5 Things Everyone Gets Wrong Concerning Evolution Site
The Academy's Evolution Site
The concept of biological evolution is among the most fundamental concepts in biology. The Academies have long been involved in helping those interested in science understand the concept of evolution and how it permeates all areas of scientific exploration.
This site provides a wide range of sources for teachers, students and general readers of evolution. It contains the most important video clips from NOVA and the WGBH-produced science programs on DVD.
Tree of Life
The Tree of Life is an ancient symbol of the interconnectedness of life. It is an emblem of love and unity in many cultures. It also has many practical applications, like providing a framework to understand the evolution of species and how they react to changes in the environment.
The first attempts at depicting the biological world focused on the classification of species into distinct categories that had been distinguished by their physical and metabolic characteristics1. These methods, which relied on the sampling of different parts of living organisms or on sequences of small fragments of their DNA significantly expanded the diversity that could be represented in a tree of life2. These trees are mostly populated by eukaryotes, and the diversity of bacterial species is greatly underrepresented3,4.
Genetic techniques have greatly expanded our ability to depict the Tree of Life by circumventing the requirement for direct observation and experimentation. Particularly, molecular techniques allow us to construct trees by using sequenced markers, such as the small subunit ribosomal gene.
The Tree of Life has been dramatically expanded through genome sequencing. However there is a lot of diversity to be discovered. This is particularly true for microorganisms, which can be difficult to cultivate and are usually only found in a single sample5. A recent study of all genomes that are known has produced a rough draft of the Tree of Life, including numerous bacteria and archaea that have not been isolated and their diversity is not fully understood6.
The expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, helping to determine if specific habitats require special protection. The information is useful in a variety of ways, including identifying new drugs, combating diseases and improving the quality of crops. It is also useful for conservation efforts. It can help biologists identify those areas that are most likely contain cryptic species with important metabolic functions that may be at risk from anthropogenic change. Although funding to protect biodiversity are essential but the most effective way to preserve the world's biodiversity is for more people in developing countries to be empowered with the necessary knowledge to act locally in order to promote conservation from within.
Phylogeny
A phylogeny (also known as an evolutionary tree) illustrates the relationship between different organisms. Using molecular data as well as morphological similarities and distinctions, or ontogeny (the process of the development of an organism) scientists can create a phylogenetic tree which illustrates the evolutionary relationships between taxonomic groups. Phylogeny is essential in understanding the evolution of biodiversity, evolution and genetics.
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 ancestral. These shared traits may be homologous, or analogous. Homologous traits are the same in terms of their evolutionary path. Analogous traits could appear like they are, but they do not have the same ancestry. Scientists combine similar traits into a grouping referred to as a clade. For example, all of the species in a clade share the characteristic of having amniotic egg and evolved from a common ancestor which had eggs. The clades are then connected to create a phylogenetic tree to identify organisms that have the closest connection to each other.
For a more detailed and precise phylogenetic tree scientists use molecular data from DNA or RNA to identify the connections between organisms. This information is more precise and gives evidence of the evolution of an organism. Molecular data allows researchers to determine the number of species that have the same ancestor and estimate their evolutionary age.
The phylogenetic relationships of organisms can be affected by a variety of factors, including phenotypic plasticity a kind of behavior that changes in response to unique environmental conditions. This can cause a characteristic to appear more similar to one species than other species, which can obscure the phylogenetic signal. This problem can be mitigated by using cladistics, which is a an amalgamation of analogous and homologous features in the tree.
Additionally, phylogenetics can help predict the duration and rate of speciation. This information can assist conservation biologists decide which species to protect from extinction. In the end, it's the preservation of phylogenetic diversity that will lead to an ecologically balanced and complete ecosystem.
more info here behind evolution is that organisms change over time due to their interactions with their environment. 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 would evolve according to its own needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern hierarchical system of taxonomy, as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the use or non-use of traits can cause changes that can be passed on to future generations.
In the 1930s & 1940s, theories from various fields, including natural selection, genetics & particulate inheritance, came together to form a contemporary synthesis of evolution theory. This explains how evolution happens through the variation of genes in the population, and how these variants change with time due to natural selection. This model, known as genetic drift or mutation, gene flow and sexual selection, is the foundation of modern evolutionary biology and can be mathematically explained.
Recent discoveries in the field of evolutionary developmental biology have shown how variation can be introduced to a species through genetic drift, mutations, reshuffling genes during sexual reproduction, and even migration between populations. These processes, along with others such as directional selection or genetic erosion (changes in the frequency of an individual's genotype over time) can result in 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 that genotype in an individual).
Students can better understand the concept of phylogeny by using evolutionary thinking throughout all areas of biology. In a recent study conducted by Grunspan et al. It was found that teaching students about the evidence for evolution increased their acceptance of evolution during an undergraduate biology course. To learn more about how to teach about evolution, please look up The Evolutionary Potential of all Areas of Biology and Thinking Evolutionarily A Framework for Infusing 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. Evolution isn't a flims event, but a process that continues today. Viruses reinvent themselves to avoid new antibiotics and bacteria transform to resist antibiotics. Animals adapt their behavior in the wake of a changing environment. The resulting changes are often evident.
It wasn't until the late 1980s when biologists began to realize that natural selection was at work. The key to this is that different traits can confer an individual rate of survival and reproduction, and can be passed down from one generation to another.
In the past, if an allele - the genetic sequence that determines color - was present in a population of organisms that interbred, it might become more common than other allele. Over time, that would mean that the number of black moths within the 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 see evolution when an organism, like bacteria, has a high generation turnover. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. Coli that descended from a single strain. samples of each are taken regularly and more than 50,000 generations have now passed.
Lenski's research has shown that a mutation can profoundly alter the efficiency with which a population reproduces and, consequently, the rate at which it alters. It also demonstrates that evolution takes time, a fact that many find difficult to accept.
Microevolution is also evident in the fact that mosquito genes for pesticide resistance are more prevalent in populations where insecticides are used. This is because pesticides cause an enticement that favors those with resistant genotypes.
The rapidity of evolution has led to a greater recognition of its importance, especially in a world which is largely shaped by human activities. This includes the effects of climate change, pollution and habitat loss that hinders many species from adapting. Understanding the evolution process can help us make better decisions regarding the future of our planet, as well as the lives of its inhabitants.