The Academy's Evolution Site
Biology is a key concept in biology. The Academies have been for a long time involved in helping those 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 range of educational resources on 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 of the interconnectedness of life. It is seen in a variety of religions and cultures as symbolizing unity and love. It also has important practical applications, such as providing a framework to understand the history of species and how they react to changes in the environment.
Early attempts to describe the world of biology were based on categorizing organisms based on their physical and metabolic characteristics. These methods, which rely on the sampling of different parts of living organisms, or short fragments of their DNA significantly expanded the diversity that could be included in the tree of life2. However, these trees are largely made up of eukaryotes. 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 techniques allow us to construct 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 still much diversity 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 study of all genomes known to date has produced a rough draft of the Tree of Life, including a large number of archaea and bacteria that have not been isolated, and whose diversity is poorly understood6.
The expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, assisting to determine if certain habitats require protection. This information can be used in a variety of ways, from identifying the most effective medicines to combating disease to improving crops. This information is also extremely valuable in conservation efforts. It can aid biologists in identifying areas that are likely to be home to cryptic species, which could have important metabolic functions, and could be susceptible to changes caused by humans. Although funding to protect biodiversity are essential however, the most effective method to preserve 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 is also known as an evolutionary tree, illustrates the relationships between various groups of organisms. Scientists can build a phylogenetic chart that shows the evolutionary relationships between taxonomic groups using molecular data and morphological differences or similarities. The phylogeny of a tree plays an important role in understanding the relationship between genetics, biodiversity and evolution.
A basic phylogenetic tree (see Figure PageIndex 10 ) identifies the relationships between organisms with similar traits that have evolved from common ancestors. These shared traits could be either analogous or homologous. Homologous traits are the same in their evolutionary journey. Analogous traits could appear similar, but they do not have the same origins. Scientists put similar traits into a grouping called a Clade. All organisms in a group share a trait, such as amniotic egg production. They all derived from an ancestor that had these eggs. A phylogenetic tree can be constructed by connecting clades to identify the species which are the closest to one another.
Scientists make use of molecular DNA or RNA data to construct a phylogenetic graph which is more precise and precise. This information is more precise than morphological data and provides evidence of the evolutionary history of an organism or group. Researchers can utilize Molecular Data to estimate the evolutionary age of organisms and identify how many species have a common ancestor.
The phylogenetic relationship can be affected by a number of factors that include the phenomenon of phenotypicplasticity. This is a type of behavior that changes as a result of particular environmental conditions. This can cause a trait to appear more similar to a species than to the other which can obscure the phylogenetic signal. This problem can be mitigated by using cladistics, which is a an amalgamation of homologous and analogous features in the tree.
In addition, phylogenetics can help predict the duration and rate of speciation. This information can assist conservation biologists in deciding which species to safeguard from extinction. In the end, it's the preservation of phylogenetic diversity that will result in an ecosystem that is complete and balanced.
Evolutionary Theory
The main idea behind evolution is that organisms develop various characteristics over time based on their interactions with their environments. Many scientists have proposed theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism could evolve according to its own requirements as well as the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern taxonomy system that is hierarchical as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the use or non-use of traits can lead to changes that are passed on to the next generation.
In the 1930s & 1940s, concepts from various fields, including genetics, natural selection, and particulate inheritance, were brought together to form a modern theorizing of evolution. This defines how evolution occurs by the variation in genes within a population and how these variations change with time due to natural selection. This model, which incorporates genetic drift, mutations in gene flow, and sexual selection, can be mathematically described mathematically.
Recent developments in evolutionary developmental biology have demonstrated how variations can be introduced to a species via genetic drift, mutations and reshuffling of genes during sexual reproduction and migration between populations. These processes, along with others such as the directional selection process and the erosion of genes (changes in the frequency of genotypes over time), can lead towards evolution. Evolution is defined as changes in the genome over time as well as changes in phenotype (the expression of genotypes in individuals).
Incorporating evolutionary thinking into all areas of biology education can increase student understanding of the concepts of phylogeny and evolutionary. In a study by Grunspan and co., it was shown that teaching students about the evidence for evolution boosted their acceptance of evolution during the course of a college biology. For more details on how to teach about evolution look up The Evolutionary Power of Biology in All Areas of Biology or Thinking Evolutionarily as a Framework for Infusing Evolution into Life Sciences Education.
Evolution in Action
Scientists have studied evolution through looking back in the past--analyzing fossils and comparing species. They also study living organisms. However, evolution isn't something that occurred in the past; it's an ongoing process happening in the present. Viruses reinvent themselves to avoid new drugs and bacteria evolve to resist antibiotics. Animals adapt their behavior in the wake of a changing world. The changes that result are often apparent.
It wasn't until the late 1980s when biologists began to realize that natural selection was in action. The key is the fact that different traits confer the ability to survive at different rates and reproduction, and they can be passed down from one generation to the next.
In 무료 에볼루션 , when one particular allele, the genetic sequence that defines color in a population of interbreeding species, it could rapidly become more common than the other alleles. Over time, that would mean the number of black moths within a population could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.
It is easier to observe evolution when an organism, like bacteria, has a high generation turnover. Since 에볼루션 사이트 , Richard Lenski, a biologist, has been tracking twelve populations of E.coli that descend from one strain. The samples of each population have been collected regularly, and more than 500.000 generations of E.coli have been observed to have passed.
Lenski's research has demonstrated that mutations can alter the rate at which change occurs and the effectiveness at which a population reproduces. It also shows that evolution takes time, a fact that some find difficult to accept.
Another example of microevolution is how mosquito genes for resistance to pesticides are more prevalent in populations in which insecticides are utilized. This is due to the fact that the use of pesticides creates a selective pressure that favors those with resistant genotypes.
The rapidity of evolution has led to a growing recognition of its importance especially in a planet shaped largely by human activity. This includes pollution, climate change, and habitat loss that hinders many species from adapting. Understanding the evolution process will aid you in making better decisions regarding the future of the planet and its inhabitants.