The Academy's Evolution Site
The concept of biological evolution is a fundamental concept in biology. The Academies are involved in helping those interested in science to understand evolution theory and how it is incorporated throughout all fields of scientific research.
This site provides students, teachers and general readers with a variety of learning resources about evolution. It includes key 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 appears in many spiritual traditions and cultures as symbolizing unity and love. It also has many practical applications, like providing a framework to understand the evolution of species and how they respond to changes in environmental conditions.
The first attempts at depicting the biological world focused on categorizing organisms into distinct categories which were identified by their physical and metabolic characteristics1. These methods are based on the sampling of different parts of organisms or short DNA fragments, have significantly increased the diversity of a tree of Life2. These trees are mostly populated by eukaryotes, and bacteria are largely underrepresented3,4.
Genetic techniques have greatly broadened our ability to visualize the Tree of Life by circumventing the requirement for direct observation and experimentation. We can create trees using molecular techniques like the small-subunit ribosomal gene.
The Tree of Life has been greatly expanded thanks to genome sequencing. However there is still a lot of diversity to be discovered. This is especially the case for microorganisms which are difficult to cultivate, and are usually found in a single specimen5. A recent analysis of all genomes resulted in an unfinished draft of a Tree of Life. This includes a wide range of bacteria, archaea and other organisms that haven't yet been identified or the diversity of which 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. 에볼루션카지노 can be utilized in a variety of ways, including finding new drugs, fighting diseases and enhancing crops. This information is also extremely valuable to conservation efforts. It can help biologists identify the areas most likely to contain cryptic species with important metabolic functions that could be at risk of anthropogenic changes. Although funds to protect biodiversity are essential however, the most effective method to ensure the preservation of biodiversity around the world is for more people living in developing countries to be empowered with the necessary knowledge to take action locally to encourage conservation from within.
Phylogeny
A phylogeny is also known as an evolutionary tree, illustrates the relationships between various groups of organisms. Scientists can build a phylogenetic chart that shows the evolution of taxonomic groups based on molecular data and morphological similarities or differences. The role of phylogeny is crucial in understanding genetics, biodiversity and evolution.
A basic phylogenetic tree (see Figure PageIndex 10 Determines the relationship between organisms with similar traits and evolved from an ancestor that shared traits. These shared traits can be analogous, or homologous. Homologous traits are similar in their evolutionary path. Analogous traits may look like they are however they do not have the same ancestry. Scientists put similar traits into a grouping referred to as a Clade. For instance, all of the species in a clade share the characteristic of having amniotic egg and evolved from a common ancestor which had these eggs. A phylogenetic tree can be built by connecting the clades to identify the species which are the closest to each other.
Scientists use molecular DNA or RNA data to create a phylogenetic chart which is more precise and precise. This information is more precise and provides evidence of the evolution of an organism. The analysis of molecular data can help researchers determine the number of species who share a common ancestor and to estimate their evolutionary age.
The phylogenetic relationship can be affected by a variety of factors that include the phenomenon of phenotypicplasticity. This is a kind of behavior that changes in response to specific environmental conditions. This can cause a particular trait to appear more similar in one species than another, obscuring the phylogenetic signal. However, this problem can be cured by the use of techniques such as cladistics that incorporate a combination of similar and homologous traits into the tree.
In addition, phylogenetics helps determine the duration and speed at which speciation takes place. This information can assist conservation biologists in making choices about which species to save from extinction. It is ultimately the preservation of phylogenetic diversity which will lead to an ecosystem that is complete and balanced.
Evolutionary Theory
The fundamental concept of evolution is that organisms develop distinct characteristics over time due to their interactions with their environments. Many scientists have proposed 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 individual needs, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1844-1829), who believed that the use or non-use of certain traits can result in changes that are passed on to the next generation.
In the 1930s and 1940s, concepts from a variety of fields -- including genetics, natural selection, and particulate inheritance -- came together to create the modern evolutionary theory synthesis which explains how evolution is triggered by the variation of genes within a population, and how those variants change in time due to natural selection. This model, which includes genetic drift, mutations as well as gene flow and sexual selection, can be mathematically described.
Recent discoveries in the field of evolutionary developmental biology have demonstrated the ways in which variation can be introduced to a species through mutations, genetic drift and reshuffling of genes during sexual reproduction and migration between populations. These processes, along with others such as directionally-selected selection and erosion of genes (changes in frequency of genotypes over time) can lead to evolution. Evolution is defined as changes in the genome over time, as well as changes in phenotype (the expression of genotypes in individuals).
Students can gain a better understanding of phylogeny by incorporating evolutionary thinking in all areas of biology. A recent study by Grunspan and colleagues, for instance, showed that teaching about the evidence supporting evolution increased students' understanding of evolution in a college-level biology course. To learn more about how to teach about evolution, see The Evolutionary Potential in all Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution in Life Sciences Education.
Evolution in Action
Traditionally scientists have studied evolution through studying fossils, comparing species and studying living organisms. Evolution is not a distant event, but a process that continues today. Viruses evolve to stay away from new drugs and bacteria evolve to resist antibiotics. Animals alter their behavior as a result of a changing world. The changes that result are often easy to see.
It wasn't until late 1980s when biologists began to realize that natural selection was also at work. The reason is that different traits confer different rates of survival and reproduction (differential fitness) and are passed 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 prevalent than other alleles. As time passes, that could mean the number of black moths in 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 observe evolution when an organism, like 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 500.000 generations 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 demonstrates that evolution is slow-moving, a fact that many find hard to accept.
Another example of microevolution is that mosquito genes that confer resistance to pesticides appear more frequently in populations in which insecticides are utilized. That's because the use of pesticides creates a selective pressure that favors individuals with resistant genotypes.
click through the up coming website page of evolution has led to a greater recognition of its importance particularly in a world that is largely shaped by human activity. This includes pollution, climate change, and habitat loss that hinders many species from adapting. Understanding the evolution process can assist you in making better choices about the future of the planet and its inhabitants.