The Academy's Evolution Site

Biological evolution is one of the most fundamental concepts in biology. The Academies are committed to helping those interested in science comprehend the evolution theory and how it is incorporated in all areas of scientific research.

This site provides teachers, students and general readers with a wide range of learning resources on 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 of the interconnectedness of all life. It appears in many religions and cultures as an emblem of unity and love. It has many practical applications as well, such as providing a framework to understand the evolution of species and how they respond to changes in environmental conditions.

Early attempts to represent the world of biology were based on categorizing organisms based on their metabolic and physical 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. These trees are mostly populated of eukaryotes, 에볼루션 바카라 체험 while bacterial diversity is vastly underrepresented3,4.

By avoiding the need for direct observation and experimentation, genetic techniques have enabled us to depict the Tree of Life in a much more accurate way. In particular, molecular methods allow us to build trees using sequenced markers, such as the small subunit ribosomal RNA gene.

Despite the rapid expansion of the Tree of Life through genome sequencing, much biodiversity still is waiting to be discovered. This is especially relevant to microorganisms that are difficult to cultivate and are typically present in a single sample5. Recent analysis of all genomes has produced an unfinished draft of the Tree of Life. This includes a large number of archaea, bacteria, and other organisms that have not yet been identified or their diversity is not well understood6.

The expanded Tree of Life can be used to assess the biodiversity of a specific area and determine if certain habitats need special protection. The information is useful in a variety of ways, including identifying new drugs, combating diseases and improving the quality of crops. This information is also useful to conservation efforts. It helps biologists discover areas most likely to be home to cryptic species, which may have important metabolic functions, and could be susceptible to changes caused by humans. While funds to protect biodiversity are crucial but the most effective way to preserve the world's biodiversity is for more people living in developing countries to be equipped with the knowledge to act locally in order to promote conservation from within.

Phylogeny

A phylogeny (also known as an evolutionary tree) illustrates the relationship between different organisms. Scientists can construct an phylogenetic chart which shows the evolutionary relationships between taxonomic categories using molecular information and morphological similarities or differences. Phylogeny is crucial in understanding evolution, biodiversity and genetics.

A basic phylogenetic tree (see Figure PageIndex 10 Identifies the relationships between organisms with similar traits and evolved from an ancestor that shared traits. These shared traits can be analogous or homologous. Homologous traits are similar in terms of their evolutionary path. Analogous traits might appear like they are but they don't have the same origins. Scientists group similar traits together into a grouping known as a clade. Every organism in a group share a trait, such as amniotic egg production. They all came from an ancestor who had these eggs. The clades then join to form a phylogenetic branch to determine which organisms have the closest relationship to.

Scientists utilize DNA or RNA molecular data to build a phylogenetic chart that is more accurate and precise. This information is more precise than morphological information and provides evidence of the evolution background of an organism or group. Researchers can use Molecular Data to determine the age of evolution of organisms and determine how many organisms have an ancestor common to all.

Phylogenetic relationships can be affected by a number of factors such as the phenomenon of phenotypicplasticity. This is a type behaviour that can change in response to specific environmental conditions. This can cause a trait to appear more resembling to one species than another which can obscure the phylogenetic signal. This problem can be addressed by using cladistics. This is a method that incorporates a combination of homologous and analogous features in the tree.

Furthermore, phylogenetics may help predict the time and pace of speciation. This information can assist conservation biologists in making decisions about which species to safeguard from disappearance. In the end, it's the preservation of phylogenetic diversity which will create an ecosystem that is balanced and complete.

Evolutionary Theory

The central theme in evolution is that organisms change over time due to their interactions with their environment. A variety of theories about evolution have been developed by a variety of scientists, including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing gradually according to its requirements, the Swedish botanist Carolus Linnaeus (1707-1778) who developed the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits cause changes that could be passed onto offspring.

In the 1930s and 1940s, concepts from a variety of fields -- including genetics, natural selection and 에볼루션코리아 particulate inheritance - came together to create the modern evolutionary theory, which defines how evolution occurs through the variations of genes within a population and how these variants change over time due to natural selection. This model, called genetic drift or mutation, gene flow, and sexual selection, 에볼루션 게이밍 is the foundation of current evolutionary biology, and is mathematically described.

Recent discoveries in evolutionary developmental biology have shown how variation can be introduced to a species by genetic drift, mutations and reshuffling of genes during sexual reproduction and the movement between populations. These processes, as well as other ones like the directional selection process and the erosion of genes (changes in frequency of genotypes over time) can result in evolution. Evolution is defined as changes in the genome over time as well as changes in the phenotype (the expression of genotypes within individuals).

Incorporating evolutionary thinking into all areas of biology education can improve students' understanding of phylogeny and evolutionary. A recent study conducted by Grunspan and colleagues, for 에볼루션 슬롯게임 instance revealed that teaching students about the evidence for evolution increased students' understanding of evolution in a college biology course. For more details about how to teach evolution read The Evolutionary Potency in all Areas of Biology or Thinking Evolutionarily A Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Scientists have traditionally studied evolution by looking in the past, studying fossils, and comparing species. They also study living organisms. Evolution is not a past moment; it is a process that continues today. The virus reinvents itself to avoid new antibiotics and bacteria transform to resist antibiotics. Animals alter their behavior because of a changing environment. The changes that occur are often visible.

But it wasn't until the late 1980s that biologists realized that natural selection can be observed in action as well. The key is that different characteristics result in different rates of survival and reproduction (differential fitness) and are passed from one generation to the next.

In the past, if an allele - the genetic sequence that determines colour - was found in a group of organisms that interbred, it could become more prevalent than any other allele. In time, this could mean the number of black moths within the population could 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 species has a rapid turnover of its generation like bacteria. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that are descended from a single strain. Samples from each population were taken frequently and more than 50,000 generations of E.coli have been observed to have passed.

Lenski's research has revealed that mutations can drastically alter the rate at which a population reproduces--and so the rate at which it alters. It also proves that evolution takes time--a fact that many are unable to accept.

Microevolution is also evident in the fact that mosquito genes for resistance to pesticides are more prevalent in areas where insecticides are used. This is due to pesticides causing an exclusive pressure that favors individuals who have resistant genotypes.

The speed at which evolution can take place has led to a growing appreciation of its importance in a world that is shaped by human activity--including climate changes, pollution and the loss of habitats which prevent many species from adapting. Understanding evolution will assist you in making better choices regarding the future of the planet and its inhabitants.