The Academy's Evolution Site
Biology is one of the most important concepts in biology. The Academies have long been involved in helping those interested in science comprehend the concept of evolution and how it permeates every area of scientific inquiry.
This site provides a wide range of resources for teachers, students, and general readers 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, represents the interconnectedness of all life. It is used in many religions and cultures as symbolizing unity and love. It can be used in many practical ways as well, including providing a framework to understand the history of species and how they respond to changing environmental conditions.
Early attempts to describe the world of biology were founded on categorizing organisms on their physical and metabolic characteristics. These methods, based on the sampling of different parts of living organisms, or sequences of short DNA fragments, significantly increased the variety that could be included in a tree of life2. However, these trees are largely composed of eukaryotes; bacterial diversity is not represented in a large way3,4.
Genetic techniques have greatly broadened our ability to represent the Tree of Life by circumventing the need for direct observation and experimentation. Particularly, molecular techniques allow us to construct trees using sequenced markers such as the small subunit of ribosomal RNA gene.
The Tree of Life has been significantly expanded by genome sequencing. However there is still a lot of diversity to be discovered. 에볼루션 바카라사이트 is particularly true for microorganisms that are difficult to cultivate and are usually found in one sample5. A recent analysis of all known genomes has produced a rough draft version of the Tree of Life, including a large number of bacteria and archaea that have not been isolated, and their diversity is not fully understood6.
The expanded Tree of Life can be used to evaluate the biodiversity of a specific area and determine if particular habitats require special protection. This information can be utilized in a variety of ways, from identifying new medicines to combating disease to enhancing the quality of the quality of crops. The information is also beneficial in conservation efforts. It can aid biologists in identifying the areas that are most likely to contain cryptic species with potentially important metabolic functions that may be vulnerable to anthropogenic change. While funds to protect biodiversity are important, the best way to conserve the biodiversity of the world is to equip more people in developing countries with the knowledge they need to take action locally and encourage conservation.
Phylogeny
A phylogeny is also known as an evolutionary tree, shows the relationships between different groups of organisms. Scientists can build a phylogenetic chart that shows the evolutionary relationships between 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 Finds the connections between organisms that have similar characteristics and have evolved from an ancestor with common traits. These shared traits can be analogous, or homologous. Homologous traits are identical in their evolutionary roots and analogous traits appear similar, but do not share the identical origins. Scientists group similar traits into a grouping called a Clade. For instance, all of the organisms in a clade share the trait of having amniotic eggs and evolved from a common ancestor which had eggs. A phylogenetic tree can be constructed by connecting the clades to identify the organisms that are most closely related to one another.
Scientists utilize molecular DNA or RNA data to create a phylogenetic chart that is more precise and precise. This data is more precise than morphological data and provides evidence of the evolutionary history of an individual or group. Researchers can use Molecular Data to calculate the age of evolution of organisms and determine the number of organisms that have the same ancestor.
Phylogenetic relationships can be affected by a variety of factors, including the phenotypic plasticity. This is a type of behavior that changes in response to unique environmental conditions. This can cause a characteristic to appear more like a species another, obscuring the phylogenetic signal. This problem can be mitigated by using cladistics. This is a method that incorporates the combination of analogous and homologous features in the tree.
Additionally, phylogenetics can help determine the duration and rate at which speciation occurs. This information can help conservation biologists decide the species they should safeguard from extinction. In the end, it is the conservation of phylogenetic diversity which will create an ecosystem that is complete and balanced.
Evolutionary Theory
The fundamental concept in evolution is that organisms alter over time because of their interactions with their environment. Many scientists have developed 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 developed the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the usage or non-use of traits can cause changes that can be passed on to future generations.
In the 1930s and 1940s, concepts from a variety of fields--including genetics, natural selection, and particulate inheritance - came together to create the modern synthesis of evolutionary theory, which defines how evolution happens through the variation of genes within a population, and how these variants change over time as a result of natural selection. This model, called genetic drift, mutation, gene flow and sexual selection, is a cornerstone of the current evolutionary biology and can be mathematically explained.
Recent discoveries in the field of evolutionary developmental biology have demonstrated that variation can be introduced into a species by mutation, genetic drift and reshuffling of genes in sexual reproduction, as well as through migration between populations. These processes, along with other ones 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 change in the genome of the species over time, and also by changes in phenotype over time (the expression of the genotype in an individual).
Incorporating evolutionary thinking into all aspects of biology education could increase student understanding of the concepts of phylogeny and evolutionary. In a study by Grunspan and co., it was shown that teaching students about the evidence for evolution increased their understanding of evolution in a college-level course in biology. To learn more about how to teach about evolution, read The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution into Life Sciences Education.
Evolution in Action
Traditionally scientists have studied evolution through looking back--analyzing fossils, comparing species and observing living organisms. Evolution is not a past moment; it is an ongoing process. Viruses evolve to stay away from new antibiotics and bacteria transform to resist antibiotics. Animals alter their behavior in the wake of the changing environment. The results are often evident.
It wasn't until the late 1980s that biologists began to realize that natural selection was also at work. The main reason is that different traits can confer a different rate of survival and reproduction, and they can be passed on from one generation to another.
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 the other alleles. In time, this could mean that the number of moths with black pigmentation in a population may increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.
It is easier to see evolutionary change when the species, like bacteria, has a high generation turnover. 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 500.000 generations of E.coli have been observed to have passed.
에볼루션 has demonstrated that a mutation can profoundly alter the efficiency with which a population reproduces--and so, the rate at which it alters. It also demonstrates that evolution takes time, which is difficult for some to accept.
Microevolution is also evident in the fact that mosquito genes for resistance to pesticides are more prevalent in populations where insecticides have been used. This is because pesticides cause an exclusive pressure that favors those who have resistant genotypes.
The speed of evolution taking place has led to an increasing appreciation of its importance in a world shaped by human activities, including climate change, pollution, and the loss of habitats that hinder many species from adjusting. Understanding the evolution process can help us make better decisions regarding the future of our planet, and the life of its inhabitants.