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 the sciences comprehend the evolution theory and how it is incorporated in all areas of scientific research.

This site provides a wide range of tools for students, teachers, and general readers on evolution. It includes important video clips from NOVA and WGBH's science programs on DVD.

Tree of Life

The Tree of Life is an ancient symbol that symbolizes the interconnectedness of all life. It is an emblem of love and unity across many cultures. It also has practical applications, like providing a framework for understanding the evolution of species and how they respond to changes in the environment.

Early attempts to represent the world of biology were founded on categorizing organisms on their physical and metabolic characteristics. These methods, which are based on the sampling of different parts of organisms, or DNA fragments 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.

Genetic techniques have greatly expanded our ability to represent the Tree of Life by circumventing the need for direct observation and experimentation. We can create trees by using molecular methods like the small-subunit ribosomal gene.

The Tree of Life has been dramatically expanded through genome sequencing. However there is still a lot of biodiversity to be discovered. This is especially true for microorganisms that are difficult to cultivate and are typically found in one sample5. A recent analysis of all genomes produced an initial draft of a Tree of Life. This includes a wide range of bacteria, archaea and other organisms that have not yet been identified or the diversity of which is not well understood6.

This expanded Tree of Life can be used to assess the biodiversity of a specific region and determine if certain habitats require special protection. The information can be used in a range of ways, from identifying new treatments to fight disease to enhancing the quality of crop yields. The information is also incredibly beneficial to conservation efforts. It helps biologists discover areas that are most likely to have cryptic species, which could have important metabolic functions and are susceptible to human-induced change. While funds to protect biodiversity are important, the most effective way to conserve the world's biodiversity is to equip more people in developing nations with the knowledge they need to take action locally and encourage conservation.

Phylogeny

A phylogeny, also known as an evolutionary tree, shows the connections between different groups of organisms. Utilizing molecular data as well as morphological similarities and distinctions, or ontogeny (the process of the development of an organism) scientists can create a phylogenetic tree that illustrates the evolutionary relationship between taxonomic groups. The concept of phylogeny is fundamental to understanding evolution, biodiversity and genetics.

A basic phylogenetic tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms with similar traits that evolved from common ancestors. These shared traits are either homologous or 에볼루션바카라 analogous. Homologous traits share their evolutionary roots, while analogous traits look similar but do not have the identical origins. Scientists group similar traits into a grouping known as a Clade. Every organism in a group share a characteristic, for example, amniotic egg production. They all came from an ancestor that had these eggs. The clades are then linked to form a phylogenetic branch that can determine which organisms have the closest connection to each other.

For a more precise and accurate phylogenetic tree, scientists use molecular data from DNA or RNA to identify the relationships among organisms. This data is more precise than the morphological data and gives evidence of the evolutionary background of an organism or group. Researchers can utilize Molecular Data to determine the age of evolution of organisms and identify the number of organisms that have the same ancestor.

The phylogenetic relationships of organisms can be influenced by several factors, including phenotypic flexibility, a type of behavior that alters in response to unique environmental conditions. This can cause a characteristic to appear more resembling to one species than to the other and obscure the phylogenetic signals. However, this problem can be reduced by the use of techniques such as cladistics that combine analogous and homologous features into the tree.

In addition, 에볼루션사이트 phylogenetics can aid in predicting the duration and rate of speciation. This information will assist conservation biologists in making decisions about which species to save from disappearance. In the end, it is the conservation of phylogenetic variety that will lead to an ecosystem that is complete and 에볼루션 무료체험 balanced.

Evolutionary Theory

The central theme in evolution is that organisms change over time as a result of their interactions with their environment. Many theories of evolution have been developed by a wide variety of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop slowly according to its requirements and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits causes changes that could be passed on to offspring.

In the 1930s and 1940s, ideas from various fields, including genetics, natural selection, and particulate inheritance--came together to create the modern evolutionary theory that explains how evolution occurs through the variation of genes within a population and how these variants change over time as a result of natural selection. This model, which incorporates mutations, genetic drift, gene flow and sexual selection can be mathematically described.

Recent discoveries in the field of evolutionary developmental biology have demonstrated that genetic variation can be introduced into a species through mutation, genetic drift, and reshuffling of genes in sexual reproduction, as well as by migration between populations. These processes, along with others such as directional selection or genetic erosion (changes in the frequency of a genotype over time) can lead to evolution that is defined as changes in the genome of the species over time and also by changes in phenotype over time (the expression of the genotype within the individual).

Incorporating evolutionary thinking into all aspects of biology education can increase student understanding of the concepts of phylogeny as well as evolution. In a study by Grunspan and co. It was found that teaching students about the evidence for evolution boosted their understanding of evolution in an undergraduate biology course. For more information on how to teach about evolution look up The Evolutionary Potential in All Areas of Biology or Thinking Evolutionarily A Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Scientists have traditionally looked at evolution through the past, analyzing fossils and comparing species. They also observe living organisms. Evolution is not a distant moment; it is an ongoing process that continues to be observed today. Viruses reinvent themselves to avoid new drugs and bacteria evolve to resist antibiotics. Animals alter their behavior because of a changing environment. The changes that occur are often apparent.

But it wasn't until the late-1980s that biologists realized that natural selection can be seen in action, as well. The key is the fact that different traits can confer a different rate of survival as well as reproduction, and may be passed on from one generation to the next.

In the past, if an allele - the genetic sequence that determines color - was present in a population of organisms that interbred, it could become more prevalent 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.

Monitoring evolutionary changes in action is easier when a particular species has a rapid generation turnover such as bacteria. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that descend from a single strain. Samples from 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 demonstrated that mutations can alter the rate of change and the rate at which a population reproduces. It also shows evolution takes time, 에볼루션사이트 a fact that is hard for some to accept.

Microevolution can also be seen in the fact that mosquito genes for resistance to pesticides are more prevalent in areas that have used insecticides. This is because pesticides cause an enticement that favors those with resistant genotypes.

The rapidity of evolution has led to an increasing awareness of its significance particularly in a world which is largely shaped by human activities. This includes pollution, climate change, and habitat loss that hinders many species from adapting. Understanding evolution can help us make smarter decisions regarding the future of our planet, and the lives of its inhabitants.