The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies have been for a long time involved in helping people who are interested in science understand the concept of evolution and how it affects every area of scientific inquiry.

This site offers a variety of sources for teachers, students and general readers of evolution. It contains the most important video clips from NOVA and WGBH's science programs on DVD.

Tree of Life

The Tree of Life is an ancient symbol of 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 many practical applications in addition to providing a framework to understand the evolution of species and how they react to changing environmental conditions.

The earliest attempts to depict the world of biology focused on the classification of species into distinct categories that were identified by their physical and metabolic characteristics1. These methods rely on the sampling of different parts of organisms or DNA fragments have significantly increased the diversity of a Tree of Life2. The trees are mostly composed of eukaryotes, while the diversity of bacterial species is greatly underrepresented3,4.

Genetic techniques have significantly expanded our ability to represent the Tree of Life by circumventing the requirement for direct observation and experimentation. We can construct trees using molecular techniques, such as the small-subunit ribosomal gene.

The Tree of Life has been greatly expanded thanks to genome sequencing. However there is still a lot of biodiversity to be discovered. This is particularly true for microorganisms, which can be difficult to cultivate and are typically only found in a single specimen5. A recent study of all genomes known to date has produced a rough draft version of the Tree of Life, including a large number of archaea and bacteria that have not been isolated and their diversity is not fully understood6.

The expanded Tree of Life is particularly useful for assessing the biodiversity of an area, helping to determine whether specific habitats require protection. This information can be utilized in many ways, including finding new drugs, battling diseases and improving crops. The information is also incredibly beneficial for conservation efforts. It can help biologists identify the areas most likely to contain cryptic species that could have important metabolic functions that could be at risk from anthropogenic change. While conservation funds are important, the most effective method to protect the biodiversity of the world is to equip more people in developing countries with the information they require to act locally and promote conservation.

Phylogeny

A phylogeny (also known as an evolutionary tree) shows the relationships between organisms. Scientists can construct an phylogenetic chart which shows the evolutionary relationship of taxonomic categories using molecular information and morphological differences or similarities. The concept of phylogeny is fundamental to understanding biodiversity, evolution and genetics.

A basic phylogenetic tree (see Figure PageIndex 10 Identifies the relationships between organisms with similar traits and have evolved from an ancestor with common traits. These shared traits could be homologous, or analogous. Homologous traits are identical in their underlying evolutionary path and analogous traits appear similar, but do not share the identical origins. Scientists group similar traits into a grouping referred to as a the clade. All members of a clade have a common characteristic, like amniotic egg production. They all derived from an ancestor that had these eggs. The clades are then connected to create a phylogenetic tree to identify organisms that have the closest connection to each other.

Scientists make use of DNA or RNA molecular data to construct a phylogenetic graph that is more accurate and detailed. This information is more precise than morphological data and provides evidence of the evolution history of an organism or group. The analysis of molecular data can help researchers determine the number of species who share the same ancestor and 에볼루션 사이트 estimate their evolutionary age.

The phylogenetic relationship can be affected by a variety of factors, including the phenotypic plasticity. This is a type behaviour that can change in response to specific environmental conditions. This can cause a particular trait to appear more like a species another, obscuring the phylogenetic signal. This issue can be cured by using cladistics, which incorporates a combination of homologous and analogous features in the tree.

Additionally, phylogenetics can aid in predicting the duration and rate of speciation. This information can assist conservation biologists make decisions about which species they should protect from extinction. In the end, it is the conservation of phylogenetic variety which will create an ecosystem that is complete and balanced.

Evolutionary Theory

The main idea behind evolution is that organisms change over time due to 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 a living thing would develop according to its own requirements as well as the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern taxonomy system that is hierarchical and Jean-Baptiste Lamarck (1844-1829), who suggested that the use or non-use of certain traits can result in changes that can be passed on to future generations.

In the 1930s & 1940s, theories from various fields, including genetics, natural selection and particulate inheritance, came together to form a modern synthesis of evolution theory. This defines how evolution is triggered by the variation in genes within the population, and how these variants change over time as a result of natural selection. This model, which encompasses genetic drift, mutations in gene flow, and 에볼루션 sexual selection is mathematically described.

Recent advances in the field of evolutionary developmental biology have shown the ways in which variation can be introduced to a species by genetic drift, mutations, reshuffling genes during sexual reproduction, and even migration between populations. These processes, as well as others such as directional selection or genetic erosion (changes in the frequency of an individual's genotype over time) can result in evolution that is defined as 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).

Students can gain a better understanding of the concept of phylogeny by using evolutionary thinking into all aspects of biology. A recent study by Grunspan and colleagues, 에볼루션 사이트 for example, showed that teaching about the evidence supporting evolution increased students' acceptance of evolution in a college-level biology course. For 에볼루션 무료체험 (Socialrator.com) more details on how to teach about evolution, see The Evolutionary Potency in All Areas of Biology or Thinking Evolutionarily as a Framework for Integrating Evolution into Life Sciences Education.

Evolution in Action

Traditionally scientists have studied evolution by looking back, studying fossils, comparing species, and observing living organisms. But evolution isn't just something that happened in the past; it's an ongoing process, that is taking place right now. Viruses reinvent themselves to avoid new antibiotics and bacteria transform to resist antibiotics. Animals alter their behavior because of a changing world. The resulting changes 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 result in the ability to survive at different rates and reproduction, and can be passed down from one generation to the next.

In the past, if one particular allele, the genetic sequence that defines color in a group of interbreeding organisms, it could rapidly become more common than all other alleles. As time passes, that could mean that the number of black moths within a particular population could rise. 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 particular species has a fast generation turnover like bacteria. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. Coli that descended from a single strain; samples of each population are taken regularly and over 50,000 generations have now passed.

Lenski's research has demonstrated that mutations can alter the rate of change and the effectiveness of a population's reproduction. It also shows evolution takes time, a fact that is difficult for 에볼루션 사이트 some to accept.

Another example of microevolution is how mosquito genes that are resistant to pesticides appear more frequently in areas in which insecticides are utilized. That's because the use of pesticides causes a selective pressure that favors people who have resistant genotypes.

The rapidity of evolution has led to a greater appreciation of its importance, especially in a world that is largely shaped by human activity. This includes pollution, climate change, and 에볼루션 바카라 habitat loss that prevents many species from adapting. Understanding evolution can help you make better decisions regarding the future of the planet and its inhabitants.