The Academy's Evolution Site

Biological evolution is a central concept in biology. The Academies are committed to helping those interested in the sciences learn about the theory of evolution and how it is permeated in all areas of scientific research.

This site provides students, teachers and general readers with a range of learning resources on evolution. It contains 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 a symbol of love and unity across many cultures. It also has practical uses, like providing a framework for understanding the evolution of species and how they respond to changing environmental conditions.

Early attempts to describe the world of biology were founded on categorizing organisms on their metabolic and physical characteristics. These methods depend on the sampling of different parts of organisms, 에볼루션 룰렛 or fragments of DNA have greatly increased the diversity of a Tree of Life2. However the trees are mostly made up of eukaryotes. Bacterial diversity is not represented in a large way3,4.

By avoiding the necessity for direct experimentation and observation genetic techniques have allowed us to depict the Tree of Life in a more precise way. We can construct trees by using molecular methods, such as the small-subunit ribosomal gene.

Despite the dramatic expansion of the Tree of Life through genome sequencing, much biodiversity still is waiting to be discovered. This is especially true for 에볼루션 게이밍 microorganisms that are difficult to cultivate and are typically found in one sample5. A recent study of all known genomes has created a rough draft of the Tree of Life, including numerous bacteria and archaea that are not isolated and which are not well understood.

This expanded Tree of Life can be used to assess the biodiversity of a specific area and determine if certain habitats need special protection. This information can be utilized in a range of ways, from identifying new treatments to fight disease to improving crops. It is also useful for conservation efforts. It can aid biologists in identifying the areas that are most likely to contain cryptic species with significant metabolic functions that could be at risk from anthropogenic change. Although funding to protect biodiversity are crucial but the most effective way to protect the world's biodiversity is for more people living in developing countries to be equipped with the knowledge to take action locally to encourage conservation from within.

Phylogeny

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

A basic phylogenetic tree (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 homologous, or analogous. Homologous traits are the same in terms of their evolutionary paths. Analogous traits might appear similar however they do not have the same ancestry. Scientists put similar traits into a grouping called a the clade. All members of a clade share a characteristic, 에볼루션 슬롯게임 like amniotic egg production. They all derived from an ancestor with these eggs. A phylogenetic tree can be built by connecting the clades to determine the organisms that are most closely related to one another.

Scientists use DNA or RNA molecular data to build a phylogenetic chart that is more precise and detailed. This information is more precise and gives evidence of the evolution of an organism. The analysis of molecular data can help researchers identify the number of organisms that have an ancestor common to them and estimate their evolutionary age.

The phylogenetic relationship can be affected by a variety of factors, including the phenotypic plasticity. This is a kind of behavior that alters in response to specific environmental conditions. This can make a trait appear more similar to a species than to the other, obscuring the phylogenetic signals. This issue can be cured by using cladistics. This is a method that incorporates a combination of homologous and analogous traits in the tree.

Additionally, phylogenetics can help determine the duration and speed at which speciation takes place. This information will assist conservation biologists in deciding which species to safeguard from extinction. In the end, it's the conservation of phylogenetic diversity that will lead to an ecosystem that is balanced and complete.

Evolutionary Theory

The central theme in evolution is that organisms change over time due to their interactions with their environment. Many scientists have developed 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 needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern taxonomy system that is hierarchical, as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the usage or non-use of traits can cause changes that are passed on to the

In the 1930s and 1940s, concepts from a variety of fields -- including genetics, natural selection, and particulate inheritance--came together to form the modern synthesis of evolutionary theory, which defines 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 current evolutionary biology, and can be mathematically described.

Recent discoveries in the field of evolutionary developmental biology have demonstrated that variation can be introduced into a species by mutation, genetic drift and reshuffling of genes in sexual reproduction, and 에볼루션 게이밍 also through migration between populations. These processes, along with others like directional selection and genetic erosion (changes in the frequency of the genotype over time), can lead to evolution, which is defined by change in the genome of the species over time and the change in phenotype as time passes (the expression of that genotype in the individual).

Incorporating evolutionary thinking into all aspects of biology education can increase students' understanding of phylogeny and evolution. In a recent study conducted by Grunspan and colleagues. It was demonstrated that teaching students about the evidence for evolution boosted 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 the Concept of Evolution into Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution through looking back--analyzing fossils, comparing species and observing living organisms. Evolution is not a past event, but an ongoing process. Bacteria transform and 에볼루션 무료 바카라 resist antibiotics, viruses re-invent themselves and are able to evade new medications and animals alter their behavior to the changing environment. The resulting changes are often easy to see.

But it wasn't until the late 1980s that biologists realized that natural selection can be seen in action, as well. The reason is that different traits confer different rates of survival and reproduction (differential fitness) and are passed down from one generation to the next.

In the past, when one particular allele, the genetic sequence that defines color in a group of interbreeding species, it could quickly become more prevalent than all other alleles. As time passes, that could mean that the number of black moths in the 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 a species, such as bacteria, has a rapid generation turnover. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that descend from a single strain. Samples from each population have been collected frequently and more than 500.000 generations of E.coli 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 demonstrates that evolution takes time--a fact that many find hard to accept.

Another example of microevolution is how mosquito genes that are resistant to pesticides appear more frequently in populations where insecticides are used. Pesticides create an enticement that favors those with resistant genotypes.

The speed at which evolution can take place has led to a growing awareness of its significance in a world that is shaped by human activity, including climate change, pollution and the loss of habitats that hinder many species from adjusting. Understanding the evolution process will aid you in making better decisions regarding the future of the planet and its inhabitants.