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The Academy's Evolution Site

Biological evolution is one of the most fundamental concepts in biology. The Academies are involved in helping those who are interested in science to learn about the theory of evolution and how it is incorporated in all areas of scientific research.

This site provides teachers, students and general readers with a wide range of educational resources on 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 is used in many spiritual traditions and cultures as an emblem of unity and love. It has many practical applications as well, such as providing a framework for understanding the evolution of species and how they respond to changes in environmental conditions.

The first attempts at depicting the biological world focused on separating species into distinct categories that were identified by their physical and metabolic characteristics1. These methods depend on the collection of various parts of organisms or DNA fragments have greatly increased the diversity of a Tree of Life2. These trees are mostly populated by eukaryotes, and bacteria are largely underrepresented3,4.

In avoiding the necessity of direct experimentation and observation, genetic techniques have allowed us to represent the Tree of Life in a more precise manner. We can create trees by using molecular methods like the small-subunit ribosomal gene.

Despite the massive growth of the Tree of Life through genome sequencing, a large amount of biodiversity awaits discovery. This is particularly true for microorganisms that are difficult to cultivate and are typically only represented in a single specimen5. Recent analysis of all genomes resulted in an unfinished draft of the Tree of Life. This includes a wide range of archaea, bacteria, and other organisms that haven't yet been isolated or the diversity of which is not fully understood6.

The expanded Tree of Life can be used to assess the biodiversity of a particular area and determine if certain habitats require special protection. This information can be used in a variety of ways, such as finding new drugs, fighting diseases and improving crops. This information is also extremely beneficial for conservation efforts. It can help biologists identify those areas that are most likely contain cryptic species with important metabolic functions that may be at risk from anthropogenic change. Although funds to protect biodiversity are essential, ultimately the best way to protect the world's biodiversity 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 various groups of organisms. By using molecular information similarities and differences in morphology or ontogeny (the process of the 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 biodiversity, evolution and genetics.

A basic phylogenetic Tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms with similar traits that evolved from common ancestors. These shared traits can be either analogous or homologous. Homologous traits are identical in their evolutionary roots, while analogous traits look similar, but do not share the identical origins. Scientists put similar traits into a grouping referred to as a clade. Every organism in a group have a common characteristic, like amniotic egg production. They all evolved from an ancestor that had these eggs. The clades then join to form a phylogenetic branch that can determine the organisms with the closest relationship.

Scientists utilize DNA or RNA molecular information to create a phylogenetic chart that is more precise and precise. This data is more precise than morphological data and provides evidence of the evolutionary background of an organism or group. The analysis of molecular data can help researchers identify the number of organisms that share an ancestor common to them and estimate their evolutionary age.

The phylogenetic relationship can be affected by a variety of factors, including the phenomenon of phenotypicplasticity. This is a kind of behavior that alters as a result of specific 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 issue can be reduced by the use of techniques such as cladistics that incorporate a combination of analogous and 에볼루션 코리아 homologous features into the tree.

In addition, phylogenetics can help predict the time and pace of speciation. This information can aid conservation biologists to make decisions about which species to protect from the threat of extinction. Ultimately, it is the preservation of phylogenetic diversity that will create an ecologically balanced and complete ecosystem.

Evolutionary Theory

The central theme of evolution is that organisms acquire different features over time due to their interactions with their surroundings. Many scientists have proposed 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 and needs, 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 lead to changes that can be passed on to future generations.

In the 1930s and 에볼루션 무료체험 1940s, ideas from a variety of fields -- including genetics, natural selection, and particulate inheritance -- came together to form the modern evolutionary theory that explains how evolution occurs 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 the foundation of the current 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 by mutation, genetic drift and reshuffling of genes during sexual reproduction, and also through the movement of populations. These processes, as well as others like directional selection and genetic erosion (changes in the frequency of a genotype over time) can lead to evolution that is defined as change in the genome of the species over time and also by changes in phenotype over time (the expression of that genotype within the individual).

Students can gain a better understanding of the concept of phylogeny through incorporating evolutionary thinking throughout all areas of biology. A recent study conducted by Grunspan and colleagues, for example demonstrated that teaching about the evidence supporting evolution helped students accept the concept of evolution in a college-level biology course. To learn more about how to teach about evolution, see The Evolutionary Potential in 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 observe living organisms. However, evolution isn't something that occurred in the past. It's an ongoing process that is that is taking place today. Bacteria mutate and resist antibiotics, viruses evolve and elude new medications and animals change their behavior in response to the changing environment. The changes that occur are often apparent.

However, it wasn't until late 1980s that biologists understood that natural selection could be observed in action as well. The key is that different characteristics result in different rates of survival and reproduction (differential fitness), and can be passed from one generation to the next.

In the past, if one allele - the genetic sequence that determines colour was present in a population of organisms that interbred, it might become more common than other allele. In time, this could mean that the number of black moths within a particular population could rise. The same is true for 에볼루션코리아 - Www.bookpalcomics.Com - many other characteristics--including morphology and behavior--that vary among populations of organisms.

It is easier to observe evolution when the species, like bacteria, has a high 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 500.000 generations of E.coli have passed.

Lenski's work has demonstrated that a mutation can profoundly alter the rate at which a population reproduces--and so the rate at which it alters. It also shows evolution takes time, 에볼루션 바카라 무료체험 which is difficult for some to accept.

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

The speed at which evolution can take place has led to an increasing recognition of its importance in a world shaped by human activity, including climate change, pollution and the loss of habitats which prevent many species from adapting. Understanding the evolution process will help us make better choices about the future of our planet and the lives of its inhabitants.