The Academy's Evolution Site

Biology is one of the most important concepts in biology. The Academies are involved in helping those who are interested in science understand evolution theory and how it is permeated throughout all fields of scientific research.

This site provides a range of sources for teachers, students and general readers of evolution. It includes the most important video clips from NOVA and WGBH's 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 cultures and spiritual beliefs as an emblem of unity and love. It has numerous practical applications as well, such as providing a framework to understand the history of species, and how they respond to changing environmental conditions.

Early attempts to describe the biological world were built on categorizing organisms based on their physical and metabolic 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. These trees are mostly populated by eukaryotes and bacterial diversity is vastly underrepresented3,4.

By avoiding the necessity for direct experimentation and observation, genetic techniques have made it possible to represent the Tree of Life in a much more accurate way. Trees can be constructed using molecular methods like the small-subunit ribosomal gene.

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

This expanded Tree of Life can be used to evaluate the biodiversity of a particular area and 에볼루션 게이밍 determine if particular habitats require special protection. This information can be utilized in a variety of ways, such as identifying new drugs, combating diseases and improving crops. This information is also extremely beneficial to conservation efforts. It can help biologists identify areas that are most likely to be home to cryptic species, which may have vital metabolic functions and be vulnerable to changes caused by humans. Although funding to protect biodiversity are crucial however, the most effective method to ensure the preservation of biodiversity around the world is for more people in developing countries to be empowered with the necessary knowledge to act locally to promote conservation from within.

Phylogeny

A phylogeny (also called an evolutionary tree) illustrates the relationship between organisms. Scientists can build a phylogenetic chart that shows the evolutionary relationships between taxonomic groups using molecular data and morphological similarities or 에볼루션 게이밍코리아 (Algowiki.win) differences. Phylogeny plays a crucial role in understanding biodiversity, genetics and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 Finds the connections between organisms that have similar characteristics and 에볼루션 슬롯 have evolved from an ancestor that shared traits. These shared traits could be either homologous or analogous. Homologous traits are identical in their underlying evolutionary path, 에볼루션 바카라 체험 [Recommended Web site] while analogous traits look similar but do not have the same ancestors. Scientists arrange similar traits into a grouping known as a the clade. For instance, all of the species in a clade have the characteristic of having amniotic egg and evolved from a common ancestor who had these eggs. The clades then join to form a phylogenetic branch that can determine which organisms have the closest connection to each other.

To create a more thorough and precise phylogenetic tree scientists use molecular data from DNA or RNA to establish the relationships between organisms. This information is more precise and provides evidence of the evolution history of an organism. Researchers can use Molecular Data to determine the age of evolution of living organisms and discover how many organisms share an ancestor common to all.

The phylogenetic relationships of organisms can be influenced by several factors including phenotypic plasticity, a kind of behavior that changes in response to unique environmental conditions. This can cause a characteristic to appear more similar to one species than another and obscure the phylogenetic signals. This problem can be mitigated by using cladistics, which is a a combination of homologous and analogous traits in the tree.

In addition, phylogenetics can aid in predicting the time and pace of speciation. This information will assist conservation biologists in deciding which species to safeguard from extinction. In the end, it's the preservation of phylogenetic diversity which will lead to an ecologically balanced and complete ecosystem.

Evolutionary Theory

The fundamental concept of evolution is that organisms acquire different features over time based on their interactions with their surroundings. Many scientists have developed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism could evolve according to its individual needs as well as the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical taxonomy as well as Jean-Baptiste Lamarck (1844-1829), who believed that the use or non-use of traits can lead to changes that are passed on to the next generation.

In the 1930s and 1940s, ideas from a variety of fields--including genetics, natural selection and particulate inheritance -- came together to form the current synthesis of evolutionary theory, which defines how evolution happens through the variations of genes within a population, and how those variations change in time due to natural selection. This model, which encompasses genetic drift, mutations, gene flow and sexual selection is mathematically described.

Recent advances in the field of evolutionary developmental biology have revealed how variations can be introduced to a species through mutations, genetic drift, reshuffling genes during sexual reproduction and the movement between populations. These processes, in conjunction with others such as directional selection and gene erosion (changes to the frequency of genotypes over time) can lead to evolution. Evolution is defined by changes in the genome over time, as well as changes in the phenotype (the expression of genotypes in individuals).

Incorporating evolutionary thinking into all areas of biology education could increase student understanding of the concepts of phylogeny and evolution. A recent study by Grunspan and colleagues, for example revealed that teaching students about the evidence supporting evolution helped students accept the concept of evolution in a college biology course. To find out more about how to teach about evolution, please see The Evolutionary Potential of all Areas of Biology and Thinking Evolutionarily: A Framework for Infusing the Concept of Evolution into Life Sciences Education.

Evolution in Action

Scientists have traditionally studied evolution by looking in the past, analyzing fossils and comparing species. They also study living organisms. Evolution isn't a flims event, but an ongoing process that continues to be observed today. The virus reinvents itself to avoid new drugs and 에볼루션바카라 bacteria evolve to resist antibiotics. Animals alter their behavior in the wake of the changing environment. The results are usually evident.

However, it wasn't until late 1980s that biologists realized that natural selection could be observed in action as well. The key is that various traits have different rates of survival and reproduction (differential fitness) and can 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. As time passes, this could mean that the number of moths that have black pigmentation may increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

It is easier to see evolution when an organism, like bacteria, has a high generation turnover. 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 regularly, and over 500.000 generations have passed.

Lenski's research has shown that a mutation can profoundly alter the speed at the rate at which a population reproduces, and consequently, the rate at which it alters. It also shows that evolution takes time, a fact that some people are unable to accept.

Another example of microevolution is the way mosquito genes for resistance to pesticides are more prevalent in populations in which insecticides are utilized. This is due to the fact that the use of pesticides causes a selective pressure that favors people with resistant genotypes.

The rapidity of evolution has led to a growing appreciation of its importance especially in a planet that is largely shaped by human activity. This includes climate change, pollution, and habitat loss that prevents many species from adapting. Understanding evolution can help us make smarter decisions about the future of our planet, as well as the lives of its inhabitants.