The Academy's Evolution Site

Biology is a key concept in biology. The Academies are involved in helping those who are interested in science understand evolution theory and how it is permeated throughout all fields of scientific research.

This site provides students, teachers and general readers with a variety 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 of the interconnectedness of all life. It appears in many religions and cultures as an emblem of unity and 에볼루션 바카라 love. It also has many practical applications, such as providing a framework for understanding the history of species and how they react to changes in environmental conditions.

Early attempts to describe the world of biology were founded on categorizing organisms on their metabolic and physical characteristics. These methods, based on the sampling of various parts of living organisms or on short fragments of their DNA significantly increased the variety that could be included in the tree of life2. However these trees are mainly made up of eukaryotes. Bacterial diversity remains vastly underrepresented3,4.

Genetic techniques have greatly broadened 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 such as 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 true for microorganisms that are difficult to cultivate, and are typically present in a single sample5. A recent analysis of all genomes that are known has produced a rough draft version of the Tree of Life, including numerous bacteria and archaea that have not been isolated, and whose diversity is poorly understood6.

The expanded Tree of Life is particularly useful for assessing the biodiversity of an area, helping to determine whether specific habitats require protection. This information can be utilized in a variety of ways, from identifying new treatments to fight disease to improving crops. This information is also extremely valuable in conservation efforts. It can help biologists identify areas that are likely to have cryptic species, which may have important metabolic functions, and could be susceptible to human-induced change. Although funds to protect biodiversity are crucial but the most effective way to preserve the world's biodiversity is for more people in developing countries to be equipped with the knowledge to act locally in order to promote conservation from within.

Phylogeny

A phylogeny (also called an evolutionary tree) depicts the relationships between organisms. Using 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 categories. Phylogeny is crucial in understanding the evolution of biodiversity, evolution and genetics.

A basic phylogenetic tree (see Figure PageIndex 10 Identifies the relationships between organisms that have similar traits and have evolved from a common ancestor. These shared traits can be either homologous or analogous. Homologous traits are the same in terms of their evolutionary path. Analogous traits might appear like they are, but they do not have the same ancestry. Scientists combine similar traits into a grouping called a clade. For instance, all the organisms that make up a clade have the characteristic of having amniotic egg and evolved from a common ancestor who had eggs. The clades are then linked to create a phylogenetic tree to determine the organisms with the closest connection to each other.

Scientists utilize DNA or 에볼루션코리아 RNA molecular information to build a phylogenetic chart which is more precise and precise. This data is more precise than morphological data and provides evidence of the evolution background of an organism or 에볼루션게이밍 group. Researchers can use Molecular Data to calculate the age of evolution of living organisms and discover the number of organisms that share the same ancestor.

The phylogenetic relationships of organisms are influenced by many factors including phenotypic plasticity, a kind of behavior that alters in response to specific environmental conditions. This can make a trait appear more similar to one species than another, obscuring the phylogenetic signals. However, this problem can be reduced by the use of techniques like cladistics, which include a mix of similar and homologous traits into the tree.

In addition, phylogenetics can help predict the time and pace of speciation. This information can help conservation biologists decide which species they should protect from the threat of extinction. It is ultimately the preservation of phylogenetic diversity which will result in a complete and balanced ecosystem.

Evolutionary Theory

The fundamental concept of evolution is that organisms develop distinct characteristics over time based on their interactions with their environments. Many scientists have proposed theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that a living thing would develop according to its own needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern taxonomy system that is hierarchical and 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 next generation.

In the 1930s and 1940s, theories from various fields, including natural selection, genetics, and particulate inheritance -- came together to form the current evolutionary theory, which defines how evolution occurs through the variations of genes within a population and how those variants change over time due to natural selection. This model, which encompasses mutations, genetic drift, gene flow and sexual selection is mathematically described.

Recent developments in the field of evolutionary developmental biology have shown the ways in which variation can be introduced to a species through mutations, genetic drift and reshuffling of genes during sexual reproduction, and even migration between populations. These processes, as well as others like directional selection and genetic erosion (changes in the frequency of the genotype over time) can lead to evolution, which is defined by change in the genome of the species over time, and also the change in phenotype as time passes (the expression of the genotype within the individual).

Students can gain a better understanding of phylogeny by incorporating evolutionary thinking in all areas of biology. In a study by Grunspan and co. It was found that teaching students about the evidence for evolution boosted their understanding of evolution during the course of a college biology. For more information on how to teach about evolution read The Evolutionary Potential in All Areas of Biology or 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 a thing that occurred in the past; it's an ongoing process that is taking place today. Bacteria transform and resist antibiotics, viruses reinvent themselves and escape new drugs and animals alter their behavior in response to the changing climate. The changes that result are often visible.

It wasn't until the 1980s that biologists began realize that natural selection was at work. The reason is that different characteristics result in different rates of survival and reproduction (differential fitness), and 에볼루션사이트 can be passed down from one generation to the next.

In the past, if an allele - the genetic sequence that determines colour - appeared 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 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, biologist Richard Lenski has been tracking twelve populations of E. coli that descended from a single strain. samples of each population are taken on a regular basis and more than 500.000 generations have passed.

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

Another example of microevolution is the way mosquito genes for resistance to pesticides appear more frequently in populations where insecticides are used. This is due to pesticides causing a selective pressure which favors those who have resistant genotypes.

The rapid pace of evolution taking place has led to an increasing recognition of its importance in a world that is shaped by human activity--including climate changes, pollution and the loss of habitats that hinder the species from adapting. Understanding the evolution process can assist you in making better choices regarding the future of the planet and its inhabitants.