Profile
What Will Evolution Site Be Like In 100 Years? The Academy's Evolution Site The concept of biological evolution is among the most important concepts in biology. 에볼루션바카라 have been active for a long time in helping people who are interested in science understand the concept of evolution and how it influences all areas of scientific exploration. This site provides teachers, students and general readers with a wide range of learning resources on 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 a symbol of love and harmony in a variety of cultures. It also has practical applications, such as providing a framework to understand the history of species and how they react to changes in environmental conditions. The first attempts at depicting the biological world focused on separating organisms into distinct categories which were distinguished by physical and metabolic characteristics1. These methods, which are based on the collection of various parts of organisms or short DNA fragments have significantly increased the diversity of a Tree of Life2. These trees are mostly populated of eukaryotes, while the diversity of bacterial species is greatly underrepresented3,4. Genetic techniques have greatly broadened our ability to visualize the Tree of Life by circumventing the need for direct observation and experimentation. Particularly, molecular methods allow us to construct trees by using sequenced markers like the small subunit 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 particularly true of microorganisms that are difficult to cultivate and are typically only present in a single specimen5. A recent analysis of all genomes has produced an unfinished draft of the Tree of Life. This includes a variety of archaea, bacteria, and other organisms that haven't yet been identified or the diversity of which is not well understood6. This expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, assisting to determine whether specific habitats require special protection. This information can be used in a variety of ways, from identifying new treatments to fight disease to enhancing the quality of crops. This information is also extremely beneficial in conservation efforts. It can help biologists identify the areas that are most likely to contain cryptic species with important metabolic functions that could be at risk from anthropogenic change. While funding to protect biodiversity are important, the best method to protect the world's biodiversity is to empower more people in developing countries with the knowledge they need to take action locally and encourage conservation. Phylogeny A phylogeny, also known as an evolutionary tree, illustrates the relationships between various groups of organisms. By using molecular information as well as morphological similarities and distinctions, or ontogeny (the course of development of an organism), scientists can build an phylogenetic tree that demonstrates the evolutionary relationships between taxonomic categories. Phylogeny is crucial in understanding evolution, biodiversity and genetics. A basic phylogenetic Tree (see Figure PageIndex 10 Finds the connections between organisms that have similar characteristics and have evolved from an ancestor with common traits. These shared traits are either analogous or homologous. Homologous traits are similar in their evolutionary origins while analogous traits appear similar but do not have the identical origins. Scientists put similar traits into a grouping called a Clade. All members of a clade have a common characteristic, for example, amniotic egg production. They all evolved from an ancestor that had these eggs. The clades are then linked to form a phylogenetic branch that can determine the organisms with the closest relationship to. Scientists make use of DNA or RNA molecular information to create a phylogenetic chart which is more precise and detailed. This data is more precise than the morphological data and gives evidence of the evolutionary history of an organism or group. Researchers can use Molecular Data to determine the age of evolution of organisms and determine the number of organisms that have an ancestor common to all. The phylogenetic relationship can be affected by a number of factors, including phenotypicplasticity. This is a type of behavior that alters as a result of specific environmental conditions. This can cause a particular trait to appear more similar in one species than another, clouding the phylogenetic signal. However, this problem can be solved through the use of techniques such as cladistics that include a mix of analogous and homologous features into the tree. Additionally, phylogenetics can help predict the time and pace of speciation. This information can help conservation biologists make decisions about the species they should safeguard from extinction. It is ultimately the preservation of phylogenetic diversity that will create an ecologically balanced and complete ecosystem. Evolutionary Theory The central theme in evolution is that organisms change over time due to their interactions with their environment. Many scientists have proposed theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that a living thing would develop according to its own requirements, the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern hierarchical taxonomy as well as Jean-Baptiste Lamarck (1844-1829), who believed that the use or non-use of traits can lead to changes that can be passed on to future generations. In the 1930s and 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 the population and how these variations alter over time due to natural selection. This model, called genetic drift or mutation, gene flow, and sexual selection, is a cornerstone of modern evolutionary biology and is mathematically described. Recent advances in the field of evolutionary developmental biology have shown the ways in which variation can be introduced to a species through genetic drift, mutations and reshuffling of genes during sexual reproduction, and even migration between populations. These processes, as well as other ones like directional selection and genetic erosion (changes in the frequency of a genotype over time) can result in evolution that is defined as changes in the genome of the species over time and also the change in phenotype as time passes (the expression of the genotype in an individual). Students can gain a better understanding of the concept of phylogeny by using evolutionary thinking in all aspects of biology. In a study by Grunspan and colleagues. It was demonstrated that teaching students about the evidence for evolution boosted their understanding of evolution during an undergraduate biology course. To learn more about how to teach about evolution, read The Evolutionary Potential of All Areas of Biology and Thinking Evolutionarily: A Framework for Infusing Evolution in Life Sciences Education. Evolution in Action Traditionally, scientists have studied evolution by looking back, studying fossils, comparing species and studying living organisms. But evolution isn't a thing that occurred in the past. It's an ongoing process that is happening right now. Bacteria transform and resist antibiotics, viruses evolve and are able to evade new medications, and animals adapt their behavior in response to the changing climate. The changes that occur are often evident. It wasn't until the 1980s that biologists began to realize that natural selection was also in play. The key is the fact that different traits result in the ability to survive at different rates 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 organisms, it could quickly become more prevalent than other alleles. In time, this could mean that the number of moths with black pigmentation 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 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 are descended from a single strain. Samples from each population were taken regularly and more than 50,000 generations of E.coli have been observed to have passed. Lenski's research has revealed that mutations can drastically alter the rate at which a population reproduces and, consequently, the rate at which it changes. It also shows that evolution is slow-moving, a fact that some people find hard to accept. Another example of microevolution is the way mosquito genes that confer resistance to pesticides show up more often in areas where insecticides are used. This is due to pesticides causing an exclusive pressure that favors individuals who have resistant genotypes. The speed at which evolution takes place has led to a growing appreciation of its importance in a world shaped by human activity--including climate change, pollution, and the loss of habitats that prevent many species from adjusting. Understanding the evolution process will help us make better decisions about the future of our planet, as well as the life of its inhabitants.
Forum Role: Participant
Topics Started: 0
Replies Created: 0