20 Things You Need To Know About Evolution Site

The Academy's Evolution Site

Biology is one of the most important concepts in biology. The Academies have long been involved in helping those interested in science comprehend the theory of evolution and how it permeates all areas of scientific exploration.

This site provides students, teachers and general readers with a range of learning resources on evolution. It includes key video clip 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 spiritual traditions and cultures as an emblem of unity and love. It has numerous practical applications as well, such as providing a framework to understand the history of species, and how they respond to changes in environmental conditions.

Early attempts to represent the biological world were built on categorizing organisms based on their physical and metabolic characteristics. These methods, based on sampling of different parts of living organisms or sequences of short fragments of their DNA, significantly expanded the diversity that could be included in a tree of life2. However the trees are mostly composed of eukaryotes; bacterial diversity remains vastly underrepresented3,4.

Genetic techniques have significantly expanded our ability to depict the Tree of Life by circumventing the need for direct observation and experimentation. Particularly, molecular methods allow us to build trees by using sequenced markers like the small subunit ribosomal gene.

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

The expanded Tree of Life is particularly useful in assessing the diversity of an area, helping to determine whether specific habitats require protection. This information can be utilized in a range of ways, from identifying the most effective medicines to combating disease to improving the quality of crops. This information is also extremely useful to conservation efforts. It helps biologists determine the areas most likely to contain cryptic species that could have important metabolic functions that could be at risk from anthropogenic change. Although funding to protect biodiversity are crucial, ultimately the best way to protect 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 called an evolutionary tree, illustrates the relationships between groups of organisms. Scientists can build an phylogenetic chart which shows the evolutionary relationship of taxonomic groups based on molecular data and morphological similarities or differences. Phylogeny plays a crucial role in understanding the relationship between genetics, biodiversity and evolution.

A basic phylogenetic tree (see Figure PageIndex 10 Finds the connections between organisms that have similar characteristics and have evolved from an ancestor with common traits. These shared traits could be analogous or homologous. Homologous traits are identical in their underlying evolutionary path, while analogous traits look similar but do not have the same ancestors. Scientists put similar traits into a grouping called a Clade. Every organism in a group share a characteristic, for example, amniotic egg production. They all derived from an ancestor that had these eggs. A phylogenetic tree can be constructed by connecting the clades to determine the organisms who are the closest to one another.

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

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

Additionally, phylogenetics can help determine the duration and rate of speciation. This information can aid conservation biologists in making choices about which species to protect from the threat of extinction. In the end, it's the conservation of phylogenetic diversity which will create an ecosystem that is complete and balanced.

Evolutionary Theory

The fundamental concept of evolution is that organisms develop various characteristics over time based on their interactions with their environments. Many scientists have developed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that a living thing would evolve according to its individual requirements and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical taxonomy as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the usage or non-use of traits can lead to changes that can be passed on to future generations.

In the 1930s and 1940s, theories from various areas, including genetics, natural selection and particulate inheritance, came together to form a contemporary evolutionary theory. This describes how evolution occurs by the variation of genes in the population and how these variations alter over time due to natural selection. This model, called genetic drift mutation, gene flow and sexual selection, is the foundation of modern evolutionary biology and is mathematically described.

Recent advances in evolutionary developmental biology have shown the ways in which variation can be introduced to a species through genetic drift, mutations and reshuffling of genes during sexual reproduction, and even migration between populations. These processes, along with others such as directionally-selected selection and 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, as well as changes in the phenotype (the expression of genotypes within individuals).

Students can better understand the concept of phylogeny through incorporating evolutionary thinking in all areas of biology. In a study by Grunspan et al. It was found that teaching students about the evidence for evolution boosted their acceptance of evolution during an undergraduate biology course. For more details on how to teach evolution look up The Evolutionary Power of Biology in all Areas of Biology or Thinking Evolutionarily A Framework for Integrating Evolution into Life Sciences Education.

Evolution in Action

Scientists have traditionally studied evolution through looking back in the past, studying fossils, and comparing species. They also observe living organisms. Evolution is not a past event; it is an ongoing process. Viruses evolve to stay away from new medications and bacteria mutate to resist antibiotics. Animals alter their behavior as a result of a changing world. The results are usually visible.

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

In the past, if 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 particular population could rise. 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 the species, like bacteria, has a high generation turnover. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that are descended from a single strain. Samples of each population have been collected regularly and more than 500.000 generations of E.coli have been observed to have passed.

Lenski's research has demonstrated that mutations can alter the rate at which change occurs and the effectiveness at which a population reproduces. It also proves that evolution is slow-moving, a fact that some are unable to accept.

Microevolution can also be seen in the fact that mosquito genes for pesticide resistance are more prevalent in areas where insecticides have been used. This is because pesticides cause a selective pressure which favors those who have resistant genotypes.

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