15 Amazing Facts About Evolution Site
The Academy's Evolution Site
The concept of biological evolution is among the most central concepts in biology. The Academies have long been involved in helping those interested in science understand the theory of evolution and how it influences all areas of scientific research.
This site provides a wide range of sources for teachers, students and general readers of evolution. It also includes important video clips from NOVA and WGBH produced science programs on DVD.
Tree of Life
The Tree of Life is an ancient symbol that represents the interconnectedness of all life. It is a symbol of love and harmony in a variety of cultures. It can be used in many practical ways as well, including providing a framework to understand the evolution of species and how they respond to changing environmental conditions.
The earliest attempts to depict the biological world focused on the classification of organisms into distinct categories that were distinguished by physical and metabolic characteristics1. These methods are based on the collection of various parts of organisms or short fragments of DNA, have greatly increased the diversity of a tree of Life2. However, these trees are largely made up of eukaryotes. Bacterial diversity is not represented in a large way3,4.
By avoiding the necessity for direct experimentation and observation genetic techniques have made it possible to depict the Tree of Life in a more precise manner. Particularly, molecular techniques allow us to construct trees by using sequenced markers, such as the small subunit ribosomal gene.
The Tree of Life has been dramatically expanded through genome sequencing. However there is a lot of biodiversity to be discovered. This is especially true of microorganisms, which are difficult to cultivate and are typically only found in a single specimen5. A recent analysis of all known genomes has created a rough draft of the Tree of Life, including many bacteria and archaea that are not 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 certain habitats require special protection. This information can be utilized in a variety of ways, including finding new drugs, battling diseases and enhancing crops. It is also beneficial to conservation efforts. It can aid biologists in identifying the areas most likely to contain cryptic species with important metabolic functions that could be at risk of anthropogenic changes. While funds to protect biodiversity are important, the best method to preserve the world's biodiversity is to equip the people of developing nations with the information they require to act locally and support conservation.
Phylogeny
A phylogeny, also called an evolutionary tree, shows the relationships between groups of organisms. Utilizing molecular data as well as morphological similarities and distinctions, or ontogeny (the process of the development of an organism), scientists can build an phylogenetic tree that demonstrates the evolutionary relationships between taxonomic categories. The concept of phylogeny is fundamental to understanding evolution, biodiversity and genetics.
A basic phylogenetic tree (see Figure PageIndex 10 ) identifies the relationships between organisms that share similar traits that evolved from common ancestral. These shared traits could be either analogous or homologous. Homologous traits are similar in their evolutionary path. Analogous traits may look similar, but they do not share the same origins. Scientists arrange similar traits into a grouping known as a the clade. For instance, all of the organisms in a clade share the characteristic of having amniotic egg and evolved from a common ancestor that had eggs. The clades then join to form a phylogenetic branch that can determine which organisms have the closest relationship to.
To create a more thorough and precise phylogenetic tree scientists rely on molecular information from DNA or RNA to determine the relationships among organisms. This information is more precise than morphological information and gives evidence of the evolutionary history of an organism or group. Researchers can use Molecular Data to calculate the age of evolution of living organisms and discover how many species share a common ancestor.
The phylogenetic relationships of organisms can be influenced by several factors including phenotypic plasticity, a type of behavior that changes in response to unique environmental conditions. This can cause a characteristic to appear more similar in one species than another, obscuring the phylogenetic signal. This problem can be mitigated by using cladistics, which is a a combination of homologous and analogous features in the tree.
In addition, phylogenetics can aid in predicting the duration and rate 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 preservation of phylogenetic diversity that will result in an ecosystem that is balanced and complete.
Evolutionary Theory
The fundamental concept of evolution is that organisms develop various characteristics over time as a result of their interactions with their environments. 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 could develop according to its own requirements, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical system of taxonomy and Jean-Baptiste Lamarck (1844-1829), who suggested that the use or non-use of traits can cause changes that are passed on to the next generation.
In the 1930s and 1940s, ideas from a variety of fields--including natural selection, genetics, and particulate inheritance -- came together to create the modern synthesis of evolutionary theory which 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, which includes genetic drift, mutations in gene flow, and sexual selection is mathematically described mathematically.
Recent discoveries in evolutionary developmental biology have demonstrated how variations can be introduced to a species by mutations, genetic drift and reshuffling of genes during sexual reproduction and migration between populations. These processes, as well as others, such as directionally-selected selection and erosion of genes (changes in frequency of genotypes over time) can result in evolution. Evolution is defined as changes in the genome over time, as well as changes in the phenotype (the expression of genotypes in individuals).
Incorporating evolutionary thinking into all areas of biology education can improve student understanding of the concepts of phylogeny as well as evolution. In a recent study by Grunspan and co. It was found that teaching students about the evidence for evolution boosted their acceptance of evolution during a college-level course in biology. For 에볼루션바카라사이트 on how to teach about evolution read The Evolutionary Power of Biology in All Areas of Biology or Thinking Evolutionarily as a Framework for Integrating Evolution into Life Sciences Education.
Evolution in Action
Scientists have looked at evolution through the past--analyzing fossils and comparing species. They also study living organisms. But evolution isn't just something that happened in the past. It's an ongoing process happening right now. Bacteria mutate and resist antibiotics, viruses reinvent themselves and escape new drugs and animals change their behavior to the changing climate. The resulting changes are often evident.
It wasn't until the 1980s that biologists began to realize that natural selection was in action. The reason is that different traits have different rates of survival and reproduction (differential fitness) and are transferred from one generation to the next.
In the past when one particular allele--the genetic sequence that defines color in a group of interbreeding organisms, it could quickly become more common than other alleles. As time passes, that could mean the number of black moths within a particular population could rise. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.
Observing evolutionary change in action is much easier when a species has a rapid turnover of its generation, as with bacteria. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that descend from one strain. Samples of each population have been collected regularly, and more than 50,000 generations of E.coli have passed.
Lenski's research has revealed that a mutation can profoundly alter the rate at the rate at which a population reproduces, and consequently, the rate at which it changes. It also demonstrates that evolution takes time--a fact that many are unable to accept.
Another example of microevolution is that mosquito genes for resistance to pesticides are more prevalent in areas where insecticides are employed. That's because the use of pesticides creates a selective pressure that favors those with resistant genotypes.
The rapid pace of evolution taking place has led to an increasing appreciation of its importance in a world shaped by human activity--including climate change, pollution, and the loss of habitats that hinder the species from adapting. Understanding evolution will aid you in making better decisions about the future of our planet and its inhabitants.