The Academy's Evolution Site

Biological evolution is one of the most fundamental concepts in biology. The Academies have long been involved in helping those interested in science comprehend the theory of evolution and how it affects all areas of scientific research.

This site provides students, teachers and general readers with a range of learning resources about evolution. It also includes important video clips from NOVA and WGBH produced science programs on DVD.

Tree of Life

The Tree of Life, an ancient symbol, symbolizes the interconnectedness of all life. It is a symbol of love and unity in many cultures. It also has practical applications, such as providing a framework for understanding the history of species and how they react to changing environmental conditions.

Early attempts to describe the world of biology were based on categorizing organisms based on their physical and metabolic characteristics. These methods, which rely on sampling of different parts of living organisms, or sequences of small fragments of their DNA greatly increased the variety of organisms that could be represented in the tree of life2. However, these trees are largely composed of eukaryotes; bacterial diversity remains vastly underrepresented3,4.

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

Despite the massive expansion of the Tree of Life through genome sequencing, much biodiversity still remains to be discovered. This is particularly true of microorganisms, which can be difficult to cultivate and are typically only represented in a single specimen5. A recent study of all known genomes has produced a rough draft version of the Tree of Life, including a large number of archaea and 에볼루션 무료 바카라 bacteria that are not isolated and whose diversity is poorly understood6.

This expanded Tree of Life can be used to evaluate the biodiversity of a specific region and determine if particular habitats need special protection. The information can be used in a range of ways, from identifying new medicines to combating disease to enhancing crop yields. This information is also extremely useful for conservation efforts. It can help biologists identify the areas that are most likely to contain cryptic species with important metabolic functions that could be at risk of anthropogenic changes. While funds to protect biodiversity are important, the most effective method to preserve the world's biodiversity is to equip more people in developing nations with the necessary knowledge to act locally and support conservation.

Phylogeny

A phylogeny, also known as an evolutionary tree, illustrates the connections between different groups of organisms. By using molecular information as well as morphological similarities and distinctions or ontogeny (the process of the development of aeciation takes place. This information can assist conservation biologists in deciding which species to safeguard from the threat of extinction. In the end, it's the conservation of phylogenetic diversity which will create an ecosystem that is balanced and complete.

Evolutionary Theory

The fundamental concept in evolution is that organisms alter over time because of their interactions with their environment. A variety of theories about evolution have been proposed by a variety of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop gradually according to its needs, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that the use or misuse of traits can cause changes that can be passed onto offspring.

In the 1930s and 1940s, theories from various areas, including natural selection, genetics & particulate inheritance, merged to form a modern evolutionary theory. This defines how evolution occurs by the variation in genes within the population and how these variants alter over time due to natural selection. This model, which includes genetic drift, mutations as well as gene flow and sexual selection can be mathematically described mathematically.

Recent developments in the field of evolutionary developmental biology have shown that variation can be introduced into a species via mutation, genetic drift and 에볼루션 슬롯게임 무료 바카라 (Bbs.airav.Cc) reshuffling of genes during sexual reproduction, as well as through the movement of populations. These processes, as well as other ones like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time) can lead to evolution, which is defined by changes in the genome of the species over time, 에볼루션 바카라 무료 바카라 (reviews over at Airav) and also the change in phenotype over time (the expression of the genotype in the individual).

Incorporating evolutionary thinking into all areas of biology education could increase student understanding of the concepts of phylogeny and evolutionary. A recent study by Grunspan and colleagues, for instance demonstrated that teaching about the evidence for evolution helped students accept the concept of evolution in a college biology class. To learn 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

Traditionally scientists have studied evolution through looking back, 에볼루션코리아 studying fossils, comparing species and studying living organisms. But evolution isn't a thing that happened in the past, it's an ongoing process taking place in the present. Bacteria evolve and resist antibiotics, viruses reinvent themselves and are able to evade new medications and animals alter their behavior in response to the changing climate. The changes that result are often easy to see.

It wasn't until the late 1980s that biologists began to realize that natural selection was in play. The key is that different traits have different rates of survival and reproduction (differential fitness) and can be transferred from one generation to the next.

In the past, when one particular allele - the genetic sequence that controls coloration - was present in a group of interbreeding organisms, it might quickly become more common than other alleles. In time, this could mean 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.

It is easier to see evolutionary change when an organism, like bacteria, has a high generation turnover. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that descend from a single strain. The samples of each population were taken frequently and more than 50,000 generations of E.coli 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 evolves. It also demonstrates that evolution takes time, a fact that many find difficult to accept.

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

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