• 목록
• 답변
• 글쓰기
• 게시판 리스트 옵션
  • 수정
  • 삭제

The Academy's Evolution Site

Biological evolution is one of the most central concepts in biology. The Academies have been active for a long time in helping those interested in science understand the theory of evolution and how it influences all areas of scientific exploration.

This site provides a range of tools for students, 바카라 에볼루션 teachers and general readers of evolution. It contains 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 appears in many cultures and spiritual beliefs as symbolizing unity and love. It also has many practical uses, like providing a framework for understanding the history of species and how they respond to changes in the environment.

Early attempts to represent the biological world were founded on categorizing organisms 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 the diversity of bacterial species is greatly underrepresented3,4.

By avoiding the necessity for direct experimentation and observation genetic techniques have allowed us to depict the Tree of Life in a more precise manner. Particularly, molecular methods allow us to construct trees by using sequenced markers such as the small subunit ribosomal RNA gene.

The Tree of Life has been significantly expanded by genome sequencing. However there is a lot of diversity to be discovered. This is particularly true for microorganisms that are difficult to cultivate and which are usually only found in one sample5. Recent analysis of all genomes produced an initial draft of a Tree of Life. This includes a variety of archaea, bacteria and other organisms that haven't yet been identified or whose diversity has not been well understood6.

This expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, helping to determine if certain habitats require special protection. This information can be utilized in a variety of ways, from identifying new treatments to fight disease to improving crops. The information is also incredibly beneficial to conservation efforts. It helps biologists determine the areas most likely to contain cryptic species with important metabolic functions that could be at risk from anthropogenic change. Although funds to protect biodiversity are essential, ultimately the best way to ensure the preservation of biodiversity around the world is for more people living in developing countries to be empowered with the necessary knowledge to act locally to promote conservation from within.

Phylogeny

A phylogeny (also known as an evolutionary tree) depicts the relationships between organisms. Using molecular data as well as morphological similarities and distinctions or ontogeny (the course of development of an organism) scientists can construct a phylogenetic tree which illustrates the evolutionary relationship between taxonomic categories. Phylogeny plays a crucial role in understanding biodiversity, genetics and evolution.

A basic phylogenetic tree (see Figure PageIndex 10 Finds the connections between organisms with similar characteristics and have evolved from a common ancestor. These shared traits can be analogous, or homologous. Homologous characteristics are identical in terms of their evolutionary journey. Analogous traits could appear similar, but they do not have the same origins. Scientists put similar traits into a grouping referred to as a clade. For instance, all of the organisms that make up a clade have the characteristic of having amniotic eggs. They evolved from a common ancestor that had these eggs. A phylogenetic tree is constructed by connecting the clades to identify the species who are the closest to each other.

To create a more thorough and precise phylogenetic tree scientists use molecular data from DNA or RNA to identify the relationships among organisms. This information is more precise and provides evidence of the evolution history of an organism. Researchers can use Molecular Data to calculate the age of evolution of organisms and identify the number of organisms that share an ancestor common to all.

Phylogenetic relationships can be affected by a number of factors, including phenotypicplasticity. This is a type behavior that changes as a result of specific environmental conditions. This can cause a characteristic to appear more similar to one species than another and obscure the phylogenetic signals. This problem can be addressed by using cladistics. This is a method that incorporates the combination of analogous and homologous features in the tree.

In addition, 에볼루션 무료 바카라 phylogenetics helps predict the duration and rate at which speciation occurs. This information can assist conservation biologists in making choices about which species to save from disappearance. In the end, it's the preservation of phylogenetic diversity that will result in an ecosystem that is balanced and complete.

Evolutionary Theory

The main idea behind evolution is that organisms develop various characteristics over time as a result of their interactions with their environments. Many scientists have proposed theories of evolution, 에볼루션 바카라 사이트 무료 에볼루션 바카라 - www.E10100.com, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism would evolve according to its individual needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern hierarchical system of taxonomy as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the use or non-use of traits can cause changes that can be passed on to future generations.

In the 1930s and 1940s, ideas from different areas, including natural selection, genetics & particulate inheritance, were brought together to form a modern theorizing of evolution. This describes how evolution occurs by the variations in genes within the population, and how these variants alter over time due to natural selection. This model, which incorporates genetic drift, mutations as well as gene flow and sexual selection, can be mathematically described.

Recent discoveries in the field of evolutionary developmental biology have shown how variation can be introduced to a species through mutations, genetic drift, reshuffling genes during sexual reproduction and the movement between populations. These processes, as well as other ones like directionally-selected selection and erosion of genes (changes to the frequency of genotypes over time), can lead towards evolution. Evolution is defined as changes in the genome over time as well as changes in phenotype (the expression of genotypes in an individual).

Students can better understand phylogeny by incorporating evolutionary thinking in all areas of biology. A recent study conducted by Grunspan and colleagues, 에볼루션 무료 바카라 for example revealed that teaching students about the evidence for evolution increased students' acceptance of evolution in a college-level biology class. For more information about how to teach evolution read The Evolutionary Potential in all Areas of Biology or Thinking Evolutionarily as a Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Scientists have traditionally studied evolution through looking back in the past, studying fossils, and comparing species. They also study living organisms. But evolution isn't just something that happened in the past; it's an ongoing process that is that is taking place right now. Viruses evolve to stay away from new drugs and bacteria evolve to resist antibiotics. Animals alter their behavior because of a changing world. The resulting changes are often easy to see.

It wasn't until the late 1980s that biologists began realize that natural selection was in play. The key is that different characteristics result in different rates of survival and reproduction (differential fitness), and can be transferred from one generation to the next.

In the past, if an allele - the genetic sequence that determines colour was found in a group of organisms that interbred, it might become more prevalent than any other allele. Over time, that would mean the number of black moths in a population could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

Observing evolutionary change in action is much easier when a species has a rapid turnover of its generation, as with bacteria. Since 1988 biologist Richard Lenski has been tracking twelve populations of E. coli that descended from a single strain; samples from each population are taken on a regular basis and 무료에볼루션 over 50,000 generations have now passed.

Lenski's research has shown that mutations can drastically alter the efficiency with which a population reproduces and, consequently the rate at which it alters. 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 confer resistance to pesticides appear more frequently in populations in which insecticides are utilized. That's because the use of pesticides causes a selective pressure that favors people who have resistant genotypes.

The rapid pace at which evolution takes place has led to a growing awareness of its significance in a world shaped by human activities, including climate change, pollution and the loss of habitats that prevent the species from adapting. Understanding evolution will help us make better decisions about the future of our planet and the lives of its inhabitants.