The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies have long been involved in helping people who are interested in science understand the concept of evolution and how it influences all areas of scientific research.

This site offers a variety of tools for teachers, students 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 is an ancient symbol that symbolizes the interconnectedness of life. It is a symbol of love and harmony in a variety of cultures. It has many practical applications in addition to providing a framework for understanding the history 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 metabolic and physical characteristics. These methods, based on sampling of different parts of living organisms or on short fragments of their DNA, significantly expanded the diversity that could be represented in a tree of life2. The trees are mostly composed by eukaryotes and bacterial diversity is vastly underrepresented3,4.

Genetic techniques have greatly broadened our ability to depict the Tree of Life by circumventing the need for direct observation and experimentation. Trees can be constructed using molecular methods like the small-subunit ribosomal gene.

The Tree of Life has been significantly expanded by genome sequencing. However there is still a lot of diversity to be discovered. This is especially true of microorganisms, which can be difficult to cultivate and are usually only represented in a single sample5. A recent analysis of all genomes that are known has created a rough draft of the Tree of Life, 바카라 에볼루션 (https://freeevolution27919.suomiblog.com/) including numerous bacteria and 에볼루션 무료 바카라 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 protection. The information can be used in a variety of ways, from identifying the most effective treatments to fight disease to enhancing the quality of crops. It is also beneficial for conservation efforts. It helps biologists discover areas that are likely to be home to cryptic species, which could have important metabolic functions and are susceptible to the effects of human activity. Although funds to protect biodiversity are essential but the most effective way to ensure the preservation of biodiversity around the world is for more people in developing countries to be empowered with the knowledge to take action locally to encourage conservation from within.

Phylogeny

A phylogeny (also called an evolutionary tree) depicts the relationships between different organisms. Using molecular data similarities and 에볼루션 무료 바카라 differences in morphology or ontogeny (the course of development of an organism) scientists can create a phylogenetic tree which illustrates the evolutionary relationship between taxonomic groups. The role of phylogeny is crucial in understanding genetics, biodiversity and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms with similar traits that have evolved from common ancestral. These shared traits can be either homologous or analogous. Homologous traits are similar in their evolutionary journey. Analogous traits might appear similar, but they do not have the same origins. Scientists group similar traits together into a grouping referred to as a Clade. All organisms in a group share a trait, such as amniotic egg production. They all came from an ancestor with these eggs. A phylogenetic tree can be constructed by connecting clades to identify the organisms who are the closest to each other.

To create a more thorough 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 the morphological data and gives evidence of the evolutionary background of an organism or group. Researchers can use Molecular Data to estimate the age of evolution of living organisms and discover how many organisms share the same ancestor.

The phylogenetic relationships between species can be influenced by several factors, including phenotypic plasticity an aspect of behavior 에볼루션 슬롯게임 that alters in response to unique environmental conditions. This can cause a trait to appear more like a species another, obscuring the phylogenetic signal. However, this issue can be reduced by the use of techniques such as cladistics which include a mix of homologous and analogous features into the tree.

In addition, phylogenetics can help predict the duration and rate of speciation. This information can 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 result in an ecosystem that is complete and balanced.

Evolutionary Theory

The main idea behind evolution is that organisms change over time due to their interactions with their environment. Several theories of evolutionary change have been developed by a variety of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop gradually according to its needs and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that the use or non-use of traits cause changes that can be passed on to offspring.

In the 1930s and 1940s, theories from a variety of fields -- including genetics, natural selection, and particulate inheritance - came together to form the modern synthesis of evolutionary theory, which defines how evolution is triggered by the variations of genes within a population, 에볼루션 무료 바카라 and how these variants change over time due to natural selection. This model, which encompasses mutations, genetic drift as well as gene flow and sexual selection can be mathematically described.

Recent discoveries in the field of evolutionary developmental biology have shown how variations can be introduced to a species by genetic drift, mutations, reshuffling genes during sexual reproduction and 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, which is defined by changes in the genome of the species over time and also by changes in phenotype over time (the expression of that genotype in an individual).

Incorporating evolutionary thinking into all aspects of biology education can increase students' understanding of phylogeny as well as evolution. A recent study conducted by Grunspan and 무료에볼루션 colleagues, for example revealed that teaching students about the evidence for evolution helped students accept the concept of evolution in a college biology course. To learn more about how to teach about evolution, read The Evolutionary Potential of all Areas of Biology and Thinking Evolutionarily: A Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Scientists have traditionally studied evolution through looking back in 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 adapt their behavior because of a changing environment. The results 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 characteristics result in different rates of survival and reproduction (differential fitness) and are passed down from one generation to the next.

In the past, if a certain allele - the genetic sequence that determines color - appeared in a population of organisms that interbred, it could be more prevalent than any other allele. Over time, this would mean that the number of moths sporting black pigmentation in a population could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

It is easier to observe evolution when a species, such as bacteria, has a rapid generation turnover. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that descend from a single strain. Samples from each population have been taken regularly, and more than 50,000 generations of E.coli have passed.

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

Microevolution can also be seen in the fact that mosquito genes that confer resistance to pesticides are more common in populations that have used insecticides. This is because the use of pesticides causes a selective pressure that favors those who have resistant genotypes.

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