The Academy's Evolution Site
The concept of biological evolution is a fundamental concept in biology. The Academies are involved in helping those interested in science to understand evolution theory and how it is incorporated in all areas of scientific research.
This site provides students, teachers and general readers with a wide range of learning resources about evolution. It contains key video clips from NOVA and WGBH produced science programs on DVD.
Tree of Life
The Tree of Life, an ancient symbol, symbolizes the interconnectedness of all life. It is seen in a variety of religions and cultures as symbolizing unity and love. It also has important practical uses, like providing a framework for understanding the evolution of species and how they respond to changes in the environment.
The first attempts to depict the biological world were founded on categorizing organisms on their physical and metabolic characteristics. These methods, which depend on the collection of various parts of organisms or fragments of DNA, have greatly increased the diversity of a tree of Life2. These trees are mostly populated by eukaryotes, and bacterial diversity is vastly underrepresented3,4.
By avoiding the need for direct observation and experimentation, genetic techniques have made it possible to depict the Tree of Life in a more precise manner. Particularly, molecular methods allow us to build trees using sequenced markers such as the small subunit ribosomal gene.
Despite the rapid expansion of the Tree of Life through genome sequencing, a large amount of biodiversity is waiting to be discovered. This is particularly true of microorganisms, which are difficult to cultivate and are often only represented in a single specimen5. 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 have not yet been isolated, or whose diversity has not been fully understood6.
The expanded Tree of Life is particularly useful in assessing the diversity of an area, assisting to determine if specific habitats require special protection. This information can be used in a range of ways, from identifying the most effective medicines to combating disease to improving crops. It is also useful in conservation efforts. It can help biologists identify areas that are most likely to be home to cryptic species, which could perform important metabolic functions, and could be susceptible to changes caused by humans. While funds to protect biodiversity are essential, the best way to conserve the world's biodiversity is to empower the people of developing nations with the knowledge they need to take action locally and encourage conservation.
Phylogeny
A phylogeny (also called an evolutionary tree) illustrates the relationship between species. Scientists can create an phylogenetic chart which shows the evolutionary relationships between taxonomic groups using molecular data and morphological differences or similarities. The concept of phylogeny is fundamental to understanding the evolution of biodiversity, evolution and genetics.
A basic phylogenetic tree (see Figure PageIndex 10 Determines the relationship between organisms that have similar traits and have evolved from a common ancestor. These shared traits could be either homologous or analogous. Homologous traits are similar in their evolutionary roots and analogous traits appear similar but do not have the identical origins. Scientists put similar traits into a grouping called a the clade. For instance, all of the organisms in a clade share the trait of having amniotic egg and evolved from a common ancestor which had these eggs. The clades are then linked to create a phylogenetic tree to identify organisms that have the closest connection to each other.
For a more precise and accurate phylogenetic tree scientists use molecular data from DNA or RNA to establish the relationships between organisms. This information is more precise and provides evidence of the evolution of an organism. Researchers can use Molecular Data to determine the age of evolution of organisms and identify how many organisms share an ancestor common to all.
Phylogenetic relationships can be affected by a number of factors that include phenotypicplasticity. This is a type behavior that changes in response to specific environmental conditions. This can cause a trait to appear more similar to a species than to the other which can obscure the phylogenetic signal. However, this problem can be reduced by the use of techniques like cladistics, which incorporate a combination of analogous and homologous features into the tree.
In addition, phylogenetics helps predict the duration and rate at which speciation takes place. This information can assist conservation biologists decide which species they should protect from the threat of extinction. Ultimately, it is the preservation of phylogenetic diversity that will result in a complete and balanced ecosystem.
Evolutionary Theory
The main idea behind evolution is that organisms develop different features over time based on their interactions with their surroundings. Many scientists have developed theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism could develop according to its own requirements and needs, 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 use or non-use of certain traits can result in changes that are passed on to the next generation.
In the 1930s & 1940s, concepts from various fields, including genetics, natural selection and particulate inheritance, were brought together to form a modern synthesis of evolution theory. This describes how evolution is triggered by the variations in genes within a population and how these variations alter over time due to natural selection. This model, which incorporates genetic drift, mutations, gene flow and sexual selection can be mathematically described.
Recent developments in evolutionary developmental biology have demonstrated the ways in which variation can be introduced to a species by genetic drift, mutations and reshuffling of genes during sexual reproduction, and even migration between populations. These processes, along with others like directional selection and genetic erosion (changes in the frequency of a genotype over time) can result in evolution, which is defined by change in the genome of the species over time, and also the change in phenotype as time passes (the expression of the genotype in an individual).
Incorporating evolutionary thinking into all aspects of biology education can increase students' understanding of phylogeny and evolutionary. In a study by Grunspan et al. It was found that teaching students about the evidence for evolution boosted their acceptance of evolution during the course of a college biology. For more details about how to teach 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 traditionally studied evolution through looking back in the past, analyzing fossils and comparing species. They also observe living organisms. But evolution isn't a thing that occurred in the past; it's an ongoing process, that is taking place in the present. Bacteria evolve and resist antibiotics, viruses evolve and elude new medications and animals alter their behavior in response to the changing climate. The resulting changes are often evident.
It wasn't until late 1980s that biologists understood that natural selection could be seen in action, as well. The key is that various traits have different rates of survival and reproduction (differential fitness) and are transferred from one generation to the next.
In the past, if one particular allele, the genetic sequence that determines coloration--appeared in a group of interbreeding organisms, it might quickly become more common than the other alleles. In time, this could mean the number of black moths within a population could 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 fast generation turnover such as bacteria. Since 에볼루션 카지노 사이트 , Richard Lenski, a biologist, has been tracking twelve populations of E.coli that descend from a single strain. Samples of each population have been taken regularly and more than 500.000 generations of E.coli have passed.
Lenski's research has shown that mutations can drastically alter the efficiency with the rate at which a population reproduces, and consequently, the rate at which it evolves. It also proves that evolution takes time--a fact that many find hard to accept.
Microevolution is also evident in the fact that mosquito genes for resistance to pesticides are more prevalent in populations that have used insecticides. This is because the use of pesticides causes a selective pressure that favors individuals with resistant genotypes.
The rapid pace at which evolution can take place has led to an increasing awareness of its significance in a world shaped by human activities, including climate change, pollution, and the loss of habitats that prevent many species from adapting. Understanding the evolution process can aid you in making better decisions regarding the future of the planet and its inhabitants.