The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies have long been involved in helping those interested in science understand the concept of evolution and how it permeates all areas of scientific research.

This site provides teachers, students and general readers with a wide range of educational resources on evolution. It contains important video clips from NOVA and the 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 appears in many spiritual traditions and cultures as a symbol of unity and love. It also has practical applications, such as providing a framework for understanding the evolution of species and how they respond to changes in environmental conditions.

Early attempts to describe the world of biology were based on categorizing organisms based on their metabolic and physical characteristics. These methods, which are based on the collection of various parts of organisms, or fragments of DNA, have greatly increased the diversity of a Tree of Life2. The trees are mostly composed by eukaryotes, and bacteria are largely underrepresented3,4.

By avoiding the necessity for direct experimentation and observation, genetic techniques have made it possible to depict the Tree of Life in a more precise manner. In particular, molecular methods enable us to create trees by using sequenced markers, such as the small subunit ribosomal gene.

Despite the massive expansion of the Tree of Life through genome sequencing, a lot of biodiversity remains to be discovered. This is especially the case for microorganisms which are difficult to cultivate and are typically found in one sample5. Recent analysis of all genomes has produced a rough draft of a Tree of Life. This includes a variety of archaea, bacteria and other organisms that haven't yet been isolated, 에볼루션카지노 or the diversity of which is not fully understood6.

The expanded Tree of Life can be used to evaluate the biodiversity of a specific region and determine if specific habitats require special protection. This information can be utilized in a variety of ways, such as finding new drugs, battling diseases and improving the quality of crops. The information is also incredibly beneficial to conservation efforts. It can help biologists identify areas most likely to be home to cryptic species, which may have important metabolic functions and be vulnerable to changes caused by humans. While funds to protect biodiversity are essential, the best method to protect the world's biodiversity is to empower more people in developing nations with the necessary knowledge to act locally and support conservation.

Phylogeny

A phylogeny, also called an evolutionary tree, shows the connections between different groups of organisms. Utilizing molecular data as well as morphological similarities and distinctions or ontogeny (the process of the development of an organism), scientists can build a phylogenetic tree which illustrates the evolutionary relationship between taxonomic categories. The concept of phylogeny is fundamental to understanding biodiversity, evolution and genetics.

A basic phylogenetic Tree (see Figure PageIndex 10 ) determines the relationship between organisms that share similar traits that have evolved from common ancestors. These shared traits could be either analogous or homologous. Homologous characteristics are identical in their evolutionary paths. Analogous traits may look like they are but they don't have the same ancestry. Scientists organize similar traits into a grouping known as a clade. For instance, all of the organisms that make up a clade share the trait of having amniotic eggs. They evolved from a common ancestor who had eggs. A phylogenetic tree is constructed by connecting the clades to identify the organisms who are the closest to one another.

For a more detailed and accurate phylogenetic tree scientists rely on molecular information from DNA or RNA to determine the relationships between organisms. This information is more precise and gives evidence of the evolution of an organism. Molecular data allows researchers to identify the number of organisms that share the same ancestor and estimate their evolutionary age.

The phylogenetic relationships of a species can be affected by a variety of factors such as phenotypicplasticity. This is a type of behavior that alters as a result of unique environmental conditions. This can cause a characteristic to appear more similar to one species than another, clouding the phylogenetic signal. This problem can be addressed by using cladistics. This is a method that incorporates an amalgamation of homologous and analogous traits in the tree.

In addition, phylogenetics helps determine the duration and speed at which speciation occurs. This information can aid conservation biologists in deciding which species to safeguard from extinction. In the end, it's the conservation of phylogenetic diversity that will result in an ecosystem that is balanced and complete.

Evolutionary Theory

The main idea behind evolution is that organisms develop various characteristics over time due to their interactions with their environment. Many theories of evolution have been developed by a variety 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 conceived the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits can cause changes that could be passed onto offspring.

In the 1930s and 1940s, theories from a variety of fields--including genetics, natural selection and particulate inheritance -- came together to create the modern evolutionary theory synthesis that explains how evolution occurs through the variations of genes within a population and how those variations change over time due to natural selection. This model, which incorporates genetic drift, mutations as well as gene flow and sexual selection, can be mathematically described mathematically.

Recent developments in evolutionary developmental biology have shown how variations can be introduced to a species by mutations, genetic drift and reshuffling of genes during sexual reproduction, and even 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 changes in the genome of the species over time, and also by changes in phenotype as time passes (the expression of the genotype within the individual).

Students can gain a better understanding of the concept of phylogeny through incorporating evolutionary thinking into all aspects of biology. In a recent study conducted by Grunspan and co. It was demonstrated that teaching students about the evidence for evolution increased their understanding of evolution during the course of a college biology. For more information about how to teach evolution read The Evolutionary Potential in all Areas of Biology or Thinking Evolutionarily: a Framework for Integrating Evolution into Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution by studying fossils, comparing species, and observing living organisms. However, evolution isn't something that occurred in the past. It's an ongoing process that is that is taking place today. Viruses reinvent themselves to avoid new antibiotics and bacteria transform to resist antibiotics. Animals alter their behavior as a result of a changing world. The changes that result are often visible.

However, it wasn't until late 1980s that biologists understood that natural selection could be observed in action as well. The reason 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 when one particular allele - the genetic sequence that determines coloration--appeared in a population of interbreeding organisms, it could quickly become more common than all other alleles. Over time, that would 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.

Monitoring evolutionary changes in action is easier when a species has a fast generation turnover, as with bacteria. Since 1988 biologist Richard Lenski has been tracking twelve populations of E. Coli that descended from a single strain. samples of each population are taken every day, and over fifty thousand generations have passed.

Lenski's research has shown that mutations can drastically alter the rate at the rate at which a population reproduces, and consequently the rate at which it alters. It also demonstrates that evolution takes time, which is difficult for some to accept.

Another example of microevolution is that mosquito genes for resistance to pesticides appear more frequently in populations where insecticides are used. That's because the use of pesticides creates a selective 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 that prevents many species from adapting. Understanding the evolution process will help us make better decisions about the future of our planet and the lives of its inhabitants.