15 Reasons Not To Overlook Evolution Site

The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies are involved in helping those who are interested in the sciences understand evolution theory and how it can be applied across all areas of scientific research.

This site offers a variety of tools for students, teachers as well as general readers 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 has many practical applications as well, such as providing a framework for understanding the evolution of species and how they respond to changes in environmental conditions.

The first attempts at depicting the biological world focused on separating organisms into distinct categories which had been identified by their physical and metabolic characteristics1. These methods are based on the collection of various parts of organisms or DNA fragments, have significantly increased the diversity of a tree of Life2. These trees are largely composed by eukaryotes and bacteria are largely underrepresented3,4.

Genetic techniques have significantly expanded our ability to depict the Tree of Life by circumventing the requirement for direct observation and experimentation. In particular, molecular methods allow us to construct trees using sequenced markers, such as the small subunit ribosomal RNA 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 true for microorganisms that are difficult to cultivate and are usually found in one sample5. A recent analysis of all genomes resulted in an initial draft of a Tree of Life. This includes a wide range of archaea, bacteria and other organisms that have not yet been isolated, or whose diversity has not been thoroughly understood6.

The expanded Tree of Life can be used to determine the diversity of a specific area and determine if specific habitats need special protection. The information can be used in a range of ways, from identifying the most effective medicines to combating disease to enhancing the quality of crops. This information is also extremely beneficial to conservation efforts. It can aid biologists in identifying areas that are most likely to have cryptic species, which may have vital metabolic functions and be vulnerable to changes caused by humans. While funding to protect biodiversity are important, the best method to protect the world's biodiversity is to equip more people in developing countries with the information they require to act locally and promote conservation.

Phylogeny

A phylogeny (also known as an evolutionary tree) illustrates the relationship between organisms. Scientists can construct a phylogenetic diagram that illustrates the evolutionary relationships between taxonomic groups using molecular data and morphological differences or similarities. The phylogeny of a tree plays an important role in understanding biodiversity, genetics and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 Finds the connections between organisms that have similar traits and have evolved from an ancestor with common traits. These shared traits are either homologous or analogous. Homologous traits are similar in their evolutionary journey. Analogous traits might appear similar however they do not have the same origins. Scientists arrange similar traits into a grouping called a Clade. Every organism in a group have a common trait, such as amniotic egg production. They all evolved from an ancestor with these eggs. A phylogenetic tree can be constructed by connecting the clades to identify the species who are the closest to one another.

Scientists make use of DNA or RNA molecular information to construct a phylogenetic graph which is more precise and detailed. This information is more precise than morphological data and provides evidence of the evolutionary background of an organism or group. Researchers can use Molecular Data to determine the evolutionary age of organisms and identify the number of organisms that share an ancestor common to all.

The phylogenetic relationships of organisms can be affected by a variety of factors, including phenotypic flexibility, a kind of behavior that alters in response to specific environmental conditions. This can cause a trait to appear more similar to one species than to another, obscuring the phylogenetic signals. However, this problem can be reduced by the use of methods such as cladistics which include a mix of homologous and analogous features into the tree.

Furthermore, phylogenetics may help predict the time and pace of speciation. This information can aid conservation biologists in making decisions about which species to protect from extinction. In the end, it's the preservation of phylogenetic diversity which will create an ecosystem that is balanced and complete.

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, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism would develop according to its own requirements and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern taxonomy system that is hierarchical, as well as Jean-Baptiste Lamarck (1844-1829), who believed that the use or absence of certain traits can result in changes that can be passed on to future generations.

In the 1930s and 1940s, ideas from a variety of fields--including genetics, natural selection and particulate inheritance--came together to create the modern evolutionary theory synthesis that explains how evolution is triggered by the variations of genes within a population, and how those variants change over time due to natural selection. This model, known as genetic drift, mutation, gene flow and sexual selection, is a cornerstone of current evolutionary biology, and is mathematically described.

Recent discoveries in the field of evolutionary developmental biology have demonstrated that variation can be introduced into a species through mutation, genetic drift and reshuffling of genes in sexual reproduction, as well as through migration between populations. These processes, as well as others like directional selection and genetic erosion (changes in the frequency of a genotype over time) can lead to evolution, which is defined by changes in the genome of the species over time, and also by changes in phenotype over time (the expression of the genotype in an individual).

Students can better understand the concept of phylogeny through incorporating 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' acceptance of evolution in a college biology course. For more details on how to teach about evolution read 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 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 happening today. Bacteria mutate and resist antibiotics, viruses reinvent themselves and escape new drugs and animals change their behavior to the changing climate. The changes that result are often easy to see.

It wasn't until late 1980s that biologists began realize that natural selection was also at work. The key is that different traits have different rates of survival and reproduction (differential fitness) and can be transferred from one generation to the next.

In the past, if an allele - the genetic sequence that determines colour was found in a group of organisms that interbred, it could become more common than other allele. Over time, that would mean the number of black moths within a population could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

The ability to observe evolutionary change is easier when a particular species has a rapid generation turnover, as with bacteria. Since  에볼루션 사이트  has been tracking twelve populations of E. coli that descended from a single strain; samples of each population are taken on a regular basis and more than 500.000 generations have been observed.

Lenski's research has shown that a mutation can profoundly alter the speed at which a population reproduces and, consequently the rate at which it changes. It also demonstrates that evolution takes time, a fact that is difficult for some to accept.

Microevolution is also evident in the fact that mosquito genes for pesticide resistance are more common in populations where insecticides are used. This is because pesticides cause a selective pressure which favors those with resistant genotypes.

The rapid pace at which evolution takes place has led to a growing appreciation of its importance in a world that is shaped by human activities, including climate change, pollution and the loss of habitats that prevent the species from adapting. Understanding evolution can help us make smarter choices about the future of our planet as well as the life of its inhabitants.