자유게시판

• 목록
• 게시판 리스트 옵션
  • 수정
  • 삭제

The Academy's Evolution Site

Biology is one of the most important 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 research.

This site provides students, teachers and 에볼루션바카라 general readers with a variety of educational resources on evolution. It contains important 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 used in many religions and cultures as an emblem of unity and love. It also has important practical applications, like providing a framework to understand the evolution of species and how they respond to changing environmental conditions.

The first attempts at depicting the world of biology focused on the classification of organisms into distinct categories which were distinguished by their physical and metabolic characteristics1. These methods, which depend on the sampling of different parts of organisms, or DNA fragments, have significantly increased the diversity of a Tree of Life2. These trees are mostly populated of eukaryotes, while bacteria are largely underrepresented3,4.

Genetic techniques have significantly expanded our ability to visualize the Tree of Life by circumventing the requirement for direct observation and experimentation. Particularly, molecular techniques allow us to build trees by using sequenced markers like the small subunit ribosomal gene.

The Tree of Life has been greatly expanded thanks to genome sequencing. However there is still a lot of biodiversity to be discovered. This is particularly relevant to microorganisms that are difficult to cultivate and are typically present in a single sample5. Recent analysis of all genomes produced an unfinished draft of the Tree of Life. This includes a wide range of archaea, bacteria and other organisms that have not yet been identified or the diversity of which is not fully understood6.

This expanded Tree of Life is particularly useful for assessing the biodiversity of an area, which can help to determine whether specific habitats require protection. This information can be utilized in a range of ways, from identifying new treatments to fight disease to enhancing the quality of crop yields. This information is also extremely useful for conservation efforts. It can help biologists identify the areas most likely to contain cryptic species with significant metabolic functions that could be at risk from anthropogenic change. While conservation funds are important, the best way to conserve the world's biodiversity is to equip the people of developing nations with the knowledge they need to take action locally and encourage conservation.

Phylogeny

A phylogeny (also called an evolutionary tree) depicts the relationships between organisms. Scientists can construct a phylogenetic chart that shows the evolution of taxonomic groups based on molecular data and morphological differences or similarities. Phylogeny plays a crucial role in understanding biodiversity, genetics and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 ) identifies the relationships between organisms that share similar traits that have evolved from common ancestral. These shared traits can be homologous, or analogous. Homologous characteristics are identical in their evolutionary journey. Analogous traits could appear like they are, but they do not have the same origins. Scientists group similar traits into a grouping referred to as a the clade. Every organism in a group have a common characteristic, like amniotic egg production. They all derived from an ancestor that had these eggs. A phylogenetic tree is then built by connecting the clades to identify the species who are the closest to each other.

Scientists use DNA or RNA molecular data to construct a phylogenetic graph that is more accurate and detailed. This information is more precise than morphological data and provides evidence of the evolutionary history of an organism or group. The analysis of molecular data can help researchers identify the number of species that have the same ancestor and estimate their evolutionary age.

The phylogenetic relationships between species can be influenced by several factors, including phenotypic plasticity a type of behavior that alters in response to specific environmental conditions. This can cause a characteristic to appear more like a species another, obscuring the phylogenetic signal. This problem can be mitigated by using cladistics, 에볼루션 which is a an amalgamation of homologous and analogous features in the tree.

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

Evolutionary Theory

The central theme in evolution is that organisms change over time as a result of their interactions with their environment. Several theories of evolutionary change have been proposed by a wide variety of scientists, including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who believed that an organism would evolve slowly according to its needs as well as the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits cause changes that can be passed on to the offspring.

In the 1930s & 1940s, ideas from different fields, including genetics, natural selection and particulate inheritance, came together to create a modern theorizing of evolution. This describes how evolution is triggered by the variation in genes within the population and how these variations change over time as a result of natural selection. This model, known as genetic drift mutation, gene flow and sexual selection, is a key element of the current evolutionary biology and can be mathematically described.

Recent discoveries in the field of evolutionary developmental biology have demonstrated that genetic variation can be introduced into a species via genetic drift, mutation, and reshuffling genes during sexual reproduction, and also through migration between populations. These processes, as well as others, such as directionally-selected selection and erosion of genes (changes in the frequency of genotypes over time), can lead towards evolution. Evolution is defined as changes in the genome over time and changes in the phenotype (the expression of genotypes within individuals).

Incorporating evolutionary thinking into all aspects of biology education could increase students' understanding of phylogeny and evolution. A recent study by Grunspan and colleagues, for instance revealed that teaching students 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 Potential of All Areas of Biology and Thinking Evolutionarily: A Framework for Infusing the Concept of Evolution into Life Sciences Education.

Evolution in Action

Scientists have looked at evolution through the past, analyzing fossils and comparing species. They also study living organisms. Evolution isn't a flims moment; it is an ongoing process. Bacteria transform and resist antibiotics, viruses reinvent themselves and escape new drugs and animals alter their behavior to the changing environment. The changes that occur are often evident.

It wasn't until the 1980s that biologists began to realize that natural selection was in action. The main reason is that different traits result in the ability to survive at different rates and reproduction, and can be passed on from one generation to the next.

In the past, if a certain allele - the genetic sequence that determines color - was found in a group of organisms that interbred, it could be more common than other allele. As time passes, 에볼루션 바카라 사이트 바카라 - Demilked.Com, that 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.

Observing evolutionary change in action is easier when a species has a fast generation turnover like bacteria. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that are descended from a single strain. Samples from each population were taken regularly, and more than 50,000 generations of E.coli have passed.

Lenski's work has shown that mutations can alter the rate at which change occurs and the efficiency at which a population reproduces. It also proves that evolution takes time, a fact that some people are unable to accept.

Another example of microevolution is the way mosquito genes for resistance to pesticides are more prevalent in populations where insecticides are used. That's because the use of pesticides causes a selective pressure that favors people with resistant genotypes.

The rapid pace at which evolution takes place has led to an increasing recognition of its importance in a world shaped by human activities, including climate changes, pollution and the loss of habitats which prevent many species from adjusting. Understanding evolution will assist you in making better choices regarding the future of the planet and its inhabitants.