So You ve Purchased Evolution Site ... Now What

The Academy's Evolution Site

Biological evolution is a central concept in biology. The Academies are committed to helping those interested in science understand evolution theory and how it can be applied throughout all fields of scientific research.

This site provides teachers, students and general readers with a range of learning resources 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 a symbol of love and harmony in a variety of cultures. It also has many practical uses, like providing a framework for understanding the history of species and how they react to changing environmental conditions.

Early attempts to describe the world of biology were based on categorizing organisms based on their metabolic and physical characteristics. These methods, based on the sampling of different parts of living organisms or sequences of small fragments of their DNA significantly expanded the diversity that could be represented in the tree of life2. However these trees are mainly comprised of eukaryotes, and bacterial diversity is still largely unrepresented3,4.

In avoiding the necessity of direct observation and experimentation genetic techniques have allowed us to represent the Tree of Life in a more precise way. Trees can be constructed by using molecular methods, such as the small-subunit ribosomal gene.

Despite the massive growth of the Tree of Life through genome sequencing, a large amount of biodiversity awaits discovery. This is especially true for microorganisms that are difficult to cultivate, and which are usually only found in a single specimen5. A recent study of all known genomes has produced a rough draft of the Tree of Life, 에볼루션 사이트 including a large number of bacteria and archaea that have not been isolated and which are not well understood.

This expanded Tree of Life can be used to assess the biodiversity of a particular area and determine if specific habitats need special protection. The information is useful in a variety of ways, such as finding new drugs, fighting diseases and improving the quality of crops. The information is also incredibly useful in conservation efforts. It can help biologists identify areas that are most likely to have cryptic species, which could perform important metabolic functions, and 무료에볼루션 could be susceptible to changes caused by humans. While funds to protect biodiversity are essential, the best method to protect 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 is also known as an evolutionary tree, reveals the relationships between various groups of organisms. Scientists can create a phylogenetic chart that shows the evolution of taxonomic groups based on molecular data and morphological differences or similarities. Phylogeny plays a crucial role in understanding biodiversity, genetics and 무료 에볼루션 evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 Finds the connections between organisms that have similar traits and have evolved from an ancestor that shared traits. These shared traits are either analogous or homologous. Homologous traits are identical in their evolutionary origins while analogous traits appear like they do, but don't have the identical origins. Scientists organize similar traits into a grouping known as a the clade. Every organism in a group have a common trait, such as amniotic egg production. They all derived from an ancestor who had these eggs. A phylogenetic tree is then built by connecting the clades to identify the organisms who are the closest to one another.

To create a more thorough and precise phylogenetic tree scientists make use of molecular data from DNA or RNA to identify the connections between organisms. This information is more precise and gives evidence of the evolutionary history of an organism. Researchers can use Molecular Data to calculate the evolutionary age of organisms and identify the number of organisms that have a common ancestor.

The phylogenetic relationships of a species can be affected by a number of factors, including the phenotypic plasticity. This is a type behavior that alters in response to particular environmental conditions. This can cause a characteristic to appear more similar to one species than another, clouding the phylogenetic signal. This problem can be addressed by using cladistics, which is a the combination of homologous and analogous traits in the tree.

Additionally, phylogenetics can help predict the duration and rate at which speciation occurs. This information will assist conservation biologists in making decisions about which species to safeguard from disappearance. It is ultimately the preservation of phylogenetic diversity which will result in a complete and balanced ecosystem.

Evolutionary Theory

The main idea behind evolution is that organisms alter over time because of their interactions with their environment. A variety of theories about evolution have been developed by a wide range of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing gradually according to its needs, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits can cause changes that can be passed on to the offspring.

In the 1930s and 1940s, ideas from different fields, including natural selection, genetics & particulate inheritance, came together to form a contemporary evolutionary theory. This explains how evolution is triggered by the variation of genes in a population and how these variants change over time as a result of natural selection. This model, which is known as genetic drift mutation, gene flow and sexual selection, 에볼루션 is the foundation of modern evolutionary biology and can be mathematically described.

Recent developments in the field of evolutionary developmental biology have revealed that variations can be introduced into a species by mutation, 에볼루션 게이밍 genetic drift and reshuffling genes during sexual reproduction, as well as through the movement of 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 the change in phenotype as time passes (the expression of that genotype in an individual).

Students can better understand phylogeny by incorporating evolutionary thinking throughout all areas of biology. A recent study by Grunspan and colleagues, for example demonstrated that teaching about the evidence for evolution helped students accept the concept of evolution in a college-level biology class. For more details on 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 studied evolution by looking in the past, analyzing fossils and comparing species. They also observe living organisms. But evolution isn't a thing that happened in the past; it's an ongoing process, taking place today. Viruses reinvent themselves to avoid new drugs and bacteria evolve to resist antibiotics. Animals adapt their behavior as a result of a changing world. The resulting changes are often evident.

It wasn't until late-1980s that biologists realized that natural selection can be seen in action, as well. The key is that various traits confer different rates of survival and reproduction (differential fitness), and can be passed from one generation to the next.

In the past when one particular allele--the genetic sequence that determines coloration--appeared in a population of interbreeding species, it could quickly become more common than other alleles. Over time, this would mean that the number of moths that have black pigmentation in a group may 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 tracked twelve populations of E.coli that are descended from one strain. Samples of each population have been taken frequently and more than 500.000 generations of E.coli have been observed to have passed.

Lenski's work has shown that mutations can alter the rate at which change occurs and 에볼루션 카지노 the effectiveness at which a population reproduces. It also demonstrates that evolution is slow-moving, a fact that many find difficult to accept.

Another example of microevolution is that mosquito genes for resistance to pesticides are more prevalent in areas where insecticides are employed. This is due to pesticides causing an exclusive pressure that favors those with resistant genotypes.

The rapidity of evolution has led to a growing awareness of its significance especially in a planet shaped largely by human activity. This includes the effects of climate change, pollution and habitat loss that prevents many species from adapting. Understanding the evolution process can help us make better decisions about the future of our planet, and the life of its inhabitants.