This Is The History Of Evolution Site

The Academy's Evolution Site

Biology is a key concept in biology. The Academies are involved in helping those who are interested in science to learn about the theory of evolution and how it can be applied in all areas of scientific research.

This site offers a variety of tools for teachers, students, and general readers 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 symbolizes the interconnectedness of all life. It is an emblem of love and harmony in a variety of 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 approaches to depicting the world of biology focused on the classification of species into distinct categories that had been distinguished by physical and metabolic characteristics1. These methods, based on the sampling of different parts of living organisms, or short fragments of their DNA, significantly increased the variety that could be included in a tree of life2. The trees are mostly composed of eukaryotes, while the diversity of bacterial species is greatly underrepresented3,4.

In avoiding the necessity of direct observation and experimentation genetic techniques have allowed us to represent the Tree of Life in a much more accurate way. Trees can be constructed using molecular methods such as the small subunit ribosomal gene.

The Tree of Life has been dramatically expanded through genome sequencing. However there is a lot of biodiversity to be discovered. This is particularly true for microorganisms that are difficult to cultivate and are often only found in a single specimen5. A recent study of all genomes that are known has produced a rough draft version of the Tree of Life, including a large number of archaea and bacteria that have not been isolated and whose diversity is poorly understood6.

This expanded Tree of Life can be used to assess the biodiversity of a specific area and determine if particular habitats need special protection. This information can be utilized in a variety of ways, including finding new drugs, battling diseases and improving the quality of crops. This information is also valuable in conservation efforts. It helps biologists determine the areas most likely to contain cryptic species with important metabolic functions that could be at risk from anthropogenic change. Although funding to safeguard biodiversity are vital, ultimately the best way to protect the world's biodiversity is for more people in developing countries to be equipped with the knowledge to take action locally to encourage conservation from within.

Phylogeny

A phylogeny (also known as an evolutionary tree) shows the relationships between organisms. Scientists can build a phylogenetic chart that shows the evolutionary relationships between taxonomic groups based on molecular data and morphological differences or similarities. Phylogeny is crucial in understanding biodiversity, evolution and genetics.

A basic phylogenetic tree (see Figure PageIndex 10 Determines the relationship between organisms with similar traits and have evolved from an ancestor that shared traits. These shared traits could be analogous or homologous. Homologous traits are similar in their evolutionary origins, while analogous traits look similar but do not have the identical origins. Scientists combine similar traits into a grouping called a the clade. For instance, all of the species in a clade share the trait of having amniotic eggs. They evolved from a common ancestor that had eggs. A phylogenetic tree is then constructed by connecting the clades to determine the organisms who are the closest to each other.

Scientists utilize DNA or RNA molecular data to build a phylogenetic chart that is more accurate and precise. This information is more precise and gives evidence of the evolution history of an organism. The analysis of molecular data can help researchers identify the number of species that share an ancestor common to them and estimate their evolutionary age.

The phylogenetic relationship can be affected by a number of factors such as phenotypicplasticity. This is a kind of behavior that changes due to particular environmental conditions. This can cause a characteristic to appear more similar to one species than another, clouding the phylogenetic signal. However, this problem can be reduced by the use of methods such as cladistics which combine homologous and analogous features into the tree.

Furthermore, phylogenetics may aid in predicting the duration and rate of speciation. This information can assist conservation biologists in deciding which species to save from the threat of extinction. It is ultimately the preservation of phylogenetic diversity which will lead to a complete and balanced ecosystem.

Evolutionary Theory

The fundamental concept in evolution is that organisms change over time due to their interactions with their environment. Many theories of evolution 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 and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that the use or non-use of traits causes changes that could be passed onto offspring.

In the 1930s and 1940s, ideas from a variety of fields--including genetics, natural selection and particulate inheritance - came together to form the modern evolutionary theory, which defines how evolution is triggered by the variation of genes within a population, and how these variants change over time due to natural selection. This model, which includes genetic drift, mutations as well as gene flow and sexual selection is mathematically described.

Recent discoveries in the field of evolutionary developmental biology have demonstrated how variations can be introduced to a species via genetic drift, mutations and reshuffling of genes during sexual reproduction and the movement between populations. These processes, along with others such as directional selection or genetic erosion (changes in the frequency of a genotype over time), can lead to evolution that is defined as change in the genome of the species over time, and also by changes in phenotype as time passes (the expression of the genotype in an individual).

Students can better understand phylogeny by incorporating evolutionary thinking into all aspects of biology. A recent study by Grunspan and colleagues, for instance demonstrated that teaching about the evidence that supports evolution helped students accept the concept of evolution in a college-level biology course. For more information on 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 by looking back, studying fossils, comparing species, and studying living organisms. Evolution is not a distant event; it is a process that continues today. Bacteria evolve and resist antibiotics, viruses reinvent themselves and elude new medications, and animals adapt their behavior to a changing planet. The results are usually evident.

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

In the past when one particular allele - the genetic sequence that defines color in a population of interbreeding organisms, it could quickly become more common than other alleles. Over time, this would mean that the number of moths that have black pigmentation could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

It is easier to observe evolution when an organism, like bacteria, has a high generation turnover. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that are descended from one strain.  click through the next webpage  from each population were taken regularly and more than 50,000 generations of E.coli have been observed to have passed.

Lenski's work has demonstrated that a mutation can dramatically alter the rate at which a population reproduces--and so the rate at which it alters. It also shows that evolution takes time, which is hard for some to accept.

Another example of microevolution is that mosquito genes for resistance to pesticides are more prevalent in populations where insecticides are used. Pesticides create an exclusive pressure that favors those with resistant genotypes.

The rapidity of evolution has led to a growing awareness of its significance especially in a planet that is largely shaped by human activity. This includes the effects of climate change, pollution and habitat loss, which prevents many species from adapting. Understanding evolution can help us make smarter choices about the future of our planet and the life of its inhabitants.