The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies have been active for a long time in helping people who are interested in science understand the concept of evolution and how it permeates all areas of scientific research.

This site provides teachers, 무료 에볼루션 students and general readers with a variety of learning resources about evolution. It contains key video clips from NOVA and WGBH produced science programs on DVD.

Tree of Life

The Tree of Life is an ancient symbol that symbolizes the interconnectedness of all life. It is a symbol of love and unity in many cultures. It also has practical applications, 에볼루션 바카라 무료체험 에볼루션 게이밍 (Bbs.darkml.net) such as providing a framework for understanding the evolution of species and how they react to changes in the environment.

The earliest attempts to depict the world of biology focused on categorizing species into distinct categories that had been distinguished by their physical and metabolic characteristics1. 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 by eukaryotes, and bacterial diversity is vastly underrepresented3,4.

Genetic techniques have greatly expanded our ability to visualize the Tree of Life by circumventing the requirement for direct observation and 에볼루션 바카라 experimentation. Particularly, molecular techniques enable us to create trees by using sequenced markers like the small subunit of 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 study of all genomes known to date has produced a rough draft of the Tree of Life, including a large number of bacteria and archaea that are not isolated and whose diversity is poorly understood6.

This expanded Tree of Life can be used to determine the diversity of a specific region and determine if certain habitats need special protection. This information can be utilized in a variety of ways, including finding new drugs, fighting diseases and improving crops. This information is also extremely beneficial in conservation efforts. It can aid biologists in identifying the areas most likely to contain cryptic species with potentially significant metabolic functions that could be at risk from anthropogenic change. Although funds to protect biodiversity are crucial but the most effective way to ensure the preservation of biodiversity around the world is for more people in developing countries to be empowered with the necessary knowledge to take action locally to encourage conservation from within.

Phylogeny

A phylogeny (also known as an evolutionary tree) illustrates the relationship between different organisms. Scientists can create a phylogenetic diagram that illustrates the evolutionary relationship of taxonomic categories using molecular information and morphological similarities or differences. The role of phylogeny is crucial in understanding genetics, biodiversity and evolution.

A basic phylogenetic tree (see Figure PageIndex 10 ) determines the relationship between organisms with similar traits that have evolved from common ancestors. These shared traits could be analogous, or homologous. Homologous traits are similar in terms of their evolutionary path. Analogous traits might appear similar however they do not share the same origins. Scientists combine similar traits into a grouping referred to as a Clade. All members of a clade have a common characteristic, like amniotic egg production. They all evolved from an ancestor who had these eggs. A phylogenetic tree is constructed by connecting the clades to determine the organisms which are the closest to each other.

Scientists make use of DNA or RNA molecular information to construct a phylogenetic graph which is more precise and precise. This information is more precise and provides evidence of the evolution of an organism. Molecular data allows researchers to identify the number of species that share a common ancestor and to estimate their evolutionary age.

The phylogenetic relationships of organisms can be affected by a variety of factors, including phenotypic flexibility, an aspect of behavior that alters in response to specific environmental conditions. This can cause a trait to appear more resembling to one species than to the other, obscuring the phylogenetic signals. This issue can be cured by using cladistics, which incorporates a combination of homologous and analogous traits in the tree.

In addition, phylogenetics can aid in predicting the duration and rate of speciation. This information can assist conservation biologists in making decisions about which species to protect from disappearance. In the end, it's the conservation of phylogenetic diversity that will lead to an ecosystem that is complete and balanced.

Evolutionary Theory

The fundamental concept of evolution is that organisms develop distinct characteristics over time based on their interactions with their environments. Several theories of evolutionary change have been developed by a wide variety of scientists, including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing gradually according to its needs and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that the use or non-use of traits causes changes that can be passed on to offspring.

In the 1930s and 1940s, ideas from a variety of fields--including natural selection, genetics, 에볼루션 바카라 무료체험 and particulate inheritance -- came together to create the modern synthesis of evolutionary theory, which defines how evolution happens through the variations of genes within a population, and how those variations change over time due to natural selection. This model, called genetic drift mutation, gene flow, and sexual selection, is the foundation of the current evolutionary biology and can be mathematically explained.

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

Students can better understand the concept of phylogeny through incorporating evolutionary thinking throughout all aspects of biology. A recent study conducted by Grunspan and colleagues, for instance demonstrated that teaching about the evidence that supports evolution increased students' understanding of evolution in a college biology class. To find out more about how to teach about evolution, read The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Traditionally scientists have studied evolution through looking back--analyzing fossils, comparing species, and studying living organisms. However, evolution isn't something that occurred in the past, it's an ongoing process that is that is taking place in the present. The virus reinvents itself to avoid new medications and bacteria mutate to resist antibiotics. Animals adapt their behavior in the wake of the changing environment. The changes that result are often easy to see.

It wasn't until late 1980s when biologists began to realize that natural selection was also at work. The main reason is that different traits can confer the ability to survive at different rates as well as reproduction, and may be passed on from one generation to the next.

In the past, if one allele - the genetic sequence that determines color - was present in a population of organisms that interbred, it might become more prevalent than any other allele. In time, this could mean the number of black moths within 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 particular species has a fast generation turnover, as with bacteria. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that descend from one strain. Samples from each population were taken regularly and more than 50,000 generations of E.coli have been observed to have passed.

Lenski's work has shown that mutations can alter the rate of change and the effectiveness at which a population reproduces. It also shows evolution takes time, which is difficult for some to accept.

Microevolution can be observed in the fact that mosquito genes for resistance to pesticides are more common in populations that have used insecticides. This is because pesticides cause a selective pressure which favors individuals who have resistant genotypes.

The rapidity of evolution has led to a greater recognition of its importance especially in a planet which is largely shaped by human activities. This includes the effects of climate change, pollution and habitat loss that prevents many species from adapting. Understanding the evolution process can help us make better decisions regarding the future of our planet, as well as the life of its inhabitants.