The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies have long been involved in helping people who are interested in science comprehend the concept of evolution and how it affects all areas of scientific exploration.

This site provides a range of sources for students, teachers and general readers of 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, represents the interconnectedness of all life. It is an emblem of love and harmony in a variety of cultures. It also has important practical applications, like providing a framework for understanding the evolution of species and how they react to changes in environmental conditions.

Early attempts to represent the world of biology were founded on categorizing organisms on their metabolic and physical characteristics. These methods, based on the sampling of different parts of living organisms, or sequences of short fragments of their DNA significantly increased the variety that could be represented in the tree of life2. However the trees are mostly made up of eukaryotes. Bacterial diversity remains vastly underrepresented3,4.

Genetic techniques have greatly broadened our ability to visualize the Tree of Life by circumventing the requirement for direct observation and experimentation. Particularly, molecular techniques allow us to build trees by using sequenced markers like the small subunit of ribosomal RNA gene.

Despite the dramatic growth of the Tree of Life through genome sequencing, a large amount of biodiversity is waiting to be discovered. This is especially true of microorganisms, which can be difficult to cultivate and are often only present in a single sample5. A recent analysis of all genomes has produced an unfinished draft of the Tree of Life. This includes a wide range of bacteria, archaea and other organisms that haven't yet been identified or whose diversity has not been thoroughly understood6.

This expanded Tree of Life is particularly useful for assessing the biodiversity of an area, helping to determine if certain habitats require protection. This information can be used in a range of ways, from identifying the most effective treatments to fight disease to improving crop yields. This information is also beneficial for 에볼루션 바카라사이트에볼루션 바카라 무료체험사이트 (click here to read) conservation efforts. It helps biologists discover areas that are likely to have cryptic species, which may have important metabolic functions, and could be susceptible to changes caused by humans. While conservation funds are important, the most effective method to preserve the world's biodiversity is to empower more people in developing nations with the information they require to act locally and support conservation.

Phylogeny

A phylogeny is also known as an evolutionary tree, e phylogenetic relationships between organisms can be influenced by several factors, including phenotypic flexibility, a kind of behavior that alters in response to specific environmental conditions. This can cause a characteristic to appear more resembling to one species than another, obscuring the phylogenetic signals. However, this issue can be solved through the use of methods such as cladistics that include a mix of similar and homologous traits into the tree.

Additionally, phylogenetics aids determine the duration and speed at which speciation takes place. 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 main idea behind evolution is that organisms develop various characteristics over time due to their interactions with their environments. A variety of theories about evolution have been proposed by a variety of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who believed that an organism would evolve gradually according to its needs, the Swedish botanist Carolus Linnaeus (1707-1778) who developed modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits can cause changes that can be passed on to the offspring.

In the 1930s and 1940s, theories from various areas, including genetics, natural selection and particulate inheritance, merged to form a contemporary synthesis of evolution theory. This describes 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 is known as genetic drift mutation, gene flow, and sexual selection, is a cornerstone of the current evolutionary biology and can be mathematically explained.

Recent advances in evolutionary developmental biology have demonstrated the ways in which variation can be introduced to a species by genetic drift, mutations and reshuffling of genes during sexual reproduction and 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 lead to evolution which is defined by change in the genome of the species over time and the change in phenotype as time passes (the expression of that genotype in the individual).

Students can better understand the concept of phylogeny through incorporating evolutionary thinking throughout all aspects of biology. In a study by Grunspan and co. It was found that teaching students about the evidence for evolution boosted their understanding of evolution in the course of a college biology. To find out more about how to teach about evolution, look up The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily: A Framework for Infusing the Concept of Evolution into Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution through looking back--analyzing fossils, comparing species, and observing living organisms. Evolution isn't a flims moment; it is an ongoing process that continues to be observed today. Bacteria transform and resist antibiotics, viruses evolve and escape new drugs and animals change their behavior in response to the changing climate. The resulting changes are often easy to see.

It wasn't until the 1980s when biologists began to realize that natural selection was also in action. The key is that different characteristics result in different rates of survival and reproduction (differential fitness) and can be passed down from one generation to the next.

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 common than other allele. 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.

Monitoring evolutionary changes in action is easier when a species has a fast generation turnover such as bacteria. 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 500.000 generations have passed.

Lenski's research has revealed that mutations can alter the rate of change and the effectiveness at which a population reproduces. It also proves that evolution takes time--a fact that some people are unable to accept.

Another example of microevolution is the way mosquito genes that are resistant to pesticides are more prevalent in populations where insecticides are employed. This is because the use of pesticides creates a selective pressure that favors individuals who have resistant genotypes.

The rapid pace at which evolution takes place has led to an increasing recognition of its importance in a world shaped by human activities, including climate changes, pollution and 에볼루션 무료체험 the loss of habitats which prevent the species from adapting. Understanding the evolution process will help us make better choices about the future of our planet, as well as the life of its inhabitants.