The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies are committed to helping those who are interested in science to understand 에볼루션 게이밍 evolution theory and how it can be applied throughout all fields of scientific research.

This site provides a range of tools for teachers, students as well as general readers about evolution. It also includes 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 all life. It is used in many spiritual traditions and 에볼루션 블랙잭 cultures as an emblem of unity and love. It can be used in many practical ways as well, including providing a framework for understanding the evolution of species and how they respond to changing environmental conditions.

Early attempts to represent the biological world were based on categorizing organisms based on their physical and metabolic characteristics. These methods, which are based on the sampling of different parts of organisms, or DNA fragments, have significantly increased the diversity of a tree of Life2. These trees are largely 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 need for direct observation and experimentation. Particularly, molecular techniques allow us to build trees by using sequenced markers like the small subunit of ribosomal RNA gene.

The Tree of Life has been dramatically expanded through genome sequencing. However there is a lot of biodiversity to be discovered. This is especially true of microorganisms, which can be difficult to cultivate and are usually only found in a single sample5. A recent analysis of all genomes that are known has created a rough draft of the Tree of Life, including many bacteria and archaea that have not been isolated and their diversity is not fully understood6.

The expanded Tree of Life can be used to assess the biodiversity of a specific region and determine if specific habitats require special protection. This information can be used in many ways, including finding new drugs, battling diseases and enhancing crops. The information is also valuable for conservation efforts. It helps biologists discover areas that are likely to have species that are cryptic, which could have vital metabolic functions, and could be susceptible to the effects of human activity. Although funding to protect biodiversity are crucial, ultimately the best way to preserve the world's biodiversity is for more people in developing countries to be empowered with the necessary knowledge to act locally in order to promote conservation from within.

Phylogeny

A phylogeny (also called an evolutionary tree) depicts the relationships between species. By using molecular information similarities and differences in morphology, or ontogeny (the process of the develogenetic signal. However, this issue can be solved through the use of methods such as cladistics that incorporate a combination of homologous and analogous features into the tree.

Additionally, phylogenetics can help determine the duration and rate at which speciation takes place. This information can help conservation biologists decide which species to protect from extinction. In the end, it's the preservation of phylogenetic diversity which will create an ecosystem that is complete and balanced.

Evolutionary Theory

The fundamental concept of evolution is that organisms develop distinct characteristics over time as a result of their interactions with their environments. Many scientists have developed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism would develop according to its own requirements and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1844-1829), 에볼루션 게이밍 who suggested that the use or non-use of traits can lead to changes that can be passed on to future generations.

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

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

Incorporating evolutionary thinking into all areas of biology education could increase student understanding of the concepts of phylogeny and evolutionary. A recent study conducted by Grunspan and colleagues, for instance revealed that teaching students about the evidence that supports evolution increased students' understanding of evolution in a college-level biology course. For more details on how to teach about evolution read The Evolutionary Potency in All Areas of Biology or Thinking Evolutionarily A Framework for Integrating Evolution into Life Sciences Education.

Evolution in Action

Scientists have traditionally studied evolution through looking back in the past, studying fossils, and comparing species. They also observe living organisms. But evolution isn't just something that happened in the past. It's an ongoing process happening today. Bacteria mutate and resist antibiotics, viruses evolve and are able to evade new medications and animals alter their behavior in response to the changing environment. The results are often visible.

It wasn't until the late 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 are passed down 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 prevalent than any other allele. Over time, that would mean that the number of black moths in a particular population could rise. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

It is easier to track evolution when an organism, like bacteria, has a rapid generation turnover. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that descend from a single strain. Samples of each population have been collected regularly, and more than 50,000 generations of E.coli have passed.

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

Another example of microevolution is that mosquito genes that confer resistance to pesticides are more prevalent in populations where insecticides are used. This is because the use of pesticides creates a pressure that favors those who have 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 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 as well as the lives of its inhabitants.