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

The Academy's Evolution Site

The concept of biological evolution is among the most important concepts in biology. The Academies are involved in helping those who are interested in science learn about the theory of evolution and how it is incorporated across all areas of scientific research.

This site provides teachers, students and general readers with a range of educational resources on evolution. It includes the most 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 all life. It is a symbol of love and unity in many cultures. It also has many practical applications, like providing a framework to understand the history of species and how they react to changes in the environment.

Early attempts to describe the biological world were founded on categorizing organisms on their physical and metabolic characteristics. These methods depend on the collection of various parts of organisms or fragments of DNA have greatly increased the diversity of a Tree of Life2. However the trees are mostly made up of eukaryotes. Bacterial diversity is still largely unrepresented3,4.

Genetic techniques have greatly broadened our ability to represent the Tree of Life by circumventing the need for direct observation and experimentation. Particularly, molecular methods enable us to create trees using sequenced markers, such as the small subunit of 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 relevant to microorganisms that are difficult to cultivate and are typically 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 numerous bacteria and archaea that have not been isolated and their diversity is not fully understood6.

The expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, helping to determine if specific habitats require special protection. This information can be used in many ways, including identifying new drugs, combating diseases and improving crops. It is also valuable for conservation efforts. It can help biologists identify areas that are most likely to be home to cryptic species, which could have vital metabolic functions and be vulnerable to human-induced change. While funds to protect biodiversity are crucial but the most effective way to ensure the preservation of biodiversity around the world 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, reveals the relationships between different groups of organisms. Scientists can build a phylogenetic chart that shows the evolutionary relationships between taxonomic categories using molecular information and morphological similarities or differences. The role of phylogeny is crucial in understanding genetics, biodiversity and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 ) determines the relationship 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 their evolutionary journey. Analogous traits might appear like they are, but they do not have the same ancestry. Scientists group similar traits together into a grouping called a clade. All organisms in a group share a characteristic, for example, 에볼루션 무료체험 amniotic egg production. They all came from an ancestor that had these eggs. The clades then join to form a phylogenetic branch that can determine which organisms have the closest relationship.

Scientists utilize molecular DNA or RNA data to construct a phylogenetic graph that is more accurate and precise. This information is more precise and provides evidence of the evolution of an organism. Researchers can use Molecular Data to estimate the age of evolution of organisms and identify how many species share an ancestor common to all.

The phylogenetic relationships of a species can be affected by a number of factors such as phenotypicplasticity. This is a kind of behaviour that can change due to unique environmental conditions. This can cause a trait to appear more similar to a species than to the other and obscure the phylogenetic signals. However, this issue can be solved through the use of methods like cladistics, which combine homologous and 에볼루션 무료체험 (knowing it) analogous features into the tree.

Additionally, phylogenetics aids determine the duration and rate at which speciation occurs. This information can aid conservation biologists to make decisions about which species they should protect from the threat of extinction. Ultimately, it is the preservation of phylogenetic diversity which will create an ecologically balanced and complete ecosystem.

Evolutionary Theory

The central theme in evolution is that organisms change over time as a result of their interactions with their environment. Many scientists have developed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism would develop according to its own requirements, the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the usage or non-use of certain traits can result in changes that are passed on to the

In the 1930s and 1940s, theories from a variety of fields--including genetics, natural selection, and particulate inheritance - came together to create the modern evolutionary theory that explains how evolution happens through the variation of genes within a population, and how those variations change over time as a result of natural selection. This model, called genetic drift or mutation, gene flow, and 에볼루션 sexual selection, is a key element of the current evolutionary biology and can be mathematically described.

Recent discoveries in evolutionary developmental biology have shown the ways in which variation can be introduced to a species via mutations, genetic drift, reshuffling genes during sexual reproduction, and even migration between populations. These processes, along with others, such as directionally-selected selection and erosion of genes (changes in the frequency of genotypes over time) can lead to evolution. Evolution is defined by changes in the genome over time, 무료에볼루션 as well as changes in phenotype (the expression of genotypes within individuals).

Incorporating evolutionary thinking into all areas of biology education can increase students' understanding of phylogeny and evolution. In a recent study conducted by Grunspan and colleagues. It was demonstrated that teaching students about the evidence for evolution increased their acceptance of evolution during an undergraduate biology course. To find out more about how to teach about evolution, please see The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Traditionally scientists have studied evolution through looking back--analyzing fossils, comparing species, and studying living organisms. But evolution isn't just something that occurred in the past; it's an ongoing process happening in the present. Bacteria transform and resist antibiotics, viruses evolve and are able to evade new medications, and animals adapt their behavior to the changing climate. The changes that result are often easy to see.

It wasn't until the late 1980s when biologists began to realize that natural selection was in play. The key to this is that different traits can confer an individual rate of survival as well as reproduction, and may be passed on from generation to generation.

In the past, if one particular allele--the genetic sequence that defines color in a group of interbreeding species, it could quickly become more prevalent than all other alleles. As time passes, this could mean that the number of moths with black pigmentation 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 easier when a particular species has a rapid generation turnover such as bacteria. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that descend from one strain. The samples of each population have been collected regularly and more than 50,000 generations of E.coli have been observed to have passed.

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

Microevolution is also evident in the fact that mosquito genes that confer 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 selective pressure that favors those with resistant genotypes.

The rapid pace at which evolution can take place has led to a growing appreciation of its importance in a world shaped by human activity--including climate change, pollution and the loss of habitats that hinder the species from adapting. Understanding the evolution process can help us make better decisions about the future of our planet as well as the life of its inhabitants.