The Academy's Evolution Site
The concept of biological evolution is a fundamental concept in biology. The Academies are committed to helping those interested in science understand evolution theory and how it is permeated throughout all fields of scientific research.
This site provides a wide range of tools for students, teachers and general readers of 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 of the interconnectedness of all life. It is a symbol of love and unity in many cultures. It also has important practical uses, like providing a framework to understand the history of species and how they respond to changing environmental conditions.
Early attempts to represent 에볼루션바카라사이트 were built on categorizing organisms based on their metabolic and physical characteristics. These methods, which rely on the sampling of different parts of living organisms, or short DNA fragments, significantly increased the variety that could be represented in the tree of life2. These trees are mostly populated by eukaryotes, and bacterial diversity is vastly underrepresented3,4.
Genetic techniques have greatly expanded our ability to visualize the Tree of Life by circumventing the requirement for direct observation and experimentation. Trees can be constructed by using molecular methods such as the small subunit ribosomal gene.
Despite the massive growth of the Tree of Life through genome sequencing, a large amount of biodiversity remains to be discovered. This is particularly true for microorganisms, which are difficult to cultivate and are often only represented in a single specimen5. A recent analysis of all genomes produced an unfinished draft of a 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 thoroughly understood6.
The expanded Tree of Life is particularly useful for assessing the biodiversity of an area, assisting to determine if certain habitats require protection. The information is useful in many ways, including identifying new drugs, combating diseases and enhancing crops. This information is also extremely useful to conservation efforts. It can help biologists identify areas most likely to have cryptic species, which may perform important metabolic functions, and could be susceptible to changes caused by humans. While funds to protect biodiversity are essential, the best method to preserve the world's biodiversity is to empower the people of developing nations with the knowledge they need to act locally and promote conservation.
Phylogeny
A phylogeny, also known as an evolutionary tree, illustrates the relationships between various groups of organisms. Scientists can build a phylogenetic diagram that illustrates the evolutionary relationship of taxonomic categories using molecular information and morphological similarities or differences. Phylogeny is essential in understanding biodiversity, evolution and genetics.
A basic phylogenetic Tree (see Figure PageIndex 10 Determines the relationship between organisms that have similar traits and evolved from a common ancestor. These shared traits can be either homologous or analogous. Homologous characteristics are identical in terms of their evolutionary path. Analogous traits could appear similar but they don't share the same origins. Scientists organize similar traits into a grouping referred to as a the clade. For instance, all the species in a clade have the characteristic of having amniotic eggs and evolved from a common ancestor which had these eggs. 바카라 에볼루션 is constructed by connecting clades to identify the species which are the closest to one another.
Scientists use DNA or RNA molecular information to create a phylogenetic chart that is more precise and precise. This information is more precise and provides evidence of the evolutionary history of an organism. Researchers can utilize Molecular Data to calculate the evolutionary age of organisms and determine how many species have an ancestor common to all.
The phylogenetic relationships between species can be affected by a variety of factors, including phenotypic flexibility, a kind of behavior that alters in response to specific environmental conditions. This can cause a trait to appear more resembling to one species than another which can obscure the phylogenetic signal. This issue can be cured by using cladistics, which is a a combination of analogous and homologous features in the tree.
Additionally, phylogenetics can help predict the duration and rate of speciation. This information can help conservation biologists decide which species to protect from the threat of extinction. It is ultimately the preservation of phylogenetic diversity that will create a complete and balanced ecosystem.
Evolutionary Theory
The main idea behind evolution is that organisms alter over time because of 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 could develop according to its own needs and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical taxonomy, 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, concepts from various fields, including genetics, natural selection, and particulate inheritance--came together to create the modern synthesis of evolutionary theory that explains how evolution is triggered by the variation of genes within a population and how these variants change in time due to natural selection. This model, known as genetic drift mutation, gene flow, and sexual selection, is the foundation of the current evolutionary biology and can be mathematically explained.
Recent developments in the field of evolutionary developmental biology have revealed that genetic variation 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, along with others like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time) can lead to evolution which is defined by changes in the genome of the species over time and the change in phenotype as time passes (the expression of that genotype in an individual).
Students can better understand the concept of phylogeny by using evolutionary thinking throughout all areas of biology. In a study by Grunspan et al. It was demonstrated that teaching students about the evidence for evolution increased their understanding of evolution in a college-level course in biology. To learn more about how to teach about evolution, please read The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution into Life Sciences Education.
Evolution in Action
Scientists have studied evolution through looking back in the past, studying fossils, and comparing species. They also observe living organisms. But evolution isn't just something that occurred in the past. It's an ongoing process, happening right now. Bacteria mutate and resist antibiotics, viruses re-invent themselves and escape new drugs, and animals adapt their behavior in response to the changing climate. The results are usually evident.
However, it wasn't until late 1980s that biologists understood that natural selection can be seen in action, as well. The main reason is that different traits can confer a different rate of survival and reproduction, and they can be passed on from generation to generation.
In the past when one particular allele, the genetic sequence that determines coloration--appeared in a group of interbreeding species, it could quickly become more prevalent than all other alleles. As time passes, this could mean that the number of moths that have black pigmentation in a population could 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 the species, like bacteria, has a high generation turnover. Since 에볼루션게이밍 , Richard Lenski, a biologist, has studied twelve populations of E.coli that descend from a single strain. Samples from each population were taken frequently and more than 50,000 generations of E.coli have been observed to have passed.
Lenski's research has demonstrated that mutations can alter the rate of change and the effectiveness of a population's reproduction. It also shows that evolution takes time--a fact that some are unable to accept.
Another example of microevolution is the way mosquito genes for resistance to pesticides appear more frequently in populations where insecticides are employed. This is because the use of pesticides causes a selective pressure that favors people with resistant genotypes.
The rapidity of evolution has led to a growing awareness of its significance, especially in a world that is largely shaped by human activity. This includes pollution, climate change, and habitat loss that hinders many species from adapting. Understanding the evolution process can help us make smarter decisions regarding the future of our planet as well as the life of its inhabitants.