The Academy's Evolution Site
Biology is one of the most important concepts in biology. The Academies are involved in helping those interested in science understand evolution theory and how it can be applied in all areas of scientific research.
This site provides a wide range of sources for teachers, students, and general readers on evolution. It has the most important video clips from NOVA and the WGBH-produced science programs on DVD.
Tree of Life
The Tree of Life is an ancient symbol that symbolizes the interconnectedness of all life. It appears in many cultures and spiritual beliefs as symbolizing unity and love. 에볼루션 코리아 has many practical applications as well, such as providing a framework for understanding the history of species and how they respond to changing environmental conditions.
Early approaches to depicting the world of biology focused on the classification of organisms into distinct categories which had been distinguished by their physical and metabolic characteristics1. These methods, which relied on the sampling of various parts of living organisms or short DNA fragments, significantly increased the variety that could be represented in a tree of life2. However the trees are mostly comprised of eukaryotes, and bacterial diversity remains vastly underrepresented3,4.
By avoiding the necessity for direct observation and experimentation, genetic techniques have made it possible to depict the Tree of Life in a more precise way. We can construct trees using molecular methods such as the small subunit ribosomal gene.
Despite the massive expansion of the Tree of Life through genome sequencing, a large amount of biodiversity awaits discovery. This is especially true for microorganisms that are difficult to cultivate, and which are usually only found in one sample5. A recent analysis of all genomes that are known has produced a rough draft version of the Tree of Life, including numerous archaea and bacteria that are not isolated and their diversity is not fully understood6.
This expanded Tree of Life can be used to determine the diversity of a specific region and determine if certain habitats need special protection. This information can be utilized in a range of ways, from identifying the most effective treatments to fight disease to enhancing the quality of crops. This information is also extremely useful for conservation efforts. It can help biologists identify the areas that are most likely to contain cryptic species with important metabolic functions that could be vulnerable to anthropogenic change. While funds to protect biodiversity are important, the best method to preserve the world's biodiversity is to equip more people in developing nations with the knowledge they need to act locally and support conservation.
Phylogeny
A phylogeny is also known as an evolutionary tree, illustrates the connections between groups of organisms. Scientists can construct a phylogenetic chart that shows the evolution of taxonomic groups using molecular data and morphological similarities or differences. Phylogeny plays a crucial role in understanding the relationship between genetics, biodiversity and evolution.
A basic phylogenetic Tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms that share similar traits that evolved from common ancestors. These shared traits can be either homologous or analogous. Homologous traits share their evolutionary roots while analogous traits appear similar, but do not share the identical origins. Scientists group similar traits together into a grouping known as a clade. All members of a clade share a characteristic, like amniotic egg production. They all evolved from an ancestor with these eggs. A phylogenetic tree is then built by connecting the clades to identify the species which are the closest to each other.
Scientists utilize molecular DNA or RNA data to construct a phylogenetic graph which is more precise and precise. This information is more precise and provides evidence of the evolution history of an organism. Researchers can utilize Molecular Data to determine the evolutionary age of living organisms and discover the number of organisms that share a common ancestor.
The phylogenetic relationships between organisms can be influenced by several factors including phenotypic plasticity, a type of behavior that alters in response to specific environmental conditions. This can cause a trait to appear more similar to one species than another, clouding the phylogenetic signal. However, 에볼루션 바카라 무료체험 can be cured by the use of techniques such as cladistics that combine analogous and homologous features into the tree.
Additionally, phylogenetics aids predict the duration and rate at which speciation takes place. This information can aid conservation biologists to decide the species they should safeguard from extinction. Ultimately, it is the preservation of phylogenetic diversity that will result in a complete and balanced ecosystem.
Evolutionary Theory
The main idea behind evolution is that organisms change over time due to their interactions with their environment. A variety of theories about evolution have been developed by a wide variety of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop gradually according to its requirements as well as the Swedish botanist Carolus Linnaeus (1707-1778) who developed the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits causes changes that could be passed onto offspring.
In the 1930s and 1940s, concepts from a variety of fields -- including natural selection, genetics, and particulate inheritance--came together to create the modern evolutionary theory synthesis which explains how evolution happens through the variations of genes within a population, and how those variations change in time due to natural selection. This model, which incorporates mutations, genetic drift, gene flow and sexual selection can be mathematically described mathematically.
Recent advances in the field of evolutionary developmental biology have demonstrated the ways in which variation can be introduced to a species through genetic drift, mutations, reshuffling genes during sexual reproduction, and even migration between populations. These processes, as well as others like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time), can lead to evolution which is defined by changes in the genome of the species over time and the change in phenotype over time (the expression of that genotype within the individual).
Incorporating evolutionary thinking into all areas of biology education can improve student understanding of the concepts of phylogeny as well as evolution. A recent study conducted by Grunspan and colleagues, for instance revealed that teaching students about the evidence supporting evolution increased students' understanding of evolution in a college-level biology class. For more information about how to teach evolution look up 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
Traditionally scientists have studied evolution through looking back--analyzing fossils, comparing species, and observing living organisms. But 에볼루션 바카라 무료체험 isn't just something that happened in the past; it's an ongoing process, that is taking place in the present. Bacteria mutate and resist antibiotics, viruses reinvent themselves and escape new drugs and animals alter their behavior to the changing climate. The results are often evident.
It wasn't until the late 1980s when biologists began to realize that natural selection was also in action. The key is that different traits confer different rates of survival and reproduction (differential fitness) and can be passed down from one generation to the next.
In the past, if a certain allele - the genetic sequence that determines colour appeared in a population of organisms that interbred, it might become more prevalent than any other allele. Over time, that would 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.
Monitoring evolutionary changes in action is much easier when a species has a rapid generation turnover like bacteria. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that descend from a single strain. Samples of each population have been taken frequently and more than 50,000 generations of E.coli have passed.
Lenski's work has shown that mutations can alter the rate of change and the rate at which a population reproduces. It also shows that evolution takes time, a fact that is hard for some to accept.
Another example of microevolution is how mosquito genes for resistance to pesticides show up more often in areas in which insecticides are utilized. This is due to the fact that the use of pesticides creates a selective pressure that favors people with resistant genotypes.
The speed of evolution taking place has led to an increasing awareness of its significance in a world shaped by human activity, including climate change, pollution and the loss of habitats which prevent many species from adjusting. Understanding the evolution process can help us make smarter decisions about the future of our planet, and the lives of its inhabitants.