The Academy's Evolution Site
The concept of biological evolution is among the most central concepts in biology. The Academies have been active for a long time in helping those interested in science understand the concept of evolution and how it influences every area of scientific inquiry.
This site provides a wide range of tools for students, teachers, and general readers on evolution. It includes key 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 all life. It is used in many cultures and spiritual beliefs as an emblem of unity and love. It can be used in many practical ways as well, such as providing a framework for understanding the history of species, and how they react to changing environmental conditions.
The earliest attempts to depict the biological world focused on categorizing species into distinct categories that had been distinguished by physical and metabolic characteristics1. These methods are based on the collection of various parts of organisms or DNA fragments, have greatly increased the diversity of a tree of Life2. However these trees are mainly made up of eukaryotes. Bacterial diversity is not represented in a large way3,4.
Genetic techniques have greatly broadened our ability to represent the Tree of Life by circumventing the requirement for direct observation and experimentation. In particular, molecular methods enable us to create trees using sequenced markers like the small subunit ribosomal RNA gene.
에볼루션카지노 of Life has been dramatically expanded through genome sequencing. However there is a lot of biodiversity to be discovered. This is particularly true of microorganisms that are difficult to cultivate and are usually only represented in a single specimen5. A recent study of all genomes known to date has produced a rough draft of the Tree of Life, including many archaea and bacteria that are not isolated and whose diversity is poorly understood6.
The expanded Tree of Life can be used to determine the diversity of a specific region and determine if certain habitats need special protection. This information can be used in a variety of ways, such as finding new drugs, fighting diseases and enhancing crops. This information is also extremely beneficial for conservation efforts. It can aid biologists in identifying areas that are most likely to be home to species that are cryptic, which could perform important metabolic functions and be vulnerable to changes caused by humans. While funding to protect biodiversity are important, the best method to preserve the world's biodiversity is to empower more people in developing countries with the knowledge they need to act locally and support conservation.
Phylogeny
A phylogeny (also known as an evolutionary tree) illustrates the relationship between organisms. Utilizing molecular data, morphological similarities and differences or ontogeny (the process of the development of an organism) scientists can create a phylogenetic tree that 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 Identifies the relationships between organisms that have similar characteristics and have evolved from an ancestor that shared traits. These shared traits can be homologous, or analogous. Homologous characteristics are identical in terms of their evolutionary paths. Analogous traits might appear like they are but they don't share the same origins. visit put similar traits into a grouping referred to as a Clade. All members of a clade share a trait, such as amniotic egg production. They all came from an ancestor with these eggs. The clades are then connected to create a phylogenetic tree to determine which organisms have the closest connection to each other.
Scientists utilize DNA or RNA molecular information to build a phylogenetic chart which is more precise and precise. This information is more precise than morphological information and provides evidence of the evolutionary history of an organism or group. The analysis of molecular data can help researchers determine the number of organisms that have an ancestor common to them and estimate their evolutionary age.
The phylogenetic relationship can be affected by a number of factors that include the phenotypic plasticity. This is a type of behavior that alters due to particular environmental conditions. This can make a trait appear more similar to a species than to the other which can obscure the phylogenetic signal. However, 에볼루션게이밍 can be solved through the use of methods such as cladistics that include a mix of analogous and homologous features into the tree.
Additionally, phylogenetics can help predict the length and speed of speciation. This information can help conservation biologists make decisions about the species they should safeguard from the threat of extinction. In the end, it's the preservation of phylogenetic diversity that will result in an ecosystem that is complete and balanced.
Evolutionary Theory
The central theme in evolution is that organisms change over time due to 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 a living thing would develop according to its own needs as well as the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern taxonomy system that is hierarchical and Jean-Baptiste Lamarck (1844-1829), who suggested that the usage or non-use of traits can lead to changes that are passed on to the
In the 1930s & 1940s, concepts from various fields, such as genetics, natural selection, and particulate inheritance, were brought together to create a modern theorizing of evolution. This defines how evolution happens through the variation in genes within a population and how these variations change over time as a result of natural selection. This model, which includes genetic drift, mutations, gene flow and sexual selection, can be mathematically described.
Recent advances in the field of evolutionary developmental biology have shown the ways in which variation can be introduced to a species through genetic drift, mutations or reshuffling of genes in sexual reproduction and the movement between populations. These processes, along with others like directional selection and genetic erosion (changes in the frequency of the genotype over time), can lead to evolution that is defined as change in the genome of the species over time and the change in phenotype as time passes (the expression of that genotype in an individual).
Incorporating evolutionary thinking into all areas of biology education can improve student understanding of the concepts of phylogeny as well as evolution. A recent study conducted 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-level biology class. For more information about how to teach evolution read The Evolutionary Potency in All Areas of Biology or Thinking Evolutionarily as a Framework for Integrating Evolution into Life Sciences Education.
Evolution in Action
Scientists have traditionally looked at evolution through the past, studying fossils, and comparing species. They also study living organisms. Evolution isn't a flims moment; it is an ongoing process that continues to be observed today. Bacteria transform and resist antibiotics, viruses reinvent themselves and elude new medications and animals change their behavior to the changing climate. The results are usually visible.
It wasn't until late-1980s that biologists realized that natural selection can be observed in action as well. The key is the fact that different traits can confer a different rate of survival as well as reproduction, and may be passed down from one generation to the next.
In the past when one particular allele, the genetic sequence that defines color in a population of interbreeding organisms, it could rapidly become more common than all other alleles. Over time, this would mean that the number of moths that have black pigmentation in a population may increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.
The ability to observe evolutionary change is much easier when a species has a rapid turnover of its generation, as with bacteria. Since 1988 biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain; samples of each population are taken every day and more than 500.000 generations have passed.
Lenski's research has shown that a mutation can dramatically alter the rate at which a population reproduces--and so, the rate at which it evolves. It also shows evolution takes time, a fact that is difficult for some to accept.
Microevolution is also evident in the fact that mosquito genes for resistance to pesticides are more prevalent in populations that have used insecticides. This is due to the fact that the use of pesticides causes a selective pressure that favors people with resistant genotypes.
The speed at which evolution takes place has led to an increasing appreciation of its importance in a world that is shaped by human activity, including climate change, pollution and the loss of habitats that hinder many species from adjusting. Understanding the evolution process can help us make better decisions about the future of our planet, and the life of its inhabitants.