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 understand the theory of evolution and how it affects all areas of scientific research.

This site provides students, teachers and general readers with a variety 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 is an ancient symbol that symbolizes the interconnectedness of life. It is an emblem of love and unity across many cultures. It also has practical applications, like providing a framework to understand the history of species and how they react to changes in environmental conditions.

The earliest attempts to depict the biological world focused on separating species into distinct categories that had been distinguished by their physical and metabolic characteristics1. These methods, which rely on the sampling of different parts of living organisms, or short fragments of their DNA greatly increased the variety of organisms that could be included in the tree of life2. These trees are largely composed by eukaryotes and bacterial diversity is vastly underrepresented3,4.

In avoiding the necessity of direct observation and experimentation genetic techniques have allowed us to depict the Tree of Life in a more precise way. We can create trees 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 a lot of biodiversity to be discovered. This is particularly true of microorganisms, which are difficult to cultivate and are usually only represented in a single sample5. A recent analysis of all genomes resulted in a rough draft of the Tree of Life. This includes a large number of bacteria, archaea and other organisms that have not yet been isolated, or the diversity of which is not well understood6.

This expanded Tree of Life is particularly useful for assessing the biodiversity of an area, helping to determine if specific habitats require protection. The information can be used in a variety of ways, from identifying the most effective treatments to fight disease to enhancing the quality of the quality of crops. This information is also extremely valuable to conservation efforts. It helps biologists determine those areas that are most likely contain cryptic species with important metabolic functions that may be at risk from anthropogenic change. While funds to protect biodiversity are important, the most effective method to preserve the biodiversity of the world is to equip more people in developing countries with the knowledge they need to act locally and support conservation.

Phylogeny

A phylogeny (also known as an evolutionary tree) depicts the relationships between organisms. Using molecular data as well as morphological similarities and distinctions, or ontogeny (the course of development of an organism), 에볼루션 코리아 scientists can build an phylogenetic tree that demonstrates the evolutionary relationships between taxonomic groups. Phylogeny plays a crucial role in understanding the relationship between genetics, biodiversity and evolution.

A basic phylogenetic tree (see Figure PageIndex 10 Determines the relationship between organisms with similar traits and evolved from a common ancestor. These shared traits could be either analogous or homologous. Homologous traits are identical in their evolutionary origins while analogous traits appear similar but do not have the same origins. Scientists organize similar traits into a grouping called a the clade. For instance, all of the organisms in a clade share the characteristic of having amniotic egg and evolved from a common ancestor who had eggs. A phylogenetic tree can be built by connecting the clades to identify the organisms who are the closest to one another.

For a more detailed and accurate phylogenetic tree scientists make use of molecular data from DNA or RNA to establish the relationships among organisms. This information is more precise than the morphological data and provides evidence of the evolutionary background of an organism or group. Researchers can utilize Molecular Data to determine the evolutionary age of living organisms and discover how many species share the same ancestor.

The phylogenetic relationships of a species can be affected by a number of factors, including phenotypicplasticity. This is a type behavior that alters due to unique environmental conditions. This can cause a trait to appear more similar in one species than another, clouding the phylogenetic signal. However, this issue can be solved through the use of techniques such as cladistics which combine homologous and analogous features into the tree.

In addition, phylogenetics can aid in predicting the length and speed of speciation. This information can help conservation biologists decide which species to protect from the threat of extinction. In the end, it is the conservation of phylogenetic variety that will result in an ecosystem that is balanced and complete.

Evolutionary Theory

The central theme in evolution is that organisms change over time as a result of their interactions with their environment. Many theories of evolution have been proposed by a variety of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing slowly according to its needs as well as the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that the use or misuse of traits cause changes that can be passed on to the offspring.

In the 1930s and 1940s, 에볼루션 ideas from different fields, including genetics, natural selection, and particulate inheritance, merged to form a modern evolutionary theory. This describes how evolution is triggered by the variation in genes within the population, and how these variants change over time as a result of natural selection. This model, which incorporates mutations, genetic drift in gene flow, and sexual selection can be mathematically described mathematically.

Recent developments in the field of evolutionary developmental biology have demonstrated that variations can be introduced into a species through mutation, genetic drift, and reshuffling genes during sexual reproduction, and also through migration between populations. These processes, along with others, 에볼루션 코리아 such as directional selection and gene erosion (changes in the frequency of genotypes over time), can lead towards evolution. Evolution is defined as changes in the genome over time and changes in the phenotype (the expression of genotypes in individuals).

Students can better understand phylogeny by incorporating evolutionary thinking into all areas of biology. A recent study by Grunspan and colleagues, for example, showed that teaching about the evidence for evolution helped students accept the concept of evolution in a college-level biology class. For more information about how to teach evolution read The Evolutionary Potency in All Areas of Biology or Thinking Evolutionarily A Framework for 에볼루션 블랙잭 (Marvelvsdc.Faith) Integrating Evolution into Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution through studying fossils, comparing species, and studying living organisms. But evolution isn't a thing that occurred in the past. It's an ongoing process, that is taking place in the present. Bacteria mutate and resist antibiotics, viruses re-invent themselves and are able to evade new medications and animals alter their behavior to the changing climate. The changes that result are often visible.

But it wasn't until the late 1980s that biologists realized that natural selection could be observed in action as well. The key to this is that different traits can confer the ability to survive at different rates as well as reproduction, and may be passed down from one generation to the next.

In the past, if one particular allele - the genetic sequence that determines coloration--appeared in a group of interbreeding organisms, it could quickly become more common than all other alleles. In time, this could mean that the number of moths with black pigmentation in a group may increase. The same is true for many other characteristics--including morphology and 에볼루션 바카라 사이트 behavior--that vary among populations of organisms.

It is easier to observe evolution when a species, such as bacteria, 에볼루션 has a rapid generation turnover. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that are descended from one strain. Samples from each population have been 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 efficiency with which a population reproduces--and so, the rate at which it changes. It also shows that evolution takes time, 에볼루션 바카라 체험 a fact that some are unable to accept.

Microevolution can also be seen in the fact that mosquito genes for pesticide resistance are more common in populations where insecticides have been used. This is because the use of pesticides creates a selective pressure that favors those with resistant genotypes.

The rapid pace at which evolution takes place has led to an increasing awareness of its significance in a world shaped by human activity--including climate change, pollution and the loss of habitats which prevent many species from adapting. Understanding the evolution process can help us make smarter decisions regarding the future of our planet, and the life of its inhabitants.