing environment. The changes that result are often visible.
에볼루션 게이밍 wasn't until the late 1980s when biologists began to realize that natural selection was at work. The key is that various traits confer different rates of survival and reproduction (differential fitness) and can be passed down from one generation to the next.
In the past, if one particular allele, the genetic sequence that defines color in a population of interbreeding organisms, it might quickly become more common than the other alleles. In time, this could mean the number of black moths in a particular population could rise. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.
The ability to observe evolutionary change is easier when a particular species has a fast generation turnover, as with bacteria. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that descend from one 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 work has demonstrated that a mutation can profoundly alter the speed at which a population reproduces and, consequently the rate at which it changes. It also shows evolution takes time, something that is difficult for some to accept.
Another example of microevolution is how mosquito genes that confer resistance to pesticides are more prevalent in areas in which insecticides are utilized. This is due to the fact that the use of pesticides causes a selective pressure that favors individuals with resistant genotypes.
The rapidity of evolution has led to a greater recognition of its importance especially in a planet that is largely shaped by human activity. This includes pollution, climate change, and habitat loss, which prevents many species from adapting. Understanding evolution can help us make better choices about the future of our planet, as well as the lives of its inhabitants.