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7 Things About Evolution Site You'll Kick Yourself For Not Knowing
The Academy's Evolution Site

Biological evolution is a central concept in biology. The Academies are committed to helping those interested in the sciences comprehend the evolution theory and how it can be applied across all areas of scientific research.

This site provides students, teachers and general readers with a wide range 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, an ancient symbol, represents the interconnectedness of all life. It is seen in a variety of religions and cultures as symbolizing unity and love. It also has many practical applications, like providing a framework to understand the evolution of species and how they respond to changing environmental conditions.

Early approaches to depicting the biological world focused on categorizing organisms into distinct categories which were distinguished by their physical and metabolic characteristics1. These methods rely on the collection of various parts of organisms or DNA fragments have greatly increased the diversity of a Tree of Life2. The trees are mostly composed by eukaryotes, and 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 need for direct observation and experimentation. We can create trees using molecular techniques, such as the small-subunit ribosomal gene.

Despite the dramatic growth of the Tree of Life through genome sequencing, a lot of biodiversity remains to be discovered. This is particularly true for microorganisms, which can be difficult to cultivate and are often only present in a single specimen5. A recent analysis of all known genomes has produced a rough draft of the Tree of Life, including a large number of bacteria and archaea that are not isolated and which are not well understood.

talks about it expanded Tree of Life is particularly useful in assessing the diversity of an area, assisting to determine whether specific habitats require special protection. This information can be used in many ways, including finding new drugs, fighting diseases and enhancing crops. This information is also valuable to conservation efforts. It can aid biologists in identifying 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 funds to protect biodiversity are important, the most effective way to conserve the world's biodiversity is to empower the people of developing nations with the knowledge they need to act locally and support conservation.

Phylogeny

A phylogeny (also called an evolutionary tree) shows the relationships between organisms. Using molecular data, morphological similarities and differences, or ontogeny (the process of the development of an organism) scientists can construct a phylogenetic tree which illustrates the evolution of taxonomic groups. Phylogeny is essential in understanding evolution, biodiversity and genetics.

A basic phylogenetic Tree (see Figure PageIndex 10 Identifies the relationships between organisms with similar characteristics and have evolved from an ancestor with common traits. These shared traits can be either analogous or homologous. Homologous traits are similar in their underlying evolutionary path while analogous traits appear similar but do not have the identical origins. Scientists organize similar traits into a grouping known as a Clade. 에볼루션 바카라 체험 of a clade have a common trait, such as amniotic egg production. They all came from an ancestor with these eggs. A phylogenetic tree is then constructed by connecting clades to identify the organisms that are most closely related to one another.

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

Phylogenetic relationships can be affected by a number of factors, including the phenomenon of phenotypicplasticity. This is a type behavior that changes as a result of unique environmental conditions. This can cause a trait to appear more similar to a species than another and obscure the phylogenetic signals. However, this problem can be solved through the use of techniques such as cladistics that incorporate a combination of 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. In the end, it's the conservation of phylogenetic variety that will lead to an ecosystem that is balanced and complete.

Evolutionary Theory

The main idea behind evolution is that organisms alter over time because of their interactions with their environment. A variety of theories about evolution have been proposed by a wide variety of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing slowly according to its requirements as well as the Swedish botanist Carolus Linnaeus (1707-1778) who developed 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 on to the offspring.

In the 1930s and 1940s, theories from various fields, including genetics, natural selection and particulate inheritance -- came together to form the current synthesis of evolutionary theory which explains how evolution happens through the variation of genes within a population and how these variants change in time due to natural selection. This model, which incorporates genetic drift, mutations in gene flow, and sexual selection, can be mathematically described.

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

Incorporating evolutionary thinking into all aspects of biology education can improve student understanding of the concepts of phylogeny and evolution. A recent study conducted by Grunspan and colleagues, for example demonstrated that teaching about the evidence for evolution increased students' acceptance of evolution in a college biology class. For more information on how to teach evolution, see The Evolutionary Potential in All Areas of Biology or Thinking Evolutionarily: a Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution through looking back, studying fossils, comparing species, and observing living organisms. But evolution isn't a thing that occurred in the past. It's an ongoing process happening in the present. The virus reinvents itself to avoid new medications and bacteria mutate to resist antibiotics. Animals alter their behavior in the wake of a changing world. The results are usually evident.

It wasn't until late 1980s that biologists understood that natural selection could be observed in action as well. The key is that different characteristics result in different rates of survival and reproduction (differential fitness) and can be passed from one generation to the next.

In the past, if an allele - the genetic sequence that determines color - appeared in a population of organisms that interbred, it could be more common than other allele. In time, this could mean that the number of moths sporting black pigmentation in a population could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

Monitoring evolutionary changes in action is much easier when a species has a rapid generation turnover such as bacteria. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain. samples of each are taken regularly and over 50,000 generations have now passed.


Lenski's research has shown that mutations can drastically alter the rate at which a population reproduces and, consequently the rate at which it evolves. It also demonstrates that evolution takes time, something that is difficult for some to accept.

Microevolution can also be seen in the fact that mosquito genes for resistance to pesticides are more prevalent in areas where insecticides are used. Pesticides create a selective pressure which favors individuals who have resistant genotypes.

The rapidity of evolution has led to an increasing awareness of its significance especially in a planet that is largely shaped by human activity. This includes pollution, climate change, and habitat loss that hinders many species from adapting. Understanding the evolution process will aid you in making better decisions regarding the future of the planet and its inhabitants.

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