The Academy's Evolution Site
The concept of biological evolution is a fundamental concept in biology. The Academies have been for a long time involved in helping those interested in science understand the concept of evolution and how it affects every area of scientific inquiry.
This site provides teachers, students and general readers with a wide range of learning resources on evolution. It has key video clips from NOVA and WGBH's science programs on DVD.
Tree of Life
The Tree of Life, an ancient symbol, symbolizes the interconnectedness of all life. It is a symbol of love and unity in many cultures. It has many practical applications as well, including providing a framework for understanding the evolution of species and how they respond to changing environmental conditions.
Early approaches to depicting the world of biology focused on separating organisms into distinct categories that were identified by their physical and metabolic characteristics1. These methods, based on sampling of different parts of living organisms, or short fragments of their DNA significantly increased the variety that could be included in the tree of life2. However 무료 에볼루션 are mainly made up of eukaryotes. Bacterial diversity remains vastly underrepresented3,4.
Genetic techniques have greatly broadened our ability to visualize the Tree of Life by circumventing the requirement for direct observation and experimentation. Trees can be constructed using molecular techniques like the small-subunit ribosomal gene.
The Tree of Life has been greatly expanded thanks to genome sequencing. However there is still a lot of diversity to be discovered. This is particularly true for microorganisms, which are difficult to cultivate and are often only represented in a single specimen5. A recent study of all genomes known to date has produced 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 evaluate the biodiversity of a particular area and determine if certain habitats need special protection. This information can be used in a variety of ways, such as identifying new drugs, combating diseases and enhancing crops. It is also valuable to conservation efforts. It can help biologists identify those areas that are most likely contain cryptic species that could have significant metabolic functions that could be vulnerable to anthropogenic change. Although funding to protect biodiversity are essential however, the most effective method to protect the world's biodiversity is for more people living in developing countries to be empowered with the knowledge to act locally in order to promote conservation from within.
Phylogeny
A phylogeny (also called an evolutionary tree) illustrates the relationship between species. Scientists can build a phylogenetic diagram that illustrates the evolutionary relationships between taxonomic groups based on molecular data and morphological differences or similarities. The role of phylogeny is crucial 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 evolved from common ancestral. These shared traits can be analogous, or homologous. Homologous traits are the same in their evolutionary path. Analogous traits could appear similar however they do not have the same origins. Scientists group similar traits together into a grouping called a Clade. Every organism in a group have a common characteristic, for example, amniotic egg production. They all derived from an ancestor who had these eggs. The clades then join to form a phylogenetic branch to determine which organisms have the closest connection to each other.
Scientists use DNA or RNA molecular data to build a phylogenetic chart which is more precise and detailed. This data is more precise than morphological information and provides evidence of the evolution history of an individual or group. Researchers can use Molecular Data to calculate the age of evolution of organisms and identify how many organisms share the same ancestor.
The phylogenetic relationships of a species can be affected by a variety of factors, including the phenotypic plasticity. This is a type of behavior that changes due to particular environmental conditions. This can cause a characteristic to appear more like a species another, obscuring the phylogenetic signal. This issue can be cured by using cladistics, which incorporates a combination of analogous and homologous features in the tree.
In addition, phylogenetics can help predict the length and speed of speciation. This information can assist conservation biologists in making decisions about which species to save from the threat of extinction. In the end, it's the preservation of phylogenetic diversity which will create an ecosystem that is complete and balanced.
Evolutionary Theory
The main idea behind evolution is that organisms change over time as a result of their interactions with their environment. Many scientists have proposed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that a living thing would evolve according to its own needs and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern taxonomy system that is hierarchical and Jean-Baptiste Lamarck (1844-1829), who believed that the use or non-use of traits can cause changes that can be passed on to future generations.
In the 1930s and 1940s, concepts from various fields, including genetics, natural selection and particulate inheritance--came together to create the modern synthesis of evolutionary theory that explains how evolution happens through the variation of genes within a population, and how these variants change in time due to natural selection. 에볼루션 무료 바카라 , called genetic drift, mutation, gene flow and sexual selection, is the foundation of modern evolutionary biology and is mathematically described.
Recent developments in the field of evolutionary developmental biology have revealed that variations can be introduced into a species via mutation, genetic drift, and reshuffling genes during sexual reproduction, as well as through migration between populations. These processes, as well as others like directional selection and genetic erosion (changes in the frequency of the genotype over time), can lead to evolution, which is defined by change in the genome of the species over time and the change in phenotype as time passes (the expression of that genotype in an individual).
Incorporating evolutionary thinking into all aspects of biology education could increase student understanding of the concepts of phylogeny as well as evolution. In a recent study by Grunspan et al., it was shown that teaching students about the evidence for evolution boosted their acceptance of evolution during an undergraduate biology course. For more details on how to teach about evolution, see The Evolutionary Potency in All Areas of Biology or Thinking Evolutionarily as a Framework for Infusing 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. Evolution is not a distant event, but an ongoing process. Bacteria transform and resist antibiotics, viruses reinvent themselves and escape new drugs and animals alter their behavior in response to the changing environment. The changes that occur are often visible.
It wasn't until late-1980s that biologists realized that natural selection can be observed in action as well. The main reason is that different traits result in a different rate of survival as well as reproduction, and may be passed on from one generation to the next.
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. 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 particular species has a rapid generation turnover, as with bacteria. Since 1988 biologist Richard Lenski has been tracking twelve populations of E. Coli that descended from a single strain; samples of each population are taken regularly, and over 500.000 generations have been observed.
Lenski's research has shown that mutations can drastically alter the rate at which a population reproduces and, consequently the rate at which it evolves. It also shows that evolution takes time, something that is difficult for some to accept.
Microevolution is also evident in the fact that mosquito genes for pesticide resistance are more prevalent in populations where insecticides have been used. Pesticides create a selective pressure which favors individuals who have resistant genotypes.
The rapidity of evolution has led to a growing appreciation of its importance, especially in a world which is largely shaped by human activities. This includes pollution, climate change, and habitat loss that hinders many species from adapting. Understanding the evolution process can help us make better decisions about the future of our planet, and the lives of its inhabitants.