The Academy's Evolution Site

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

This site provides a wide range of resources for teachers, students and general readers of evolution. It also includes important video clips 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 life. It appears in many cultures and spiritual beliefs as symbolizing unity and love. It also has important practical uses, like providing a framework to understand the evolution of species and how they respond to changes in environmental conditions.

Early approaches to depicting the biological world focused on the classification of organisms into distinct categories which were identified by their physical and metabolic characteristics1. These methods, which depend on the sampling of different parts of organisms or DNA fragments have significantly increased the diversity of a tree of Life2. These trees are largely composed of eukaryotes, while bacterial diversity is vastly underrepresented3,4.

Genetic techniques have greatly expanded our ability to represent the Tree of Life by circumventing the need for direct observation and experimentation. Particularly, molecular techniques enable us to create trees by using sequenced markers, such as the small subunit ribosomal gene.

Despite the rapid expansion of the Tree of Life through genome sequencing, a large amount of biodiversity is waiting to be discovered. This is particularly true for microorganisms that are difficult to cultivate, and which are usually only found in a single specimen5. A recent analysis of all genomes that are known has created a rough draft of the Tree of Life, including a large number of bacteria and archaea that are not isolated and whose diversity is poorly understood6.

This expanded Tree of Life can be used to assess the biodiversity of a particular area and determine if specific habitats require special protection. The information is useful in a variety of ways, such as finding new drugs, fighting diseases and enhancing crops. This information is also extremely beneficial in conservation efforts. It can aid biologists in identifying areas that are likely to be home to species that are cryptic, which could perform important metabolic functions and are susceptible to the effects of human activity. While funding to protect biodiversity are important, 에볼루션바카라 the best way to conserve the world's biodiversity is to empower more people in developing nations with the information they require to take action locally and encourage conservation.

Phylogeny

A phylogeny, also called an evolutionary tree, illustrates the connections between various groups of organisms. Scientists can construct a phylogenetic diagram that illustrates the evolution of taxonomic groups based on molecular data and morphological similarities or differences. The phylogeny of a tree plays an important role in understanding the relationship between genetics, biodiversity and evolution.

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 could be analogous, 에볼루션 블랙잭 or homologous. Homologous traits share their evolutionary roots while analogous traits appear similar but do not have the same origins. Scientists combine similar traits into a grouping known as a clade. All members of a clade share a trait, such as amniotic egg production. They all derived from an ancestor who had these eggs. The clades then join to create a phylogenetic tree to identify organisms that have the closest relationship to.

For a more precise and accurate phylogenetic tree, scientists use molecular data from DNA or RNA to establish the connections between organisms. This information is more precise than the morphological data and gives evidence of the evolutionary history of an organism or group. Molecular data allows researchers to determine the number of organisms who share the same ancestor and estimate their evolutionary age.

The phylogenetic relationships between species can be influenced by several factors, including phenotypic plasticity a kind of behavior that changes in response to specific environmental conditions. This can make a trait appear more similar to a species than to the other, obscuring the phylogenetic signals. This problem can be mitigated by using cladistics. This is a method that incorporates a combination of analogous and homologous features in the tree.

In addition, phylogenetics helps predict the duration and rate of speciation. This information can assist conservation biologists decide which species they should protect from extinction. In the end, it's the preservation of phylogenetic diversity that will lead to an ecologically balanced and complete ecosystem.

Evolutionary Theory

The main idea behind evolution is that organisms change over time as a result of their interactions with their environment. Many scientists have come up with theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism would evolve 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 use or absence of traits can cause changes that are passed on to the

In the 1930s and 1940s, ideas from a variety of fields--including natural selection, genetics, and particulate inheritance -- came together to form the modern evolutionary theory synthesis which explains how evolution happens through the variations of genes within a population and how those variants change over time as a result of natural selection. This model, which incorporates genetic drift, mutations as well as gene flow and sexual selection is mathematically described.

Recent discoveries in the field of evolutionary developmental biology have revealed that variation can be introduced into a species through mutation, genetic drift, and reshuffling of genes during sexual reproduction, as well as through the movement of populations. These processes, in conjunction with others, 에볼루션 무료체험 바카라 에볼루션 체험 - relevant web-site - such as the directional selection process and the erosion of genes (changes in the frequency of genotypes over time) can lead to evolution. Evolution is defined by changes in the genome over time and changes in phenotype (the expression of genotypes within individuals).

Incorporating evolutionary thinking into all aspects of biology education can increase student understanding of the concepts of phylogeny and evolutionary. In a recent study by Grunspan and colleagues. It was found that teaching students about the evidence for evolution increased their understanding of evolution in an undergraduate biology course. To find out more about how to teach about evolution, please see The Evolutionary Potential of all Areas of Biology and Thinking Evolutionarily: A Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution by looking back--analyzing fossils, comparing species, 에볼루션 and studying living organisms. Evolution isn't a flims event; it is an ongoing process. Bacteria mutate and resist antibiotics, viruses re-invent themselves and escape new drugs, and animals adapt their behavior in response to the changing climate. The resulting changes are often easy to see.

However, it wasn't until late-1980s that biologists realized that natural selection can be seen in action, as well. The key to this is that different traits can confer the ability to survive at different rates and reproduction, and they can be passed down from one generation to the next.

In the past, when one particular allele--the genetic sequence that controls coloration - was present in a population of interbreeding organisms, it could rapidly become more common than all other alleles. In time, this could mean that the number of black moths 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 observe evolution 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 of each population are taken regularly and more than 500.000 generations have passed.

Lenski's research has shown that mutations can drastically alter the rate at which a population reproduces--and so, the rate at which it changes. It also shows that evolution is slow-moving, a fact that some people find hard to accept.

Another example of microevolution is the way mosquito genes for resistance to pesticides show up more often in populations in which insecticides are utilized. This is because pesticides cause an exclusive pressure that favors those who have resistant genotypes.

The rapidity of evolution has led to a greater recognition of its importance especially in a planet which is largely shaped by human activities. This includes pollution, climate change, and habitat loss, which prevents many species from adapting. Understanding evolution can help us make smarter decisions regarding the future of our planet, as well as the life of its inhabitants.