20 Things You Need To Know About Evolution Site
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 people who are interested in science comprehend the concept of evolution and how it influences all areas of scientific exploration.
This site provides teachers, students and general readers with a range of learning resources on evolution. It also includes important video clips from NOVA and WGBH produced science programs on DVD.
Tree of Life
The Tree of Life, an ancient symbol, symbolizes the interconnectedness of all life. It appears in many religions and cultures as a symbol of unity and love. It also has important practical applications, such as providing a framework for understanding the history of species and how they react to changes in the environment.
The first attempts to depict the biological world were founded on categorizing organisms on their physical and metabolic characteristics. These methods, based on the sampling of different parts of living organisms, or sequences of short DNA fragments, significantly expanded the diversity that could be represented in the tree of life2. However these trees are mainly comprised of eukaryotes, and bacterial diversity is still largely unrepresented3,4.
Genetic techniques have greatly broadened our ability to visualize the Tree of Life by circumventing the requirement for direct observation and experimentation. Particularly, molecular methods allow us to construct trees by using sequenced markers, such as the small subunit of ribosomal RNA gene.
Despite the massive growth of the Tree of Life through genome sequencing, a large amount of biodiversity is waiting to be discovered. This is especially relevant to microorganisms that are difficult to cultivate and which are usually only found in one sample5. Recent analysis of all genomes produced an unfinished draft of the Tree of Life. This includes a large number of archaea, bacteria, and other organisms that have not yet been identified or the diversity of which is not fully understood6.
The expanded Tree of Life is particularly useful for assessing the biodiversity of an area, assisting to determine if certain habitats require protection. This information can be utilized in a variety of ways, such as identifying new drugs, combating diseases and enhancing crops. It is also beneficial to conservation efforts. It helps biologists discover areas that are most likely to have species that are cryptic, which could have important metabolic functions, and could be susceptible to the effects of human activity. Although funds to protect biodiversity are essential but the most effective way to protect the world's biodiversity is for more people in developing countries to be empowered with the necessary knowledge to act locally to promote conservation from within.
Phylogeny
A phylogeny (also known as an evolutionary tree) depicts the relationships between different organisms. Scientists can construct an phylogenetic chart which shows the evolutionary relationships between taxonomic groups using molecular data and morphological similarities or differences. Phylogeny is essential in understanding 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 evolved from common ancestral. These shared traits can be either analogous or homologous. Homologous traits share their evolutionary roots while analogous traits appear like they do, but don't have the same origins. Scientists combine similar traits into a grouping referred to as a Clade. For instance, all of the organisms that make up a clade share the characteristic of having amniotic eggs and evolved from a common ancestor which had eggs. The clades are then linked to create a phylogenetic tree to identify organisms that have the closest connection to each other.
Scientists use molecular DNA or RNA data to construct a phylogenetic graph that is more precise and precise. This information is more precise than morphological data and gives evidence of the evolutionary history of an organism or group. talks about it allows researchers to identify the number of organisms that share a common ancestor and to estimate their evolutionary age.
The phylogenetic relationships between species can be influenced by several factors, including phenotypic plasticity a type of behavior that alters in response to unique environmental conditions. This can cause a trait to appear more resembling to one species than to another and obscure the phylogenetic signals. However, this issue can be cured by the use of methods such as cladistics which combine similar and homologous traits into the tree.
Furthermore, phylogenetics may aid in predicting the length and speed of speciation. This information can assist conservation biologists decide which species to protect from the threat of extinction. Ultimately, it is the preservation of phylogenetic diversity which will create an ecosystem that is complete and balanced.
Evolutionary Theory
The fundamental concept of evolution is that organisms develop various characteristics over time based on their interactions with their environment. Many scientists have come up with theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism would evolve according to its individual requirements as well as the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy and Jean-Baptiste Lamarck (1844-1829), who suggested that the use or non-use of traits can cause changes that are passed on to the next generation.
In the 1930s and 1940s, ideas from different areas, including genetics, natural selection and particulate inheritance, were brought together to create a modern evolutionary theory. This defines how evolution is triggered by the variations in genes within a population and how these variants change with time due to natural selection. This model, which is known as genetic drift, mutation, gene flow, and sexual selection, is a cornerstone of modern evolutionary biology and can be mathematically explained.
Recent developments in evolutionary developmental biology have revealed the ways in which variation can be introduced to a species by mutations, genetic drift and reshuffling of genes during sexual reproduction and migration between populations. These processes, as well as others like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time) can lead to evolution which is defined by change in the genome of the species over time, and the change in phenotype as time passes (the expression of the genotype within the individual).
Students can better understand the concept of phylogeny through incorporating evolutionary thinking into all areas of biology. In a recent study conducted by Grunspan and colleagues., it was shown that teaching students about the evidence for evolution increased their acceptance of evolution during the course of a college biology. To learn 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
Traditionally scientists have studied evolution through studying fossils, comparing species and studying living organisms. But evolution isn't a thing that happened in the past; it's an ongoing process, happening right now. The virus reinvents itself to avoid new medications and bacteria mutate to resist antibiotics. Animals alter their behavior because of the changing environment. The results are usually easy to see.
But it wasn't until the late 1980s that biologists understood that natural selection can be observed in action as well. The reason is that different traits have different rates of survival and reproduction (differential fitness) and are transferred from one generation to the next.
In the past when one particular allele - the genetic sequence that controls coloration - was present in a group of interbreeding organisms, it might quickly become more common than the other alleles. Over time, that would 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.
Observing evolutionary change in action is much easier when a species has a rapid turnover of its generation like bacteria. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that are descended from a single strain. The samples of each population have been collected regularly, and more than 50,000 generations of E.coli have been observed to have passed.
Lenski's research has demonstrated that mutations can alter the rate of change and the efficiency at which a population reproduces. It also shows that evolution takes time, a fact that is hard for some to accept.
Microevolution is also evident in the fact that mosquito genes for pesticide resistance are more common in populations that have used insecticides. This is because pesticides cause a selective pressure which favors those with resistant genotypes.
The rapidity of evolution has led to an increasing recognition of its importance particularly in a world which is largely shaped by human activities. This includes climate change, pollution, and habitat loss, which prevents many species from adapting. Understanding evolution can help us make smarter choices about the future of our planet, and the life of its inhabitants.