Five Killer Quora Answers To Evolution Site

The Academy's Evolution Site

Biological evolution is one of the most fundamental concepts in biology. The Academies have long been involved in helping people who are interested in science comprehend the theory of evolution and how it permeates all areas of scientific research.

This site provides students, teachers and general readers with a variety of educational resources on evolution. It contains important video clips from NOVA and the WGBH-produced science programs on DVD.

Tree of Life

The Tree of Life, an ancient symbol, represents the interconnectedness of all life. It is a symbol of love and harmony in a variety of cultures. It also has practical applications, like providing a framework for understanding the history of species and how they respond to changes in environmental conditions.

The earliest attempts to depict the biological world focused on categorizing organisms into distinct categories which had been distinguished by their physical and metabolic characteristics1. These methods rely on the collection of various parts of organisms or short fragments of DNA, have greatly increased the diversity of a tree of Life2. The trees are mostly composed of eukaryotes, while the diversity of bacterial species is greatly underrepresented3,4.

Genetic techniques have greatly expanded our ability to visualize the Tree of Life by circumventing the requirement for direct observation and experimentation. In particular, molecular methods enable us to create trees by using sequenced markers like the small subunit of ribosomal RNA gene.

The Tree of Life has been greatly expanded thanks to genome sequencing. However there is a lot of diversity to be discovered. This is especially true of microorganisms, which can be difficult to cultivate and are usually only present in a single specimen5. A recent study of all genomes that are known has created a rough draft of the Tree of Life, including numerous archaea and bacteria that have not been isolated and whose diversity is poorly understood6.

The expanded Tree of Life can be used to determine the diversity of a specific region and determine if particular habitats need special protection. The information can be used in a range of ways, from identifying the most effective medicines to combating disease to improving crops. It is also beneficial for conservation efforts. It helps biologists discover areas most likely to have species that are cryptic, which could have important metabolic functions and be vulnerable to changes caused by humans. While funds to protect biodiversity are essential, ultimately the best way to protect the world's biodiversity is for more people in developing countries to be empowered with the knowledge to act locally in order to promote conservation from within.

Phylogeny

A phylogeny (also called an evolutionary tree) illustrates the relationship between different organisms. Utilizing molecular data similarities and differences in morphology, or ontogeny (the course of development of an organism) scientists can create an phylogenetic tree that demonstrates the evolutionary relationships between taxonomic categories. The role of phylogeny is crucial in understanding the relationship between genetics, biodiversity and evolution.

A basic phylogenetic tree (see Figure PageIndex 10 Finds the connections between organisms with similar characteristics and have evolved from an ancestor that shared traits. These shared traits may be homologous, or analogous. Homologous traits are identical in their evolutionary origins, while analogous traits look similar but do not have the identical origins. Scientists arrange similar traits into a grouping known as a clade. For instance, all of the organisms in a clade have the characteristic of having amniotic eggs. They evolved from a common ancestor who had eggs. A phylogenetic tree can be constructed by connecting the clades to identify the species which are the closest to each other.

Scientists utilize molecular DNA or RNA data to build a phylogenetic chart that is more precise and precise. This information is more precise than morphological information and gives evidence of the evolutionary history of an organism or group. The use of molecular data lets researchers identify the number of species that have a common ancestor and to estimate their evolutionary age.

The phylogenetic relationships between species can be influenced by several factors, including phenotypic flexibility, a kind of behavior that alters in response to specific environmental conditions. This can cause a particular trait to appear more similar in one species than other species, which can obscure the phylogenetic signal. However, this problem can be reduced by the use of methods like cladistics, which combine similar and homologous traits into the tree.

Additionally, phylogenetics aids determine the duration and rate at which speciation occurs. This information can assist conservation biologists in making decisions about which species to save from the threat of extinction. It is ultimately the preservation of phylogenetic diversity that will result in an ecologically balanced and complete ecosystem.

Evolutionary Theory

The central theme 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 individual requirements, the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern taxonomy system that is hierarchical and Jean-Baptiste Lamarck (1844-1829), who believed that the usage or non-use of traits can lead to changes that are passed on to the next generation.

In the 1930s and 1940s, theories from a variety of fields--including genetics, natural selection and particulate inheritance - came together to create the modern synthesis of evolutionary theory, which defines how evolution occurs through the variation of genes within a population, and how these variants change in time as a result of natural selection. This model, which includes mutations, genetic drift, gene flow and sexual selection can be mathematically described.

Recent developments in the field of evolutionary developmental biology have shown that variation 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, as well as 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 and changes in the phenotype (the expression of genotypes in an individual).

Incorporating evolutionary thinking into all areas of biology education can increase student understanding of the concepts of phylogeny as well as evolution. In a study by Grunspan and co. It was found that teaching students about the evidence for evolution boosted their understanding of evolution in a college-level course in biology. To learn more about how to teach about evolution, see The Evolutionary Potential of all Areas of Biology and Thinking Evolutionarily: A Framework for Infusing the Concept of Evolution into Life Sciences Education.

Evolution in Action

Scientists have traditionally studied evolution by looking in the past--analyzing fossils and comparing species. They also observe living organisms. But evolution isn't just something that occurred in the past. It's an ongoing process taking place today. Bacteria evolve and resist antibiotics, viruses re-invent themselves and are able to evade new medications, and animals adapt their behavior to a changing planet. The results are often apparent.

It wasn't until late 1980s that biologists began to realize that natural selection was also in action. 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, when one particular allele - the genetic sequence that determines coloration--appeared in a population of interbreeding species, it could quickly become more prevalent than all other alleles. In time, this could 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 easier when a species has a rapid generation turnover like bacteria. Since 1988 biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain. samples of each population are taken on a regular basis and over 500.000 generations have been observed.

Lenski's research has revealed that mutations can alter the rate of change and the rate of a population's reproduction. It also shows evolution takes time, which is hard for some to accept.

Another example of microevolution is how mosquito genes for resistance to pesticides show up more often in areas where insecticides are employed. This is because pesticides cause an enticement that favors those with resistant genotypes.

The speed of evolution taking place has led to a growing awareness of its significance in a world that is shaped by human activity--including climate change, pollution and the loss of habitats which prevent the species from adapting. Understanding evolution can help us make better decisions about the future of our planet and the lives of its inhabitants.