The Academy's Evolution Site

Biological evolution is one of the most important concepts in biology. The Academies have been active for a long time in helping people who are interested in science comprehend the theory of evolution and how it permeates every area of scientific inquiry.

This site provides students, teachers and general readers with a wide range of learning resources about evolution. It includes key video clip 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 used in many cultures and spiritual beliefs as an emblem of unity and love. It can be used in many practical ways as well, including providing a framework for understanding the evolution of species and how they respond to changes in environmental conditions.

Early attempts to represent the world of biology were founded on categorizing organisms on their metabolic and physical characteristics. These methods, which relied on sampling of different parts of living organisms or on short fragments of their DNA, greatly increased the variety of organisms that could be represented in the tree of life2. However, these trees are largely made up of eukaryotes. Bacterial diversity is still largely unrepresented3,4.

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

The Tree of Life has been greatly expanded thanks to genome sequencing. However there is a lot of diversity to be discovered. This is especially relevant to microorganisms that are difficult to cultivate, and 에볼루션 카지노 사이트 are typically found in a single specimen5. A recent analysis of all genomes that are known has produced a rough draft version of the Tree of Life, including many archaea and bacteria that have not been isolated, and whose diversity is poorly understood6.

This expanded Tree of Life can be used to evaluate the biodiversity of a particular area and determine if particular habitats require special protection. This information can be utilized in a variety of ways, such as finding new drugs, battling diseases and improving the quality of crops. This information is also extremely useful to conservation efforts. It helps biologists determine the areas most likely to contain cryptic species with potentially important metabolic functions that could be at risk of anthropogenic changes. While conservation funds are important, the most effective way to conserve the world's biodiversity is to empower the people of developing nations with the knowledge they need to act locally and promote conservation.

Phylogeny

A phylogeny, also known as an evolutionary tree, reveals the connections 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 construct a phylogenetic tree that illustrates the evolutionary relationships between taxonomic categories. Phylogeny plays a crucial role in understanding biodiversity, genetics and evolution.

A basic phylogenetic tree (see Figure PageIndex 10 Determines the relationship between organisms that have similar traits and have evolved from a common ancestor. These shared traits can be either homologous or analogous. Homologous traits are similar in terms of their evolutionary journey. Analogous traits may look like they are, but they do not have the same origins. Scientists combine similar traits into a grouping called a Clade. For example, all of the species in a clade have the characteristic of having amniotic eggs. They evolved from a common ancestor that had eggs. A phylogenetic tree is constructed by connecting clades to determine the organisms who are the closest to one another.

To create a more thorough and precise phylogenetic tree scientists use molecular data from DNA or RNA to determine the relationships between organisms. This information is more precise and provides evidence of the evolutionary history of an organism. The use of molecular data lets researchers identify the number of organisms who share an ancestor common to them and estimate their evolutionary age.

The phylogenetic relationships of a species can be affected by a number of factors such as the phenotypic plasticity. This is a kind of behaviour that can change due to particular environmental conditions. This can cause a particular trait to appear more similar to one species than other species, 에볼루션 슬롯게임 코리아 (http://bbs.0817ch.com) which can obscure the phylogenetic signal. However, this issue can be cured by the use of methods such as cladistics which incorporate a combination of similar and homologous traits into the tree.

In addition, phylogenetics can help predict the length and speed of speciation. This information will assist conservation biologists in making choices about which species to save from the threat of extinction. In the end, it's 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 develop different features over time due to their interactions with their environments. A variety of theories about evolution have been proposed by a variety of scientists, including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who believed that an organism would evolve slowly in accordance with 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 무료 에볼루션 misuse of traits causes changes that could be passed onto offspring.

In the 1930s & 1940s, concepts from various fields, such as natural selection, genetics & particulate inheritance, were brought together to form a modern synthesis of evolution theory. This defines how evolution happens through the variation of genes in a population and how these variations 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 current evolutionary biology, and can be mathematically described.

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

Incorporating evolutionary thinking into all aspects of biology education could increase student understanding of the concepts of phylogeny and evolution. A recent study conducted by Grunspan and colleagues, for instance demonstrated that teaching about the evidence supporting evolution increased students' understanding of evolution in a college-level biology class. For more details about how to teach evolution read The Evolutionary Potency in All Areas of Biology or Thinking Evolutionarily: a Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution through looking back--analyzing fossils, comparing species, and observing living organisms. Evolution is not a distant event, but a process that continues today. Bacteria mutate and resist antibiotics, viruses evolve and escape new drugs and animals alter their behavior to the changing environment. The changes that result are often evident.

However, it wasn't until late-1980s that biologists realized that natural selection could be seen in action, as well. The main reason is that different traits result in an individual rate of survival and reproduction, and can be passed down from one generation to another.

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

Observing evolutionary change in action is easier when a particular species has a fast generation turnover such as bacteria. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that descend from one strain. The samples of each population were taken regularly, and more than 50,000 generations of E.coli have passed.

Lenski's research has shown that mutations can drastically alter the efficiency with which a population reproduces--and so the rate at which it evolves. It also shows that evolution takes time, a fact that some find difficult to accept.

Another example of microevolution is how mosquito genes that confer resistance to pesticides show up more often in populations in which insecticides are utilized. This is because pesticides cause a selective pressure which favors those with resistant genotypes.

The rapid pace at which evolution takes place has led to a growing awareness of its significance in a world that is shaped by human activities, including climate changes, pollution and the loss of habitats that hinder many species from adapting. Understanding evolution will help us make better choices about the future of our planet, and the life of its inhabitants.