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Why We Are In Love With Evolution Site (And You Should Also!)
The Academy's Evolution Site

Biology is a key concept in biology. The Academies are involved in helping those interested in science to comprehend the evolution theory and how it is permeated across all areas of scientific research.

This site provides teachers, students and general readers with a wide range of learning resources on evolution. It has the most important video clips from NOVA and WGBH-produced science programs on DVD.

Tree of Life

The Tree of Life is an ancient symbol of the interconnectedness of life. It is an emblem of love and unity in many cultures. It also has 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 world of biology focused on separating species into distinct categories that were identified by their physical and metabolic characteristics1. These methods, based on the sampling of various parts of living organisms or on short fragments of their DNA, significantly increased the variety that could be represented in the tree of life2. The trees are mostly composed of eukaryotes, while the diversity of bacterial species is greatly underrepresented3,4.

In avoiding the necessity of direct observation and experimentation, genetic techniques have allowed us to depict the Tree of Life in a more precise manner. We can construct trees using molecular methods such as the small subunit ribosomal gene.

The Tree of Life has been significantly expanded by genome sequencing. However, there is still much diversity to be discovered. This is particularly true for microorganisms that are difficult to cultivate, and are usually found in a single specimen5. Recent analysis of all genomes produced an unfinished draft of a Tree of Life. This includes a variety of archaea, bacteria and other organisms that have not yet been isolated, or whose diversity has not been well understood6.

This expanded Tree of Life can be used to determine the diversity of a particular area and determine if specific habitats require special protection. This information can be used in a range of ways, from identifying the most effective treatments to fight disease to enhancing the quality of crops. It is also useful in conservation efforts. It can help biologists identify the areas that are most likely to contain cryptic species that could have important metabolic functions that may be at risk of anthropogenic changes. While funding to protect biodiversity are important, the most effective method to protect the world's biodiversity is to equip the people of developing nations with the knowledge they need to act locally and promote conservation.

Phylogeny

A phylogeny (also called an evolutionary tree) shows the relationships between different organisms. Using molecular data, morphological similarities and differences or ontogeny (the course of development of an organism) scientists can construct an phylogenetic tree that demonstrates the evolutionary relationship between taxonomic categories. Phylogeny is essential in understanding the evolution of biodiversity, evolution and genetics.


A basic phylogenetic tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms that share similar traits that evolved from common ancestors. These shared traits may be homologous, or analogous. Homologous traits are identical in their evolutionary origins and analogous traits appear like they do, but don't have the same ancestors. Scientists put similar traits into a grouping called a the clade. For instance, all of the species in a clade have the characteristic of having amniotic eggs and evolved from a common ancestor that had eggs. A phylogenetic tree is constructed by connecting the clades to determine the organisms that are most closely related to one another.

Scientists use DNA or RNA molecular data to create a phylogenetic chart that is more accurate and detailed. This information is more precise and provides evidence of the evolution of an organism. Researchers can utilize Molecular Data to estimate the age of evolution of organisms and determine the number of organisms that have the same ancestor.

The phylogenetic relationship can be affected by a variety of factors such as the phenomenon of phenotypicplasticity. This is a type of behavior that alters due to specific environmental conditions. This can cause a characteristic to appear more similar to a species than to the other and obscure the phylogenetic signals. This issue can be cured by using cladistics, which incorporates a combination of homologous and analogous traits in the tree.

In addition, phylogenetics can aid in predicting the length and speed of speciation. This information will assist conservation biologists in making choices about which species to safeguard from disappearance. Ultimately, it is the preservation of phylogenetic diversity which will create an ecosystem that is complete and balanced.

simply click the next document of evolution is that organisms develop various characteristics over time as a result of their interactions with their surroundings. Several theories of evolutionary change have been proposed by a variety of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop gradually according to its needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that the use or non-use of traits can cause changes that could be passed onto offspring.

In the 1930s & 1940s, concepts from various fields, including genetics, natural selection, and particulate inheritance, merged to form a modern evolutionary theory. This explains how evolution is triggered by the variation in genes within the population and how these variations alter over time due to natural selection. This model, which encompasses genetic drift, mutations, gene flow and sexual selection, can be mathematically described.

Recent developments in the field of evolutionary developmental biology have shown that variations can be introduced into a species by mutation, genetic drift and reshuffling of genes during sexual reproduction, as well as by migration between populations. These processes, along with other ones like the directional selection process and the erosion of genes (changes in the frequency of genotypes over time), can lead towards evolution. Evolution is defined as changes in the genome over time, as well as changes in phenotype (the expression of genotypes in individuals).

Incorporating evolutionary thinking into all areas of biology education can improve student understanding of the concepts of phylogeny and evolutionary. In a study by Grunspan and co. It was demonstrated that teaching students about the evidence for evolution boosted their understanding of evolution during an undergraduate biology course. For more details about how to teach evolution read The Evolutionary Power of Biology in all Areas of Biology or Thinking Evolutionarily as a Framework for Integrating Evolution into Life Sciences Education.

Evolution in Action

Traditionally scientists have studied evolution by looking back--analyzing fossils, comparing species, and studying living organisms. Evolution is not a distant event; it is a process that continues today. Viruses reinvent themselves to avoid new medications and bacteria mutate to resist antibiotics. Animals adapt their behavior as a result of a changing world. The changes that result are often evident.

It wasn't until the 1980s that biologists began realize that natural selection was in action. The reason is that different traits confer different rates of survival and reproduction (differential fitness) and 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 population of interbreeding organisms, it might quickly become more prevalent than all other alleles. Over time, that would mean the number of black moths in the 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 rapid generation turnover. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that descend from one strain. Samples from each population have been collected frequently and more than 50,000 generations of E.coli have been observed to have passed.

Lenski's work has shown that mutations can alter the rate at which change occurs and the rate at which a population reproduces. It also demonstrates that evolution takes time--a fact that many are unable to accept.

Microevolution is also evident in the fact that mosquito genes for resistance to pesticides are more prevalent in areas where insecticides are used. This is due to pesticides causing an enticement that favors those with resistant genotypes.

The speed at which evolution takes place has led to an increasing appreciation of its importance in a world shaped by human activities, including climate change, pollution, and the loss of habitats which prevent the species from adapting. Understanding evolution can help us make smarter decisions regarding the future of our planet, as well as the lives of its inhabitants.