The Academy's Evolution Site

The concept of biological evolution is among the most important concepts in biology. The Academies are committed to helping those who are interested in science to learn about the theory of evolution and how it is permeated across all areas of scientific research.

This site provides students, teachers and general readers with a variety of learning resources about evolution. It contains key video clips from NOVA and the 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 across many cultures. It also has important practical applications, such as providing a framework for understanding the evolution of species and how they react to changing environmental conditions.

Early approaches to depicting the biological world focused on categorizing organisms into distinct categories which had been distinguished by their physical and metabolic characteristics1. These methods, which rely on the collection of various parts of organisms, or fragments of DNA, have significantly increased the diversity of a Tree of Life2. However these trees are mainly comprised of eukaryotes, and bacterial diversity is still largely unrepresented3,4.

Genetic techniques have significantly expanded our ability to visualize the Tree of Life by circumventing the need for direct observation and experimentation. In particular, molecular methods allow us to build trees using sequenced markers like the small subunit ribosomal RNA gene.

Despite the rapid growth of the Tree of Life through genome sequencing, 에볼루션 사이트 a large amount of biodiversity remains to be discovered. This is especially true of microorganisms, which are difficult to cultivate and are usually only found in a single sample5. A recent study of all genomes that are known has produced a rough draft version of the Tree of Life, including numerous bacteria and archaea that have not been isolated, 에볼루션 사이트 and their diversity is not fully understood6.

The expanded Tree of Life is particularly useful in assessing the diversity of an area, assisting to determine whether specific habitats require protection. This information can be utilized in a range of ways, from identifying new remedies to fight diseases to enhancing the quality of crops. This information is also extremely valuable for conservation efforts. It can help biologists identify areas most likely to be home to cryptic species, which may perform important metabolic functions and are susceptible to the effects of human activity. While funds to protect biodiversity are essential, the best way to conserve the world's biodiversity is to empower the people of developing nations with the knowledge they need to take action locally and encourage conservation.

Phylogeny

A phylogeny, also called an evolutionary tree, illustrates the relationships between different groups of organisms. Scientists can construct an phylogenetic fety.net/bbs/board.php?bo_table=free&wr_id=119599">에볼루션 사이트 phylogenetics aids determine the duration and rate at which speciation takes place. This information can assist conservation biologists in making decisions about which species to save from the threat of extinction. In the end, it's the preservation of phylogenetic diversity which will lead to an ecologically balanced and complete ecosystem.

Evolutionary Theory

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

In the 1930s and 1940s, concepts from various fields, including natural selection, genetics, and particulate inheritance -- came together to form the current synthesis of evolutionary theory which explains how evolution is triggered by the variation of genes within a population, and how those variants change in time as a result of natural selection. This model, known as genetic drift, mutation, 에볼루션게이밍 gene flow and sexual selection, is a cornerstone of modern evolutionary biology and can be mathematically explained.

Recent discoveries in evolutionary developmental biology have shown the ways in which variation can be introduced to a species through genetic drift, mutations or reshuffling of genes in sexual reproduction, and even migration between populations. These processes, as well as others like directional selection and genetic erosion (changes in the frequency of the genotype over time) can result in evolution that is defined as change in the genome of the species over time, 에볼루션 바카라 게이밍 (Funsilo.Date) and the change in phenotype as time passes (the expression of the genotype in an individual).

Students can better understand the concept of phylogeny by using evolutionary thinking throughout all areas of biology. In a study by Grunspan et al. It was found that teaching students about the evidence for evolution increased their understanding of evolution during a college-level course in biology. For more information on how to teach about evolution, please see The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily: A Framework for Infusing Evolution in Life Sciences Education.

Evolution in Action

Scientists have traditionally studied evolution by looking in the past, analyzing fossils and comparing species. They also study living organisms. However, evolution isn't something that occurred in the past; it's an ongoing process taking place right now. Bacteria transform and resist antibiotics, viruses evolve and escape new drugs and animals alter their behavior to a changing planet. The changes that result are often apparent.

It wasn't until late-1980s that biologists realized that natural selection could be seen in action, as well. The key to this is that different traits can confer a different rate of survival and 에볼루션 무료 바카라 reproduction, and they can be passed down from one generation to another.

In the past, if one particular allele - the genetic sequence that controls coloration - was present in a population of interbreeding organisms, it might quickly become more common than other alleles. Over time, this would mean that the number of moths that have black pigmentation in a group 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 evolution when an organism, like bacteria, has a high generation turnover. Since 1988 biologist Richard Lenski has been tracking twelve populations of E. Coli that descended from a single strain; samples from each population are taken on a regular basis and over fifty thousand generations have passed.

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

Another example of microevolution is how mosquito genes for resistance to pesticides are more prevalent in areas where insecticides are employed. Pesticides create an exclusive pressure that favors those who have resistant genotypes.

The speed at which evolution takes place has led to a growing recognition of its importance in a world that is shaped by human activities, 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 about the future of our planet and its inhabitants.