The Academy's Evolution Site
The concept of biological evolution is among the most fundamental concepts in biology. The Academies have long been involved in helping those interested in science understand the concept of evolution and how it affects all areas of scientific exploration.
This site provides students, teachers and general readers with a range of learning resources about evolution. It has the most 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 appears in many cultures and spiritual beliefs as an emblem of unity and love. It also has many practical applications, like providing a framework for understanding the history of species and how they respond to changes in the environment.
The first attempts at depicting the world of biology 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 different parts of organisms, or DNA fragments, have significantly increased the diversity of a tree of Life2. However the trees are mostly made up of eukaryotes. Bacterial diversity is still largely unrepresented3,4.
By avoiding the need for direct experimentation and observation, genetic techniques have enabled us to depict the Tree of Life in a much more accurate way. Particularly, molecular methods enable us to create trees using sequenced markers, such as the small subunit ribosomal RNA gene.
Despite the rapid expansion of the Tree of Life through genome sequencing, a lot of biodiversity is waiting to be discovered. This is especially true of microorganisms, which can be difficult to cultivate and are often only represented in a single sample5. Recent analysis of all genomes produced an initial draft of the Tree of Life. This includes a wide range of archaea, bacteria, and other organisms that haven't yet been isolated, or the diversity of which is not well understood6.
The expanded Tree of Life can be used to determine the diversity of a particular area and determine if specific habitats need special protection. This information can be utilized in a variety of ways, such as identifying new drugs, combating diseases and improving the quality of crops. This information is also extremely valuable for conservation efforts. It can help biologists identify areas that are likely to be home to cryptic species, which may perform important metabolic functions, and could be susceptible to changes caused by humans. Although funding to protect biodiversity are crucial, ultimately the best way to preserve the world's biodiversity is for more people living in developing countries to be empowered with the knowledge to act locally in order to promote conservation from within.
Phylogeny
A phylogeny, also known as an evolutionary tree, illustrates the relationships between different groups of organisms. Scientists can create an phylogenetic chart which shows the evolutionary relationships between taxonomic groups based on molecular data and morphological similarities or differences. Phylogeny is crucial in understanding biodiversity, evolution and genetics.
A basic phylogenetic Tree (see Figure PageIndex 10 ) determines the relationship between organisms with similar traits that have evolved from common ancestral. These shared traits can be either analogous or homologous. Homologous traits are identical in their underlying evolutionary path, while analogous traits look similar, but do not share the identical origins. Scientists group similar traits together into a grouping referred to as a clade. For example, all of the organisms that make up a clade share the trait of having amniotic eggs and evolved from a common ancestor which had eggs. The clades are then linked to form a phylogenetic branch to determine which organisms have the closest relationship to.
Scientists make use of DNA or RNA molecular information to build a phylogenetic chart that is more precise and precise. This information is more precise than the morphological data and provides evidence of the evolutionary history of an individual or group. Researchers can utilize Molecular Data to estimate the age of evolution of living organisms and discover how many organisms have the same ancestor.
The phylogenetic relationships of a species can be affected by a number of factors, including the phenotypic plasticity. This is a type behaviour that can change in response to specific environmental conditions. This can make a trait appear more similar to one species than another, obscuring the phylogenetic signals. This issue can be cured by using cladistics. This is a method that incorporates the combination of homologous and analogous traits in the tree.
In addition, phylogenetics helps determine the duration and speed at which speciation occurs. This information can help conservation biologists decide which species they should protect from extinction. Ultimately, it is the preservation of phylogenetic diversity that will create a complete and balanced ecosystem.
Evolutionary Theory
The fundamental concept in evolution is that organisms change over time due to 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 envisioned an organism developing slowly in accordance with its needs and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits cause changes that can be passed on to offspring.
In the 1930s and 1940s, ideas from a variety of fields--including genetics, natural selection, and particulate inheritance -- came together to form the current evolutionary theory 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 incorporates 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 revealed that variations can be introduced into a species via mutation, genetic drift and reshuffling genes during sexual reproduction, as well as through the movement of populations. These processes, as well as others such as directional selection and gene erosion (changes in the frequency of genotypes over time) can result in evolution. Evolution is defined by changes in the genome over time, as well as changes in the phenotype (the expression of genotypes in individuals).
Incorporating evolutionary thinking into all aspects of biology education can improve students' understanding of phylogeny as well as evolution. In a recent study by Grunspan and co. It was demonstrated that teaching students about the evidence for evolution increased their acceptance of evolution during a college-level course in biology. For more information about how to teach evolution look up The Evolutionary Potency in All Areas of Biology or Thinking Evolutionarily: a Framework for Integrating Evolution into Life Sciences Education.
Evolution in Action
Scientists have looked at evolution through the past, studying fossils, and comparing species. They also observe living organisms. Evolution is not a past event, but a process that continues today. Bacteria mutate and resist antibiotics, viruses re-invent themselves and elude new medications and animals alter their behavior in response to the changing climate. The resulting changes are often visible.
It wasn't until the late 1980s when biologists began to realize that natural selection was at work. The key is that different characteristics result in 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 defines color in a population of interbreeding species, it could rapidly become more common than the other alleles. In time, this could mean that the number of moths sporting black pigmentation in a population may increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.
Monitoring evolutionary changes in action is easier when a species has a rapid turnover of its generation like bacteria. Since 1988, biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain. samples of each are taken every day, and over fifty thousand generations have been observed.
Going In this article has revealed that mutations can alter the rate at which change occurs and the effectiveness at which a population reproduces. It also proves that evolution takes time--a fact that some people are unable to accept.
Another example of microevolution is the way mosquito genes that are resistant to pesticides are more prevalent in populations where insecticides are employed. This is because pesticides cause an enticement that favors individuals who have resistant genotypes.
에볼루션 바카라 of evolution has led to a greater recognition of its importance especially in a planet which is largely shaped by human activities. This includes climate change, pollution, and habitat loss that hinders many species from adapting. Understanding the evolution process will aid you in making better decisions about the future of our planet and its inhabitants.