The Academy's Evolution Site

Biology is one of the most important concepts in biology. The Academies have long been involved in helping people who are interested in science comprehend the theory of evolution and how it permeates all areas of scientific research.

This site provides students, teachers and general readers with a variety of learning resources on evolution. It has key video clips from NOVA and the WGBH-produced science programs on DVD.

Tree of Life

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

The earliest attempts to depict the biological world focused on separating organisms into distinct categories that had been distinguished by their physical and metabolic characteristics1. These methods, based on the sampling of different parts of living organisms or on sequences of small fragments of their DNA significantly expanded the diversity that could be represented in the tree of life2. These trees are largely composed by eukaryotes, and bacterial diversity is vastly underrepresented3,4.

Genetic techniques have significantly expanded our ability to visualize the Tree of Life by circumventing the requirement for direct observation and experimentation. Particularly, molecular techniques enable us to create trees by using sequenced markers such as the small subunit ribosomal RNA gene.

The Tree of Life has been greatly expanded thanks to genome sequencing. However there is a lot of biodiversity to be discovered. This is especially the case for microorganisms which are difficult to cultivate and 에볼루션 바카라 무료체험 are typically found in one sample5. A recent analysis of all genomes resulted in an unfinished draft of the Tree of Life. This includes a wide range of bacteria, archaea and other organisms that haven't yet been isolated, or their diversity is not thoroughly understood6.

This expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, which can help to determine if certain habitats require protection. This information can be utilized in a variety of ways, 에볼루션 바카라 무료 such as finding new drugs, fighting diseases and improving crops. The information is also incredibly beneficial in conservation efforts. It can help biologists identify the areas that are most likely to contain cryptic species with potentially important metabolic functions that may be vulnerable to anthropogenic change. Although funding to safeguard biodiversity are vital, ultimately the best way to ensure the preservation of biodiversity around the world is for more people in developing countries to be empowered with the knowledge to act locally to promote conservation from within.

Phylogeny

A phylogeny, also called an evolutionary tree, shows the connections between groups of organisms. By using molecular information similarities and differences in morphology or ontogeny (the course of development of an organism), scientists can build a phylogenetic tree which illustrates the evolutionary relationships between taxonomic categories. The phylogeny of a tree plays an important role in understanding genetics, biodiversity and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 ) determines the relationship between organisms with similar traits that evolved from common ancestors. These shared traits can be analogous or homologous. Homologous traits are similar in terms of their evolutionary journey. Analogous traits may look similar however they do not share the same origins. Scientists organize similar traits into a grouping referred to as a the clade. For example, 에볼루션 바카라사이트 all of the organisms that make up a clade share the characteristic of having amniotic egg and evolved from a common ancestor who had eggs. The clades then join to create a phylogenetic tree to identify organisms that have the closest relationship.

For a more precise and precise phylogenetic tree scientists rely on molecular information from DNA or RNA to identify the relationships between organisms. This information is more precise than the morphological data and provides evidence of the evolution history of an individual or group. Researchers can utilize Molecular Data to estimate the evolutionary age of living organisms and 무료에볼루션 discover how many organisms have an ancestor common to all.

The phylogenetic relationships of a species can be affected by a number of factors such as phenotypicplasticity. This is a kind of behavior that alters as a result of unique environmental conditions. This can cause a characteristic to appear more similar to one species than to another and obscure the phylogenetic signals. This problem can be mitigated by using cladistics, which incorporates a combination of analogous and 에볼루션 바카라사이트 homologous features in the tree.

Additionally, phylogenetics can help predict the length and speed of speciation. This information can aid conservation biologists to decide the species they should safeguard from the threat of extinction. In the end, it is the conservation of phylogenetic diversity that will lead to an ecosystem that is balanced and complete.

Evolutionary Theory

The main idea behind evolution is that organisms alter over time because of their interactions with their environment. Many scientists have developed theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism would evolve according to its individual needs, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern taxonomy system that is hierarchical, as well as Jean-Baptiste Lamarck (1844-1829), who believed that the use or absence of traits can cause changes that can be passed on to future generations.

In the 1930s and 1940s, concepts from a variety of fields--including genetics, natural selection, and particulate inheritance - came together to create the modern synthesis of evolutionary theory that explains how evolution happens through the variations of genes within a population and how those variants change over time as a result of natural selection. This model, known as genetic drift, mutation, gene flow, and sexual selection, is a key element of modern evolutionary biology and can be mathematically explained.

Recent developments in the field of evolutionary developmental biology have shown that variations can be introduced into a species via mutation, genetic drift and reshuffling genes during sexual reproduction, as well as through migration between populations. These processes, as well as other ones 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, 에볼루션 블랙잭 and also by changes in phenotype over time (the expression of the genotype in the individual).

Incorporating evolutionary thinking into all aspects of biology education can increase student understanding of the concepts of phylogeny and evolution. In a study by Grunspan and co. It was found that teaching students about the evidence for evolution boosted their understanding of evolution during an undergraduate biology course. For more information about how to teach evolution, see The Evolutionary Power of Biology 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, studying fossils, comparing species, and observing living organisms. Evolution isn't a flims event; it is an ongoing process. Viruses evolve to stay away from new antibiotics and bacteria transform to resist antibiotics. Animals adapt their behavior as a result of a changing environment. The results are usually easy to see.

However, it wasn't until late-1980s that biologists realized that natural selection can be observed in action as well. The key to this is that different traits confer a different rate of survival as well as reproduction, and 무료 에볼루션 may be passed on from one generation to another.

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

It is easier to see evolutionary change when an organism, like bacteria, has a rapid generation turnover. Since 1988 the 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 more than fifty thousand generations have been observed.

Lenski's research has demonstrated that mutations can alter the rate of change and the effectiveness of a population's reproduction. It also demonstrates that evolution takes time, a fact that is hard for some to accept.

Microevolution is also evident in the fact that mosquito genes for resistance to pesticides are more prevalent in populations that have used insecticides. That's because the use of pesticides creates a pressure that favors people with resistant genotypes.

The speed at which evolution can take place has led to a growing awareness of its significance in a world that is shaped by human activities, including climate change, pollution, and the loss of habitats that prevent many species from adjusting. Understanding evolution will help us make better choices about the future of our planet as well as the life of its inhabitants.