9 Signs You're A Evolution Site Expert
The Academy's Evolution Site
Biology is a key concept in biology. The Academies have long been involved in helping those interested in science understand the theory of evolution and how it affects every area of scientific inquiry.
This site provides students, teachers and general readers with a wide range of educational resources on evolution. It contains key video clips from NOVA and WGBH produced science programs on DVD.
Tree of Life
The Tree of Life is an ancient symbol that symbolizes the interconnectedness of all life. It is seen in a variety of religions and cultures as a symbol of unity and love. It also has practical uses, like providing a framework for understanding the evolution of species and how they react to changes in environmental conditions.
The first attempts at depicting the biological world focused on the classification of organisms into distinct categories that were identified by their physical and metabolic characteristics1. These methods depend on the sampling of different parts of organisms or short DNA fragments, have significantly increased the diversity of a tree of Life2. However these trees are mainly made up of eukaryotes. Bacterial diversity is still largely unrepresented3,4.
Genetic techniques have greatly expanded our ability to represent the Tree of Life by circumventing the requirement for direct observation and experimentation. Particularly, molecular methods enable us to create trees by using sequenced markers like the small subunit ribosomal RNA gene.
에볼루션 바카라 무료 of Life has been significantly expanded by genome sequencing. However there is a lot of biodiversity to be discovered. This is especially true for microorganisms that are difficult to cultivate and which are usually only found in one sample5. A recent study of all genomes that are known has produced a rough draft version of the Tree of Life, including many archaea and bacteria that have not been isolated and whose diversity is poorly understood6.
This expanded Tree of Life is particularly useful in assessing the diversity of an area, which can help to determine whether specific habitats require protection. This information can be used in a variety of ways, from identifying the most effective remedies to fight diseases to enhancing the quality of crop yields. The information is also incredibly useful in conservation efforts. It can help biologists identify those areas that are most likely contain cryptic species with important metabolic functions that may be at risk from anthropogenic change. While funds to safeguard biodiversity are vital but the most effective way to preserve the world's biodiversity is for more people in developing countries to be empowered with the knowledge to act locally to promote conservation from within.
Phylogeny
A phylogeny (also called an evolutionary tree) illustrates the relationship between organisms. Using molecular data as well as morphological similarities and distinctions or ontogeny (the process of the development of an organism) scientists can construct an phylogenetic tree that demonstrates the evolutionary relationship between taxonomic categories. The phylogeny of a tree plays an important role in understanding genetics, biodiversity and evolution.
A basic phylogenetic tree (see Figure PageIndex 10 ) identifies the relationships between organisms with similar traits that have evolved from common ancestral. These shared traits can be either homologous or analogous. Homologous traits share their underlying evolutionary path and analogous traits appear like they do, but don't have the identical origins. Scientists put similar traits into a grouping known as a Clade. For example, all of the organisms that make up a clade share the characteristic of having amniotic eggs. They evolved from a common ancestor who had these eggs. The clades are then connected to form a phylogenetic branch that can determine the organisms with the closest connection to each other.
Scientists use DNA or RNA molecular data to construct a phylogenetic graph which is more precise and precise. This information is more precise than morphological data and gives evidence of the evolutionary history of an organism or group. Researchers can use Molecular Data to determine the evolutionary age of living organisms and discover the number of organisms that have the same ancestor.
The phylogenetic relationships between species can be affected by a variety of factors, including phenotypic plasticity a type of behavior that alters in response to specific environmental conditions. This can cause a characteristic to appear more like a species another, clouding the phylogenetic signal. However, this issue can be solved through the use of methods like cladistics, which incorporate a combination of analogous and homologous features into the tree.
Additionally, phylogenetics can help determine the duration and rate of speciation. This information can assist conservation biologists make decisions about which species to protect from extinction. It is ultimately the preservation of phylogenetic diversity that will create an ecosystem that is complete and balanced.
Evolutionary Theory
The central theme of evolution is that organisms acquire distinct characteristics over time due to their interactions with their environments. Many scientists have developed 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, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical system of taxonomy, as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the usage or non-use of traits can lead to changes that are passed on to the next generation.
In the 1930s & 1940s, theories from various fields, including genetics, natural selection and particulate inheritance, came together to form a modern theorizing of evolution. This defines how evolution is triggered by the variation of genes in the population, and how these variants change over time as a result of natural selection. This model, known as genetic drift, mutation, gene flow, and sexual selection, is a cornerstone of modern evolutionary biology and can be mathematically explained.
Recent discoveries in the field of evolutionary developmental biology have revealed that variations can be introduced into a species by mutation, genetic drift, and reshuffling of genes in sexual reproduction, as well as through migration between populations. These processes, in conjunction with other ones like directionally-selected selection and erosion of genes (changes in the frequency of genotypes over time) can result in evolution. Evolution is defined as changes in the genome over time, as well as changes in phenotype (the expression of genotypes in an individual).
Students can better understand the concept of phylogeny by using evolutionary thinking throughout all aspects of biology. In a recent study by Grunspan and co. It was demonstrated that teaching students about the evidence for evolution boosted their acceptance of evolution during an undergraduate biology course. For more information on how to teach about evolution, look up The Evolutionary Potential of All Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution in Life Sciences Education.
Evolution in Action
Traditionally, scientists have studied evolution through looking back--analyzing fossils, comparing species and studying living organisms. Evolution isn't a flims event, but an ongoing process that continues to be observed today. The virus reinvents itself to avoid new drugs and bacteria evolve to resist antibiotics. Animals adapt their behavior because of a changing environment. The resulting changes are often evident.
However, it wasn't until late 1980s that biologists realized that natural selection could be observed in action as well. The key is the fact that different traits confer an individual rate of survival and reproduction, and they can be passed down from one generation to another.
In the past, if an allele - the genetic sequence that determines colour was present in a population of organisms that interbred, it could be more prevalent than any other allele. As time passes, this could mean that the number of moths sporting black pigmentation may increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.
Observing evolutionary change in action is easier when a species has a rapid turnover of its generation such as bacteria. Since 1988, biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain; samples of each population are taken every day, and over fifty thousand generations have been observed.
Lenski's research has revealed that mutations can drastically alter the rate at which a population reproduces and, consequently, the rate at which it evolves. It also proves that evolution is slow-moving, a fact that some find hard to accept.
Microevolution is also evident in the fact that mosquito genes for pesticide resistance are more prevalent in areas where insecticides have been used. This is because the use of pesticides causes a selective pressure that favors those with resistant genotypes.
The speed of evolution taking place has led to a growing recognition of its importance in a world that is shaped by human activities, including climate changes, pollution and the loss of habitats that prevent many species from adjusting. Understanding evolution can help us make better decisions regarding the future of our planet and the life of its inhabitants.