5 Things That Everyone Doesn't Know About Evolution Site

The Academy's Evolution Site

Biology is one of the most central concepts in biology. The Academies have long been involved in helping those interested in science understand the concept of evolution and how it affects every area of scientific inquiry.

This site offers a variety of sources for teachers, students, and general readers on evolution. It has the most important video clips from NOVA and the 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 across many cultures. It also has important practical uses, like providing a framework to understand the history of species and how they respond to changing environmental conditions.

The first attempts at depicting the biological world focused on categorizing species into distinct categories that had been distinguished by physical and metabolic characteristics1. These methods, based on sampling of different parts of living organisms or on sequences of small fragments of their DNA significantly expanded the diversity that could be included in a tree of life2. However, these trees are largely composed of eukaryotes; bacterial diversity is still largely unrepresented3,4.

Genetic techniques have significantly expanded our ability to depict the Tree of Life by circumventing the requirement for direct observation and experimentation. Trees can be constructed using molecular techniques 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 particularly true of microorganisms, which are difficult to cultivate and are often only found in a single specimen5. A recent analysis of all genomes resulted in a rough draft of the Tree of Life. This includes a wide range of bacteria, archaea and other organisms that have not yet been isolated, or their diversity is not well understood6.

This expanded Tree of Life can be used to determine the diversity of a specific region and determine if particular habitats require special protection. This information can be utilized in a range of ways, from identifying new medicines to combating disease to improving the quality of crops. This information is also extremely useful in conservation efforts. It helps biologists discover areas most likely to be home to cryptic species, which could have vital metabolic functions, and could be susceptible to the effects of human activity. While funding to protect biodiversity are essential, the best way to conserve the world's biodiversity is to equip the people of developing nations with the knowledge they need to act locally and promote conservation.

Phylogeny

A phylogeny, also known as an evolutionary tree, shows the relationships between groups of organisms. Scientists can build a phylogenetic diagram that illustrates the evolutionary relationships between taxonomic groups based on molecular data and morphological similarities or differences. The concept of phylogeny is fundamental to understanding biodiversity, evolution and genetics.

A basic phylogenetic tree (see Figure PageIndex 10 ) determines the relationship between organisms with similar traits that evolved from common ancestors. These shared traits could be analogous, or homologous. Homologous traits are identical in their evolutionary roots, while analogous traits look like they do, but don't have the identical origins. Scientists put similar traits into a grouping referred to as a clade. All organisms in a group have a common trait, such as amniotic egg production. They all derived from an ancestor that had these eggs.  hop over to here  join to create a phylogenetic tree to determine which organisms have the closest relationship to.

Scientists use DNA or RNA molecular information to build a phylogenetic chart that is more precise and detailed. This information is more precise and gives evidence of the evolutionary history of an organism. Researchers can use Molecular Data to estimate the age of evolution of living organisms and discover how many organisms share a common ancestor.

The phylogenetic relationship can be affected by a variety of factors such as the phenomenon of phenotypicplasticity. This is a type of behaviour that can change as a result of specific environmental conditions.  hop over to here  can cause a trait to appear more similar to one species than another, obscuring the phylogenetic signal. However, this problem can be solved through the use of techniques such as cladistics that include a mix of homologous and analogous features into the tree.

In addition, phylogenetics helps determine the duration and speed at which speciation occurs. 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 conservation of phylogenetic diversity that will lead to an ecosystem that is balanced and complete.

Evolutionary Theory

The fundamental concept of evolution is that organisms acquire distinct characteristics over time as a result of their interactions with their environment. Many scientists have come up with theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism would develop according to its own requirements and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern taxonomy system that is hierarchical and Jean-Baptiste Lamarck (1844-1829), who suggested 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 various fields, including natural selection, genetics, and particulate inheritance -- came together to form the current evolutionary theory, which defines how evolution is triggered by the variation of genes within a population, and how those variations change in time as a result of natural selection. This model, which encompasses genetic drift, mutations in gene flow, and sexual selection is mathematically described.

Recent developments in the field of evolutionary developmental biology have demonstrated the ways in which variation can be introduced to a species through genetic drift, mutations, reshuffling genes during sexual reproduction and the movement between populations. These processes, along with other ones like directional selection and gene erosion (changes in the frequency of genotypes over time) can result in evolution. Evolution is defined as changes in the genome over time and changes in the phenotype (the expression of genotypes in individuals).

Students can gain a better understanding of the concept of phylogeny through incorporating evolutionary thinking into all aspects of biology. In a recent study by Grunspan and colleagues., it was shown that teaching students about the evidence for evolution boosted their understanding of evolution in a college-level course in biology. For more information on how to teach about evolution, look up The Evolutionary Potential of all Areas of Biology and Thinking Evolutionarily: A Framework for Infusing Evolution in Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution by looking back--analyzing fossils, comparing species and observing living organisms. However, evolution isn't something that occurred in the past. It's an ongoing process, taking place today. Bacteria evolve and resist antibiotics, viruses reinvent themselves and elude new medications, and animals adapt their behavior to the changing climate. The changes that result are often visible.

However, it wasn't until late 1980s that biologists realized that natural selection can be observed in action as well. The key is the fact that different traits result in an individual rate of survival and reproduction, and can be passed on from generation to generation.

In the past, if one particular allele--the genetic sequence that defines color in a population of interbreeding organisms, it might rapidly become more common than other alleles. In time, this could mean that the number of moths sporting black pigmentation 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 a species, such as bacteria, has a rapid generation turnover. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that are descended from one strain. Samples from each population were taken regularly, and more than 50,000 generations of E.coli have been observed to have passed.

Lenski's research has shown that mutations can drastically alter the efficiency with which a population reproduces--and so the rate at which it alters. It also demonstrates that evolution takes time, something that is hard for some to accept.

Another example of microevolution is that mosquito genes that confer resistance to pesticides show up more often in areas where insecticides are employed. Pesticides create a selective pressure which favors those with resistant genotypes.

The speed of evolution taking place has led to an increasing recognition of its importance in a world that is shaped by human activity, including climate change, pollution and the loss of habitats that hinder many species from adapting. Understanding the evolution process will assist you in making better choices regarding the future of the planet and its inhabitants.