20 Fun Details About Evolution Site
The Academy's Evolution Site
Biological evolution is one of the most central concepts in biology. The Academies are committed to helping those interested in science to learn about the theory of evolution and how it is incorporated across all areas of scientific research.
This site provides students, teachers and general readers with a 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 is an ancient symbol that represents the interconnectedness of all life. It is a symbol of love and unity across many cultures. It has many practical applications as well, such as providing a framework to understand the history of species and how they respond to changing environmental conditions.
Early approaches to depicting the biological world focused on the classification of organisms into distinct categories which had been distinguished by physical and metabolic characteristics1. These methods, which relied on sampling of different parts of living organisms or sequences of small fragments of their DNA, significantly expanded the diversity that could be represented in the tree of life2. The trees are mostly composed by eukaryotes, and bacterial diversity is vastly underrepresented3,4.
Genetic techniques have greatly broadened our ability to represent the Tree of Life by circumventing the requirement for direct observation and experimentation. Trees can be constructed using molecular methods such as the small subunit ribosomal gene.
Despite the massive expansion of the Tree of Life through genome sequencing, much biodiversity still is waiting to be discovered. This is especially true for microorganisms that are difficult to cultivate, and are usually found in a single specimen5. Recent analysis of all genomes resulted in an initial draft of the Tree of Life. This includes a large number of bacteria, archaea and other organisms that haven't yet been isolated or the diversity of which is not fully understood6.
This expanded Tree of Life is particularly useful in assessing the diversity of an area, which can help to determine if certain habitats require 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 the quality of crops. This information is also valuable for conservation efforts. It can help biologists identify the areas most likely to contain cryptic species with important metabolic functions that could be at risk from anthropogenic change. Although funding to safeguard 무료에볼루션 are vital but the most effective way to preserve 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 is also known as an evolutionary tree, illustrates the relationships between groups of organisms. Scientists can build an phylogenetic chart which shows the evolutionary relationship of taxonomic groups based on molecular data and morphological differences or similarities. The concept of phylogeny is fundamental to understanding the evolution of biodiversity, evolution and genetics.
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 ancestral. These shared traits may be homologous, or analogous. Homologous characteristics are identical in terms of their evolutionary path. Analogous traits might appear like they are but they don't have the same origins. Scientists arrange similar traits into a grouping known as a clade. For instance, all of the organisms in a clade have the characteristic of having amniotic eggs. They evolved from a common ancestor who had eggs. A phylogenetic tree is then constructed by connecting clades to identify the species that are most closely related to each other.
Scientists utilize molecular DNA or RNA data to construct a phylogenetic graph that is more precise and precise. This data is more precise than morphological information and provides evidence of the evolution background of an organism or group. The analysis of molecular data can help researchers determine the number of species that share an ancestor common to them and estimate their evolutionary age.
Phylogenetic relationships can be affected by a number of factors, including phenotypicplasticity. This is a kind of behavior that changes as a result of specific environmental conditions. This can make a trait appear more resembling to one species than to another, obscuring the phylogenetic signals. This problem can be mitigated by using cladistics, which incorporates an amalgamation of homologous and analogous traits in the tree.
Additionally, phylogenetics can aid in predicting the duration and rate of speciation. This information will assist conservation biologists in deciding which species to save from the threat of extinction. In the end, it's the conservation of phylogenetic variety that will result in an ecosystem that is complete and balanced.
무료에볼루션 of evolution is that organisms develop different features over time as a result of their interactions with their surroundings. Many scientists have proposed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism would develop according to its own requirements as well as the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical system of taxonomy, as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the usage or non-use of certain traits can result in changes that can be passed on to future generations.
In the 1930s and 1940s, concepts from various areas, including natural selection, genetics & particulate inheritance, came together to form a modern synthesis of evolution theory. This describes how evolution is triggered by the variations in genes within a population and how these variants alter over time due to natural selection. This model, which is known as genetic drift, mutation, gene flow and sexual selection, is a cornerstone of the current evolutionary biology and can be mathematically explained.
Recent developments in the field of evolutionary developmental biology have revealed that variation can be introduced into a species by genetic drift, mutation, and reshuffling of genes during sexual reproduction, and also through migration between populations. These processes, as well as other ones like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time) can lead to evolution that is defined as changes in the genome of the species over time and also by changes in phenotype over time (the expression of the genotype in the individual).
Incorporating evolutionary thinking into all areas of biology education can increase student understanding of the concepts of phylogeny and evolution. A recent study by Grunspan and colleagues, for example revealed that teaching students about the evidence for evolution increased students' understanding of evolution in a college-level biology class. To learn more about how to teach about evolution, see 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 through looking back, studying fossils, comparing species, and observing living organisms. Evolution is not a past moment; it is a process that continues today. Viruses evolve to stay away from new medications and bacteria mutate to resist antibiotics. Animals adapt their behavior because of a changing environment. The changes that result are often evident.
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 can confer a different rate of survival as well as reproduction, and may be passed down from one generation to the next.
In the past when one particular allele--the genetic sequence that defines color in a population of interbreeding organisms, it might rapidly become more common than other alleles. In time, this could mean that the number of moths with black pigmentation in a group may increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.
The ability to observe evolutionary change is easier when a species has a fast generation turnover, as with bacteria. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. coli that descended from a single strain. samples of each population are taken every day, and over 500.000 generations have passed.
Lenski's work has demonstrated that a mutation can dramatically alter the efficiency with the rate at which a population reproduces, and consequently, the rate at which it changes. It also proves that evolution takes time, a fact that some find hard to accept.
Microevolution can be observed in the fact that mosquito genes that confer resistance to pesticides are more prevalent in areas that have used insecticides. That's because the use of pesticides creates a selective pressure that favors those who have resistant genotypes.
The rapidity of evolution has led to a growing appreciation of its importance particularly in a world which is largely shaped by human activities. This includes climate change, pollution, and habitat loss that hinders many species from adapting. Understanding evolution will help you make better decisions regarding the future of the planet and its inhabitants.