The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies have been for a long time involved in helping those interested in science understand the theory of evolution and how it affects all areas of scientific exploration.

This site provides teachers, students and general readers with a range of learning 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 all life. It is an emblem of love and unity in many cultures. It has numerous practical applications in addition to providing a framework to understand the evolution of species and how they react to changes in environmental conditions.

The first attempts to depict the world of biology were built on categorizing organisms based on their metabolic and physical characteristics. These methods, based on the sampling of different parts of living organisms or short fragments of their DNA greatly increased the variety of organisms that could be represented in the tree of life2. These trees are mostly populated by eukaryotes and bacterial diversity is vastly underrepresented3,4.

By avoiding the need for direct observation and experimentation, 에볼루션 코리아카지노 (Xiaoditech writes) genetic techniques have made it possible to depict the Tree of Life in a more precise manner. 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 still much biodiversity to be discovered. This is especially relevant to microorganisms that are difficult to cultivate and are usually 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 a large number of archaea and bacteria that have not been isolated, and whose diversity is poorly understood6.

The expanded Tree of Life can be used to assess the biodiversity of a specific region and determine if specific habitats need special protection. This information can be used in a variety of ways, from identifying new remedies to fight diseases to improving the quality of crops. The information is also useful for conservation efforts. It helps biologists determine the areas that are most likely to contain cryptic species that could have significant metabolic functions that could be at risk of anthropogenic changes. While funding to protect biodiversity are important, the best way to conserve the world's biodiversity is to empower the people of developing nations with the information they require to take action locally and encourage conservation.

Phylogeny

A phylogeny (also known as an evolutionary tree) illustrates the relationship between different organisms. Using molecular data similarities and differences in morphology, or ontogeny (the process of the development of an organism), scientists can build a phylogenetic tree that illustrates the evolutionary relationship between taxonomic categories. The role of phylogeny is crucial in understanding genetics, biodiversity and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 ) identifies the relationships between organisms that share similar traits that have evolved from common ancestors. These shared traits could be either analogous or homologous. Homologous characteristics are identical in terms of their evolutionary path. Analogous traits could appear like they are however they do not have the same origins. Scientists group similar traits into a grouping called a clade. All organisms in a group have a common characteristic, like 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 the organisms with the closest connection 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 between organisms. This data is more precise than the morphological data and provides evidence of the evolutionary history of an individual or group. Researchers can utilize Molecular Data to estimate the age of evolution of organisms and identify the number of organisms that have an ancestor common to all.

Phylogenetic relationships can be affected by a number of factors such as the phenotypic plasticity. This is a type behavior that changes as a result of particular environmental conditions. This can cause a characteristic to appear more similar to one species than other species, which can obscure the phylogenetic signal. However, this problem can be cured by the use of techniques like cladistics, which combine analogous and homologous features into the tree.

In addition, phylogenetics helps predict the duration and rate at which speciation takes place. This information can assist conservation biologists in making choices about which species to save from disappearance. In the end, it's the conservation of phylogenetic diversity that will lead to an ecosystem that is complete and balanced.

Evolutionary Theory

The main idea behind evolution is that organisms develop various characteristics over time based on their interactions with their environment. Many scientists have come up with theories of evolution, including 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 created the modern taxonomy system that is hierarchical, as well as Jean-Baptiste Lamarck (1844-1829), who believed that the use or non-use of traits can lead to changes that are passed on to the next generation.

In the 1930s and 1940s, ideas from different fields, including genetics, natural selection, and particulate inheritance, came together to form a modern theorizing of evolution. This describes how evolution occurs by the variation in genes within the population and how these variants alter over time due to natural selection. This model, which is known as genetic drift mutation, gene flow and sexual selection, is a cornerstone of the current evolutionary biology and is mathematically described.

Recent developments in the field of evolutionary developmental biology have shown that variation can be introduced into a species through mutation, genetic drift and reshuffling genes during sexual reproduction, and also through the movement of populations. These processes, as well as other ones like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time) can lead to evolution which is defined by change in the genome of the species over time, and also by changes in phenotype as time passes (the expression of the genotype in the individual).

Incorporating evolutionary thinking into all aspects of biology education can improve students' understanding of phylogeny and evolutionary. A recent study by Grunspan and colleagues, for instance, showed that teaching about the evidence supporting evolution helped students accept the concept of evolution in a college-level biology class. To find out more about how to teach about evolution, see The Evolutionary Potential of All Areas of Biology and Thinking Evolutionarily: 에볼루션 슬롯게임 슬롯, bitsdujour.com, A Framework for Infusing Evolution in Life Sciences Education.

Evolution in Action

Scientists have traditionally looked at evolution through the past--analyzing fossils and comparing species. They also study living organisms. But evolution isn't just something that happened in the past. It's an ongoing process, taking place in the present. Bacteria transform and resist antibiotics, viruses evolve and escape new drugs and 에볼루션 animals alter their behavior in response to a changing planet. The changes that result are often visible.

It wasn't until the 1980s that biologists began to realize that natural selection was in play. The key is the fact that different traits result in the ability to survive at different rates and reproduction, and they can be passed on from one generation to the next.

In the past, when one particular allele, the genetic sequence that determines coloration--appeared in a population of interbreeding species, it could rapidly become more common than all other alleles. In time, this could mean that the number of moths sporting black pigmentation in a group may increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

It is easier to see evolutionary change when an organism, like bacteria, has a rapid generation turnover. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain; samples of each population are taken every day and more than 500.000 generations have been observed.

Lenski's research has revealed that mutations can alter the rate of change and the efficiency at which a population reproduces. It also demonstrates that evolution takes time--a fact that some find hard to accept.

Another example of microevolution is that mosquito genes that confer resistance to pesticides show up more often in populations in which insecticides are utilized. Pesticides create an enticement that favors those who have resistant genotypes.

The speed of evolution taking place has led to an increasing awareness of its significance in a world shaped by human activity--including climate change, pollution, and the loss of habitats that prevent many species from adjusting. Understanding evolution can help us make smarter choices about the future of our planet as well as the life of its inhabitants.