The Academy's Evolution Site
The concept of biological evolution is among the most central concepts in biology. The Academies have long been involved in helping people who are interested in science comprehend the concept of evolution and how it influences all areas of scientific research.
This site provides students, teachers and general readers with a variety of learning resources about evolution. It includes key video clips from NOVA and the WGBH-produced science programs on DVD.
Tree of Life
The Tree of Life, an ancient symbol, represents the interconnectedness of all life. It is an emblem of love and unity across many cultures. It also has practical applications, such as providing a framework for understanding the evolution of species and how they respond to changing environmental conditions.
The first attempts to depict the world of biology were built on categorizing organisms based on their physical and metabolic characteristics. These methods are based on the collection of various parts of organisms, or DNA fragments have significantly increased the diversity of a tree of Life2. However, these trees are largely made up of eukaryotes. Bacterial diversity remains vastly underrepresented3,4.
Genetic techniques have greatly expanded our ability to visualize the Tree of Life by circumventing the need for direct observation and experimentation. Particularly, molecular methods enable us to create trees by using sequenced markers like the small subunit of ribosomal RNA gene.
The Tree of Life has been dramatically expanded through genome sequencing. However there is a lot of biodiversity to be discovered. 에볼루션사이트 is particularly relevant to microorganisms that are difficult to cultivate, and are typically present in a single sample5. Recent analysis of all genomes has produced an unfinished draft of the Tree of Life. This includes a large number of bacteria, archaea and other organisms that have not yet been isolated, or their diversity is not thoroughly understood6.
This expanded Tree of Life is particularly useful in assessing the diversity of an area, helping to determine whether specific habitats require protection. This information can be used in a variety of ways, such as identifying new drugs, combating diseases and enhancing crops. This information is also valuable to conservation efforts. It helps biologists determine those areas that are most likely contain cryptic species with potentially important metabolic functions that could be at risk of anthropogenic changes. While conservation funds are essential, the best way to conserve the world's biodiversity is to equip the people of developing nations with the knowledge they need to act locally and promote conservation.
Phylogeny
A phylogeny, also known as an evolutionary tree, reveals the connections between different groups of organisms. Scientists can construct a phylogenetic diagram that illustrates the evolution of taxonomic categories using molecular information and morphological differences or similarities. The phylogeny of a tree plays an important role in understanding the relationship between genetics, biodiversity and evolution.
A basic phylogenetic Tree (see Figure PageIndex 10 Finds the connections between organisms that have similar traits and have evolved from an ancestor with common traits. These shared traits may be analogous or homologous. Homologous traits are the same in their evolutionary journey. Analogous traits could appear similar but they don't share the same origins. Scientists arrange similar traits into a grouping called a the clade. All organisms in a group have a common characteristic, like amniotic egg production. They all evolved from an ancestor who had these eggs. A phylogenetic tree is then built by connecting the clades to identify the organisms who are the closest to each other.
To create a more thorough and precise phylogenetic tree scientists rely on molecular information from DNA or RNA to determine the connections between organisms. This information is more precise and gives evidence of the evolutionary history of an organism. The analysis of molecular data can help researchers identify the number of organisms that have the same ancestor and estimate their evolutionary age.
The phylogenetic relationships between organisms can be affected by a variety of factors, including phenotypic plasticity a type of behavior that alters in response to unique environmental conditions. This can cause a trait to appear more similar in one species than other species, which can obscure the phylogenetic signal. However, this issue can be solved through the use of techniques like cladistics, which include a mix of analogous and homologous features into the tree.
Additionally, phylogenetics can help determine the duration and speed of speciation. This information can assist conservation biologists decide which species to protect from extinction. In the end, it's the preservation of phylogenetic diversity that 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 come up with 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 needs as well as the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical system of taxonomy and Jean-Baptiste Lamarck (1844-1829), who suggested that the use or absence of traits can cause changes that are passed on to the
In the 1930s & 1940s, ideas from different fields, including genetics, natural selection and particulate inheritance, came together to create a modern synthesis of evolution theory. This describes how evolution occurs by the variation in genes within the population, and how these variations change over time as a result of natural selection. This model, which is known as genetic drift or mutation, gene flow and sexual selection, is a key element of the current evolutionary biology and is mathematically described.
Recent developments in evolutionary developmental biology have revealed how variation can be introduced to a species by genetic drift, mutations and reshuffling of genes during sexual reproduction, and even migration between populations. These processes, in conjunction with other ones like directionally-selected selection and erosion of genes (changes in frequency of genotypes over time), can lead towards evolution. Evolution is defined as changes in the genome over time as well as changes in phenotype (the expression of genotypes in individuals).
Incorporating evolutionary thinking into all aspects of biology education can improve student understanding of the concepts of phylogeny and evolutionary. A recent study by Grunspan and colleagues, for example demonstrated that teaching about the evidence supporting evolution increased students' understanding of evolution in a college biology class. For more details on how to teach evolution look up The Evolutionary Power of Biology in all Areas of Biology or Thinking Evolutionarily A Framework for Infusing Evolution into Life Sciences Education.
Evolution in Action
Traditionally, scientists have studied evolution through studying fossils, comparing species, and studying living organisms. But evolution isn't a thing that happened in the past. It's an ongoing process, happening today. Bacteria transform and resist antibiotics, viruses re-invent themselves and elude new medications and animals alter their behavior to the changing environment. The results are often visible.
It wasn't until the 1980s when biologists began to realize that natural selection was also in play. The key is that various traits have different rates of survival and reproduction (differential fitness) and are passed from one generation to the next.
In 에볼루션 슬롯게임 , if one allele - the genetic sequence that determines colour was present in a population of organisms that interbred, it could become more common than any other allele. In time, this could mean that the number of moths that have black pigmentation 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 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 are descended from a single strain. The samples of each population have been collected regularly, and more than 500.000 generations of E.coli have been observed to have passed.
Lenski's work has demonstrated that mutations can drastically alter the efficiency with which a population reproduces--and so the rate at which it changes. 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 that confer resistance to pesticides are more common in populations where insecticides are used. This is because the use of pesticides causes a selective pressure that favors individuals with resistant genotypes.
The rapid pace at which evolution takes place has led to a growing appreciation of its importance in a world shaped by human activities, including climate changes, pollution and the loss of habitats that hinder the species from adapting. Understanding evolution can help us make smarter decisions about the future of our planet as well as the life of its inhabitants.