What Freud Can Teach Us About Evolution Site

The Academy's Evolution Site

The concept of biological evolution is among the most central concepts in biology. The Academies are involved in helping those who are interested in science to learn about the theory of evolution and how it is incorporated throughout all fields of scientific research.

This site provides teachers, students and general readers with a wide range of learning resources about evolution. It includes key video clip from NOVA and WGBH produced science programs on DVD.

Tree of Life

The Tree of Life, an ancient symbol, symbolizes the interconnectedness of all life. It is used in many religions and cultures as an emblem of unity and love. It also has important practical applications, like providing a framework to understand the history of species and how they react to changes in environmental conditions.

Early attempts to represent the world of biology were built on categorizing organisms based on their metabolic and physical characteristics. These methods, which rely on the collection of various parts of organisms or short DNA fragments have greatly increased the diversity of a Tree of Life2. However, 에볼루션 무료 바카라 these trees are largely composed of eukaryotes; bacterial diversity is not represented in a large way3,4.

Genetic techniques have significantly expanded our ability to represent the Tree of Life by circumventing the requirement for direct observation and 에볼루션코리아 experimentation. We can construct trees by using molecular methods like the small-subunit ribosomal gene.

The Tree of Life has been significantly expanded by genome sequencing. However there is a lot of diversity 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 created a rough draft of the Tree of Life, including a large number of bacteria and archaea that have not been isolated, and their diversity is not fully understood6.

This expanded Tree of Life is particularly useful for 에볼루션 사이트 assessing the biodiversity of an area, helping to determine if specific habitats require special protection. This information can be utilized in a range of ways, from identifying new treatments to fight disease to improving the quality of crops. The information is also valuable to conservation efforts. It can help biologists identify areas most likely to have species that are cryptic, which could have vital metabolic functions, and could be susceptible to human-induced change. While conservation funds are important, the best method to preserve the world's biodiversity is to equip the people of developing nations with the knowledge they need to act locally and promote conservation.

Phylogeny

A phylogeny, also called an evolutionary tree, reveals the relationships between various groups of organisms. Using molecular data as well as morphological similarities and distinctions, or ontogeny (the process of the development of an organism) scientists can construct a phylogenetic tree that illustrates the evolution of taxonomic categories. Phylogeny is essential in understanding the evolution of biodiversity, 에볼루션 무료체험 evolution and genetics.

A basic phylogenetic Tree (see Figure PageIndex 10 Identifies the relationships between organisms that have similar traits and 에볼루션 룰렛 슬롯 - X 7cq explained in a blog post - have evolved from an ancestor that shared traits. These shared traits can be homologous, or analogous. Homologous traits are identical in their underlying evolutionary path and analogous traits appear similar but do not have the same origins. Scientists group similar traits together into a grouping referred to as a Clade. For example, all of the species in a clade share the characteristic of having amniotic eggs. They evolved from a common ancestor which had these eggs. A phylogenetic tree can be built by connecting the clades to identify the organisms which 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 determine the relationships among organisms. This information is more precise and provides evidence of the evolution of an organism. Molecular data allows researchers to identify the number of species that have an ancestor common to them and estimate their evolutionary age.

The phylogenetic relationships of organisms can be influenced by several factors, including phenotypic flexibility, a kind of behavior that alters in response to specific environmental conditions. This can cause a trait to appear more resembling to one species than to the other, obscuring the phylogenetic signals. This issue can be cured by using cladistics. This is a method that incorporates a combination of homologous and analogous features in the tree.

Additionally, phylogenetics aids determine the duration and rate of speciation. This information can help conservation biologists decide which species to protect from the threat of extinction. Ultimately, it is the preservation of phylogenetic diversity that will result in an ecologically balanced and complete ecosystem.

Evolutionary Theory

The central theme of evolution is that organisms acquire different features over time as a result of their interactions with their surroundings. A variety of theories about evolution have been proposed by a wide range of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who believed that an organism would evolve gradually according to its needs and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who developed the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that the use or non-use of traits cause changes that could be passed on to the offspring.

In the 1930s and 1940s, ideas from a variety of fields--including natural selection, genetics, and particulate inheritance -- came together to create the modern evolutionary theory that explains 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 in gene flow, and sexual selection is mathematically described.

Recent developments in the field of evolutionary developmental biology have demonstrated that genetic variation can be introduced into a species by mutation, genetic drift, and reshuffling of genes in sexual reproduction, and also through migration between populations. These processes, along with others like directional selection and genetic erosion (changes in the frequency of the genotype over time) can result in 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 that genotype in the individual).

Incorporating evolutionary thinking into all aspects of biology education could increase student understanding of the concepts of phylogeny and evolution. A recent study conducted by Grunspan and colleagues, for example, showed that teaching about the evidence supporting evolution increased students' acceptance of evolution in a college biology class. For more information on how to teach about evolution, please see The Evolutionary Potential in all Areas of Biology and Thinking Evolutionarily: A Framework for Infusing the Concept of Evolution into Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution through looking back--analyzing fossils, comparing species and observing living organisms. But evolution isn't a thing that happened in the past; it's an ongoing process that is taking place today. Bacteria evolve and resist antibiotics, viruses evolve and escape new drugs and animals alter their behavior to the changing climate. The changes that result are often apparent.

However, it wasn't until late-1980s that biologists realized that natural selection can be observed in action as well. The key is that various characteristics result in different rates of survival and reproduction (differential fitness), and can be transferred 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 organisms, it might quickly become more prevalent than all other alleles. In time, this could mean that the number of moths that have 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 see evolutionary change when a species, such as bacteria, has a high generation turnover. Since 1988, biologist Richard Lenski has been tracking twelve populations of E. coli that descended from a single strain; samples from each population are taken regularly and over 50,000 generations have now passed.

Lenski's research has shown that a mutation can dramatically alter the speed at the rate at which a population reproduces, and consequently, the rate at which it changes. It also proves that evolution is slow-moving, a fact that many find difficult to accept.

Microevolution can be observed in the fact that mosquito genes for pesticide resistance are more prevalent in areas where insecticides have been used. That's because the use of pesticides causes a selective pressure that favors individuals with resistant genotypes.

The rapidity of evolution has led to a growing appreciation of its importance, especially in a world shaped largely by human activity. This includes the effects of climate change, pollution and habitat loss that prevents many species from adapting. Understanding evolution can help you make better decisions about the future of our planet and its inhabitants.