9 Signs That You're The Evolution Site Expert

The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies are committed to helping those who are interested in the sciences comprehend the evolution theory and how it is permeated throughout all fields of scientific research.

This site offers a variety of sources for students, teachers, and general readers on evolution. It includes key video clips from NOVA and WGBH-produced science programs on DVD.

Tree of Life

The Tree of Life, an ancient symbol, symbolizes the interconnectedness of all life. It is an emblem of love and unity in many cultures. It also has practical applications, like providing a framework for understanding the evolution of species and how they react to changes in the environment.

The first attempts at depicting the world of biology focused on the classification of organisms into distinct categories which had been identified by their physical and metabolic characteristics1. These methods, which relied on the sampling of various parts of living organisms or on sequences of short fragments of their DNA, greatly increased the variety of organisms that could be represented in a tree of life2. These trees are largely composed of eukaryotes, while bacteria are largely underrepresented3,4.

Genetic techniques have significantly expanded our ability to depict the Tree of Life by circumventing the requirement for direct observation and experimentation. We can construct trees using molecular methods such as the small subunit ribosomal gene.

Despite the massive growth of the Tree of Life through genome sequencing, much biodiversity still is waiting to be discovered. This is especially the case for microorganisms which are difficult to cultivate, and are typically found in one sample5. A recent study of all known genomes has produced a rough draft of the Tree of Life, including a large number of archaea and bacteria that have not been isolated, and which are not well understood.

The expanded Tree of Life is particularly useful for assessing the biodiversity of an area, which can help to determine if certain habitats require special protection. This information can be used in a range of ways, from identifying the most effective treatments to fight disease to improving crop yields. It is also beneficial in conservation efforts. It helps biologists discover areas that are most likely to be home to cryptic species, which could have important metabolic functions, and could be susceptible to changes caused by humans. Although funding to protect biodiversity are essential but the most effective way to preserve the world's biodiversity is for more people in developing countries to be equipped with the knowledge to take action locally to encourage conservation from within.

Phylogeny

A phylogeny is also known as an evolutionary tree, illustrates the connections between various groups of organisms. Using molecular data, morphological similarities and differences, or ontogeny (the course of development of an organism), scientists can build a phylogenetic tree which illustrates the evolutionary relationship between taxonomic categories. The role of phylogeny is crucial in understanding biodiversity, genetics and evolution.

A basic phylogenetic tree (see Figure PageIndex 10 Finds the connections between organisms that have similar traits and have evolved from a common ancestor. These shared traits can be analogous or homologous. Homologous traits share their evolutionary origins, while analogous traits look similar but do not have the same ancestors. Scientists organize similar traits into a grouping called a the clade. For instance, all the organisms that make up a clade share the trait of having amniotic eggs. They evolved from a common ancestor who had eggs. The clades then join to form a phylogenetic branch that can identify organisms that have the closest relationship.

For a more precise and accurate phylogenetic tree, scientists make use of molecular data from DNA or RNA to determine the connections between organisms. This information is more precise and gives evidence of the evolution of an organism. Molecular data allows researchers to identify the number of organisms that have an ancestor common to them and estimate their evolutionary age.

The phylogenetic relationships of organisms can be influenced by several factors including phenotypic plasticity, a kind of behavior that changes in response to specific environmental conditions. This can cause a characteristic to appear more resembling to one species than to another, obscuring the phylogenetic signals. However, this issue can be solved through the use of techniques such as cladistics that combine homologous and analogous features into the tree.

Additionally, phylogenetics can help predict the duration and rate at which speciation takes place. This information can assist conservation biologists in deciding which species to save from disappearance. In the end, it's the conservation of phylogenetic diversity that will result in an ecosystem that is complete and balanced.

Evolutionary Theory

The fundamental concept in evolution is that organisms change over time as a result of their interactions with their environment. Many scientists have proposed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism could evolve according to its own needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern taxonomy system that is hierarchical as well as Jean-Baptiste Lamarck (1844-1829), who believed that the use or non-use of traits can cause changes that are passed on to the

In the 1930s and 1940s, concepts from a variety of fields--including natural selection, genetics, and particulate inheritance -- came together to form the modern evolutionary theory that explains how evolution occurs through the variations of genes within a population, and how those variations change in time as a result of natural selection. This model, which encompasses mutations, genetic drift in gene flow, and sexual selection can be mathematically described.

Recent developments in the field of evolutionary developmental biology have demonstrated how variations can be introduced to a species through mutations, genetic drift and reshuffling of genes during sexual reproduction and migration between populations. These processes, along with others, such as the directional selection process and the erosion of genes (changes in frequency of genotypes over time) can result in evolution. Evolution is defined as changes in the genome over time as well as 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 throughout all areas of biology. A recent study conducted by Grunspan and colleagues, for instance demonstrated that teaching about the evidence that supports evolution increased students' understanding of evolution in a college-level biology class. For more information about how to teach evolution read The Evolutionary Potency 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 looking back, studying fossils, comparing species, and observing living organisms. Evolution is not a distant event, but an ongoing process. Viruses evolve to stay away from new medications and bacteria mutate to resist antibiotics. Animals adapt their behavior in the wake of a changing world. The results are often apparent.

It wasn't until late 1980s that biologists understood that natural selection could be seen in action, as well. The key is that various characteristics result in different rates of survival and reproduction (differential fitness) and are transferred from one generation to the next.

In the past, when one particular allele, the genetic sequence that defines color in a population of interbreeding organisms, it might quickly become more common than the other alleles. Over time, that would mean the number of black moths within 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 track evolutionary change when the species, like bacteria, has a rapid generation turnover. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that descend from a single strain. Samples of each population have been taken regularly and more than 50,000 generations of E.coli have passed.

Lenski's work has demonstrated that a mutation can dramatically alter the rate at which a population reproduces--and so, the rate at which it changes. It also shows evolution takes time, which is difficult for some to accept.

Microevolution is also evident in the fact that mosquito genes for pesticide resistance are more common in populations where insecticides are used. That's because the use of pesticides creates a pressure that favors individuals with resistant genotypes.

에볼루션 바카라  of evolution has led to a greater appreciation of its importance particularly in a world 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 aid you in making better decisions about the future of our planet and its inhabitants.