The Academy's Evolution Site
The concept of biological evolution is among the most fundamental concepts in biology. The Academies are involved in helping those who are interested in the sciences understand evolution theory and how it can be applied across all areas of scientific research.
This site provides students, teachers and general readers with a variety of educational resources on evolution. It includes key video clips from NOVA and WGBH-produced science programs on DVD.
Tree of Life
The Tree of Life is an ancient symbol that symbolizes the interconnectedness of life. It is a symbol of love and unity in many cultures. It has numerous practical applications as well, including providing a framework to understand the history of species and how they react to changing environmental conditions.
The earliest attempts to depict the biological world focused on the classification of species into distinct categories that were distinguished by their physical and metabolic characteristics1. These methods, which relied on the sampling of different parts of living organisms or sequences of short DNA fragments, greatly increased the variety of organisms that could be represented in the tree of life2. These trees are largely composed of eukaryotes, while bacteria are largely underrepresented3,4.
By avoiding the necessity for direct experimentation and observation, genetic techniques have allowed us to depict the Tree of Life in a much more accurate way. Particularly, molecular methods allow us to construct trees using sequenced markers like the small subunit ribosomal RNA gene.
Despite the rapid growth of the Tree of Life through genome sequencing, a lot of biodiversity remains to be discovered. This is especially true for microorganisms that are difficult to cultivate and are usually found in one sample5. A recent analysis of all known genomes has produced a rough draft version of the Tree of Life, including many bacteria and archaea that have not been isolated and their diversity is not fully understood6.
This expanded Tree of Life can be used to assess the biodiversity of a specific area and determine if specific habitats require special protection. This information can be utilized in many ways, including finding new drugs, fighting diseases and improving the quality of crops. The information is also beneficial to conservation efforts. It can aid biologists in identifying areas most likely to have cryptic species, which may perform important metabolic functions and are susceptible to changes caused by humans. While funding to protect biodiversity are essential, the best way to conserve the biodiversity of the world is to equip the people of developing nations with the information they require to act locally and promote conservation.
Phylogeny
A phylogeny (also called an evolutionary tree) shows the relationships between species. Using molecular data as well as morphological similarities and distinctions or ontogeny (the course of development of an organism), scientists can build a phylogenetic tree which illustrates the evolutionary relationship between taxonomic groups. The role of phylogeny is crucial in understanding biodiversity, genetics and evolution.
A basic phylogenetic Tree (see Figure PageIndex 10 Determines the relationship between organisms with similar characteristics and have evolved from a common ancestor. These shared traits can be analogous or homologous. Homologous traits are the same in terms of their evolutionary path. Analogous traits may look similar, but they do not have the same ancestry. Scientists group similar traits together into a grouping called a clade. For instance, all of the organisms that make up a clade share the characteristic of having amniotic eggs. They evolved from a common ancestor which had eggs. The clades then join to form a phylogenetic branch that can determine which organisms have the closest relationship.
Scientists use DNA or RNA molecular data to construct a phylogenetic graph which is more precise and precise. This information is more precise and gives evidence of the evolutionary history of an organism. The use of molecular data lets researchers determine the number of species who share an ancestor common to them and estimate their evolutionary age.
The phylogenetic relationship can be affected by a number of factors that include phenotypicplasticity. This is a kind of behavior that changes due to unique environmental conditions. This can cause a characteristic to appear more similar in one species than another, obscuring the phylogenetic signal. This problem can be mitigated by using cladistics, which incorporates an amalgamation of homologous and analogous features in the tree.
Additionally, phylogenetics can help determine the duration and rate of speciation. This information can aid conservation biologists in making choices about which species to safeguard from disappearance. In the end, it is the preservation of phylogenetic diversity which will create an ecosystem that is complete and balanced.
Evolutionary Theory
The central theme of evolution is that organisms acquire different features over time due to their interactions with their surroundings. A variety of theories about evolution have been proposed by a wide variety of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop slowly according to its needs and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits can cause changes that could be passed on to the offspring.
In the 1930s and 1940s, theories from various fields, such as natural selection, genetics & particulate inheritance, were brought together to create a modern theorizing of evolution. 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, which is known as genetic drift mutation, gene flow and sexual selection, is the foundation of the current evolutionary biology and is mathematically described.
Recent discoveries in the field of evolutionary developmental biology have revealed that genetic variation can be introduced into a species through mutation, genetic drift, and reshuffling of genes in sexual reproduction, and also through migration between populations. These processes, along with others such as directional selection or genetic erosion (changes in the frequency of a genotype over time) can result in evolution that is defined as change in the genome of the species over time, and also the change in phenotype over time (the expression of the genotype in an individual).
Students can gain a better understanding of the concept of phylogeny through incorporating evolutionary thinking throughout all aspects of biology. A recent study conducted by Grunspan and colleagues, for instance demonstrated that teaching about the evidence supporting evolution increased students' understanding of evolution in a college biology course. For mouse click the up coming internet site about how to teach evolution read The Evolutionary Power of Biology in all Areas of Biology or Thinking Evolutionarily: a Framework for Integrating Evolution into Life Sciences Education.
Evolution in Action
Scientists have traditionally looked at evolution through the past--analyzing fossils and comparing species. They also observe living organisms. However, evolution isn't something that happened in the past; it's an ongoing process that is happening right now. Bacteria transform and resist antibiotics, viruses re-invent themselves and escape new drugs and animals change their behavior to the changing climate. The changes that result are often visible.
However, it wasn't until late-1980s that biologists realized that natural selection can be observed in action as well. The main reason is that different traits can confer a different rate of survival as well as reproduction, and may be passed down from one generation to another.
In the past, if a certain allele - the genetic sequence that determines colour appeared in a population of organisms that interbred, it might become more prevalent than any other allele. Over time, that would 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.
mouse click the up coming internet site in action is much easier when a species has a rapid generation turnover like bacteria. Since 1988 biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain. samples of each are taken every day and over 50,000 generations have now passed.
Lenski's work has demonstrated that a mutation can dramatically alter the efficiency with the rate at which a population reproduces, and consequently, the rate at which it evolves. It also demonstrates that evolution takes time, something that is hard for some to accept.
Another example of microevolution is that mosquito genes that are resistant to pesticides show up more often in populations where insecticides are used. This is due to the fact that the use of pesticides creates a pressure that favors individuals with resistant genotypes.
The rapidity of evolution has led to a greater awareness of its significance, especially in a world which is largely shaped by human activities. This includes climate change, pollution, and habitat loss that hinders many species from adapting. Understanding the evolution process can help us make smarter decisions regarding the future of our planet as well as the life of its inhabitants.