The Academy's Evolution Site
The concept of biological evolution is among the most important concepts in biology. The Academies are committed to helping those interested in the sciences comprehend the evolution theory and how it can be applied across all areas of scientific research.
This site provides a range of sources for teachers, students, and general readers on evolution. It contains key 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 an emblem of love and unity in many cultures. It also has many practical uses, like providing a framework to understand the evolution of species and how they respond to changing environmental conditions.
The earliest attempts to depict the biological world focused on separating species into distinct categories that had been distinguished by physical and metabolic characteristics1. These methods are based on the sampling of different parts of organisms or fragments of DNA, have greatly increased the diversity of a Tree of Life2. The trees are mostly composed of eukaryotes, while bacterial diversity is vastly underrepresented3,4.
By avoiding the necessity for direct experimentation and observation, genetic techniques have enabled us to represent the Tree of Life in a more precise manner. Trees can be constructed using molecular techniques such as the small subunit ribosomal gene.
Despite the massive expansion of the Tree of Life through genome sequencing, a large amount of biodiversity remains to be discovered. This is particularly true for microorganisms that are difficult to cultivate and are typically only represented in a single sample5. A recent analysis of all genomes resulted in an unfinished draft of a Tree of Life. This includes a wide range of archaea, bacteria, and other organisms that have not yet been isolated, or whose diversity has not been well understood6.
This expanded Tree of Life is particularly useful for assessing the biodiversity of an area, assisting to determine if certain habitats require protection. This information can be utilized in a variety of ways, from identifying the most effective treatments to fight disease to improving crop yields. This information is also beneficial for conservation efforts. It can aid biologists in identifying areas that are likely to be home to species that are cryptic, which could perform important metabolic functions and are susceptible to changes caused by humans. While 에볼루션 슬롯게임 are important, the most effective method to protect the world's biodiversity is to equip more people in developing countries with the information they require to act locally and support conservation.
Phylogeny
A phylogeny is also known as an evolutionary tree, reveals the connections between various groups of organisms. Scientists can build an phylogenetic chart which shows the evolution of taxonomic groups using molecular data and morphological similarities or differences. 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 ancestors. These shared traits could be either analogous or homologous. Homologous traits are similar in their evolutionary origins and analogous traits appear similar, but do not share the same origins. Scientists organize similar traits into a grouping known as a Clade. For instance, all of the species in a clade share the characteristic of having amniotic egg and evolved from a common ancestor that had eggs. The clades are then connected to create a phylogenetic tree to determine which organisms have the closest relationship to.
Scientists utilize DNA or RNA molecular data to build a phylogenetic chart that is more accurate and detailed. This information is more precise and provides evidence of the evolution history of an organism. The analysis of molecular data can help researchers identify the number of species who share the same ancestor and estimate their evolutionary age.
The phylogenetic relationships of organisms are influenced by many factors, including phenotypic plasticity a kind of behavior that alters in response to unique environmental conditions. This can cause a characteristic to appear more resembling to one species than another, obscuring the phylogenetic signals. This issue can be cured by using cladistics, which incorporates a combination of homologous and analogous traits in the tree.
In addition, phylogenetics can help predict the duration and rate of speciation. This information can assist conservation biologists decide which species to protect from the threat of extinction. In the end, it's the conservation of phylogenetic diversity that will result in an ecosystem that is complete and balanced.
Evolutionary Theory
The main idea behind evolution is that organisms acquire various characteristics over time based on their interactions with their environment. Many theories of evolution have been proposed by a wide variety of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop gradually according to its requirements and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who developed modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits can cause changes that could be passed on to offspring.
In click homepage and 1940s, ideas from various fields, including genetics, natural selection, and particulate inheritance -- came together to create the modern evolutionary theory, which defines how evolution happens through the variation of genes within a population and how those variations change in time as a result of natural selection. This model, which encompasses genetic drift, mutations, gene flow and sexual selection can be mathematically described.
Recent advances in the field of evolutionary developmental biology have shown how variation can be introduced to a species through mutations, genetic drift or reshuffling of genes in sexual reproduction and migration between populations. These processes, along with other ones like directional selection and genetic erosion (changes in the frequency of the genotype over time) can result in evolution that is defined as change in the genome of the species over time and also the change in phenotype as time passes (the expression of that genotype in an individual).
Students can better understand the concept of phylogeny through incorporating evolutionary thinking in all aspects of biology. A recent study conducted by Grunspan and colleagues, for instance, showed that teaching about the evidence that supports evolution increased students' understanding of evolution in a college-level biology course. For more information on how to teach about evolution, see The Evolutionary Power of Biology in all Areas of Biology or Thinking Evolutionarily A Framework for Infusing Evolution into Life Sciences Education.
Evolution in Action
Scientists have studied evolution through looking back in the past, analyzing fossils and comparing species. They also study living organisms. Evolution isn't a flims event, but an ongoing process. Bacteria transform and resist antibiotics, viruses reinvent themselves and elude new medications and animals alter their behavior to the changing climate. The results are often visible.
It wasn't until late 1980s that biologists began to realize that natural selection was in action. The key to this is that different traits confer a different rate of survival and reproduction, and they can be passed down from one generation to the next.
In the past, if one allele - the genetic sequence that determines colour - was present in a population of organisms that interbred, it could become more common than any other allele. Over time, this would mean that the number of moths with black pigmentation could increase. 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 species has a rapid generation turnover like bacteria. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that descend from one strain. Samples of each population have been collected regularly, and more than 500.000 generations of E.coli have passed.
Lenski's research has demonstrated that mutations can alter the rate at which change occurs and the rate at which a population reproduces. It also demonstrates that evolution takes time, a fact that some people find difficult to accept.
Microevolution can also be seen in the fact that mosquito genes for pesticide resistance are more prevalent in populations where insecticides are used. This is because the use of pesticides causes a selective pressure that favors those with resistant genotypes.
The speed at which evolution takes place has led to a growing appreciation of its importance in a world that is shaped by human activity, including climate changes, pollution and the loss of habitats that prevent many species from adjusting. Understanding 무료에볼루션 will help you make better decisions regarding the future of the planet and its inhabitants.