The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies are committed to helping those interested in science to understand evolution theory and how it is permeated throughout all fields of scientific research.

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

Tree of Life

The Tree of Life is an ancient symbol that represents the interconnectedness of life. It is a symbol of love and unity in many cultures. It also has practical applications, such as providing a framework to understand the evolution of species and how they respond to changing environmental conditions.

The first attempts to depict the world of biology were built on categorizing organisms based on their metabolic and physical characteristics. These methods rely on the collection of various parts of organisms or fragments of DNA have greatly increased the diversity of a Tree of Life2. However, these trees are largely comprised of eukaryotes, and bacterial diversity is not represented in a large way3,4.

Genetic techniques have greatly expanded our ability to depict the Tree of Life by circumventing the need for direct observation and experimentation. Trees can be constructed using molecular methods, such as the small-subunit ribosomal gene.

Despite the dramatic expansion of the Tree of Life through genome sequencing, a lot of biodiversity is waiting to be discovered. This is especially the case for microorganisms which are difficult to cultivate and are usually present in a single sample5. A recent analysis of all genomes has produced an unfinished draft of the Tree of Life. This includes a variety of archaea, bacteria and other organisms that have not yet been isolated, or their diversity is not fully understood6.

The expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, helping to determine if specific habitats require protection. The information is useful in a variety of ways, including finding new drugs, fighting diseases and improving crops. This information is also extremely beneficial for conservation efforts. It can help biologists identify those areas that are most likely contain cryptic species with important metabolic functions that could be at risk from anthropogenic change. While funding to protect biodiversity are important, the most effective method to preserve the world's biodiversity is to empower more people in developing nations with the necessary knowledge to take action locally and encourage conservation.

Phylogeny

A phylogeny, also known as an evolutionary tree, reveals the connections between different groups of organisms. Utilizing molecular data, morphological similarities and differences or ontogeny (the process of the development of an organism) scientists can create a phylogenetic tree that illustrates the evolution of taxonomic groups. The concept of phylogeny is fundamental to understanding evolution, biodiversity and genetics.

A basic phyic diversity that will lead to an ecologically balanced and complete ecosystem.

Evolutionary Theory

The fundamental concept in evolution is that organisms change over time due to their interactions with their environment. Many scientists have proposed theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism could evolve according to its own needs as well as the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern hierarchical taxonomy and Jean-Baptiste Lamarck (1844-1829), who suggested that the use or absence of traits can lead to changes that can be passed on to future generations.

In the 1930s and 1940s, concepts from various areas, including genetics, natural selection and particulate inheritance, came together to form a contemporary theorizing of evolution. This describes how evolution happens through the variations in genes within the population, and how these variants alter over time due to natural selection. This model, known as genetic drift, mutation, gene flow, and sexual selection, is a cornerstone of the current evolutionary biology and can be mathematically explained.

Recent developments in the field of evolutionary developmental biology have shown that variations can be introduced into a species through genetic drift, 무료에볼루션 mutation, and reshuffling genes during sexual reproduction, and also through migration between populations. These processes, as well as other ones like directionally-selected selection and erosion of genes (changes in frequency of genotypes over time), 무료에볼루션 can lead towards evolution. Evolution is defined by changes in the genome over time and changes in the phenotype (the expression of genotypes within individuals).

Students can better understand phylogeny by incorporating evolutionary thinking in all aspects of biology. A recent study conducted by Grunspan and colleagues, for example revealed that teaching students about the evidence supporting evolution increased students' acceptance of evolution in a college-level biology course. To learn more about how to teach about evolution, please read The Evolutionary Potential in all Areas of Biology and 무료 에볼루션 Thinking Evolutionarily A Framework for 에볼루션 카지노 Infusing Evolution in Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution by looking back, studying fossils, comparing species, and 무료에볼루션 studying living organisms. Evolution isn't a flims event, but an ongoing process. Viruses reinvent themselves to avoid new drugs and bacteria evolve to resist antibiotics. Animals adapt their behavior because of a changing environment. The changes that result are often evident.

But it wasn't until the late-1980s that biologists realized that natural selection could be seen in action, as well. The key is the fact that different traits result in a different rate of survival and reproduction, and can be passed on from one generation to the next.

In the past, if an allele - the genetic sequence that determines colour - was found in a group of organisms that interbred, it might become more prevalent than any other allele. In time, this could mean that the number of moths that have black pigmentation in a population 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 species has a rapid turnover of its generation like bacteria. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that descend from a single strain. The samples of each population were taken frequently and more than 500.000 generations of E.coli have passed.

Lenski's research has shown that a mutation can dramatically alter the efficiency with which a population reproduces and, consequently, the rate at which it evolves. It also demonstrates that evolution takes time, something that is difficult for some to accept.

Another example of microevolution is the way mosquito genes that are resistant to pesticides show up more often in areas where insecticides are used. This is due to pesticides causing a selective pressure which favors those with resistant genotypes.

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