The Academy's Evolution Site
Biology is one of the most important concepts in biology. The Academies have been for a long time involved in helping those interested in science understand the theory of evolution and how it influences every area of scientific inquiry.
This site provides a range of tools for students, teachers, and general readers on evolution. It contains the most important video clips from NOVA and the 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 unity in many cultures. It also has important practical applications, such as providing a framework for understanding the evolution of species and how they respond to changing environmental conditions.
Early approaches to depicting the biological world focused on categorizing species into distinct categories that were identified by their physical and metabolic characteristics1. These methods, based on sampling of different parts of living organisms or small fragments of their DNA, significantly increased the variety that could be represented in the tree of life2. The trees are mostly composed by eukaryotes and bacteria are largely underrepresented3,4.
Genetic techniques have greatly expanded our ability to depict the Tree of Life by circumventing the need for direct observation and experimentation. Particularly, molecular methods allow us to construct trees using sequenced markers like the small subunit ribosomal RNA gene.
에볼루션 바카라 무료체험 of Life has been dramatically expanded through genome sequencing. However there is still a lot of diversity to be discovered. This is especially true of microorganisms, which are difficult to cultivate and are usually only represented in a single sample5. A recent analysis of all genomes that are known has produced a rough draft version of the Tree of Life, including a large number of archaea and bacteria that are not isolated and which are not well understood.
This expanded Tree of Life is particularly useful in assessing the diversity of an area, which can help to determine if specific habitats require protection. This information can be used in a range of ways, from identifying the most effective treatments to fight disease to enhancing the quality of crop yields. This information is also extremely useful to conservation efforts. It can help biologists identify areas that are likely to be home to species that are cryptic, which could have important metabolic functions and are susceptible to human-induced change. Although funding to safeguard biodiversity are vital but the most effective way to preserve the world's biodiversity is for more people in developing countries to be equipped with the knowledge to take action locally to encourage conservation from within.
Phylogeny
A phylogeny is also known as an evolutionary tree, shows the connections between groups of organisms. Scientists can build a phylogenetic diagram that illustrates the evolutionary relationship of taxonomic groups based on molecular data and morphological differences or similarities. Phylogeny plays a crucial role in understanding genetics, biodiversity and evolution.
A basic phylogenetic tree (see Figure PageIndex 10 ) determines the relationship between organisms that share similar traits that have evolved from common ancestral. These shared traits could be homologous, or analogous. Homologous traits are identical in their underlying evolutionary path while analogous traits appear similar, but do not share the same ancestors. Scientists combine similar traits into a grouping known as a Clade. For instance, all the organisms that make up a clade share the characteristic of having amniotic eggs and evolved from a common ancestor which had eggs. The clades are then linked to form a phylogenetic branch that can identify organisms that have the closest connection to each other.
Scientists utilize DNA or RNA molecular information to construct a phylogenetic graph which is more precise and detailed. This information is more precise and gives evidence of the evolutionary history of an organism. Molecular data allows researchers to identify the number of organisms that share an ancestor common to them and estimate their evolutionary age.
The phylogenetic relationships between species can be affected by a variety of factors including phenotypic plasticity, a type of behavior that changes in response to unique environmental conditions. This can make a trait appear more similar to a species than to another and obscure the phylogenetic signals. However, this issue can be solved through the use of methods like cladistics, which combine analogous and homologous features into the tree.
Additionally, phylogenetics aids determine the duration and speed of speciation. This information can help conservation biologists decide which species they should protect from extinction. In the end, it's the conservation of phylogenetic variety that will result in an ecosystem that is complete and balanced.
Evolutionary Theory
The central theme of evolution is that organisms acquire distinct characteristics over time due to their interactions with their environments. 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 requirements as well as the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical system of taxonomy and 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 and 1940s, ideas from various fields, including genetics, natural selection and particulate inheritance - came together to form the modern evolutionary theory synthesis, which defines how evolution occurs through the variation of genes within a population, and how those variants change over time as a result of natural selection. This model, which includes genetic drift, mutations in gene flow, and sexual selection can be mathematically described mathematically.
Recent discoveries in the field of evolutionary developmental biology have shown that genetic variation can be introduced into a species via genetic drift, mutation, and reshuffling of genes in sexual reproduction, as well as by migration between populations. These processes, along with others such as the directional selection process and the erosion of genes (changes in frequency of genotypes over time) can result in evolution. Evolution is defined as changes in the genome over time as well as changes in the phenotype (the expression of genotypes in individuals).
Incorporating evolutionary thinking into all aspects of biology education could increase student understanding of the concepts of phylogeny and evolution. In a study by Grunspan and colleagues. It was demonstrated that teaching students about the evidence for evolution boosted their understanding of evolution in the course of a college biology. For more details about how to teach evolution look up The Evolutionary Power of Biology in all Areas of Biology or Thinking Evolutionarily A Framework for Integrating Evolution into Life Sciences Education.
Evolution in Action
Scientists have studied evolution through looking back in the past, studying fossils, and comparing species. They also study living organisms. But 에볼루션 무료체험 isn't just something that happened in the past, it's an ongoing process, taking place today. Bacteria mutate and resist antibiotics, viruses reinvent themselves and escape new drugs and animals alter their behavior to the changing environment. The resulting changes are often easy to see.
It wasn't until the late 1980s that biologists began to realize that natural selection was also in play. The main reason is that different traits can confer the ability to survive at different rates and reproduction, and can be passed down from generation to generation.
In the past, when one particular allele--the genetic sequence that controls coloration - was present in a group of interbreeding species, it could rapidly become more common than all other alleles. In time, this could mean the number of black moths in a particular population could rise. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.
It is easier to track evolutionary change when the species, like bacteria, has a high generation turnover. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that descend from a single strain. Samples of each population were taken frequently and more than 50,000 generations of E.coli have passed.
Lenski's research has demonstrated that mutations can alter the rate of change and the effectiveness of a population's reproduction. It also shows that evolution takes time, a fact that is hard for some to accept.
Microevolution is also evident in the fact that mosquito genes that confer resistance to pesticides are more prevalent in areas where insecticides are used. This is because the use of pesticides creates a selective pressure that favors people with resistant genotypes.
The rapidity of evolution has led to a greater appreciation of its importance especially in a planet which is largely shaped by human activities. This includes the effects of climate change, pollution and habitat loss that prevents many species from adapting. Understanding the evolution process can aid you in making better decisions about the future of our planet and its inhabitants.