The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies have long been involved in helping those interested in science comprehend the concept of evolution and how it permeates every area of scientific inquiry.

This site provides a range of sources for teachers, students, and general readers on evolution. It contains key video clips from NOVA and 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 across many cultures. It has many practical applications as well, including providing a framework to understand the history of species and how they react to changes in environmental conditions.

Early approaches to depicting the biological world focused on the classification of organisms into distinct categories which had been distinguished by their physical and metabolic characteristics1. These methods, 에볼루션바카라 which relied on the sampling of different parts of living organisms or sequences of small fragments of their DNA, significantly increased the variety that could be represented in the tree of life2. The trees are mostly composed by eukaryotes and the diversity of bacterial species is greatly underrepresented3,4.

Genetic techniques have greatly expanded our ability to depict the Tree of Life by circumventing the need for direct observation and experimentation. Particularly, molecular techniques allow us to construct trees by using sequenced markers, such as the small subunit ribosomal RNA gene.

The Tree of Life has been dramatically expanded through genome sequencing. However, there is still much biodiversity to be discovered. This is especially true of microorganisms that are difficult to cultivate and 에볼루션 슬롯게임 are often only represented in a single specimen5. A recent study of all genomes that are known has produced a rough draft of the Tree of Life, 에볼루션 바카라 무료 including numerous archaea and bacteria that are not isolated and their diversity is not fully understood6.

This expanded Tree of Life is particularly useful for assessing the biodiversity of an area, which can help to determine if certain habitats require protection. This information can be used in a variety of ways, such as finding new drugs, battling diseases and 에볼루션바카라사이트 enhancing crops. This information is also extremely useful to conservation efforts. It can help biologists identify those areas that are most likely contain cryptic species with potentially significant metabolic functions that could be vulnerable to 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 act locally to promote conservation from within.

Phylogeny

A phylogeny (also known as an evolutionary tree) depicts the relationships between species. Scientists can build a phylogenetic chart that shows the evolution of taxonomic groups based on molecular data and morphological similarities or differences. The concept of phylogeny is fundamental to understanding the evolution of biodiversity, evolution and genetics.

A basic phylogenetic Tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms that share similar traits that have evolved from common ancestors. These shared traits can be homologous, or analogous. Homologous traits are similar in their evolutionary paths. Analogous traits may look like they are however they do not share the same origins. Scientists combine similar traits into a grouping known as a Clade. All organisms in a group have a common trait, such as amniotic egg production. They all came from an ancestor with these eggs. The clades then join to form a phylogenetic branch to identify organisms that have the closest connection to each other.

For a more precise and precise phylogenetic tree scientists make use of molecular data from DNA or RNA to establish the relationships between organisms. This information is more precise and provides evidence of the evolution of an organism. Researchers can utilize Molecular Data to determine the age of evolution of organisms and determine how many organisms share the same ancestor.

The phylogenetic relationships between species are influenced by many factors, including phenotypic flexibility, an aspect of behavior that changes in response to unique environmental conditions. This can cause a trait to appear more similar to a species than another and obscure the phylogenetic signals. However, 바카라 에볼루션 this problem can be solved through the use of techniques such as cladistics that combine similar and homologous traits into the tree.

Additionally, phylogenetics can help predict the duration and rate at which speciation occurs. This information will assist conservation biologists in deciding which species to save from the threat of extinction. Ultimately, it is the preservation of phylogenetic diversity that will lead to an ecosystem that is complete and balanced.

Evolutionary Theory

The main idea behind evolution is that organisms alter over time because of their interactions with their environment. Many theories of evolution have been developed by a variety of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop slowly in accordance with its requirements as well as the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1744-1829) who suggested that the use or non-use of traits causes changes that can be passed onto offspring.

In the 1930s and 에볼루션바카라 1940s, ideas from a variety of fields -- including genetics, natural selection and particulate inheritance - came together to form the current synthesis of evolutionary theory that explains how evolution is triggered by the variation of genes within a population, and how those variants change in time due to natural selection. This model, which incorporates genetic drift, 에볼루션바카라 mutations, gene flow and sexual selection, can be mathematically described mathematically.

Recent discoveries in the field of evolutionary developmental biology have shown that variations can be introduced into a species through genetic drift, mutation, and reshuffling of genes during sexual reproduction, as well as through the movement of populations. These processes, along with others like directional selection and genetic erosion (changes in the frequency of a genotype over time) can result in evolution that is defined as changes in the genome of the species over time, and also by changes in phenotype over time (the expression of that genotype in an individual).

Students can better understand phylogeny by incorporating evolutionary thinking throughout all areas of biology. A recent study by Grunspan and colleagues, for example revealed that teaching students about the evidence for evolution increased students' understanding of evolution in a college-level biology class. For more information about how to teach evolution read The Evolutionary Potential in All Areas of Biology or Thinking Evolutionarily as a Framework for Integrating 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 just something that happened in the past, it's an ongoing process that is that is taking place today. Viruses evolve to stay away from new drugs and bacteria evolve to resist antibiotics. Animals alter their behavior as a result of the changing environment. The results are usually evident.

It wasn't until late-1980s that biologists realized that natural selection could be observed in action as well. The key is the fact that different traits can confer an individual rate of survival as well as reproduction, and may be passed down from generation to generation.

In the past when one particular allele--the genetic sequence that determines coloration--appeared in a population of interbreeding organisms, it might quickly become more prevalent than all other alleles. In time, this could mean that the number of moths with black pigmentation 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 easier when a particular species has a fast generation turnover such as bacteria. Since 1988, biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain. samples of each population are taken regularly and more than fifty thousand generations have passed.

Lenski's research has revealed that a mutation can dramatically alter the rate at which a population reproduces--and so the rate at which it changes. It also proves that evolution takes time--a fact that many are unable to accept.

Microevolution can also be seen in the fact that mosquito genes that confer resistance to pesticides are more common in populations where insecticides are used. That's because the use of pesticides creates a selective pressure that favors those with resistant genotypes.

The rapidity of evolution has led to a greater recognition of its importance particularly in a world shaped largely by human activity. This includes climate change, 에볼루션 pollution, and habitat loss that hinders many species from adapting. Understanding the evolution process can assist you in making better choices regarding the future of the planet and its inhabitants.