The Academy's Evolution Site
The concept of biological evolution is among the most central concepts in biology. The Academies are involved in helping those interested in the sciences learn about the theory of evolution and how it is permeated across all areas of scientific research.
This site offers a variety of sources for teachers, students as well as general readers about evolution. It also includes important video clips from NOVA and WGBH produced science programs on DVD.
Tree of Life
The Tree of Life is an ancient symbol of the interconnectedness of all life. It appears in many spiritual traditions and cultures as a symbol of unity and love. It also has important practical applications, like providing a framework for understanding the history of species and how they respond to changing environmental conditions.
Early approaches to depicting the biological world focused on categorizing species into distinct categories that were distinguished by physical and metabolic characteristics1. These methods rely on the collection of various parts of organisms or fragments of DNA, have significantly increased the diversity of a tree of Life2. However the trees are mostly comprised of eukaryotes, and bacterial diversity remains vastly underrepresented3,4.
Genetic techniques have greatly broadened our ability to represent the Tree of Life by circumventing the need for direct observation and experimentation. Particularly, molecular techniques enable us to create trees by using sequenced markers such as the small subunit of ribosomal RNA gene.
Despite 에볼루션사이트 of the Tree of Life through genome sequencing, much biodiversity still is waiting to be discovered. This is especially true of microorganisms that are difficult to cultivate and are usually only represented in a single sample5. Recent analysis of all genomes produced an initial draft of a Tree of Life. This includes a wide range of bacteria, archaea and other organisms that haven't yet been isolated or the diversity of which is not well understood6.
The expanded Tree of Life can be used to evaluate the biodiversity of a particular area and determine if certain habitats require special protection. This information can be used in a variety of ways, including finding new drugs, fighting diseases and improving the quality of crops. This information is also extremely valuable in conservation efforts. It can aid biologists in identifying those areas that are most likely contain cryptic species with significant metabolic functions that could be vulnerable to anthropogenic change. While funding to protect biodiversity are essential, the best way to conserve the biodiversity of the world is to equip more people in developing countries with the knowledge they need to take action locally and encourage conservation.
Phylogeny
A phylogeny (also called an evolutionary tree) depicts the relationships between species. Utilizing molecular data, morphological similarities and differences or ontogeny (the course of development of an organism) scientists can create an phylogenetic tree that demonstrates the evolutionary relationships between taxonomic categories. Phylogeny plays a crucial role in understanding biodiversity, genetics and evolution.
A basic phylogenetic Tree (see Figure PageIndex 10 Identifies the relationships between organisms that have similar traits 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 don't have the same origins. Scientists organize similar traits into a grouping called a clade. All organisms in a group share a characteristic, for example, amniotic egg production. They all came from an ancestor who had these eggs. A phylogenetic tree can be built by connecting the clades to determine the organisms which are the closest to each other.
Scientists make use of molecular DNA or RNA data to construct a phylogenetic graph that is more accurate and detailed. This information is more precise and provides evidence of the evolution of an organism. Researchers can use Molecular Data to calculate the evolutionary age of organisms and identify how many species have a common ancestor.
The phylogenetic relationship can be affected by a variety of factors, including the phenomenon of phenotypicplasticity. This is a type behaviour that can change as a result of specific environmental conditions. This can cause a trait to appear more like a species another, clouding the phylogenetic signal. However, this issue can be cured by the use of techniques like cladistics, which combine analogous and homologous features into the tree.
In addition, phylogenetics can help predict the time and pace of speciation. This information will assist conservation biologists in making choices about which species to safeguard from the threat of extinction. In the end, it is the conservation of phylogenetic variety that will lead to an ecosystem that is complete and balanced.
Evolutionary Theory
The main idea behind 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 evolve according to its individual requirements, the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern taxonomy system that is hierarchical, as well as Jean-Baptiste Lamarck (1844-1829), who believed that the usage or non-use of traits can lead to 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 form the modern evolutionary theory synthesis that explains how evolution is triggered by the variation of genes within a population, and how those variants change over time as a result of natural selection. This model, which is known as genetic drift mutation, gene flow, and sexual selection, is a key element of current evolutionary biology, and is mathematically described.
Recent discoveries in the field of evolutionary developmental biology have revealed that variations can be introduced into a species via mutation, genetic drift, and reshuffling genes during sexual reproduction, as well as through migration between populations. These processes, as well as other ones like directional selection and genetic erosion (changes in the frequency of the genotype over time) can lead to evolution, which is defined by changes in the genome of the species over time, and also the change in phenotype over time (the expression of the genotype within the individual).
Incorporating evolutionary thinking into all aspects of biology education can improve students' understanding of phylogeny as well as evolution. In a study by Grunspan and colleagues. It was demonstrated that teaching students about the evidence for evolution increased their understanding of evolution in the course of a college biology. To find out more about how to teach about evolution, look up 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
Scientists have looked at evolution through the past, studying fossils, and comparing species. They also observe living organisms. But evolution isn't just something that occurred in the past, it's an ongoing process that is taking place in the present. Viruses evolve to stay away from new antibiotics and bacteria transform to resist antibiotics. Animals alter their behavior because of the changing environment. The changes that result are often visible.
It wasn't until late 1980s that biologists began to realize that natural selection was in play. The reason is that different characteristics result in different rates of survival and reproduction (differential fitness) and are passed from one generation to the next.
In the past, if one particular allele, the genetic sequence that determines coloration--appeared in a group of interbreeding species, it could quickly become more common than the other alleles. Over time, that would 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 the species, like bacteria, has a rapid generation turnover. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that descend from one strain. Samples from each population have been collected regularly, and more than 50,000 generations of E.coli have passed.
visit the next internet site has revealed that mutations can alter the rate at which change occurs and the effectiveness at which a population reproduces. It also proves that evolution is slow-moving, a fact that some are unable to accept.
Microevolution can be observed in the fact that mosquito genes that confer resistance to pesticides are more prevalent in areas where insecticides are used. This is due to the fact that the use of pesticides creates a pressure that favors people who have resistant genotypes.
The rapidity of evolution has led to a growing awareness of its significance, especially in a world which is largely shaped by human activities. This includes climate change, pollution, and habitat loss that prevents many species from adapting. Understanding the evolution process can aid you in making better decisions about the future of our planet and its inhabitants.