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The Academy's Evolution Site

Biological evolution is one of the most important concepts in biology. The Academies have been for a long time involved in helping people who are interested in science comprehend the theory of evolution and how it influences all areas of scientific research.

This site provides a wide range of sources for students, teachers and general readers of evolution. It includes 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 life. It is an emblem of love and harmony in a variety of 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.

Early attempts to represent the biological world were built on categorizing organisms based on their physical and metabolic characteristics. These methods, which relied on the sampling of different parts of living organisms, or short fragments of their DNA significantly increased the variety that could be included in the tree of life2. However these trees are mainly made up of eukaryotes. Bacterial diversity is still largely unrepresented3,4.

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

Despite the dramatic expansion of the Tree of Life through genome sequencing, a large amount of biodiversity is waiting to be discovered. This is especially true of microorganisms that are difficult to cultivate and are often only found in a single specimen5. A recent analysis of all genomes resulted in an unfinished draft of the Tree of Life. This includes a wide range of bacteria, archaea and other organisms that haven't yet been isolated, or the diversity of which is not well understood6.

The expanded Tree of Life can be used to determine the diversity of a specific area and determine if particular habitats require special protection. This information can be utilized in a variety of ways, from identifying new medicines to combating disease to enhancing the quality of crops. This information is also valuable in conservation efforts. It can aid biologists in identifying the areas most likely to contain cryptic species with significant metabolic functions that could be at risk of anthropogenic changes. Although funds to protect biodiversity are essential however, 에볼루션 바카라사이트 the most effective method to protect the world's biodiversity is for more people living in developing countries to be equipped with the knowledge to act locally in order to promote conservation from within.

Phylogeny

A phylogeny, also called an evolutionary tree, illustrates the connections between different groups of organisms. Using molecular data as well as morphological similarities and distinctions or ontogeny (the course of development of an organism) scientists can create a phylogenetic tree that illustrates the evolution of taxonomic groups. Phylogeny is crucial in understanding biodiversity, evolution and genetics.

A basic phylogenetic Tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms that share similar traits that have evolved from common ancestors. These shared traits can be analogous, or homologous. Homologous traits are similar in terms of their evolutionary paths. Analogous traits may look similar but they don't share the same origins. Scientists organize similar traits into a grouping called a Clade. Every organism in a group share a characteristic, like amniotic egg production. They all evolved from an ancestor that had these eggs. A phylogenetic tree is constructed by connecting clades to determine the organisms which are the closest to each other.

Scientists make use of DNA or RNA molecular data to create a phylogenetic chart that is more accurate and 에볼루션 바카라사이트 precise. This data is more precise than the morphological data and gives evidence of the evolutionary history of an organism or group. Researchers can use Molecular Data to calculate the age of evolution of organisms and identify how many organisms share a common ancestor.

The phylogenetic relationships between organisms are influenced by many factors, including phenotypic plasticity a kind of behavior that alters in response to unique environmental conditions. This can cause a trait to appear more like a species other species, which can obscure the phylogenetic signal. However, this problem can be solved through the use of methods such as cladistics that combine homologous and analogous features into the tree.

Furthermore, phylogenetics may aid in predicting the duration and rate of speciation. This information can assist conservation biologists in making choices about which species to protect from disappearance. Ultimately, it is the preservation of phylogenetic diversity that will create an ecologically balanced and complete ecosystem.

Evolutionary Theory

The main idea behind evolution is that organisms acquire distinct characteristics over time due to their interactions with their environment. Several theories of evolutionary change have been developed by a wide range of scientists including 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 designed the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that the use or misuse of traits causes changes that can be passed onto offspring.

In the 1930s and 1940s, ideas from different fields, such as natural selection, genetics & particulate inheritance, merged to form a contemporary synthesis of evolution theory. This describes how evolution happens through the variation in genes within a population and how these variants alter over time due to natural selection. This model, called genetic drift or mutation, gene flow, 에볼루션 바카라 and sexual selection, is a cornerstone of the current evolutionary biology and can be mathematically explained.

Recent discoveries in the field of evolutionary developmental biology have revealed that genetic variation can be introduced into a species by mutation, genetic drift and reshuffling genes during sexual reproduction, as well as through the movement of populations. These processes, along with others such as directional selection or genetic erosion (changes in the frequency of the genotype over time) can lead to evolution, which is defined by changes in the genome of the species over time and 에볼루션 바카라사이트 also the change in phenotype as time passes (the expression of that genotype within the individual).

Students can gain a better understanding of the concept of phylogeny by using evolutionary thinking throughout all aspects of biology. A recent study by Grunspan and colleagues, for instance demonstrated that teaching about the evidence that supports evolution increased students' acceptance of evolution in a college biology course. For more information on how to teach about evolution look up 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

Traditionally scientists have studied evolution through looking back, studying fossils, 무료에볼루션 comparing species and observing living organisms. Evolution is not a distant event, but a process that continues today. Bacteria transform and resist antibiotics, viruses re-invent themselves and elude new medications, and animals adapt their behavior to a changing planet. The results are often visible.

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

In the past, if one allele - the genetic sequence that determines colour - was found in a group of organisms that interbred, it could become more common than any other allele. Over time, 에볼루션코리아 this would mean that the number of moths sporting 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 see evolution when the species, like bacteria, has a rapid generation turnover. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that descend from one strain. The samples of each population have been collected frequently and more than 500.000 generations of E.coli have been observed to have passed.

Lenski's research has revealed that mutations can alter the rate at which change occurs and the rate of a population's reproduction. It also shows that evolution takes time, which is hard for some to accept.

Microevolution is also evident in the fact that mosquito genes for resistance to pesticides are more prevalent in areas where insecticides have been used. This is due to the fact that the use of pesticides creates a pressure that favors people with resistant genotypes.

The rapidity of evolution has led to a greater recognition of its importance especially in a planet that is largely shaped by human activity. This includes climate change, pollution, and habitat loss, which prevents many species from adapting. Understanding the evolution process will aid you in making better decisions regarding the future of the planet and its inhabitants.