The Biggest Problem With Evolution Site, And How You Can Repair It
The Academy's Evolution Site
Biology is one of the most important concepts 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 every area of scientific inquiry.
This site provides a wide range of resources for teachers, students and general readers of evolution. It has the most important video clips from NOVA and WGBH's science programs on DVD.
Tree of Life
The Tree of Life, an ancient symbol, represents the interconnectedness of all life. It is a symbol of love and unity in many cultures. It has numerous practical applications as well, 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 biological world were founded on categorizing organisms on their physical and metabolic characteristics. These methods, which depend on the sampling of different parts of organisms or fragments of DNA have significantly increased the diversity of a tree of Life2. However these trees are mainly composed of eukaryotes; bacterial diversity remains vastly underrepresented3,4.
By avoiding the need for direct observation and experimentation, genetic techniques have enabled us to depict the Tree of Life in a much more accurate way. Particularly, molecular techniques allow us to construct 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 still a lot of biodiversity to be discovered. This is particularly true for microorganisms that are difficult to cultivate and are often only found in a single sample5. Recent analysis of all genomes produced an initial draft of the Tree of Life. This includes a large number of bacteria, archaea and other organisms that haven't yet been isolated or the diversity of which is not thoroughly understood6.
The expanded Tree of Life can be used to assess the biodiversity of a specific area and determine if specific habitats need special protection. This information can be utilized in a variety of ways, from identifying the most effective medicines to combating disease to improving crop yields. It is also beneficial to conservation efforts. It helps biologists determine the areas that are most likely to contain cryptic species with important metabolic functions that may be vulnerable to anthropogenic change. Although funds to protect biodiversity are essential, ultimately the best way to protect the world's biodiversity 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) illustrates the relationship between organisms. Using molecular data similarities and differences in morphology, or ontogeny (the process of the development of an organism) scientists can construct an phylogenetic tree that demonstrates the evolutionary relationship between taxonomic categories. 에볼루션 게이밍 of phylogeny is crucial in understanding genetics, biodiversity and evolution.
A basic phylogenetic tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms that share similar traits that have evolved from common ancestors. These shared traits could be either homologous or analogous. Homologous characteristics are identical in terms of their evolutionary path. Analogous traits might appear like they are, but they do not have the same origins. Scientists put similar traits into a grouping known as a clade. For example, all of the species in a clade share the characteristic of having amniotic eggs and evolved from a common ancestor who had these eggs. The clades are then connected to create a phylogenetic tree to identify organisms that have the closest relationship to.
Scientists make use of molecular DNA or RNA data to construct a phylogenetic graph which is more precise and detailed. This information is more precise and gives evidence of the evolution of an organism. Researchers can use Molecular Data to calculate the age of evolution of organisms and identify how many organisms have the same ancestor.
The phylogenetic relationships of organisms are influenced by many factors, including phenotypic plasticity a kind of behavior that alters in response to unique environmental conditions. This can make a trait appear more similar to one species than another, obscuring the phylogenetic signals. This problem can be mitigated by using cladistics, which incorporates an amalgamation of analogous and homologous features in the tree.
Additionally, phylogenetics can help predict the time and pace of speciation. This information can aid conservation biologists in making choices about which species to protect from extinction. In the end, it's the preservation of phylogenetic diversity which will create an ecologically balanced and complete ecosystem.
Evolutionary Theory
The fundamental concept of evolution is that organisms develop different features over time due to their interactions with their environments. A variety of theories about evolution have been developed by a variety of scientists, including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing gradually according to its requirements and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that the use or non-use of traits can cause changes that can be passed on to the offspring.
In the 1930s and 1940s, ideas from a variety of fields--including natural selection, genetics, and particulate inheritance -- came together to create the modern synthesis of evolutionary theory, which defines 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 encompasses genetic drift, mutations as well as gene flow and sexual selection is mathematically described.
Recent developments in the field of evolutionary developmental biology have shown that variations can be introduced into a species by mutation, genetic drift, and reshuffling genes during sexual reproduction, as well as through the movement of populations. These processes, along with others such as directional selection or genetic erosion (changes in the frequency of the genotype over time) can lead to evolution that is defined as change in the genome of the species over time and also by changes in phenotype as time passes (the expression of that genotype within the individual).
Incorporating evolutionary thinking into all areas of biology education can increase student understanding of the concepts of phylogeny and evolution. A recent study by Grunspan and colleagues, for instance revealed that teaching students about the evidence for evolution increased students' understanding of evolution in a college-level biology course. For more information about how to teach evolution read 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 by looking back--analyzing fossils, comparing species and observing living organisms. However, evolution isn't something that occurred in the past, it's an ongoing process taking place right now. Viruses reinvent themselves to avoid new drugs and bacteria evolve to resist antibiotics. Animals adapt their behavior as a result of a changing environment. The results are usually visible.
It wasn't until the late 1980s that biologists began realize that natural selection was also in play. The key is the fact that different traits confer an individual rate of survival and reproduction, and they can be passed down from one generation to another.
In the past, if one particular allele, the genetic sequence that determines coloration--appeared in a population of interbreeding species, it could rapidly become more common than other alleles. Over time, that would mean that 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 evolution when an organism, like bacteria, has a high generation turnover. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that are descended from one strain. The samples of each population have been taken regularly and more than 50,000 generations of E.coli have passed.
Lenski's work has shown that mutations can alter the rate at which change occurs and the effectiveness of a population's reproduction. It also demonstrates that evolution takes time, which is hard for some to accept.
Another example of microevolution is the way mosquito genes for resistance to pesticides appear more frequently in populations where insecticides are employed. This is due to the fact that the use of pesticides creates a selective pressure that favors individuals who have resistant genotypes.
The rapid pace at which evolution can take place has led to an increasing appreciation of its importance in a world shaped by human activity, including climate change, pollution and the loss of habitats which prevent many species from adapting. Understanding evolution will help us make better decisions regarding the future of our planet, and the life of its inhabitants.