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The Academy's Evolution Site

Biology is a key concept in biology. The Academies are committed to helping those who are interested in the sciences learn about the theory of evolution and how it is incorporated in all areas of scientific research.

This site offers a variety of sources for students, teachers as well as general readers about evolution. It also 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 symbolizes the interconnectedness of life. It is an emblem of love and unity across many cultures. It can be used in many practical ways as well, including providing a framework for understanding the evolution of species and how they respond to changing environmental conditions.

The first attempts to depict the biological world were built on categorizing organisms based on their physical and metabolic characteristics. These methods are based on the collection of various parts of organisms or short fragments of DNA, have significantly increased the diversity of a Tree of Life2. These trees are largely composed of eukaryotes, while bacteria are largely underrepresented3,4.

In avoiding the necessity of direct observation and experimentation, genetic techniques have allowed us to represent the Tree of Life in a more precise way. In particular, molecular methods allow us to build trees by using sequenced markers like the small subunit ribosomal RNA gene.

Despite the dramatic growth of the Tree of Life through genome sequencing, a large amount of biodiversity awaits discovery. This is especially true of microorganisms that are difficult to cultivate and are typically only found in a single specimen5. A recent analysis of all genomes known to date has produced a rough draft version of the Tree of Life, including a large number of archaea and bacteria that are not isolated and which are not well understood.

This expanded Tree of Life can be used to determine the diversity of a specific region and determine if particular habitats need special protection. This information can be utilized in a variety of ways, such as finding new drugs, battling diseases and improving the quality of crops. This information is also useful for conservation efforts. It can aid biologists in identifying areas that are most likely to be home to species that are cryptic, which could have important metabolic functions, and could be susceptible to changes caused by humans. While funds to safeguard biodiversity are vital but the most effective way to protect the world's biodiversity 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 called an evolutionary tree) shows the relationships between different organisms. Scientists can create an phylogenetic chart which shows the evolutionary relationships between taxonomic groups using molecular data and morphological similarities or differences. Phylogeny plays a crucial role in understanding the relationship between genetics, biodiversity and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 ) determines the relationship between organisms with similar traits that have evolved from common ancestors. These shared traits could be either homologous or analogous. Homologous characteristics are identical in terms of their evolutionary journey. Analogous traits might appear similar but they don't have the same ancestry. Scientists combine similar traits into a grouping called a clade. All members of a clade have a common characteristic, like amniotic egg production. They all evolved from an ancestor who had these eggs. A phylogenetic tree is built by connecting the clades to determine the organisms who are the closest to each other.

Scientists use molecular DNA or RNA data to build a phylogenetic chart which is more precise and precise. This information is more precise and gives evidence of the evolutionary history of an organism. The analysis of molecular data can help researchers identify the number of species that share a common ancestor and to estimate their evolutionary age.

The phylogenetic relationships of a species can be affected by a number of factors such as the phenotypic plasticity. This is a type behavior that alters in response to particular environmental conditions. This can cause a characteristic to appear more resembling to one species than another, obscuring the phylogenetic signals. This problem can be addressed by using cladistics, which incorporates a combination of homologous and analogous traits in the tree.

Additionally, phylogenetics can help predict the length and speed of speciation. This information will assist conservation biologists in making decisions about which species to save from disappearance. In the end, it's the conservation of phylogenetic variety which will create an ecosystem that is complete and balanced.

Evolutionary Theory

The central theme in evolution is that organisms change over time due to their interactions with their environment. Many theories of evolution have been developed by a wide variety of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop gradually according to its requirements, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that the use or 에볼루션 바카라 사이트 무료 에볼루션 바카라 무료체험 (Metooo published an article) misuse of traits can cause changes that could be passed onto offspring.

In the 1930s & 1940s, theories from various fields, such as genetics, natural selection, and particulate inheritance, came together to form a modern theorizing of evolution. This describes how evolution is triggered by the variation in genes within the population, and how these variations alter over time due to natural selection. This model, called genetic drift mutation, gene flow and sexual selection, is a cornerstone of current evolutionary biology, and can be mathematically explained.

Recent discoveries in the field of evolutionary developmental biology have demonstrated that genetic variation can be introduced into a species through mutation, genetic drift, 에볼루션 and reshuffling of genes in sexual reproduction, as well as through the movement of populations. These processes, as well as other ones 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 change in the genome of the species over time and also the change in phenotype as time passes (the expression of the genotype in the individual).

Incorporating evolutionary thinking into all areas of biology education can increase student understanding of the concepts of phylogeny and evolution. A recent study by Grunspan and colleagues, 에볼루션바카라사이트 for example, showed that teaching about the evidence that supports evolution increased students' acceptance of evolution in a college-level biology class. For more details on how to teach about evolution look up 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 through studying fossils, 에볼루션사이트 comparing species, and studying living organisms. But evolution isn't a thing that happened in the past; it's an ongoing process that is that is taking place in the present. Bacteria mutate and resist antibiotics, viruses evolve and escape new drugs, and animals adapt their behavior in response to the changing climate. The changes that occur are often evident.

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

In the past when one particular allele, the genetic sequence that controls coloration - was present in a group of interbreeding organisms, it could quickly become more prevalent than 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.

Monitoring evolutionary changes in action is easier when a particular species has a rapid generation turnover such as bacteria. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain. samples from each population are taken every day and over 500.000 generations have been observed.

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

Microevolution can be observed in the fact that mosquito genes that confer resistance to pesticides are more common in populations where insecticides have been used. This is due to pesticides causing an enticement that favors those who have resistant genotypes.

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