Now That You've Purchased Evolution Site ... Now What

The Academy's Evolution Site

Biology is one of the most important concepts 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 exploration.

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

Tree of Life

The Tree of Life, an ancient symbol, symbolizes the interconnectedness of all life. It is seen in a variety of cultures and spiritual beliefs as symbolizing unity and love. It also has practical applications, such as providing a framework to understand the evolution of species and how they react to changes in environmental conditions.

The first attempts to depict the world of biology were built on categorizing organisms based on their physical and metabolic characteristics. These methods, based on the sampling of various parts of living organisms or small DNA fragments, significantly increased the variety that could be represented in the tree of life2. However these trees are mainly comprised of eukaryotes, and bacterial diversity is still largely unrepresented3,4.

Genetic techniques have greatly expanded our ability to depict the Tree of Life by circumventing the need for direct observation and experimentation. Particularly, molecular methods allow us to build trees by using sequenced markers, such as the small subunit ribosomal RNA gene.

The Tree of Life has been dramatically expanded through genome sequencing. However there is a lot of 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 study of all genomes known to date 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.

The expanded Tree of Life can be used to assess the biodiversity of a specific region and determine if particular habitats need special protection. This information can be used in a variety of ways, including finding new drugs, fighting diseases and improving the quality of crops. The information is also useful in conservation efforts. It helps biologists determine those areas that are most likely contain cryptic species with potentially significant metabolic functions that could be at risk from anthropogenic change. Although funds to safeguard biodiversity are vital but the most effective 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 in order to promote conservation from within.

Phylogeny


A phylogeny, also known as an evolutionary tree, shows the relationships between different groups of organisms. Using molecular data similarities and differences in morphology, or ontogeny (the course of development of an organism), scientists can build a phylogenetic tree that illustrates the evolutionary relationships between taxonomic categories. The concept of phylogeny is fundamental to 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 have evolved from common ancestors. These shared traits can be analogous or homologous. Homologous traits are the same in terms of their evolutionary paths. Analogous traits might appear similar, but they do not have the same origins. Scientists group similar traits into a grouping called a clade. For 에볼루션카지노 , all the organisms that make up a clade share the trait of having amniotic egg and evolved from a common ancestor that had these eggs. A phylogenetic tree is constructed by connecting the clades to determine the organisms which are the closest to each other.

For a more detailed and accurate phylogenetic tree scientists use molecular data from DNA or RNA to determine the relationships among organisms. This information is more precise than the morphological data and provides evidence of the evolutionary history of an individual or group. Researchers can use Molecular Data to calculate the evolutionary age of living organisms and discover the number of organisms that have the same ancestor.

The phylogenetic relationships between species can be influenced by several factors, including phenotypic plasticity a kind of behavior that alters in response to unique environmental conditions. This can cause a particular trait to appear more similar to one species than other species, which can obscure the phylogenetic signal. However, this problem can be cured by the use of methods such as cladistics that include a mix of homologous and analogous features into the tree.

In addition, phylogenetics helps determine the duration and rate at which speciation occurs. This information can assist conservation biologists decide which species to protect from extinction. In the end, it is the conservation of phylogenetic diversity which will create an ecosystem that is complete and balanced.

Evolutionary Theory

The main idea behind evolution is that organisms change over time as a result of their interactions with their environment. Many scientists have proposed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism could evolve according to its own requirements and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical system of taxonomy and 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, ideas from various fields, including genetics, natural selection and particulate inheritance--came together to create the modern evolutionary theory which 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, called genetic drift, mutation, gene flow and sexual selection, is a key element of the current evolutionary biology and can be mathematically described.

Recent advances in evolutionary developmental biology have shown the ways in which variation can be introduced to a species via mutations, genetic drift or reshuffling of genes in sexual reproduction and migration between populations. These processes, along with other ones like directional selection and genetic erosion (changes in the frequency of the genotype over time) can result in evolution which is defined by changes in the genome of the species over time and also the change in phenotype as time passes (the expression of the genotype in an individual).

Incorporating evolutionary thinking into all aspects of biology education could increase students' understanding of phylogeny and evolution. A recent study conducted by Grunspan and colleagues, for instance, showed that teaching about the evidence that supports evolution helped students accept the concept of evolution in a college biology class. To find out more about how to teach about evolution, read The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily: A Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Scientists have studied evolution by looking in the past, studying fossils, and comparing species. They also study living organisms. Evolution isn't a flims event, but a process that continues today. Bacteria mutate and resist antibiotics, viruses re-invent themselves and are able to evade new medications and animals change their behavior in response to a changing planet. The resulting changes are often visible.

It wasn't until late 1980s that biologists began to realize that natural selection was also in action. The reason is that different traits have different rates of survival and reproduction (differential fitness) and are passed down from one generation to the next.

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

The ability to observe evolutionary change is easier when a particular species has a rapid turnover of its generation such as bacteria. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that are descended from one strain. Samples of each population were taken regularly and more than 50,000 generations of E.coli have passed.

Lenski's work has demonstrated that a mutation can dramatically alter the speed at which a population reproduces and, consequently the rate at which it alters. It also shows that evolution takes time, which is hard for some to accept.

Another example of microevolution is how mosquito genes that are resistant to pesticides show up more often in areas where insecticides are employed. This is because pesticides cause an exclusive pressure that favors individuals who have resistant genotypes.

The rapid pace at which evolution can take place has led to a growing awareness of its significance in a world that is shaped by human activity, including climate change, pollution, and the loss of habitats that hinder many species from adjusting. Understanding evolution can assist you in making better choices about the future of the planet and its inhabitants.

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Pub: 23 Dec 2024 18:13 UTC
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