14 Misconceptions Commonly Held About Evolution Site
The Academy's Evolution Site
The concept of biological evolution is a fundamental concept in biology. The Academies are involved in helping those who are interested in science to understand evolution theory and how it can be applied throughout all fields of scientific research.
This site offers a variety of resources for students, teachers, and general readers on evolution. It contains key video clips 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 an emblem of love and harmony in a variety of cultures. It has many practical applications as well, such as providing a framework for understanding the history of species and how they respond to changes in environmental conditions.
Early attempts to describe the biological world were based on categorizing organisms based on their physical and metabolic characteristics. These methods, which relied on sampling of different parts of living organisms or short fragments of their DNA significantly increased the variety that could be represented in the tree of life2. These trees are largely composed by eukaryotes and bacterial diversity is vastly underrepresented3,4.
Genetic techniques have greatly expanded our ability to depict the Tree of Life by circumventing the need for direct observation and experimentation. In particular, molecular methods allow us to build trees using sequenced markers like the small subunit ribosomal gene.
Despite the rapid growth of the Tree of Life through genome sequencing, a large amount of biodiversity remains to be discovered. This is especially the case for microorganisms which are difficult to cultivate, and which are usually only found in one sample5. Recent analysis of all genomes resulted in a rough draft of the Tree of Life. This includes a large number of archaea, bacteria and other organisms that haven't yet been isolated or the diversity of which is not thoroughly understood6.
This expanded Tree of Life can be used to determine the diversity of a particular area and determine if particular habitats require special protection. This information can be used in a range of ways, from identifying the most effective remedies to fight diseases to improving crops. This information is also extremely beneficial to conservation efforts. It helps biologists discover areas that are likely to be home to cryptic species, which could perform important metabolic functions and are susceptible to human-induced change. While funds to protect biodiversity are essential, the best method to preserve the world's biodiversity is to equip more people in developing nations with the necessary knowledge to act locally and promote conservation.
Phylogeny
A phylogeny (also known as an evolutionary tree) depicts the relationships between different organisms. Utilizing molecular data as well as morphological similarities and distinctions, or ontogeny (the course of development of an organism) scientists can construct a phylogenetic tree which illustrates the evolution of taxonomic categories. The phylogeny of a tree plays an important role in understanding biodiversity, genetics and evolution.
A basic phylogenetic tree (see Figure PageIndex 10 ) determines the relationship between organisms with similar traits that evolved from common ancestral. These shared traits may be homologous, or analogous. Homologous traits are identical in their underlying evolutionary path while analogous traits appear similar, but do not share the identical origins. Scientists group similar traits together into a grouping referred to as a clade. For instance, all of the organisms that make up a clade share the trait of having amniotic eggs. They evolved from a common ancestor who had these eggs. The clades then join to form a phylogenetic branch that can identify organisms that have the closest relationship to.
For a more precise and precise phylogenetic tree scientists use molecular data from DNA or RNA to determine the relationships among organisms. This data is more precise than the morphological data and gives evidence of the evolutionary history of an organism or group. Researchers can use Molecular Data to calculate the evolutionary age of organisms and identify the number of organisms that have an ancestor common to all.
Phylogenetic relationships can be affected by a number of factors such as the phenotypic plasticity. This is a type behavior that changes as a result of unique environmental conditions. This can cause a particular trait to appear more like a species other species, which can obscure the phylogenetic signal. However, this issue can be solved through the use of methods like cladistics, which include a mix of homologous and analogous features into the tree.
Additionally, phylogenetics aids determine the duration and speed at which speciation occurs. This information can assist conservation biologists decide which species to protect from extinction. It is ultimately the preservation of phylogenetic diversity which will result in an ecologically balanced and complete ecosystem.
Evolutionary Theory
The fundamental concept of evolution is that organisms develop various characteristics over time based on their interactions with their surroundings. Many scientists have come up with theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism could evolve according to its own needs, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical taxonomy and Jean-Baptiste Lamarck (1844-1829), who suggested that the use or non-use of certain traits can result in changes that are passed on to the
In the 1930s and 1940s, theories from various fields, such as natural selection, genetics & particulate inheritance, were brought together to form a contemporary theorizing of evolution. This describes how evolution is triggered by the variations in genes within a population and how these variants change over time as a result of natural selection. This model, which incorporates genetic drift, mutations as well as gene flow and sexual selection, can be mathematically described.
Recent developments in evolutionary developmental biology have shown how variations can be introduced to a species through genetic drift, mutations and reshuffling of genes during sexual reproduction, and even migration between populations. These processes, as well as others, such as the directional selection process and the erosion of genes (changes in the frequency of genotypes over time) can lead to evolution. Evolution is defined as changes in the genome over time and changes in phenotype (the expression of genotypes in an individual).
Students can better understand the concept of phylogeny through incorporating evolutionary thinking throughout all aspects of biology. 에볼루션카지노 by Grunspan and colleagues, for example revealed that teaching students about the evidence that supports evolution helped students accept the concept of evolution in a college biology class. For more details on how to teach about evolution read The Evolutionary Potential in all Areas of Biology or Thinking Evolutionarily: a Framework for Infusing Evolution into Life Sciences Education.
Evolution in Action
Scientists have studied evolution by looking in the past, analyzing fossils and comparing species. They also observe living organisms. However, evolution isn't something that occurred in the past. It's an ongoing process, happening in the present. Bacteria mutate and resist antibiotics, viruses reinvent themselves and escape new drugs and animals alter their behavior in response to a changing planet. The changes that occur are often apparent.
It wasn't until late-1980s that biologists realized that natural selection could be seen in action, as well. The reason is that different traits have different rates of survival and reproduction (differential fitness), and can be passed down from one generation to the next.
In the past, if one particular allele, the genetic sequence that controls coloration - was present in a group of interbreeding species, it could quickly become more prevalent than all other alleles. In time, this could mean that 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.
It is easier to track evolutionary change when a species, such as bacteria, has a high generation turnover. 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 on a regular basis and over fifty thousand generations have passed.
Lenski's work has demonstrated that a mutation can profoundly alter the efficiency with which a population reproduces and, consequently, the rate at which it alters. It also shows that evolution takes time, which is hard for some to accept.
Microevolution can be observed in the fact that mosquito genes for resistance to pesticides are more common in populations where insecticides have been used. This is because pesticides cause a selective pressure which favors those with resistant genotypes.
The speed at which evolution takes place has led to an increasing awareness of its significance in a world that is shaped by human activity--including climate change, pollution and the loss of habitats that prevent many species from adapting. Understanding evolution can help us make better decisions about the future of our planet, as well as the lives of its inhabitants.