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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 science comprehend the evolution theory and 에볼루션바카라사이트 how it is permeated across all areas of scientific research.

This site provides teachers, students and general readers with a range of educational resources on evolution. It contains 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 a symbol of love and unity across many cultures. It has many practical applications as well, including providing a framework to understand the history of species, and how they react to changes in environmental conditions.

The first attempts at depicting the biological world focused on separating organisms into distinct categories that were identified by their physical and metabolic characteristics1. These methods rely on the sampling of different parts of organisms or fragments of DNA, have significantly increased the diversity of a Tree of Life2. However the trees are mostly made up of eukaryotes. Bacterial diversity is still largely unrepresented3,4.

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

Despite the rapid growth of the Tree of Life through genome sequencing, much biodiversity still is waiting to be discovered. This is especially relevant to microorganisms that are difficult to cultivate and are typically present in a single sample5. A recent analysis of all genomes has produced an unfinished draft of a Tree of Life. This includes a variety of bacteria, archaea and other organisms that have not yet been identified or whose diversity has not been fully understood6.

This expanded Tree of Life is particularly useful for assessing the biodiversity of an area, assisting to determine if specific habitats require protection. This information can be used in a variety of ways, from identifying new medicines to combating disease to enhancing crop yields. This information is also extremely valuable to conservation efforts. It can help biologists identify areas that are most likely to be home to cryptic species, which could perform important metabolic functions and are susceptible to human-induced change. While funds to protect biodiversity are crucial, ultimately the best way to ensure the preservation of biodiversity around the world is for more people living in developing countries to be equipped with the knowledge to act locally to promote conservation from within.

Phylogeny

A phylogeny, also known as an evolutionary tree, illustrates the relationships between groups of organisms. Utilizing molecular data as well as morphological similarities and distinctions or ontogeny (the course of development of an organism), scientists can build a phylogenetic tree that illustrates the evolution of taxonomic groups. 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 that have similar traits and have evolved from a common ancestor. These shared traits can be analogous, or homologous. Homologous traits are identical in their evolutionary origins while analogous traits appear similar but do not have the same origins. Scientists organize similar traits into a grouping known as a clade. All members of a clade share a trait, such as amniotic egg production. They all evolved from an ancestor who had these eggs. A phylogenetic tree is then built by connecting the clades to identify the organisms that are most closely related to one another.

Scientists utilize DNA or RNA molecular data to create a phylogenetic chart which is more precise and detailed. This information is more precise than morphological data and provides evidence of the evolutionary history of an organism or group. Researchers can utilize Molecular Data to estimate the evolutionary age of organisms and determine how many organisms share an ancestor common to all.

The phylogenetic relationships between species can be influenced by several factors, including phenotypic plasticity a kind of behavior that alters in response to unique environmental conditions. This can cause a trait to appear more similar to a species than to the other which can obscure the phylogenetic signal. However, this problem can be solved through the use of techniques like cladistics, which include a mix of analogous and homologous features into the tree.

Additionally, phylogenetics can help predict the duration and rate of speciation. This information can aid conservation biologists to decide which species to protect from the threat of extinction. It is ultimately the preservation of phylogenetic diversity that will create an ecologically balanced and complete ecosystem.

Evolutionary Theory

The fundamental concept of evolution is that organisms develop various characteristics over time based on their interactions with their surroundings. Several theories of evolutionary change have been proposed by a wide variety of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who believed that an organism would evolve slowly according to its requirements and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits cause changes that could be passed on to offspring.

In the 1930s and 1940s, theories from various fields, including genetics, natural selection, 에볼루션 바카라사이트 and particulate inheritance--came together to form the current evolutionary theory synthesis which explains how evolution is triggered by the variations of genes within a population, and how these variants change over time as a result of natural selection. This model, which is known as genetic drift or mutation, gene flow, 에볼루션 슬롯 and sexual selection, is the foundation of the current evolutionary biology and is mathematically described.

Recent discoveries in evolutionary developmental biology have revealed the ways in which variation can be introduced to a species through mutations, genetic drift or reshuffling of genes in sexual reproduction, and even migration between populations. These processes, as well as others like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time) can lead to evolution that is defined as changes in the genome of the species over time and also the change in phenotype over time (the expression of the genotype within the individual).

Incorporating evolutionary thinking into all areas of biology education could increase student understanding of the concepts of phylogeny as well as evolution. In a study by Grunspan and colleagues. It was demonstrated that teaching students about the evidence for evolution increased their understanding of evolution during a college-level course in biology. For more details on how to teach evolution look up The Evolutionary Potency in All Areas of Biology or Thinking Evolutionarily as 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 study living organisms. But evolution isn't a thing that occurred in the past; it's an ongoing process, taking place right now. Viruses evolve to stay away from new antibiotics and bacteria transform to resist antibiotics. Animals alter their behavior as a result of a changing world. The changes that result are often visible.

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

In the past, if one particular allele - the genetic sequence that controls coloration - was present in a group of interbreeding organisms, it might quickly become more common than all other alleles. In time, this could mean the number of black moths in a particular population could rise. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

It is easier to track evolution when the species, like bacteria, has a rapid generation turnover. Since 1988, 에볼루션 코리아 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 the rate at which a population reproduces. It also shows evolution takes time, a fact that is hard for some to accept.

Another example of microevolution is the way mosquito genes that are resistant to pesticides show up more often in populations where insecticides are employed. That's because the use of pesticides causes a selective pressure that favors those with resistant genotypes.

The rapidity of evolution has led to an increasing awareness of its significance, especially in a world which is largely shaped by human activities. This includes climate change, pollution, and habitat loss that hinders many species from adapting. Understanding evolution will aid you in making better decisions regarding the future of the planet and its inhabitants.