The Academy's Evolution Site
The concept of biological evolution is a fundamental concept in biology. The Academies have been active for a long time in helping those interested in science understand the concept of evolution and how it permeates all areas of scientific research.
This site provides students, teachers and general readers with a wide range of educational resources on evolution. It also includes important video clips from NOVA and WGBH produced science programs on DVD.
에볼루션 슬롯게임 of Life
The Tree of Life, an ancient symbol, symbolizes the interconnectedness of all life. It is seen in a variety of spiritual traditions and cultures as symbolizing unity and love. It has numerous practical applications as well, including providing a framework for understanding the evolution of species and how they respond to changing environmental conditions.
The earliest attempts to depict the biological world focused on separating organisms into distinct categories which were distinguished by their physical and metabolic characteristics1. These methods, which rely on the collection of various parts of organisms or fragments of DNA, have significantly increased the diversity of a tree of Life2. However the trees are mostly made up of eukaryotes. Bacterial diversity remains vastly underrepresented3,4.
Genetic techniques have greatly broadened our ability to visualize the Tree of Life by circumventing the requirement for direct observation and experimentation. We can construct trees using molecular techniques, such as the small-subunit ribosomal gene.
The Tree of Life has been greatly expanded thanks to genome sequencing. However there is still a lot of biodiversity to be discovered. This is especially true of microorganisms that are difficult to cultivate and are often only present in a single sample5. Recent analysis of all genomes produced an unfinished draft of a Tree of Life. 무료에볼루션 includes a wide range of archaea, bacteria, and other organisms that have not yet been isolated, or their diversity is not well understood6.
This expanded Tree of Life can be used to determine the diversity of a specific region and determine if particular habitats require special protection. This information can be used in a variety of ways, including identifying new drugs, combating diseases and improving crops. It is also useful for conservation efforts. It can aid biologists in identifying areas that are likely to be home to cryptic species, which could perform important metabolic functions and are susceptible to changes caused by humans. While funds to protect biodiversity are important, the most effective method to preserve the biodiversity of the world is to equip more people in developing countries with the necessary knowledge to act locally and support conservation.
Phylogeny
A phylogeny is also known as an evolutionary tree, illustrates the relationships between groups of organisms. Scientists can build a phylogenetic diagram that illustrates the evolution of taxonomic categories using molecular information and morphological similarities or differences. The phylogeny of a tree plays an important role in understanding biodiversity, genetics and evolution.
A basic phylogenetic tree (see Figure PageIndex 10 Identifies the relationships between organisms with similar traits and evolved from an ancestor with common traits. These shared traits could be analogous, or homologous. Homologous traits are the same in their evolutionary journey. Analogous traits might appear similar, but they do not have the same ancestry. Scientists group similar traits together into a grouping referred to as a clade. All members of a clade share a characteristic, like amniotic egg production. They all came from an ancestor who had these eggs. The clades are then connected to create a phylogenetic tree to determine the organisms with the closest relationship to.
To create a more thorough and accurate phylogenetic tree, scientists rely on molecular information from DNA or RNA to establish the connections between organisms. This data is more precise than morphological information and gives evidence of the evolutionary history of an organism or group. Researchers can utilize Molecular Data to determine the age of evolution of organisms and determine the number of organisms that have a common ancestor.
Phylogenetic relationships can be affected by a variety of factors, including the phenomenon of phenotypicplasticity. This is a type behavior that alters due to specific environmental conditions. This can cause a particular trait to appear more similar to one species than other species, which can obscure the phylogenetic signal. This problem can be addressed by using cladistics, which is a a combination of homologous and analogous traits in the tree.
Additionally, phylogenetics can help predict the duration and rate of speciation. This information can aid conservation biologists in deciding which species to protect from the threat of extinction. In the end, it is the conservation of phylogenetic diversity that will result in an ecosystem that is complete and balanced.
Evolutionary Theory
The fundamental concept of evolution is that organisms develop various characteristics over time as a result of their interactions with their environment. Several theories of evolutionary change have been developed by a variety of scientists, including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing slowly according to its needs and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1744-1829) who suggested that the use or non-use of traits can cause changes that can be passed on to offspring.
In the 1930s and 1940s, ideas from a variety of fields -- including natural selection, genetics, and particulate inheritance - came together to form the modern evolutionary theory synthesis which explains how evolution is triggered by the variations of genes within a population, and how these variants change over time as a result of natural selection. This model, which includes mutations, genetic drift as well as gene flow and sexual selection can be mathematically described mathematically.
Recent developments in the field of evolutionary developmental biology have demonstrated that variations can be introduced into a species by mutation, genetic drift, and reshuffling of genes in sexual reproduction, and also by migration between populations. These processes, along with others like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time) can result in evolution which is defined by changes in the genome of the species over time, and the change in phenotype as time passes (the expression of that genotype within the individual).
Students can better understand the concept of phylogeny by using evolutionary thinking in all areas of biology. A recent study by Grunspan and colleagues, for instance, showed that teaching about the evidence supporting evolution increased students' acceptance of evolution in a college-level biology course. For more details on how to teach evolution, see 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
Scientists have traditionally looked at evolution through the past, analyzing fossils and comparing species. They also observe living organisms. Evolution is not a past event, but an ongoing process that continues to be observed today. Bacteria mutate and resist antibiotics, viruses re-invent themselves and elude new medications and animals change their behavior in response to the changing climate. The changes that result are often visible.
However, it wasn't until late-1980s that biologists realized that natural selection could be seen in action, as well. The key is the fact that different traits can confer a different rate of survival and reproduction, and can be passed on from one generation to the next.
In the past, if one allele - the genetic sequence that determines colour appeared in a population of organisms that interbred, it could be more common than any other allele. In time, this could mean the number of black moths in a population could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.
Monitoring evolutionary changes in action is easier when a species has a rapid turnover of its generation, as with bacteria. Since 1988 biologist Richard Lenski has been tracking twelve populations of E. coli that descended from a single strain. samples of each population are taken regularly and more than fifty thousand generations have been observed.
Lenski's research has shown that a mutation can dramatically alter the efficiency with the rate at which a population reproduces, and consequently the rate at which it evolves. It also demonstrates that evolution is slow-moving, a fact that many find hard to accept.
Microevolution can also be seen in the fact that mosquito genes for resistance to pesticides are more prevalent in areas that have used insecticides. This is because pesticides cause an exclusive pressure that favors those with resistant genotypes.
The rapidity of evolution has led to a greater appreciation of its importance especially in a planet that is largely shaped by human activity. This includes the effects of climate change, pollution and habitat loss that hinders many species from adapting. Understanding the evolution process will help you make better decisions regarding the future of the planet and its inhabitants.