The Academy's Evolution Site

The concept of biological evolution is among the most central concepts in biology. The Academies are committed to helping those who are interested in science to learn about the theory of evolution and how it is permeated throughout all fields of scientific research.

This site provides a wide range of tools for students, teachers, and general readers on 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 is an emblem of love and unity in many cultures. It also has important practical applications, like providing a framework to understand the history of species and how they respond to changes in the environment.

The earliest attempts to depict the world of biology focused on separating species into distinct categories that were identified by their physical and metabolic characteristics1. These methods, which rely on the collection of various parts of organisms or 에볼루션 블랙잭 DNA fragments have greatly increased the diversity of a tree of Life2. The trees are mostly composed by eukaryotes, and the diversity of bacterial species is greatly underrepresented3,4.

Genetic techniques have significantly expanded our ability to represent the Tree of Life by circumventing the need for direct observation and experimentation. We can create trees using molecular techniques, such as the small-subunit ribosomal gene.

The Tree of Life has been greatly expanded thanks to genome sequencing. However there is still a lot of biodiversity to be discovered. This is particularly true of microorganisms, 무료 에볼루션 which can be difficult to cultivate and are often only found in a single 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 which are not well understood.

This 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 utilized in a variety of ways, from identifying new remedies to fight diseases to enhancing the quality of crops. This information is also beneficial to conservation efforts. It can aid biologists in identifying those areas that are most likely contain cryptic species with potentially significant metabolic functions that could be at risk from anthropogenic change. While funds to protect biodiversity are important, the best method to protect the biodiversity of the world is to equip more people in developing countries with the information they require to take action locally and encourage conservation.

Phylogeny

A phylogeny (also known as an evolutionary tree) illustrates the relationship between species. Scientists can build a phylogenetic diagram that illustrates the evolutionary relationship of taxonomic categories using molenction. In the end, it's the preservation of phylogenetic diversity which will lead to an ecosystem that is complete and balanced.

Evolutionary Theory

The fundamental concept in evolution is that organisms change over time due to their interactions with their environment. Several theories of evolutionary change have been developed by a variety of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who believed that an organism would evolve gradually according to its requirements and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits causes changes that could be passed on to the offspring.

In the 1930s and 에볼루션 게이밍 1940s, ideas 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 occurs through the variations of genes within a population, and how those variants change in time as a result of natural selection. This model, which incorporates mutations, genetic drift, gene flow and sexual selection, can be mathematically described mathematically.

Recent discoveries in evolutionary developmental biology have shown the ways in which variation can be introduced to a species via genetic drift, mutations, reshuffling 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 a genotype over time), can lead to evolution, which is defined by change in the genome of the species over time and also the change in phenotype over time (the expression of that genotype in the individual).

Students can gain a better understanding of the concept of phylogeny by using evolutionary thinking throughout all aspects of biology. In a study by Grunspan and co., it was shown that teaching students about the evidence for evolution increased their acceptance of evolution during the course of a college biology. For more information on how to teach about evolution, see The Evolutionary Potential 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, 에볼루션 사이트 and comparing species. They also observe living organisms. Evolution is not a distant moment; it is a process that continues today. Bacteria mutate and resist antibiotics, viruses reinvent themselves and escape new drugs and animals change their behavior to the changing climate. The changes that result are often visible.

It wasn't until late 1980s that biologists began to realize that natural selection was also 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 allele - the genetic sequence that determines colour - appeared in a population of organisms that interbred, 에볼루션 게이밍 it could become more prevalent than any other allele. Over time, that would mean the number of black moths within the 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 generation turnover like bacteria. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that descend from one strain. The samples of each population were taken regularly, and more than 500.000 generations of E.coli have passed.

Lenski's research has revealed that a mutation can profoundly alter the rate at which a population reproduces and, consequently, the rate at which it alters. It also proves that evolution is slow-moving, a fact that some are unable to accept.

Microevolution can also be seen in the fact that mosquito genes for pesticide resistance are more prevalent in populations where insecticides are used. This is due to pesticides causing an enticement that favors those with resistant genotypes.

The rapidity of evolution has led to a greater awareness of its significance especially in a planet which is largely shaped by human activities. This includes pollution, climate change, and habitat loss that hinders many species from adapting. Understanding the evolution process will help us make better decisions regarding the future of our planet, and the life of its inhabitants.