Are You Getting The Most You Evolution Site?

The Academy's Evolution Site

Biology is one of the most important concepts in biology. The Academies are involved in helping those interested in science understand evolution theory and how it is incorporated in all areas of scientific research.

This site offers a variety of tools for teachers, students as well as general readers about 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 all life. It is a symbol of love and harmony in a variety of cultures. It also has important practical applications, like providing a framework to understand the history of species and how they respond to changing environmental conditions.

The first attempts to depict the biological world were founded on categorizing organisms on their physical and metabolic characteristics. These methods, which relied on sampling of different parts of living organisms or sequences of small fragments of their DNA significantly increased the variety that could be included in the tree of life2. However, these trees are largely made up of eukaryotes. Bacterial diversity remains vastly underrepresented3,4.

Genetic techniques have significantly expanded our ability to visualize the Tree of Life by circumventing the requirement for direct observation and experimentation. Particularly, molecular methods allow us to construct trees by using sequenced markers, such as the small subunit ribosomal RNA gene.

The Tree of Life has been dramatically expanded through genome sequencing. However there is a lot of biodiversity to be discovered. This is particularly true for microorganisms, which are difficult to cultivate and are usually only represented in a single sample5. A recent analysis of all known genomes has produced a rough draft version of the Tree of Life, including numerous archaea and bacteria that have not been isolated, and which are not well understood.

에볼루션 게이밍  expanded Tree of Life is particularly useful for assessing the biodiversity of an area, assisting to determine if certain habitats require special protection. This information can be utilized in a range of ways, from identifying the most effective remedies to fight diseases to enhancing the quality of crop yields. This information is also beneficial 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 vulnerable to anthropogenic change. While funding to protect biodiversity are important, the best way to conserve the world's biodiversity is to empower more people in developing countries with the knowledge they need to act locally and promote conservation.

Phylogeny

A phylogeny, also called an evolutionary tree, shows the connections between various groups of organisms. Utilizing molecular data similarities and differences in morphology or ontogeny (the course of development of an organism) scientists can create a phylogenetic tree which illustrates the evolutionary relationship between taxonomic groups. 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 ) determines the relationship between organisms that share similar traits that evolved from common ancestors.  에볼루션 바카라 체험  shared traits can be either homologous or analogous. Homologous traits are similar in their underlying evolutionary path, while analogous traits look similar, but do not share the same ancestors. Scientists group similar traits into a grouping known as a Clade. Every organism in a group share a characteristic, for example, amniotic egg production. They all evolved from an ancestor that had these eggs. A phylogenetic tree is constructed by connecting clades to identify the species which are the closest to one another.

For a more detailed and precise phylogenetic tree scientists make use of molecular data from DNA or RNA to identify the connections between organisms. This information is more precise and gives evidence of the evolution history of an organism. The use of molecular data lets researchers identify the number of species that share an ancestor common to them and estimate their evolutionary age.

The phylogenetic relationships between species can be influenced by several factors including phenotypic plasticity, a type of behavior that alters in response to unique environmental conditions. This can cause a characteristic to appear more like a species another, clouding the phylogenetic signal. However, this issue can be solved through the use of techniques such as cladistics which incorporate a combination of analogous and homologous features into the tree.

In addition, phylogenetics can aid in predicting the time and pace of speciation. This information can aid conservation biologists in making decisions about which species to save from extinction. Ultimately, it is the preservation of phylogenetic diversity which will lead to a complete and balanced ecosystem.

Evolutionary Theory

The fundamental concept in evolution is that organisms alter over time because of their interactions with their environment. Many scientists have developed theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that a living thing would evolve according to its own needs, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical system of taxonomy, as well as Jean-Baptiste Lamarck (1844-1829), who suggested 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, theories from various fields, including natural selection, genetics, and particulate inheritance--came together to create the modern evolutionary theory synthesis that explains how evolution is triggered by the variation of genes within a population and how those variants change over time due to natural selection. This model, which is known as genetic drift mutation, gene flow, and sexual selection, is the foundation of the current evolutionary biology and is mathematically described.

Recent discoveries in the field of evolutionary developmental biology have shown that variations can be introduced into a species via mutation, genetic drift, and reshuffling of genes in sexual reproduction, as well as by migration between populations. These processes, in conjunction with others such as directional selection and gene erosion (changes in frequency of genotypes over time) can lead to evolution. Evolution is defined as changes in the genome over time as well as changes in phenotype (the expression of genotypes in an individual).

Students can gain a better understanding of the concept of phylogeny by using evolutionary thinking throughout all aspects of biology. A recent study by Grunspan and colleagues, for example, showed that teaching about the evidence for evolution increased students' understanding of evolution in a college-level biology course. For more details on how to teach about evolution look up The Evolutionary Potency in all Areas of Biology or Thinking Evolutionarily: a Framework for Integrating Evolution into Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution by looking back, studying fossils, comparing species and studying living organisms. But evolution isn't a thing that happened in the past, it's an ongoing process that is happening right now. Viruses evolve to stay away from new drugs and bacteria evolve to resist antibiotics. Animals alter their behavior because of a changing world. The changes that result are often easy to see.

But it wasn't until the late 1980s that biologists understood that natural selection could be observed in action as well. The key is the fact 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 defines color in a group of interbreeding species, it could quickly become more common than other alleles. Over time, that would mean 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.

Observing evolutionary change in action is much easier when a species has a rapid generation turnover, as with bacteria. Since 1988 biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain; samples from each population are taken on a regular basis and over 50,000 generations have now been observed.

Lenski's research has revealed that a mutation can dramatically alter the rate at the rate at which a population reproduces, and consequently, the rate at which it evolves. It also shows that evolution takes time, a fact that some find difficult to accept.

Another example of microevolution is how mosquito genes that are resistant to pesticides are more prevalent in populations where insecticides are employed. This is due to the fact that 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 particularly 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 us make better decisions regarding the future of our planet, and the life of its inhabitants.