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The Academy's Evolution Site

Biological evolution is one of the most fundamental concepts in biology. The Academies have been active for a long time in helping those interested in science understand the concept of evolution and how it permeates all areas of scientific exploration.

This site offers a variety of tools for students, teachers, and general readers on evolution. It includes important video clips from NOVA and WGBH's science programs on DVD.

Tree of Life

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

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

Genetic techniques have significantly expanded our ability to represent the Tree of Life by circumventing the need for direct observation and experimentation. We can create trees by using molecular methods, such as the small-subunit ribosomal gene.

Despite the dramatic expansion 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 often only present in a single sample5. A recent analysis of all genomes known to date has created a rough draft of the Tree of Life, including numerous archaea and bacteria that are not isolated and whose diversity is poorly understood6.

The expanded Tree of Life can be used to assess the biodiversity of a specific area and determine if specific habitats need special protection. The information can be used in a range of ways, from identifying the most effective medicines to combating disease to enhancing the quality of crops. This information is also extremely beneficial for conservation efforts. It can help biologists identify the areas that are most likely to contain cryptic species with important metabolic functions that may be at risk from anthropogenic change. While funds to protect biodiversity are essential, the best method to preserve the world's biodiversity is to equip more people in developing countries with the information they require to act locally and promote conservation.

Phylogeny

A phylogeny, also called an evolutionary tree, illustrates the relationships between groups of organisms. By using molecular information as well as morphological similarities and distinctions or ontogeny (the process of the development of an organism) scientists can create an phylogenetic tree that demonstrates the evolutionary relationship between taxonomic groups. 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 and evolved from an ancestor that shared traits. These shared traits can be either homologous or analogous. Homologous characteristics are identical in terms of their evolutionary paths. Analogous traits may look like they are however they do not have the same origins. Scientists group similar traits into a grouping known as a clade. For instance, all the species in a clade share the characteristic of having amniotic eggs and evolved from a common ancestor which had these eggs. A phylogenetic tree is constructed by connecting clades to determine the organisms that are most closely related to one another.

Scientists use molecular DNA or RNA data to construct a phylogenetic graph which is more precise and precise. This data is more precise than morphological data and gives evidence of the evolutionary history of an individual or group. Researchers can utilize Molecular Data to calculate the age of evolution of organisms and determine the number of organisms that share a common ancestor.

The phylogenetic relationships of organisms are influenced by many factors, including phenotypic flexibility, an aspect of behavior that alters in response to unique environmental conditions. This can cause a characteristic to appear more resembling to one species than to another which can obscure the phylogenetic signal. This problem can be addressed by using cladistics, which incorporates a combination of homologous and analogous traits in the tree.

Furthermore, phylogenetics may aid in predicting the length and speed of speciation. This information can help conservation biologists make decisions about 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 complete and balanced.

Evolutionary Theory

The fundamental concept of evolution is that organisms acquire distinct characteristics over time as a result of their interactions with their surroundings. Several theories of evolutionary change have been proposed by a variety of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing gradually according to its requirements and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that the use or misuse of traits can cause changes that could be passed on to the offspring.

In the 1930s and 1940s, ideas from a variety of fields--including genetics, natural selection, and particulate inheritance - came together to form the current evolutionary theory which explains how evolution occurs through the variations of genes within a population, and how these variants change in time as a result of natural selection. This model, which is known as genetic drift, mutation, gene flow and sexual selection, is the foundation of current evolutionary biology, and can be mathematically described.

Recent advances in the field of evolutionary developmental biology have shown how variation can be introduced to a species through genetic drift, mutations, reshuffling genes during sexual reproduction and migration between populations. These processes, in conjunction with other ones like directionally-selected selection and erosion of genes (changes to the frequency of genotypes over time), can lead towards evolution. Evolution is defined as changes in the genome over time and changes in the phenotype (the expression of genotypes within individuals).

Incorporating evolutionary thinking into all aspects of biology education can increase student understanding of the concepts of phylogeny as well as evolution. A recent study by Grunspan and 무료 에볼루션 colleagues, for example, showed that teaching about the evidence that supports evolution increased students' understanding of evolution in a college-level biology course. For more details on how to teach about evolution read The Evolutionary Potential in All Areas of Biology or Thinking Evolutionarily: a Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Scientists have traditionally looked at evolution through the past, 에볼루션 슬롯게임 무료에볼루션 바카라 체험 (www.nzdao.cn) analyzing fossils and comparing species. They also study living organisms. Evolution isn't a flims moment; it is an ongoing process that continues to be observed today. Bacteria mutate and resist antibiotics, viruses reinvent themselves and escape new drugs and animals alter their behavior in response to a changing planet. The changes that occur are often visible.

It wasn't until late 1980s when biologists began to realize that natural selection was also in action. 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, 에볼루션 바카라 체험 if an allele - the genetic sequence that determines color - was found in a group of organisms that interbred, it could become more common than any other allele. As time passes, this could mean that the number of moths with 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.

Monitoring evolutionary changes in action is easier when a species has a fast generation turnover like bacteria. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain. samples of each are taken on a regular basis, and over fifty thousand generations have been observed.

Lenski's research has revealed that mutations can drastically alter the speed at the rate at which a population reproduces, 에볼루션 바카라 체험 and consequently, the rate at which it alters. It also proves that evolution takes time--a fact that many find difficult to accept.

Microevolution is also evident in the fact that mosquito genes for pesticide resistance are more prevalent in populations that have used insecticides. Pesticides create an exclusive pressure that favors those with resistant genotypes.

The speed at which evolution takes place has led to a growing appreciation of its importance in a world that is shaped by human activities, including climate change, pollution, and the loss of habitats which prevent the species from adapting. Understanding evolution will assist you in making better choices regarding the future of the planet and its inhabitants.