The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies are committed to helping those interested in science understand evolution theory and how it is incorporated throughout all fields of scientific research.

This site provides a wide range of tools for teachers, students and general readers of evolution. It has important video clips from NOVA and the WGBH-produced science programs on DVD.

Tree of Life

The Tree of Life is an ancient symbol of the interconnectedness of all life. It appears in many spiritual traditions and cultures as symbolizing unity and love. It can be used in many practical ways as well, including providing a framework for understanding the history of species, and how they react to changing environmental conditions.

Early attempts to describe the biological world were founded on categorizing organisms on their metabolic and physical characteristics. These methods, which relied on the sampling of various parts of living organisms or on small fragments of their DNA, significantly increased the variety that could be included in the tree of life2. These trees are mostly populated of eukaryotes, while bacterial diversity is vastly underrepresented3,4.

Genetic techniques have greatly expanded our ability to represent the Tree of Life by circumventing the need for direct observation and experimentation. Trees can be constructed by 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 relevant to microorganisms that are difficult to cultivate and are usually present in a single sample5. A recent study of all genomes that are known has created a rough draft of the Tree of Life, including many archaea and bacteria that have not been isolated and which are not well understood.

This expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, helping to determine if certain habitats require protection. This information can be used in many ways, 무료 에볼루션 카지노 (www.bioguiden.se) including finding new drugs, battling diseases and improving crops. It is also beneficial for conservation efforts. It helps biologists determine the areas most likely to contain cryptic species that could have significant metabolic functions that could be at risk from anthropogenic change. 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 equipped with the knowledge to take action locally to encourage conservation from within.

Phylogeny

A phylogeny, also called an evolutionary tree, reveals the relationships between groups of organisms. Using molecular data similarities and differences in morphology or ontogeny (the process of the development of an organism) scientists can construct a phylogenetic tree which illustrates the evolutionary relationship between taxonomic categories. The role of phylogeny is crucial in understanding genetics, biodiversity and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 Determines the relationship between organisms that have similar traits and evolved from a common ancestor. These shared traits are either homologous or analogous. Homologous traits are identical in their evolutionary origins while analogous traits appear similar but do not have the same origins. Scientists group similar traits into a grouping called a the clade. All organisms in a group share a trait, such as amniotic egg production. They all evolved from an ancestor that had these eggs. The clades are then linked to create a phylogenetic tree to determine which organisms have the closest relationship to.

Scientists utilize DNA or RNA molecular information to build a phylogenetic chart that is more precise and detailed. This information is more precise than morphological information and provides evidence of the evolutionary background of an organism or group. Researchers can use Molecular Data to calculate the evolutionary age of living organisms and discover the number of organisms that share an ancestor common to all.

The phylogenetic relationships of a species can be affected by a number of factors, including the phenomenon of phenotypicplasticity. This is a type behavior that alters due to specific environmental conditions. This can make a trait appear more similar to a species than to the other and obscure the phylogenetic signals. This problem can be addressed by using cladistics, which is a a combination of homologous and analogous features in the tree.

Additionally, phylogenetics can help predict the duration and rate at which speciation takes place. This information can aid conservation biologists to decide the species they should safeguard from extinction. Ultimately, it is the preservation of phylogenetic diversity that will create a complete and balanced ecosystem.

Evolutionary Theory

The central theme in evolution is that organisms change over time as a result of their interactions with their environment. Many scientists have developed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism would develop according to its own requirements as well as the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern hierarchical system of taxonomy as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the use or non-use of traits can lead to changes that are passed on to the

In the 1930s and 1940s, concepts from various fields, including genetics, natural selection and particulate inheritance -- came together to form the modern evolutionary theory, which defines how evolution occurs through the variations of genes within a population and how those variations change over time as a result of natural selection. This model, 에볼루션 바카라 무료 which encompasses mutations, genetic drift in gene flow, and sexual selection is mathematically described mathematically.

Recent developments in evolutionary developmental biology have demonstrated the ways in which variation can be introduced to a species via genetic drift, 에볼루션 카지노 사이트 mutations or reshuffling of genes in sexual reproduction and the movement between populations. These processes, in conjunction with other ones like directional selection and gene erosion (changes to the frequency of genotypes over time) can lead to evolution. Evolution is defined as changes in the genome over time and changes in phenotype (the expression of genotypes within individuals).

Incorporating evolutionary thinking into all areas of biology education could increase student understanding of the concepts of phylogeny and evolution. A recent study conducted by Grunspan and colleagues, for instance revealed that teaching students about the evidence supporting evolution increased students' understanding of evolution in a college biology class. For more details on how to teach evolution, see The Evolutionary Potency 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 looking back, 에볼루션 바카라 무료 studying fossils, comparing species and studying living organisms. But evolution isn't just something that happened in the past, it's an ongoing process, happening right now. Bacteria evolve and resist antibiotics, viruses evolve and elude new medications and animals alter their behavior to a changing planet. The resulting changes are often visible.

It wasn't until the late 1980s that biologists began realize that natural selection was also in play. The key is that different traits have different rates of survival and reproduction (differential fitness), and can be transferred from one generation to the next.

In the past, if a certain allele - the genetic sequence that determines colour - was found in a group of organisms that interbred, it might become more common than other allele. 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.

Monitoring evolutionary changes in action is much easier when a species has a rapid generation turnover like bacteria. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that descend from one strain. Samples from each population were taken regularly and more than 50,000 generations of E.coli have passed.

Lenski's work has shown that mutations can alter the rate of change and the efficiency at which a population reproduces. It also shows evolution takes time, which is difficult for some to accept.

Microevolution is also evident in the fact that mosquito genes for pesticide resistance are more common in populations that have used insecticides. This is due to the fact that the use of pesticides causes a selective pressure that favors individuals with resistant genotypes.

The rapid pace of evolution taking place has led to an increasing awareness of its significance in a world that is shaped by human activity--including climate change, pollution, and the loss of habitats which prevent the species from adapting. Understanding the evolution process can aid you in making better decisions about the future of our planet and its inhabitants.