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The Academy's Evolution Site

Biology is one of the most important concepts in biology. The Academies have been for a long time involved in helping those interested in science understand the theory of evolution and how it influences every area of scientific inquiry.

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

Tree of Life

The Tree of Life, an ancient symbol, symbolizes the interconnectedness of all life. It is a symbol of love and unity in many cultures. It also has important practical applications, like providing a framework to understand the evolution of species and how they react to changes in environmental conditions.

Early attempts to describe the world of biology were based on categorizing organisms based on their physical and metabolic characteristics. These methods, which depend on the sampling of different parts of organisms or fragments of DNA have significantly increased the diversity of a Tree of Life2. However, these trees are largely composed of eukaryotes; bacterial diversity remains vastly underrepresented3,4.

Genetic techniques have greatly broadened our ability to visualize the Tree of Life by circumventing the requirement for direct observation and experimentation. Particularly, 에볼루션 슬롯 molecular methods enable us to create trees using sequenced markers like the small subunit of ribosomal RNA gene.

Despite the massive growth of the Tree of Life through genome sequencing, a lot of biodiversity awaits discovery. This is especially true of microorganisms, which can be difficult to cultivate and are usually only found in a single specimen5. A recent analysis of all genomes known to date has produced a rough draft version of the Tree of Life, including a large number of archaea and bacteria that have not been isolated, and their diversity is not fully understood6.

This expanded Tree of Life is particularly useful in assessing the diversity of an area, helping to determine whether specific habitats require protection. The information is useful in a variety of ways, including finding new drugs, battling diseases and improving the quality of crops. The information is also incredibly valuable to conservation efforts. It can aid biologists in identifying areas most likely to be home to cryptic species, which could have important metabolic functions and be vulnerable to changes caused by humans. While funds to protect biodiversity are crucial but the most effective way to protect the world's biodiversity is for more people living 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) shows the relationships between species. Scientists can create a phylogenetic diagram that illustrates the evolutionary relationship of taxonomic groups based on molecular data and morphological differences or similarities. Phylogeny is crucial in understanding the evolution of biodiversity, evolution and genetics.

A basic phylogenetic tree (see Figure PageIndex 10 ) determines the relationship between organisms with similar traits that evolved from common ancestral. These shared traits can be analogous, or homologous. Homologous traits are similar in terms of their evolutionary paths. Analogous traits may look similar however they do not have the same origins. Scientists put similar traits into a grouping called a the clade. For instance, 에볼루션 all of the organisms in a clade share the characteristic of having amniotic eggs and evolved from a common ancestor who had these eggs. The clades then join to create a phylogenetic tree to identify organisms that have the closest connection to each other.

For a more precise and precise phylogenetic tree scientists use molecular data from DNA or RNA to identify the relationships among organisms. This data is more precise than morphological data and provides evidence of the evolutionary history of an individual or group. Researchers can utilize Molecular Data to determine the evolutionary age of organisms and identify how many organisms share an ancestor 에볼루션 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 behaviour that can change as a result of unique environmental conditions. This can cause a trait to 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.

Furthermore, phylogenetics may help predict the length and speed of speciation. This information can assist conservation biologists make decisions about which species to protect from the threat of extinction. In the end, 에볼루션 코리아 (super fast reply) it is the preservation of phylogenetic diversity which will create an ecosystem that is complete and balanced.

Evolutionary Theory

The fundamental concept in evolution is that organisms change over time as a result of their interactions with their environment. Many scientists have come up with 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 needs 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 usage or non-use of traits can cause changes that can be passed on to future generations.

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

Recent developments in the field of evolutionary developmental biology have demonstrated that variation can be introduced into a species by mutation, genetic drift and reshuffling of genes in sexual reproduction, as well as through migration between populations. These processes, as well as others, such as directional selection and gene erosion (changes to the frequency of genotypes over time) can result in evolution. Evolution is defined as changes in the genome over time, as well as changes in phenotype (the expression of genotypes within individuals).

Incorporating evolutionary thinking into all areas of biology education can increase student understanding of the concepts of phylogeny and evolutionary. A recent study by Grunspan and colleagues, 에볼루션 for example, showed that teaching about the evidence that supports evolution helped students accept the concept of evolution in a college biology course. For more information on how to teach about evolution, please look up The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution in Life Sciences Education.

Evolution in Action

Scientists have studied evolution by looking in the past, analyzing fossils and comparing species. They also study living organisms. But evolution isn't just something that occurred in the past, it's an ongoing process, happening today. Bacteria evolve and resist antibiotics, viruses reinvent themselves and escape new drugs, and animals adapt their behavior in response to a changing planet. The changes that occur are often visible.

It wasn't until the late 1980s that biologists began realize that natural selection was in play. The key to this is that different traits can confer the ability to survive at different rates and reproduction, 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 group of interbreeding organisms, it could rapidly become more common than other alleles. As time passes, that could mean the number of black moths within 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, Richard Lenski, a biologist, has tracked twelve populations of E.coli that descend from a single strain. Samples of each population have been taken regularly and more than 50,000 generations of E.coli have been observed to have passed.

Lenski's research has shown that a mutation can profoundly alter the rate at which a population reproduces and, consequently, the rate at which it evolves. It also demonstrates that evolution is slow-moving, a fact that some find hard to accept.

Another example of microevolution is the way mosquito genes for resistance to pesticides show up more often in populations where insecticides are employed. Pesticides create a selective pressure which favors those who have resistant genotypes.

The rapidity of evolution has led to an increasing awareness of its significance, especially in a world shaped largely by human activity. This includes pollution, climate change, and habitat loss, which prevents many species from adapting. Understanding the evolution process will assist you in making better choices about the future of our planet and its inhabitants.