The Academy's Evolution Site

The concept of biological evolution is among the most important concepts in biology. The Academies are involved in helping those who are interested in science to understand evolution theory and how it is permeated throughout all fields of scientific research.

This site provides students, teachers and general readers with a wide range 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, an ancient symbol, represents the interconnectedness of all life. It is seen in a variety of cultures and spiritual beliefs as a symbol of unity and love. It has numerous practical applications in addition to providing a framework to understand the history of species, and how they react to changes in environmental conditions.

The first attempts at depicting the biological world focused on categorizing organisms into distinct categories that were identified by their physical and metabolic characteristics1. These methods rely on the sampling of different parts of organisms or short DNA fragments, have greatly increased the diversity of a Tree of Life2. However, 에볼루션 무료 바카라 바카라사이트 (reference) these trees are largely comprised of eukaryotes, and bacterial diversity remains vastly underrepresented3,4.

Genetic techniques have greatly broadened our ability to visualize the Tree of Life by circumventing the need for direct observation and experimentation. Trees can be constructed using molecular techniques like the small-subunit ribosomal gene.

The Tree of Life has been greatly expanded thanks to genome sequencing. However, there is still much biodiversity to be discovered. This is especially relevant to microorganisms that are difficult to cultivate and are usually present in a single sample5. A recent analysis of all genomes produced a rough draft of the Tree of Life. This includes a wide range of archaea, bacteria and other organisms that haven't yet been isolated, or whose diversity has not been fully understood6.

The expanded Tree of Life can be used to assess the biodiversity of a specific area and determine if particular habitats need special protection. The information can be used in a range of ways, from identifying the most effective medicines to combating disease to enhancing crops. The information is also incredibly beneficial to conservation efforts. It can help biologists identify areas that are most likely to have cryptic species, which may have important metabolic functions, and could be susceptible to changes caused by humans. Although funds to protect biodiversity are essential, ultimately the best way to preserve the world's biodiversity is for more people in developing countries to be empowered with the necessary knowledge to act locally in order to promote conservation from within.

Phylogeny

A phylogeny is also known as an evolutionary tree, illustrates the relationships between different groups of organisms. By using molecular isult of particular environmental conditions. This can cause a trait to appear more like a species other species, 에볼루션 바카라사이트 which can obscure the phylogenetic signal. This issue can be cured by using cladistics. This is a method that incorporates a combination of analogous and homologous features in the tree.

Furthermore, phylogenetics may help predict the time and pace of speciation. This information can assist conservation biologists decide the species they should safeguard from the threat of extinction. In the end, it is the conservation of phylogenetic diversity which will create an ecosystem that is complete and balanced.

Evolutionary Theory

The fundamental concept of evolution is that organisms develop distinct characteristics over time based on their interactions with their environments. Several theories of evolutionary change have been proposed by a wide range of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who believed that an organism would evolve slowly in accordance with its requirements, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits can cause changes that could be passed on to the offspring.

In the 1930s and 1940s, concepts from various fields, including genetics, natural selection, and particulate inheritance, came together to create a modern evolutionary theory. This explains how evolution occurs by the variation in genes within a population and how these variations change over time as a result of natural selection. This model, called genetic drift mutation, gene flow, and sexual selection, is the foundation of current evolutionary biology, and is mathematically described.

Recent developments in the field of evolutionary developmental biology have shown that genetic variation can be introduced into a species by mutation, genetic drift and reshuffling of genes in sexual reproduction, as well as through the movement of populations. These processes, as well as others such as the directional selection process and the erosion of genes (changes to the frequency of genotypes over time), can lead towards evolution. Evolution is defined as changes in the genome over time, as well as changes in phenotype (the expression of genotypes in individuals).

Students can better understand the concept of phylogeny by using evolutionary thinking into all areas of biology. A recent study conducted by Grunspan and colleagues, for instance, showed that teaching about the evidence for evolution helped students accept the concept of evolution in a college-level biology course. To find out more about 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 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 taking place right now. Bacteria transform and resist antibiotics, viruses reinvent themselves and elude new medications, and animals adapt their behavior to a changing planet. The changes that result are often evident.

It wasn't until the 1980s that biologists began to realize that natural selection was also in action. The main reason is that different traits result in an individual rate of survival and reproduction, and they can be passed down from one generation to another.

In the past, if a certain allele - the genetic sequence that determines color - was present in a population of organisms that interbred, it could become more prevalent than any other allele. As time passes, this could mean that the number of moths sporting black pigmentation in a population may increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

The ability to observe evolutionary change is easier when a particular species has a fast generation turnover like bacteria. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that are descended from one strain. The samples of each population have been taken frequently and more than 50,000 generations of E.coli have been observed to have passed.

Lenski's work has shown that mutations can alter the rate of change and the efficiency at which a population reproduces. It also shows that evolution is slow-moving, a fact that some find difficult to accept.

Another example of microevolution is the way mosquito genes for resistance to pesticides show up more often in areas in which insecticides are utilized. This is because pesticides cause an exclusive pressure that favors those with resistant genotypes.

The speed of evolution taking 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 prevent many species from adapting. Understanding the evolution process can aid you in making better decisions regarding the future of the planet and its inhabitants.