15 Reasons You Shouldn t Overlook Evolution Site

The Academy's Evolution Site

The concept of biological evolution is among the most central concepts in biology. The Academies are committed to helping those who are interested in science to comprehend the evolution theory and how it is incorporated across all areas of scientific research.

This site provides a wide range of resources for students, teachers as well as general readers about evolution. It has important video clips from NOVA and WGBH's science programs on DVD.

Tree of Life

The Tree of Life, an ancient symbol, represents the interconnectedness of all life. It appears in many cultures and spiritual beliefs as a symbol of unity and love. It has numerous practical applications as well, such as providing a framework to understand the history of species, and how they react to changes in environmental conditions.

Early attempts to describe the world of biology 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 short fragments of their DNA significantly increased the variety that could be included in the tree of life2. However these trees are mainly comprised of eukaryotes, and bacterial diversity remains vastly underrepresented3,4.

Genetic techniques have significantly expanded our ability to depict the Tree of Life by circumventing the requirement for direct observation and experimentation. Particularly, molecular methods allow us to construct trees by using sequenced markers such as the small subunit ribosomal RNA gene.

Despite the dramatic expansion of the Tree of Life through genome sequencing, much biodiversity still awaits discovery. This is especially the case for microorganisms which are difficult to cultivate and which are usually only present in a single sample5. A recent analysis of all genomes resulted in an unfinished draft of a Tree of Life. This includes a variety of archaea, bacteria, and other organisms that have not yet been identified or their diversity is not fully understood6.

This expanded Tree of Life can be used to evaluate the biodiversity of a specific area and determine if particular habitats need special protection. The information is useful in a variety of ways, including finding new drugs, battling diseases and improving crops. The information is also beneficial in conservation efforts. It can aid biologists in identifying the areas that are most likely to contain cryptic species with potentially important metabolic functions that may be vulnerable to anthropogenic change. Although funds to protect biodiversity are essential, ultimately the best way to ensure the preservation of biodiversity around the world is for more people living in developing countries to be equipped with the knowledge to act locally to promote conservation from within.

Phylogeny

A phylogeny (also known as an evolutionary tree) illustrates the relationship between species. Utilizing molecular data as well as morphological similarities and distinctions, or ontogeny (the process of the development of an organism) scientists can construct a phylogenetic tree which illustrates the evolutionary relationships between taxonomic categories. The concept of phylogeny is fundamental to understanding biodiversity, evolution and genetics.

A basic phylogenetic Tree (see Figure PageIndex 10 Finds the connections between organisms with similar traits and evolved from an ancestor with common traits. These shared traits could be analogous, or homologous. Homologous traits are identical in their underlying evolutionary path and analogous traits appear like they do, but don't have the same ancestors. Scientists combine similar traits into a grouping called a clade. For instance, all of the species in a clade share the characteristic of having amniotic egg and evolved from a common ancestor which had these eggs. The clades are then linked to form a phylogenetic branch that can identify organisms that have the closest relationship.

For a more precise and accurate phylogenetic tree, scientists rely on molecular information from DNA or RNA to establish the relationships between organisms. This information is more precise than morphological data and provides evidence of the evolution history of an individual or group. The use of molecular data lets researchers identify the number of organisms that share an ancestor common to them and estimate their evolutionary age.

The phylogenetic relationships of organisms can be affected by a variety of factors, including phenotypic plasticity an aspect of behavior that changes in response to unique environmental conditions. This can cause a trait to appear more similar to a species than to another and obscure the phylogenetic signals. However, this problem can be reduced by the use of methods such as cladistics which combine homologous and analogous features into the tree.

In addition, phylogenetics can help predict the duration and rate of speciation. This information can aid conservation biologists to make decisions about which species to protect from the threat of extinction. Ultimately, it is the preservation of phylogenetic diversity that will create an ecosystem that is complete and balanced.

Evolutionary Theory

The central theme of evolution is that organisms develop distinct characteristics over time due to their interactions with their environment. A variety of theories about evolution have been proposed by a variety of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who believed that an organism would evolve slowly according to its needs and 에볼루션 바카라사이트 바카라 에볼루션 사이트; qa.holoo.co.ir, needs, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that the use or non-use of traits cause changes that could be passed on to offspring.

In the 1930s and 1940s, ideas from various fields, including natural selection, genetics, and particulate inheritance -- came together to form the current evolutionary theory synthesis which explains how evolution happens through the variations of genes within a population and how those variations change over time due to natural selection. This model, which is known as genetic drift, mutation, gene flow and sexual selection, is the foundation of current evolutionary biology, and can be mathematically described.

Recent advances in evolutionary developmental biology have revealed how variation can be introduced to a species via genetic drift, mutations and reshuffling of genes during sexual reproduction and migration between populations. These processes, as well as other ones like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time), can lead to evolution which is defined by change in the genome of the species over time, and the change in phenotype as time passes (the expression of the genotype in the individual).

Students can better understand the concept of phylogeny by using evolutionary thinking in all aspects of biology. A recent study conducted by Grunspan and colleagues, 에볼루션 블랙잭 for instance demonstrated that teaching about the evidence for evolution helped students accept the concept of evolution in a college-level biology class. To learn more about how to teach about evolution, please look up The Evolutionary Potential of All Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution in Life Sciences Education.

Evolution in Action

Traditionally scientists have studied evolution through looking back, studying fossils, comparing species and studying living organisms. But evolution isn't just something that occurred in the past, it's an ongoing process happening right now. Bacteria mutate and resist antibiotics, viruses re-invent themselves and are able to evade new medications, and 에볼루션 코리아 animals adapt their behavior in response to the changing environment. The results are often apparent.

However, it wasn't until late 1980s that biologists understood that natural selection can be seen in action, as well. The main reason is that different traits can confer an individual rate of survival and reproduction, and they can be passed down from one generation to another.

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

It is easier to observe evolutionary change when the species, like bacteria, has a rapid generation turnover. Since 1988 biologist Richard Lenski has been tracking twelve populations of E. coli that descended from a single strain; samples from each population are taken every day, and over 500.000 generations have been observed.

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

Microevolution can also be seen in the fact that mosquito genes that confer resistance to pesticides are more prevalent in populations where insecticides have been used. This is because the use of pesticides causes a selective pressure that favors people with resistant genotypes.

The rapid pace of evolution taking place has led to a growing recognition of its importance in a world shaped by human activity--including climate changes, pollution and the loss of habitats which prevent many species from adapting. Understanding evolution will help us make better choices about the future of our planet, and the life of its inhabitants.