The Academy's Evolution Site

Biological evolution is one of the most central concepts in biology. The Academies have long been involved in helping those interested in science understand the concept of evolution and how it permeates all areas of scientific research.

This site provides students, teachers and general readers with a range of learning resources about evolution. It includes 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 can be used in many practical ways in addition to providing a framework for understanding the history of species and how they react to changes in environmental conditions.

Early attempts to describe the world of biology were built on categorizing organisms based on their physical and metabolic characteristics. These methods depend on the collection of various parts of organisms or DNA fragments, have greatly increased the diversity of a tree of Life2. These trees are mostly populated by eukaryotes and bacteria are largely underrepresented3,4.

By avoiding the need for direct experimentation and observation genetic techniques have allowed us to represent the Tree of Life in a more precise manner. We can construct trees using molecular techniques like the small-subunit ribosomal gene.

Despite the dramatic growth of the Tree of Life through genome sequencing, a lot of biodiversity awaits discovery. This is particularly true for 에볼루션 무료체험 microorganisms, which are difficult to cultivate and are typically only present in a single sample5. A recent analysis of all known genomes has produced a rough draft of the Tree of Life, including numerous archaea and bacteria that are not isolated and whose diversity is poorly understood6.

The expanded Tree of Life can be used to evaluate the biodiversity of a specific area and determine if specific habitats need special protection. This information can be used in a range of ways, from identifying new remedies to fight diseases to improving the quality of crops. The information is also incredibly valuable for conservation efforts. It helps biologists determine the areas most likely to contain cryptic species with important metabolic functions that could be at risk from anthropogenic change. While funds to protect biodiversity are important, the most effective method to preserve the world's biodiversity is to equip the people of developing nations with the information they require to act locally and support conservation.

Phylogeny

A phylogeny, also known as an evolutionary tree, shows the relationships between various groups of organisms. Utilizing molecular data similarities and differences in morphology or ontogeny (the course of development of an organism) scientists can construct an phylogenetic tree that demonstrates the evolution of taxonomic groups. Phylogeny is essential in understanding evolution, biodiversity and genetics.

A basic phylogenetic tree (see Figure PageIndex 10 ) determines the relationship between organisms with similar traits that evolved from common ancestors. These shared traits are either analogous or homologous. Homologous characteristics are identical in their evolutionary path. Analogous traits might appear similar, but they do not have the same ancestry. Scientists group similar traits into a grouping called a clade. For example, all of the organisms in a clade have the characteristic of having amniotic eggs. They evolved from a common ancestor who had these eggs. The clades then join to form a phylogenetic branch to determine which organisms have the closest relationship.

Scientists utilize DNA or RNA molecular information to construct a phylogenetic graph that is more precise and detailed. This information is more precise and gives evidence of the evolution of an organism. Researchers can utilize 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 are influenced by many factors including phenotypic plasticity, a type of behavior that alters in response to specific environmental conditions. This can cause a trait to appear more similar in one species than another, obscuring the phylogenetic signal. However, this problem can be solved through the use of techniques such as cladistics which incorporate a combination of homologous and analogous features into the tree.

In addition, phylogenetics can aid in predicting the length and speed of speciation. This information will assist conservation biologists in making choices about which species to protect from extinction. It is ultimately the preservation of phylogenetic diversity that will lead to a complete and balanced ecosystem.

Evolutionary Theory

The fundamental concept of evolution is that organisms develop various characteristics over time as a result of their interactions with their environment. Many scientists have proposed 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 and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern hierarchical taxonomy as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the use or absence of traits can lead to changes that are passed on to the next generation.

In the 1930s and 1940s, theories from a variety of fields -- including genetics, natural selection and particulate inheritance -- came together to create the modern evolutionary theory, which defines how evolution happens through the variation of genes within a population, and how these variants change over time as a result of natural selection. This model, which incorporates genetic drift, mutations as well as gene flow and sexual selection is mathematically described.

Recent developments in the field of evolutionary developmental biology have revealed that genetic variation can be introduced into a species by genetic drift, 에볼루션 바카라사이트 mutation, and reshuffling genes during sexual reproduction, and also through migration between populations. These processes, as well as other ones like directionally-selected selection and erosion of genes (changes to the frequency of genotypes over time) can result in evolution. Evolution is defined by changes in the genome over time and 에볼루션 바카라 무료체험 changes in phenotype (the expression of genotypes in an individual).

Incorporating evolutionary thinking into all aspects of biology education can improve student understanding of the concepts of phylogeny and evolutionary. In a study by Grunspan and colleagues. It was found that teaching students about the evidence for evolution boosted their acceptance of evolution during the course of a college biology. To learn more about how to teach about evolution, see The Evolutionary Potential in all Areas of Biology and 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 에볼루션 바카라 사이트 룰렛 (trade-Britanica.Trade) studying living organisms. But evolution isn't just something that occurred in the past, it's an ongoing process taking place today. Viruses evolve to stay away from new medications and bacteria mutate to resist antibiotics. Animals alter their behavior because of a changing world. The results are often apparent.

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

In the past, if a certain allele - the genetic sequence that determines colour was present in a population of organisms that interbred, it might become more common than any other allele. Over time, 에볼루션카지노 this would mean that the number of moths with 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.

Monitoring evolutionary changes in action is much easier when a species has a rapid turnover of its generation, as with bacteria. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain. samples of each are taken on a regular basis, and over fifty thousand generations have passed.

Lenski's research has revealed that mutations can drastically alter the speed at which a population reproduces--and so the rate at which it evolves. It also demonstrates that evolution takes time--a fact that some find difficult to accept.

Microevolution is also evident in the fact that mosquito genes that confer resistance to pesticides are more prevalent in areas where insecticides have been used. This is due to pesticides causing an exclusive pressure that favors those with resistant genotypes.

The speed at which evolution takes place has led to a growing appreciation of its importance in a world that is shaped by human activity--including climate change, pollution, and the loss of habitats that prevent the species from adapting. Understanding evolution will help you make better decisions about the future of the planet and its inhabitants.