14 Common Misconceptions About Evolution Site

The Academy's Evolution Site

The concept of biological evolution is among the most important concepts in biology. The Academies are committed to helping those who are interested in science learn about the theory of evolution and how it is incorporated across all areas of scientific research.

This site provides a range of sources for students, teachers as well as general readers about evolution. It contains 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 an emblem of love and unity across many cultures. 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 changes in environmental conditions.

The earliest attempts to depict the biological world focused on separating organisms into distinct categories that were identified by their physical and metabolic characteristics1. These methods depend on the sampling of different parts of organisms or fragments of DNA, have greatly increased the diversity of a Tree of Life2. The trees are mostly composed by eukaryotes, and bacteria are largely underrepresented3,4.

Genetic techniques have greatly broadened our ability to represent the Tree of Life by circumventing the requirement for direct observation and experimentation. Particularly, molecular techniques enable us to create trees using sequenced markers, such as the small subunit ribosomal gene.

The Tree of Life has been dramatically expanded through genome sequencing. However there is a lot of biodiversity to be discovered. This is particularly relevant to microorganisms that are difficult to cultivate, and are typically found in one sample5. Recent analysis of all genomes has produced an initial draft of the Tree of Life. This includes a variety of bacteria, archaea and other organisms that have not yet been identified or the diversity of which is not thoroughly understood6.

This expanded Tree of Life can be used to assess the biodiversity of a particular area and determine if certain habitats need special protection. This information can be used in a variety of ways, including identifying new drugs, combating diseases and improving the quality of crops. The information is also beneficial in conservation efforts. It helps biologists determine the areas most likely to contain cryptic species with important metabolic functions that could be vulnerable to anthropogenic change. While funds to protect biodiversity are essential, the best method to protect the world's biodiversity is to equip more people in developing nations with the necessary knowledge to act locally and support conservation.

Phylogeny

A phylogeny (also called an evolutionary tree) illustrates the relationship between species. Scientists can construct an phylogenetic chart which shows the evolutionary relationships between taxonomic categories using molecular information and morphological differences or similarities. The concept of phylogeny is fundamental to understanding the evolution of biodiversity, evolution and genetics.

A basic phylogenetic tree (see Figure PageIndex 10 ) identifies the relationships between organisms with similar traits that evolved from common ancestors. These shared traits can be either analogous or homologous. Homologous traits are similar in their evolutionary roots while analogous traits appear similar, but do not share the identical origins. Scientists combine similar traits into a grouping called a the clade. All members of a clade share a characteristic, like amniotic egg production. They all evolved from an ancestor that had these eggs. The clades are then linked to form a phylogenetic branch to identify organisms that have the closest relationship.

To create a more thorough and precise phylogenetic tree scientists rely on molecular information from DNA or RNA to determine the relationships among organisms. This data is more precise than morphological information and gives evidence of the evolutionary background 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 relationships between species can be influenced by several factors including phenotypic plasticity, a kind of behavior that changes in response to unique environmental conditions. This can cause a characteristic to appear more similar in one species than other species, which can obscure the phylogenetic signal. This problem can be addressed by using cladistics, which is a an amalgamation of homologous and analogous features in the tree.

Furthermore, phylogenetics may help predict the length and speed of speciation. This information will assist conservation biologists in making choices about which species to protect from the threat of extinction. In the end, it's the preservation of phylogenetic diversity that will create an ecologically balanced and complete ecosystem.

Evolutionary Theory

The fundamental concept of evolution is that organisms acquire distinct characteristics over time based on their interactions with their surroundings. Many theories of evolution have been proposed by a wide range of scientists, 에볼루션 바카라 무료 including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop slowly according to its requirements, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that the use or non-use of traits can cause changes that could be passed on to offspring.

In the 1930s and 1940s, theories from a variety of fields--including genetics, natural selection and particulate inheritance--came together to form the modern evolutionary theory synthesis, 에볼루션 바카라 무료체험 which defines how evolution is triggered by the variation of genes within a population and 에볼루션 게이밍 how those variations change over time due to natural selection. This model, which encompasses genetic drift, mutations, gene flow and sexual selection can be mathematically described.

Recent discoveries in the field of evolutionary developmental biology have demonstrated that variations can be introduced into a species by mutation, 에볼루션 바카라 genetic drift, and reshuffling of genes during sexual reproduction, as well as by migration between populations. These processes, along with others such as directional selection and gene erosion (changes in the frequency of genotypes over time), can lead towards evolution. Evolution is defined as changes in the genome over time, as well as changes in the phenotype (the expression of genotypes in an individual).

Incorporating evolutionary thinking into all aspects of biology education could increase student understanding of the concepts of phylogeny and evolutionary. In a recent study by Grunspan and colleagues. It was found that teaching students about the evidence for evolution boosted their understanding of evolution in the course of a college biology. For more information on how to teach about evolution, see The Evolutionary Power of Biology 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, analyzing fossils and comparing species. They also study living organisms. But evolution isn't just something that happened in the past; it's an ongoing process, taking place today. Bacteria transform and resist antibiotics, viruses reinvent themselves and are able to evade new medications, and animals adapt their behavior in response to the changing climate. The results are often apparent.

It wasn't until the late 1980s that biologists began to realize that natural selection was at work. The key is that various traits confer different rates of survival and reproduction (differential fitness) and are passed down from one generation to the next.

In the past, 에볼루션사이트 if one particular allele--the genetic sequence that determines coloration--appeared in a group of interbreeding organisms, it might quickly become more common than all other alleles. As time passes, that could mean that the number of black moths within a particular population could rise. 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 easier when a species has a rapid generation turnover like bacteria. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. Coli that descended from a single strain; samples from each population are taken regularly and 에볼루션 바카라사이트 more than 50,000 generations have now passed.

Lenski's research has revealed that mutations can alter the rate of change and the effectiveness of a population's reproduction. It also shows that evolution takes time, something that is hard for some to accept.

Another example of microevolution is the way mosquito genes that confer resistance to pesticides show up more often in populations where insecticides are employed. This is because pesticides cause an enticement that favors those with resistant genotypes.

The rapid pace at which evolution can take place has led to an increasing appreciation of its importance in a world shaped by human activity--including climate change, pollution, and the loss of habitats which prevent the species from adapting. Understanding the evolution process will help us make better decisions about the future of our planet as well as the life of its inhabitants.