The Academy's Evolution Site

Biological evolution is a central concept in biology. The Academies have been active for 에볼루션 a long time in helping people who are interested in science understand the theory of evolution and how it permeates all areas of scientific research.

This site provides a wide range of tools for teachers, students and general readers of evolution. It has the most important video clips from NOVA and the WGBH-produced science programs on DVD.

Tree of Life

The Tree of Life, an ancient symbol, represents the interconnectedness of all life. It is seen in a variety of spiritual traditions and cultures as an emblem of unity and love. It has numerous practical applications as well, including providing a framework to understand the evolution of species and how they react to changes in environmental conditions.

The first attempts to depict the biological world were built on categorizing organisms based on their physical and metabolic characteristics. These methods, which rely on the collection of various parts of organisms, or DNA fragments have greatly increased the diversity of a Tree of Life2. However, these trees are largely comprised of eukaryotes, and bacterial diversity remains vastly underrepresented3,4.

In avoiding the necessity of 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 build trees by using sequenced markers like the small subunit ribosomal RNA gene.

The Tree of Life has been dramatically expanded through genome sequencing. However, there is still much diversity to be discovered. This is especially true for microorganisms that are difficult to cultivate and which are usually only found in a single specimen5. Recent analysis of all genomes produced an unfinished draft of the Tree of Life. This includes a variety of bacteria, archaea and other organisms that haven't yet been isolated or whose diversity has not been thoroughly understood6.

This expanded Tree of Life can be used to assess the biodiversity of a specific area and determine if particular habitats require special protection. This information can be used in many ways, including finding new drugs, fighting diseases and improving the quality of crops. The information is also incredibly valuable to conservation efforts. It helps biologists determine the areas most likely to contain cryptic species that could have significant metabolic functions that could be at risk of anthropogenic changes. While conservation funds are important, the best way to conserve the world's biodiversity is to empower the people of developing nations with the information they require to take action locally and encourage conservation.

Phylogeny

A phylogeny (also called an evolutionary tree) depicts the relationships between species. Scientists can create an phylogenetic chart which shows the evolution of taxonomic groups based on molecular data and morphological similarities or differences. The role of phylogeny is crucial in understanding biodiversity, genetics and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms that share similar traits that evolved from common ancestors. These shared traits can be analogous, or homologous. Homologous traits are similar in their underlying evolutionary path and 무료 에볼루션 analogous traits appear like they do, but don't have the same ancestors. Scientists group similar traits into a grouping called a clade. All organisms in a group share a trait, such as amniotic egg production. They all came from an ancestor that had these eggs. A phylogenetic tree is then constructed by connecting the clades to identify the species which are the closest to each other.

To create a more thorough and accurate phylogenetic tree scientists use molecular data from DNA or RNA to identify the relationships between organisms. This information is more precise and provides evidence of the evolution of an organism. The use of molecular data lets researchers identify the number of species that have an ancestor common to them and estimate their evolutionary age.

The phylogenetic relationships of a species can be affected by a variety of factors such as the phenotypic plasticity. This is a type behaviour that can change as a result of specific environmental conditions. This can cause a trait to appear more similar to a species than to the other, obscuring the phylogenetic signals. This issue can be cured by using cladistics, which incorporates a combination of homologous and 에볼루션 analogous features in the tree.

In addition, phylogenetics can help predict the time and pace of speciation. This information can aid conservation biologists in making choices about which species to safeguard from disappearance. Ultimately, it is the preservation of phylogenetic diversity which will lead to a complete and balanced ecosystem.

Evolutionary Theory

The fundamental concept in evolution is that organisms change over time as a result of their interactions with their environment. Many scientists have proposed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism could evolve according to its individual 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 believed that the use or non-use of traits can lead to 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 form the current synthesis of evolutionary theory which explains how evolution happens through the variations of genes within a population, and how those variations change in time as a result of natural selection. This model, called genetic drift or mutation, gene flow, and sexual selection, is a cornerstone of the current evolutionary biology and can be mathematically explained.

Recent discoveries in the field of evolutionary developmental biology have shown the ways in which variation can be introduced to a species through mutations, genetic drift, 에볼루션코리아 reshuffling genes during sexual reproduction and the movement between populations. These processes, along with others such as directional selection or genetic erosion (changes in the frequency of an individual's genotype over time) can lead to evolution that is defined as changes in the genome of the species over time, and also the change in phenotype as time passes (the expression of that 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 et al. 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, see The Evolutionary Potency in All Areas of Biology or Thinking Evolutionarily A Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution through looking back, studying fossils, comparing species and observing living organisms. However, evolution isn't something that happened in the past. It's an ongoing process taking place today. Bacteria evolve and resist antibiotics, viruses evolve and are able to evade new medications, and animals adapt their behavior in response to the changing climate. The changes that result are often evident.

However, it wasn't until late 1980s that biologists realized that natural selection can be seen in action, 에볼루션 무료체험 [103.112.184.2] as well. The key is the fact that different traits result in the ability to survive at different rates as well as reproduction, and may be passed down from generation to generation.

In the past, if one particular allele, the genetic sequence that determines coloration--appeared in a population of interbreeding organisms, it might quickly become more prevalent than the other alleles. In time, this could mean that the number of black moths in a particular population could rise. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

It is easier to see evolution when the species, like bacteria, has a high generation turnover. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that descend from one strain. Samples of each population were taken frequently and more than 500.000 generations of E.coli have passed.

Lenski's research has demonstrated that mutations can alter the rate of change and the efficiency at which a population reproduces. It also demonstrates that evolution takes time, which is hard for some to accept.

Microevolution can also be seen in the fact that mosquito genes for pesticide resistance are more prevalent in areas where insecticides have been used. That's because the use of pesticides creates a selective pressure that favors those with resistant genotypes.

The speed at which evolution takes place has led to a growing 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 will aid you in making better decisions about the future of our planet and its inhabitants.