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

The Academy's Evolution Site

Biology is one of the most important concepts in biology. The Academies have long been involved in helping those interested in science understand the concept of evolution and how it affects all areas of scientific exploration.

This site provides students, teachers and general readers with a wide range of educational resources on evolution. It includes key video clip 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 seen in a variety of cultures and spiritual beliefs as a symbol of unity and love. It also has practical applications, like providing a framework to understand the evolution of species and how they respond to changes in environmental conditions.

Early attempts to describe the world of biology were built on categorizing organisms based on their physical and metabolic characteristics. These methods, which rely on the sampling of different parts of organisms, or fragments of DNA have greatly 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.

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. We can create trees using molecular methods like the small-subunit ribosomal gene.

The Tree of Life has been greatly expanded thanks to genome sequencing. However there is a lot of diversity to be discovered. This is particularly true for 에볼루션 블랙잭 microorganisms, which can be difficult to cultivate and are often only represented in a single specimen5. A recent analysis of all genomes that are known has created a rough draft of the Tree of Life, including many bacteria and archaea that have not been isolated and their diversity is not fully understood6.

The expanded Tree of Life is particularly useful in assessing the diversity of an area, which can help to determine if certain habitats require protection. This information can be utilized in a variety of ways, such as identifying new drugs, combating diseases and improving crops. The information is also incredibly beneficial to conservation efforts. It helps biologists discover areas that are most likely to have cryptic species, which may perform important metabolic functions and be vulnerable to human-induced change. While funds to protect biodiversity are important, the best way to conserve the world's biodiversity is to empower more people in developing countries with the necessary knowledge to take action locally and encourage conservation.

Phylogeny

A phylogeny, also called an evolutionary tree, shows the connections between groups of organisms. Scientists can build an phylogenetic chart which shows the evolution of taxonomic groups based on molecular data and morphological differences or similarities. The phylogeny of a tree plays an important role in understanding the relationship between genetics, biodiversity and evolution.

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 ancestral. These shared traits could be analogous, or homologous. Homologous characteristics are identical in terms of their evolutionary path. Analogous traits could appear like they are, but they do not have the same ancestry. Scientists organize similar traits into a grouping known as a the clade. All members of a clade have a common characteristic, for example, amniotic egg production. They all came from an ancestor who had these eggs. A phylogenetic tree is then constructed by connecting the clades to identify the species who are the closest to one another.

For a more precise and accurate phylogenetic tree scientists rely on molecular information from DNA or RNA to identify the relationships among organisms. This data is more precise than morphological information and gives evidence of the evolutionary background of an organism or group. Molecular data allows researchers to identify the number of organisms that have an ancestor common to them and estimate their evolutionary age.

The phylogenetic relationships between organisms are influenced by many factors including phenotypic plasticity, an aspect of behavior that changes in response to specific environmental conditions. This can cause a characteristic to appear more similar to one species than another and obscure the phylogenetic signals. However, this problem can be cured by the use of techniques like cladistics, which include a mix of analogous and homologous features into the tree.

Additionally, phylogenetics can help determine the duration and rate of speciation. This information can aid conservation biologists to decide which species to protect from extinction. In the end, it is the conservation of phylogenetic variety that will result in an ecosystem that is balanced and complete.

Evolutionary Theory

The main idea behind evolution is that organisms acquire different features over time based on their interactions with their environment. Many scientists have developed theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism would evolve according to its own requirements and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern taxonomy system that is hierarchical, as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the use or absence of traits can cause changes that are passed on to the next generation.

In the 1930s and 1940s, ideas from a variety of fields--including natural selection, genetics, and particulate inheritance - came together to form the current evolutionary theory, which defines how evolution is triggered by the variation of genes within a population, and how those variations change over time as a result of natural selection. This model, which is known as genetic drift or mutation, gene flow and sexual selection, is a cornerstone of modern evolutionary biology and can be mathematically explained.

Recent developments in the field of evolutionary developmental biology have demonstrated how variation can be introduced to a species by mutations, genetic drift or reshuffling of genes in sexual reproduction and the movement between populations. These processes, as well as others, such as 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 the phenotype (the expression of genotypes in an individual).

Incorporating evolutionary thinking into all aspects of biology education can improve students' understanding of phylogeny and evolutionary. In a recent study by Grunspan and co. It was demonstrated that teaching students about the evidence for evolution boosted their understanding of evolution during a college-level course in biology. For more details on how to teach evolution read The Evolutionary Potential in All Areas of Biology or Thinking Evolutionarily as a Framework for Integrating Evolution into Life Sciences Education.

Evolution in Action

Scientists have traditionally looked at evolution through the past, studying fossils, and comparing species. They also study living organisms. Evolution is not a distant moment; it is an ongoing process. The virus reinvents itself to avoid new medications and bacteria mutate to resist antibiotics. Animals adapt their behavior in the wake of a changing environment. The changes that result are often evident.

It wasn't until 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 from one generation to the next.

In the past, if a certain allele - the genetic sequence that determines colour - was found in a group of organisms that interbred, it could be more common than any other allele. In time, this could mean that the number of moths with black pigmentation may increase. 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 a species, such as bacteria, has a high generation turnover. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that descend from a single strain. Samples of each population have been taken regularly, and more than 500.000 generations of E.coli have been observed to have passed.

Lenski's research has revealed that mutations can drastically alter the speed at which a population reproduces and, consequently the rate at which it changes. It also demonstrates that evolution takes time, something that is difficult for some to accept.

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

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