The Academy's Evolution Site
Biology is one of the most important concepts in biology. The Academies have been for a long time involved in helping people who are interested in science understand the theory of evolution and how it permeates every area of scientific inquiry.
This site offers a variety of resources for teachers, students and general readers of evolution. It contains key video clips from NOVA and WGBH's 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 cultures and spiritual beliefs as symbolizing unity and love. It also has practical applications, like providing a framework for understanding the history of species and how they respond to changes in the environment.
The first attempts to depict the world of biology were built on categorizing organisms based on their metabolic and physical characteristics. These methods, which rely on sampling of different parts of living organisms, or sequences of short fragments of their DNA significantly increased the variety that could be included in the tree of life2. These trees are largely composed by eukaryotes, and the diversity of bacterial species is greatly underrepresented3,4.
By avoiding the necessity for direct observation and experimentation, genetic techniques have made it possible to depict the Tree of Life in a more precise way. Particularly, molecular methods allow us to construct trees using sequenced markers such as the small subunit ribosomal gene.
The Tree of Life has been greatly expanded thanks to genome sequencing. However there is still a lot of biodiversity to be discovered. This is especially the case for microorganisms which are difficult to cultivate and are typically found in one sample5. Recent analysis of all genomes resulted in an initial draft of the Tree of Life. This includes a large number of archaea, bacteria, and other organisms that haven't yet been identified or their diversity is not fully understood6.
This expanded Tree of Life can be used to determine the diversity of a specific area and determine if particular habitats need special protection. This information can be utilized in a range of ways, from identifying the most effective treatments to fight disease to improving the quality of crops. This information is also useful for conservation efforts. It can help biologists identify the areas most likely to contain cryptic species that could have important metabolic functions that could be at risk from anthropogenic change. Although funds to safeguard biodiversity are vital, ultimately the best way to preserve the world's biodiversity is for more people living in developing countries to be empowered with the necessary knowledge to take action locally to encourage conservation from within.
Phylogeny
A phylogeny (also called an evolutionary tree) illustrates the relationship between species. By using molecular information similarities and differences in morphology or ontogeny (the course of development of an organism) scientists can create a phylogenetic tree that illustrates the evolutionary relationships between taxonomic groups. The concept of phylogeny is fundamental to understanding biodiversity, evolution and genetics.
에볼루션 슬롯 (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms with similar traits that have evolved from common ancestral. These shared traits can be analogous or homologous. Homologous characteristics are identical in terms of their evolutionary journey. Analogous traits could appear like they are but they don't have the same ancestry. Scientists organize similar traits into a grouping referred to as a clade. Every organism in a group have a common characteristic, for example, amniotic egg production. They all came from an 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.
For a more precise and accurate phylogenetic tree scientists rely on molecular information from DNA or RNA to determine the connections between organisms. This information is more precise and provides evidence of the evolution history of an organism. Researchers can use Molecular Data to estimate the age of evolution of organisms and determine how many organisms have a common ancestor.
The phylogenetic relationship can be affected by a variety of factors, including the phenomenon of phenotypicplasticity. This is a kind of behavior that alters as a result of particular environmental conditions. This can cause a characteristic to appear more similar to one species than another, obscuring the phylogenetic signal. 에볼루션 바카라 체험 can be cured by using cladistics, which incorporates a combination of homologous and analogous features 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 the threat of extinction. In the end, it's the preservation of phylogenetic diversity that will result in a complete and balanced ecosystem.
Evolutionary Theory
The central theme in evolution is that organisms change over time as a result of their interactions with their environment. Many scientists have developed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism could evolve according to its own needs and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern taxonomy system that is hierarchical and Jean-Baptiste Lamarck (1844-1829), who believed that the use or non-use of certain traits can result in changes that are passed on to the next generation.
In the 1930s and 1940s, concepts from a variety of fields--including genetics, natural selection, and particulate inheritance - came together to form the current evolutionary theory, which defines how evolution is triggered by the variations of genes within a population and how these variants change over time as a result of natural selection. This model, which encompasses mutations, genetic drift, gene flow and sexual selection, can be mathematically described mathematically.
Recent advances in the field of evolutionary developmental biology have revealed how variations can be introduced to a species via genetic drift, mutations and reshuffling of genes during sexual reproduction and the movement between populations. These processes, along with others like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time) can result in evolution that is defined as changes in the genome of the species over time and also by changes in phenotype as time passes (the expression of that genotype within the individual).
Students can gain a better understanding of the concept of phylogeny through incorporating evolutionary thinking throughout all areas of biology. A recent study conducted by Grunspan and colleagues, for example, showed that teaching about the evidence that supports evolution helped students accept the concept of evolution in a college-level biology course. For more details on how to teach about evolution look up The Evolutionary Power of Biology in all Areas of Biology or Thinking Evolutionarily A Framework for Integrating 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 observe living organisms. However, evolution isn't something that happened in the past; it's an ongoing process that is happening right now. The virus reinvents itself to avoid new antibiotics and bacteria transform to resist antibiotics. Animals alter their behavior in the wake of a changing world. The changes that result are often apparent.
It wasn't until late 1980s when biologists began to realize that natural selection was also in action. The key is the fact that different traits can confer a different rate of survival and reproduction, and can be passed on from one generation to another.
In the past when one particular allele, the genetic sequence that defines color in a population of interbreeding species, it could quickly become more prevalent than all other alleles. In time, this could mean that the number of moths with black pigmentation 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 an organism, like bacteria, has a rapid generation turnover. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain. samples from each population are taken regularly and over 500.000 generations have passed.
Lenski's research has demonstrated that mutations can alter the rate at which change occurs and the rate of a population's reproduction. It also shows evolution takes time, something that is difficult for some to accept.
Microevolution can be observed in the fact that mosquito genes for resistance to pesticides are more prevalent in populations that have used insecticides. That's because the use of pesticides creates a selective pressure that favors individuals with resistant genotypes.
에볼루션 사이트 of evolution has led to a greater awareness of its significance particularly in a world shaped largely by human activity. This includes climate change, pollution, and habitat loss that prevents many species from adapting. Understanding the evolution process can help us make smarter decisions about the future of our planet and the life of its inhabitants.