The Academy's Evolution Site

Biology is one of the most central concepts in biology. The Academies are involved in helping those interested in the sciences understand evolution theory and how it is permeated throughout all fields of scientific research.

This site provides a range of sources for students, teachers, and general readers 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, symbolizes the interconnectedness of all life. It is an emblem of love and unity across many cultures. It also has practical applications, like providing a framework for understanding the evolution of species and how they respond to changes in environmental conditions.

Early attempts to represent the biological world were founded on categorizing organisms on their metabolic and physical characteristics. These methods, based on sampling of different parts of living organisms or small fragments of their DNA, significantly increased the variety that could be included in a tree of life2. However these trees are mainly comprised of eukaryotes, and bacterial diversity is still largely unrepresented3,4.

Genetic techniques have greatly expanded our ability to visualize the Tree of Life by circumventing the need for direct observation and experimentation. In particular, molecular methods enable us to create trees using sequenced markers like 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 true of microorganisms, which can be difficult to cultivate and are often only found in a single sample5. A recent study of all genomes known to date has produced 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 assess the biodiversity of a specific region and determine if particular habitats need special protection. This information can be utilized in many ways, including identifying new drugs, combating diseases and 에볼루션 카지노 사이트 enhancing crops. This information is also extremely beneficial in conservation efforts. It can aid biologists in identifying areas most likely to be home to species that are cryptic, 에볼루션카지노사이트 which could have important metabolic functions, and could be susceptible to the effects of human activity. Although funding to protect biodiversity are essential, ultimately the best way to preserve the world's biodiversity is for more people living 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) shows the relationships between different organisms. By using molecular information as well as morphological similarities and distinctions, or ontogeny (the process of the development of an organism) scientists can create an phylogenetic tree that demonstrates the evolutionary relationship between taxonomic groups. Phylogeny is crucial in understanding biodiversity, evolution and genetics.

A basic phylogenetic Tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms with similar traits that evolved from common ancestral. These shared traits can be analogous, or homologous. Homologous characteristics are identical in terms of their evolutionary paths. Analogous traits may look like they are, but they do not share the same origins. Scientists combine similar traits into a grouping called a clade. Every organism in a group share a characteristic, for example, amniotic egg production. They all evolved from an ancestor 에볼루션 사이트 who had these eggs. A phylogenetic tree can be constructed by connecting clades to identify the species that are most closely related to each other.

For a more precise and accurate phylogenetic tree, scientists rely on molecular information from DNA or RNA to determine the relationships between organisms. This information is more precise than morphological data and gives evidence of the evolutionary history of an organism or group. The use of molecular data lets researchers determine the number of species that share the same ancestor and estimate their evolutionary age.

The phylogenetic relationship can be affected by a variety of factors, including phenotypicplasticity. This is a type of behavior that alters as a result of specific environmental conditions. This can cause a characteristic to appear more similar to one species than to another which can obscure the phylogenetic signal. However, this issue can be solved through the use of techniques such as cladistics that include a mix of homologous and analogous features into the tree.

Furthermore, phylogenetics may aid in predicting the length and speed of speciation. This information can help conservation biologists decide the species they should safeguard from the threat of extinction. Ultimately, it is the preservation of phylogenetic diversity which will create an ecosystem that is complete and balanced.

Evolutionary Theory

The central theme of evolution is that organisms develop various characteristics over time based on their interactions with their environments. 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 proposed that a living organism develop slowly according to its needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits can cause changes that can be passed on to the offspring.

In the 1930s & 1940s, concepts from various areas, including natural selection, genetics & particulate inheritance, merged to create a modern synthesis of evolution theory. This defines how evolution is triggered by the variations in genes within the population, and how these variants change with time due to natural selection. This model, which is known as genetic drift mutation, gene flow and sexual selection, 무료 에볼루션 is a cornerstone of current evolutionary biology, and can be mathematically described.

Recent developments in the field of evolutionary developmental biology have shown that variations can be introduced into a species via mutation, genetic drift and reshuffling of genes during sexual reproduction, and also through migration between populations. These processes, along with others, such as directionally-selected selection and erosion of genes (changes in frequency of genotypes over time) can result in evolution. Evolution is defined by changes in the genome over time as well as changes in the phenotype (the expression of genotypes in individuals).

Incorporating evolutionary thinking into all areas of biology education could increase student understanding of the concepts of phylogeny and evolution. A recent study conducted by Grunspan and colleagues, for example revealed that teaching students about the evidence for evolution helped students accept the concept of evolution in a college biology class. To find out more about how to teach about evolution, 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

Scientists have looked at evolution through the past--analyzing fossils and comparing species. They also observe living organisms. But evolution isn't a thing that happened in the past. It's an ongoing process, taking place in the present. Bacteria mutate and resist antibiotics, viruses reinvent themselves and escape new drugs and animals change their behavior in response to the changing climate. The resulting changes are often visible.

But it wasn't until the late 1980s that biologists realized that natural selection could be seen in action, as well. The main reason is that different traits result in a different rate of survival and reproduction, and they can be passed on from one generation to the next.

In the past, if an allele - the genetic sequence that determines colour - was present in a population of organisms that interbred, it could become more common than any other allele. As time passes, 에볼루션 카지노 사이트 that could mean 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 evolutionary change when a species, such as bacteria, has a rapid generation turnover. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. Coli that descended from a single strain. samples of each population are taken regularly, and over 50,000 generations have now passed.

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

Microevolution is also evident in the fact that mosquito genes for pesticide resistance are more prevalent in areas that have used insecticides. This is due to the fact that the use of pesticides causes a selective pressure that favors people with resistant genotypes.

The rapidity of evolution has led to an increasing awareness of its significance particularly in a world shaped largely by human activity. This includes climate change, pollution, and habitat loss that prevents many species from adapting. Understanding the evolution process can help us make smarter decisions about the future of our planet and the lives of its inhabitants.