The Academy's Evolution Site

Biology is a key concept in biology. The Academies have long been involved in helping those interested in science understand the concept of evolution and how it permeates all areas of scientific exploration.

This site provides teachers, students and general readers with a variety of learning resources about evolution. It has the most important video clips from NOVA and WGBH-produced science programs on DVD.

Tree of Life

The Tree of Life is an ancient symbol that represents the interconnectedness of all life. It is a symbol of love and 에볼루션 바카라 체험 unity in many cultures. It also has practical applications, like providing a framework to understand the evolution of species and 에볼루션 코리아 how they react to changes in environmental conditions.

The earliest attempts to depict the world of biology focused on separating organisms into distinct categories which were identified by their physical and metabolic characteristics1. These methods, based on the sampling of different parts of living organisms or small fragments of their DNA, significantly increased the variety that could be represented in the tree of life2. These trees are mostly populated of eukaryotes, while bacterial diversity is vastly underrepresented3,4.

Genetic techniques have greatly expanded our ability to visualize the Tree of Life by circumventing the need for direct observation and experimentation. Particularly, molecular methods allow us to build trees by using sequenced markers such as the small subunit ribosomal gene.

Despite the massive expansion of the Tree of Life through genome sequencing, a lot of biodiversity awaits discovery. This is especially true of microorganisms, which are difficult to cultivate and are typically only represented in a single sample5. A recent study of all known genomes has produced a rough draft of the Tree of Life, including numerous archaea and bacteria that have not been isolated, and whose diversity is poorly understood6.

The expanded Tree of Life is particularly useful for assessing the biodiversity of an area, helping to determine if certain habitats require protection. This information can be utilized in a variety of ways, including finding new drugs, battling diseases and improving the quality of crops. The information is also valuable in conservation efforts. It can help biologists identify the areas most likely to contain cryptic species with significant metabolic functions that could be vulnerable to anthropogenic change. Although funds to protect biodiversity are essential but the most effective way to protect the world's biodiversity is for more people living in developing countries to be empowered with the knowledge to act locally in order to promote conservation from within.

Phylogeny

A phylogeny is also known as an evolutionary tree, shows the connections between different groups of organisms. Scientists can create an phylogenetic chart which shows the evolutionary relationship of taxonomic groups based on molecular data and morphological similarities or differences. The concept of phylogeny is fundamental to understanding evolution, biodiversity and genetics.

A basic phylogenetic tree (see Figure PageIndex 10 Identifies the relationships between organisms with similar traits and have evolved from a common ancestor. These shared traits may be analogous, or homologous. Homologous traits are similar in their evolutionary origins while analogous traits appear like they do, but don't have the same ancestors. Scientists combine similar traits into a grouping called a clade. For instance, all of the organisms that make up a clade have the characteristic of having amniotic eggs and evolved from a common ancestor that had these eggs. A phylogenetic tree is then constructed by connecting clades to identify the organisms which are the closest to each other.

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 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 living organisms and 에볼루션코리아 discover the number of organisms that have the same ancestor.

Phylogenetic relationships can be affected by a number of factors that include phenotypicplasticity. This is a kind of behavior that changes as a result of unique environmental conditions. This can cause a characteristic to appear more like a species another, 에볼루션바카라사이트 clouding the phylogenetic signal. However, this issue can be solved through the use of techniques such as cladistics which include a mix of homologous and analogous features into the tree.

In addition, phylogenetics helps determine the duration and rate at which speciation occurs. This information can help conservation biologists make decisions about which species they should protect from the threat of extinction. In the end, it's the preservation of phylogenetic diversity that will lead to an ecosystem that is balanced and complete.

Evolutionary Theory

The fundamental concept in evolution is that organisms alter over time because of their interactions with their environment. Several theories of evolutionary change have been proposed by a variety of scientists, including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing slowly in accordance with its needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that the use or misuse of traits cause changes that could be passed on to the offspring.

In the 1930s & 1940s, theories from various fields, including genetics, natural selection, and particulate inheritance, merged to form a modern theorizing of evolution. This explains how evolution occurs by the variation of genes in the population and how these variants alter over time due to 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 can be mathematically described.

Recent discoveries in the field of evolutionary developmental biology have demonstrated that variation can be introduced into a species via mutation, genetic drift and reshuffling genes during sexual reproduction, as well as through the movement of populations. These processes, as well as other ones like directionally-selected selection and erosion of genes (changes to the frequency of genotypes over time), can lead towards evolution. Evolution is defined by changes in the genome over time as well as changes in the phenotype (the expression of genotypes in an individual).

Students can gain a better understanding of the concept of phylogeny by using evolutionary thinking into all areas of biology. A recent study conducted by Grunspan and colleagues, 에볼루션카지노 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 on how to teach about evolution read The Evolutionary Potential in all Areas of Biology or Thinking Evolutionarily A Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Traditionally scientists have studied evolution by studying fossils, comparing species and studying living organisms. But evolution isn't a thing that occurred in the past; it's an ongoing process, that is taking place right now. Bacteria transform and resist antibiotics, viruses evolve and are able to evade new medications and animals change their behavior to the changing environment. The changes that result are often easy to see.

It wasn't until the late 1980s when biologists began to realize that natural selection was in play. The main reason is that different traits result in an individual rate of survival and reproduction, and can be passed on from one generation to the next.

In the past, if a certain allele - the genetic sequence that determines colour was found in a group of organisms that interbred, it could be more common than any other allele. As time passes, this could mean that the number of moths that have black pigmentation in a 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 a species, such as 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. The samples of each population have been collected frequently and more than 500.000 generations of E.coli have passed.

Lenski's work has shown that mutations can alter the rate of change and the rate at which a population reproduces. It also proves that evolution is slow-moving, a fact that many are unable to accept.

Microevolution is also evident in the fact that mosquito genes for resistance to pesticides are more prevalent in populations where insecticides have been used. This is because the use of pesticides causes a selective pressure that favors those with resistant genotypes.

The rapidity of evolution has led to a growing appreciation of its importance especially in a planet shaped largely by human activity. This includes climate change, pollution, and habitat loss, which prevents many species from adapting. Understanding evolution can assist you in making better choices about the future of our planet and its inhabitants.