The Academy's Evolution Site

Biology is a key concept in biology. The Academies have been for a long time involved in helping those interested in science understand the concept of evolution and how it permeates every area of scientific inquiry.

This site provides teachers, students and general readers with a wide range of learning resources about 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 represents the interconnectedness of all life. It appears in many cultures and spiritual beliefs as symbolizing unity and love. It also has important practical applications, like providing a framework to understand the evolution of species and how they react to changes in the environment.

The first attempts at depicting the world of biology focused on categorizing species into distinct categories that had been identified by their physical and metabolic characteristics1. These methods are based on the sampling of different parts of organisms or short DNA fragments have greatly increased the diversity of a tree of Life2. However these trees are mainly made up of eukaryotes. Bacterial diversity remains vastly underrepresented3,4.

By avoiding the necessity for direct experimentation and observation genetic techniques have enabled us to depict the Tree of Life in a much more accurate way. We can construct trees using molecular techniques, such as the small-subunit ribosomal gene.

The Tree of Life has been greatly expanded thanks to genome sequencing. However, there is still much diversity to be discovered. This is especially true of microorganisms that are difficult to cultivate and are usually only represented in a single sample5. A recent analysis of all genomes produced an initial draft of a Tree of Life. This includes a wide range of archaea, bacteria, 에볼루션 사이트 and other organisms that have not yet been isolated, or their diversity is not well understood6.

The expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, 에볼루션 블랙잭 helping to determine whether specific habitats require protection. The information can be used in a range of ways, from identifying the most effective medicines to combating disease to enhancing crops. This information is also extremely beneficial to conservation efforts. It can aid biologists in identifying areas that are likely to be home to cryptic species, which could have vital metabolic functions, and 에볼루션 사이트 could be susceptible to human-induced change. While funds to protect biodiversity are essential, the best way to conserve the world's biodiversity is to empower more people in developing nations with the knowledge they need to act locally and promote conservation.

Phylogeny

A phylogeny (also known as an evolutionary tree) shows the relationships between different organisms. Scientists can build a phylogenetic diagram that illustrates the evolution of taxonomic categories using molecular information and morphological differences or similarities. 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 ancestral. These shared traits may be homologous, or analogous. Homologous traits are similar in their underlying evolutionary path while analogous traits appear like they do, but don't have the same origins. Scientists group similar traits into a grouping known as a Clade. All members of a clade share a characteristic, like amniotic egg production. They all derived from an ancestor that had these eggs. The clades are then connected to create a phylogenetic tree to identify organisms that have the closest relationship to.

Scientists make use of DNA or RNA molecular information to create a phylogenetic chart which is more precise and detailed. This information is more precise than morphological information and gives evidence of the evolutionary history of an organism or group. Molecular data allows researchers to determine the number of species who share a common ancestor and to estimate their evolutionary age.

The phylogenetic relationships between organisms can be influenced by several factors, including phenotypic plasticity a kind of behavior that alters in response to specific environmental conditions. This can cause a characteristic to appear more similar in one species than another, clouding the phylogenetic signal. This problem can be addressed by using cladistics, which is a a combination of analogous and homologous features in the tree.

Furthermore, phylogenetics may help predict the time and pace of speciation. This information can assist conservation biologists make decisions about the species they should safeguard from extinction. Ultimately, it is the preservation of phylogenetic diversity which will result in a complete and balanced ecosystem.

Evolutionary Theory

The main idea behind evolution is that organisms change over time as a result of their interactions with their environment. A variety of theories about evolution have been proposed by a variety of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop slowly in accordance with its needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1744-1829) who suggested that use or 에볼루션 사이트 disuse of traits can cause changes that could be passed onto offspring.

In the 1930s and 1940s, concepts from various fields, including genetics, natural selection, and particulate inheritance, came together to create a modern synthesis of evolution theory. This describes how evolution happens through the variation of genes in a population and how these variations alter over time due to natural selection. This model, known as genetic drift or mutation, gene flow and sexual selection, is a key element of current evolutionary biology, and can be mathematically explained.

Recent developments in the field of evolutionary developmental biology have revealed the ways in which variation can be introduced to a species through genetic drift, mutations or reshuffling of genes in sexual reproduction, and even migration between populations. These processes, 에볼루션 무료 바카라 along with others such as directional selection or genetic erosion (changes in the frequency of an individual's genotype over time) can lead to evolution, which is defined by changes in the genome of the species over time, and the change in phenotype over time (the expression of that genotype within the individual).

Incorporating evolutionary thinking into all areas of biology education can improve students' understanding of phylogeny as well as evolution. A recent study conducted by Grunspan and colleagues, for instance, showed that teaching about the evidence for evolution increased students' acceptance of evolution in a college-level biology class. To find out more about how to teach about evolution, look up The Evolutionary Potential of All Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution in Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution through studying fossils, comparing species, and studying living organisms. Evolution isn't a flims moment; it is an ongoing process. Viruses reinvent themselves to avoid new antibiotics and bacteria transform to resist antibiotics. Animals alter their behavior as a result of the changing environment. The changes that occur are often apparent.

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

In the past, if a certain allele - the genetic sequence that determines colour - was found in a group of organisms that interbred, it could be more prevalent than any other allele. In time, this could mean that the number of moths with 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 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 were taken frequently and more than 50,000 generations of E.coli have been observed to have passed.

Lenski's work has shown that mutations can alter the rate of change and the effectiveness of a population's reproduction. It also demonstrates that evolution takes time, a fact that some people are unable to accept.

Another example of microevolution is that mosquito genes for resistance to pesticides are more prevalent in populations in which insecticides are utilized. This is due to pesticides causing an exclusive pressure that favors individuals who have resistant genotypes.

The speed at which evolution takes place has led to a growing awareness of its significance in a world that is shaped by human activity, including climate changes, pollution and the loss of habitats that prevent many species from adapting. Understanding evolution will help you make better decisions regarding the future of the planet and 에볼루션 무료체험 its inhabitants.