So , You've Purchased Evolution Site ... Now What?

The Academy's Evolution Site

Biology is a key concept in biology. The Academies have been for a long time involved in helping those interested in science comprehend the theory of evolution and how it permeates every area of scientific inquiry.

This site provides teachers, students and general readers with a variety of educational 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 represents the interconnectedness of life. It appears in many religions and cultures as an emblem of unity and love. It has many practical applications as well, including providing a framework for understanding the history of species and how they react to changing environmental conditions.

Early attempts to represent the biological world were built on categorizing organisms based on their physical and metabolic characteristics. These methods, which rely on the sampling of various parts of living organisms or small fragments of their DNA, greatly increased the variety of organisms that could be represented in a tree of life2. The trees are mostly composed by eukaryotes, and bacterial diversity is vastly underrepresented3,4.

By avoiding the necessity for direct observation and experimentation genetic techniques have made it possible to represent the Tree of Life in a much more accurate way. We can construct trees using molecular techniques such as the small subunit ribosomal gene.

Despite the massive expansion of the Tree of Life through genome sequencing, a lot of biodiversity is waiting to be discovered. This is particularly the case for microorganisms which are difficult to cultivate and are usually found in a single specimen5. Recent analysis of all genomes produced a rough draft of the Tree of Life. This includes a large number of bacteria, archaea and other organisms that have not yet been isolated or their diversity is not thoroughly understood6.

This expanded Tree of Life is particularly useful in assessing the diversity of an area, which can help to determine whether specific habitats require protection. This information can be used in a variety of ways, such as finding new drugs, fighting diseases and improving the quality of crops. The information is also useful for conservation efforts. It helps biologists determine the areas that are most likely to contain cryptic species with significant metabolic functions that could be vulnerable to anthropogenic change. While conservation funds are essential, the best way to conserve the biodiversity of the world is to equip the people of developing nations with the information they require to act locally and promote conservation.

에볼루션 무료체험  is also known as an evolutionary tree, shows the connections between different groups of organisms. Scientists can create an phylogenetic chart which shows the evolutionary relationship of taxonomic groups based on molecular data and morphological similarities or differences. Phylogeny is essential in understanding biodiversity, evolution and genetics.

A basic phylogenetic Tree (see Figure PageIndex 10 Determines the relationship between organisms that have similar traits and have evolved from a common ancestor. These shared traits can be either analogous or homologous. Homologous traits are similar in their evolutionary roots and analogous traits appear similar but do not have the same ancestors. Scientists group similar traits into a grouping referred to as a clade. Every organism in a group share a characteristic, like amniotic egg production. They all came from an ancestor who had these eggs. The clades are then connected to form a phylogenetic branch to determine which organisms have the closest relationship to.

Scientists use DNA or RNA molecular data to create a phylogenetic chart that is more precise and precise. This data is more precise than the morphological data and provides evidence of the evolutionary history of an organism or group. The use of molecular data lets researchers identify the number of organisms that share the same ancestor and estimate their evolutionary age.

The phylogenetic relationships of organisms can be influenced by several factors, including phenotypic plasticity an aspect of behavior that alters in response to unique environmental conditions. This can cause a characteristic to appear more similar to a species than another and obscure the phylogenetic signals. This problem can be mitigated by using cladistics, which incorporates the combination of analogous and homologous features in the tree.

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

Evolutionary Theory

The central theme in evolution is that organisms change over time due to their interactions with their environment. Many theories of evolution have been developed 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 slowly in accordance with its needs, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1744-1829) who suggested that the use or misuse of traits cause changes that can be passed on to the offspring.

In the 1930s & 1940s, ideas from different fields, such as genetics, natural selection, and particulate inheritance, came together to create a modern theorizing of evolution. This defines how evolution is triggered by the variation of genes in the population and how these variations alter over time due to natural selection. This model, which includes mutations, genetic drift, gene flow and sexual selection can be mathematically described.

Recent discoveries in the field of evolutionary developmental biology have demonstrated the ways in which variation can be introduced to a species via mutations, genetic drift or reshuffling of genes in sexual reproduction and the movement between populations. These processes, in conjunction with others, such as directional selection and gene erosion (changes to the frequency of genotypes over time) can result in evolution. Evolution is defined by changes in the genome over time and changes in the phenotype (the expression of genotypes within individuals).

Students can better understand the concept of phylogeny by using evolutionary thinking in all areas of biology. In a study by Grunspan and colleagues., it was shown that teaching students about the evidence for evolution increased their understanding of evolution during the course of a college biology. To find out more about how to teach about evolution, please see The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily: A Framework for Infusing Evolution in Life Sciences Education.

Evolution in Action

Scientists have studied evolution through looking back in the past, analyzing fossils and comparing species. They also observe living organisms. Evolution is not a past moment; it is an ongoing process that continues to be observed today. Bacteria evolve and resist antibiotics, viruses reinvent themselves and elude new medications and animals change their behavior to a changing planet. The results are usually easy to see.

It wasn't until late 1980s that biologists began realize that natural selection was also at work. The main reason is that different traits can confer a different rate of survival and reproduction, and can be passed on from one generation to the next.

In the past when one particular allele--the genetic sequence that defines color in a population of interbreeding organisms, it could rapidly become more common than other alleles. In time, this could mean that the number of moths that have black pigmentation in a group may 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 much easier when a species has a rapid turnover of its generation like bacteria. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that descend from a single strain. Samples from each population were taken regularly and more than 500.000 generations of E.coli have passed.

Lenski's research has demonstrated that mutations can alter the rate at which change occurs and the efficiency at which a population reproduces. It also proves that evolution takes time--a fact that many find hard to accept.

Another example of microevolution is how mosquito genes that confer resistance to pesticides appear more frequently in populations in which insecticides are utilized. This is because the use of pesticides creates a selective pressure that favors people with resistant genotypes.

The rapid pace at which evolution can take place has led to an increasing appreciation of its importance in a world shaped by human activities, including climate changes, pollution and the loss of habitats that hinder many species from adjusting. Understanding the evolution process will assist you in making better choices about the future of the planet and its inhabitants.