The Academy's Evolution Site
Biological evolution is a central concept in biology. The Academies have long been involved in helping people who are interested in science comprehend the concept of evolution and how it influences all areas of scientific research.
This site provides students, teachers and general readers with a wide range of educational resources on evolution. It has important video clips from NOVA and the WGBH-produced science programs on DVD.
Tree of Life
The Tree of Life is an ancient symbol that symbolizes the interconnectedness of life. It is a symbol of love and unity in many cultures. It has numerous practical applications as well, such as providing a framework for understanding the history of species, and how they respond to changes in environmental conditions.
The earliest attempts to depict the biological world focused on the classification of species into distinct categories that had been distinguished by physical and metabolic characteristics1. These methods, which rely on the sampling of different parts of living organisms, or sequences of short DNA fragments, significantly expanded the diversity that could be represented in a tree of life2. These trees are mostly populated by eukaryotes, and bacterial diversity is vastly underrepresented3,4.
Genetic techniques have greatly broadened our ability to visualize the Tree of Life by circumventing the need for direct observation and experimentation. In particular, molecular methods allow us to construct trees using sequenced markers such as the small subunit ribosomal RNA gene.
The Tree of Life has been greatly expanded thanks to genome sequencing. However, there is still much biodiversity to be discovered. This is particularly the case for microorganisms which are difficult to cultivate, and which are usually only found in one sample5. 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 haven't yet been isolated, or the diversity of which is not thoroughly understood6.
The expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, helping to determine if specific habitats require protection. This information can be used in a variety of ways, from identifying the most effective medicines to combating disease to enhancing crops. This information is also extremely useful for conservation efforts. It can help biologists identify those areas that are most likely contain cryptic species that could have important metabolic functions that may be at risk from anthropogenic change. While funds to safeguard biodiversity are vital however, the most effective method to preserve the world's biodiversity is for more people in developing countries to be empowered with the necessary knowledge to take action locally to encourage conservation from within.
Phylogeny
A phylogeny (also known as an evolutionary tree) illustrates the relationship between different organisms. Scientists can build a phylogenetic chart that shows the evolution of taxonomic groups based on molecular data and morphological differences or similarities. Phylogeny plays a crucial role in understanding the relationship between genetics, biodiversity and evolution.
A basic phylogenetic Tree (see Figure PageIndex 10 Finds the connections between organisms with similar traits and evolved from an ancestor with common traits. These shared traits could be analogous or homologous. Homologous characteristics are identical in their evolutionary journey. Analogous traits might appear similar but they don't have the same ancestry. Scientists group similar traits into a grouping known as a clade. For instance, all of the organisms in a clade share the characteristic of having amniotic eggs. They evolved from a common ancestor who had these eggs. The clades are then linked to create a phylogenetic tree to determine which organisms have the closest relationship to.
Scientists make use of DNA or RNA molecular data to construct a phylogenetic graph that is more accurate and precise. This information is more precise than the morphological data and provides evidence of the evolution background of an organism or group. Researchers can use Molecular Data to determine the evolutionary age of organisms and identify how many organisms share an ancestor common to all.
The phylogenetic relationships of organisms can be influenced by several factors including phenotypic plasticity, a kind of behavior that alters in response to specific environmental conditions. This can cause a particular trait to appear more similar in one species than another, clouding the phylogenetic signal. However, this problem can be reduced by the use of methods such as cladistics that incorporate a combination of analogous and homologous features into the tree.
Additionally, phylogenetics aids determine the duration and rate at which speciation takes place. This information will assist conservation biologists in making decisions about which species to protect from disappearance. In 에볼루션 슬롯게임 , it's the conservation of phylogenetic variety which will create an ecosystem that is complete and balanced.
Evolutionary Theory
The fundamental concept of evolution is that organisms acquire various characteristics over time due to their interactions with their environments. Many scientists have come up with theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that a living thing would develop according to its own requirements as well as the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical taxonomy and Jean-Baptiste Lamarck (1844-1829), who suggested that the use or absence of certain traits can result in changes that can be passed on to future generations.
In the 1930s and 1940s, concepts from various fields, including genetics, natural selection and particulate inheritance - came together to create the modern evolutionary theory synthesis that explains how evolution occurs through the variation of genes within a population and how those variations change in time due to natural selection. This model, which is known as genetic drift or mutation, gene flow, and sexual selection, is a cornerstone of modern evolutionary biology and can be mathematically described.
Recent discoveries in the field of evolutionary developmental biology have revealed that variation can be introduced into a species by mutation, genetic drift, and reshuffling genes during sexual reproduction, and also through migration between populations. These processes, along with others such as directional selection or genetic erosion (changes in the frequency of a genotype over time) can result in evolution which is defined by changes in the genome of the species over time, and also by changes in phenotype over time (the expression of the genotype in the individual).
Incorporating evolutionary thinking into all areas of biology education can increase student understanding of the concepts of phylogeny and evolutionary. In a recent study by Grunspan and co. It was demonstrated that teaching students about the evidence for evolution increased their understanding of evolution in a college-level course in biology. For more information on how to teach about evolution read The Evolutionary Power of Biology in All Areas of Biology or Thinking Evolutionarily as 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. But evolution isn't a thing that occurred in the past. It's an ongoing process that is that is taking place today. Bacteria mutate and resist antibiotics, viruses evolve and elude new medications and animals alter their behavior in response to the changing environment. The changes that result are often easy to see.
However, it wasn't until late 1980s that biologists realized that natural selection could be seen in action, as well. The main reason is that different traits can confer the ability to survive at different rates and reproduction, and they can be passed on from one generation to another.
In the past, when one particular allele - the genetic sequence that determines coloration--appeared in a population of interbreeding species, it could rapidly become more common than the other alleles. Over time, this would mean that the number of moths that have black pigmentation could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.
It is easier to track evolutionary change when a species, such as bacteria, has a high generation turnover. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that are descended from a single strain. Samples from each population were taken regularly, and more than 50,000 generations of E.coli have passed.
Lenski's research has shown that mutations can drastically alter the rate at which a population reproduces and, consequently, the rate at which it changes. It also demonstrates that evolution takes time, a fact that some people find difficult to accept.
Microevolution can be observed in the fact that mosquito genes for pesticide resistance are more prevalent in populations where insecticides have been used. This is due to pesticides causing an enticement that favors those with resistant genotypes.
The rapidity of evolution has led to a greater awareness of its significance particularly in a world that is largely shaped by human activity. This includes climate change, pollution, and habitat loss, which prevents many species from adapting. Understanding evolution can help us make better decisions about the future of our planet, as well as the lives of its inhabitants.