The Evolution Site Success Story You'll Never Be Able To
The Academy's Evolution Site
The concept of biological evolution is among the most central concepts in biology. The Academies are involved in helping those who are interested in science to understand evolution theory and how it is incorporated in all areas of scientific research.
This site provides students, teachers and general readers with a variety of educational resources on evolution. It has important video clips from NOVA and the WGBH-produced science programs on DVD.
Tree of Life
The Tree of Life is an ancient symbol that symbolizes the interconnectedness of all life. It is a symbol of love and unity across many cultures. It can be used in many practical ways in addition to providing a framework to understand the history of species, and how they react to changing environmental conditions.
The first attempts to depict the biological world were built on categorizing organisms based on their physical and metabolic characteristics. These methods, which rely on sampling of different parts of living organisms or on sequences of short fragments of their DNA, greatly increased the variety of organisms that could be included in the tree of life2. However, these trees are largely made up of eukaryotes. Bacterial diversity is not represented in a large way3,4.
Genetic techniques have greatly expanded our ability to depict the Tree of Life by circumventing the requirement for direct observation and experimentation. Particularly, molecular methods allow us to construct trees using sequenced markers, such as the small subunit ribosomal RNA gene.
Despite the massive growth of the Tree of Life through genome sequencing, a lot of biodiversity remains to be discovered. This is particularly true for microorganisms, which can be difficult to cultivate and are often only found in a single sample5. Recent analysis of all genomes has produced an unfinished draft of a Tree of Life. This includes a wide range of archaea, bacteria, and other organisms that haven't yet been isolated, or their diversity is not fully understood6.
This expanded Tree of Life is particularly useful in assessing the diversity of an area, which can help to determine whether specific habitats require protection. The information is useful in a variety of ways, including finding new drugs, fighting diseases and enhancing crops. This information is also valuable for conservation efforts. It helps biologists determine the areas that are most likely to contain cryptic species with significant metabolic functions that could be vulnerable to anthropogenic change. While funds to safeguard biodiversity are vital but the most effective way to ensure the preservation of biodiversity around the world 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 (also known as an evolutionary tree) depicts the relationships between organisms. Utilizing molecular data, morphological similarities and differences or ontogeny (the process of the development of an organism) scientists can construct an phylogenetic tree that demonstrates the evolutionary relationship between taxonomic categories. Phylogeny is crucial in understanding evolution, biodiversity and genetics.
A basic phylogenetic tree (see Figure PageIndex 10 Finds the connections between organisms with similar traits and evolved from an ancestor that shared traits. These shared traits can be either analogous or homologous. Homologous traits share their underlying evolutionary path while analogous traits appear similar but do not have the same ancestors. Scientists organize similar traits into a grouping referred to as a the clade. All organisms in a group share a characteristic, like amniotic egg production. They all derived from an ancestor that had these eggs. The clades are then connected to form a phylogenetic branch to determine which organisms have the closest relationship.
Scientists make use of molecular DNA or RNA data to create a phylogenetic chart which is more precise and precise. This information is more precise than morphological data and provides evidence of the evolution history of an organism or group. Molecular data allows researchers to determine the number of species that share an ancestor common to them and estimate their evolutionary age.
The phylogenetic relationship can be affected by a number of factors that include the phenotypic plasticity. This is a kind of behavior that changes in response to particular environmental conditions. This can cause a trait to appear more similar to a species than to the other and obscure the phylogenetic signals. However, this issue can be reduced by the use of methods such as cladistics which incorporate a combination of analogous and homologous features into the tree.
Additionally, phylogenetics aids predict the duration and rate of speciation. This information can assist conservation biologists in making decisions about which species to save from extinction. It is ultimately the preservation of phylogenetic diversity which will create an ecosystem that is complete and balanced.
Evolutionary Theory
The central theme in evolution is that organisms alter over time because of their interactions with their environment. A variety of theories about evolution have been proposed by a wide range 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 conceived modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits cause changes that could be passed onto offspring.
In 에볼루션코리아 and 1940s, ideas from a variety of 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 these variants change in time as a result of natural selection. This model, which incorporates mutations, genetic drift in gene flow, and sexual selection, can be mathematically described.
Recent developments in the field of evolutionary developmental biology have shown that variations can be introduced into a species via genetic drift, mutation, and reshuffling of genes in sexual reproduction, and also through the movement of populations. These processes, as well as other ones like directional selection and genetic erosion (changes in the frequency of a genotype over time), can lead to evolution, which is defined by change in the genome of the species over time and also the change in phenotype as time passes (the expression of that genotype within the individual).
Students can gain a better understanding of the concept of phylogeny by using evolutionary thinking into all areas of biology. A recent study by Grunspan and colleagues, for instance revealed that teaching students about the evidence that supports evolution increased students' acceptance of evolution in a college biology course. To find out more about how to teach about evolution, please read The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily: A Framework for Infusing the Concept of Evolution into Life Sciences Education.
Evolution in Action
Scientists have looked at evolution through the past, analyzing fossils and comparing species. They also study living organisms. However, evolution isn't something that happened in the past. It's an ongoing process, taking place in the present. Bacteria transform and resist antibiotics, viruses evolve and are able to evade new medications and animals change their behavior in response to the changing climate. The changes that result are often evident.
It wasn't until late 1980s that biologists understood that natural selection could be observed in action as well. The key to this is that different traits confer an individual rate of survival and reproduction, and can be passed down from generation to generation.
In the past, if an allele - the genetic sequence that determines colour - appeared in a population of organisms that interbred, it could become more prevalent than any other allele. As time passes, that 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 observe evolutionary change when the species, like bacteria, has a high generation turnover. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that descend from a single strain. Samples of each population have been collected regularly and more than 500.000 generations of E.coli have passed.
Lenski's work has shown 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 some find hard to accept.
Another example of microevolution is how mosquito genes for resistance to pesticides are more prevalent in areas where insecticides are used. Pesticides create an exclusive pressure that favors those with resistant genotypes.
The speed of evolution taking place has led to an increasing appreciation of its importance in a world that is shaped by human activity--including climate changes, pollution and the loss of habitats that hinder the species from adapting. Understanding evolution will help you make better decisions about the future of the planet and its inhabitants.