The Academy's Evolution Site

Biology is one of the most central concepts 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, students and general readers with a variety of learning resources on evolution. It includes important video clips from NOVA and the WGBH-produced science programs on DVD.

Tree of Life

The Tree of Life, an ancient symbol, represents the interconnectedness of all life. It is used in many religions and cultures as a symbol of unity and love. It has many practical applications as well, including providing a framework for understanding the history of species, and how they respond to changing environmental conditions.

The first attempts to depict the world of biology were based on categorizing organisms based on their physical and metabolic characteristics. These methods, which rely on the sampling of different parts of organisms, or fragments of DNA have greatly increased the diversity of a tree of Life2. The trees are mostly composed of eukaryotes, while bacteria are largely underrepresented3,4.

In avoiding the necessity of direct observation and experimentation genetic techniques have made it possible to depict the Tree of Life in a much more accurate way. We can create trees using molecular techniques such as the small subunit ribosomal gene.

The Tree of Life has been significantly expanded by genome sequencing. However there is a lot of biodiversity to be discovered. This is especially true for microorganisms that are difficult to cultivate, and which are usually only present in a single sample5. Recent analysis of all genomes has produced a rough draft of a Tree of Life. This includes a variety of bacteria, archaea and other organisms that have not yet been isolated or the diversity of which is not fully understood6.

This expanded Tree of Life is particularly useful in assessing the diversity of an area, which can help to determine if certain habitats require protection. This information can be used in a range of ways, from identifying new medicines to combating disease to improving crops. The information is also incredibly beneficial to conservation efforts. It can aid biologists in identifying the areas most likely to contain cryptic species with significant metabolic functions that could be at risk from anthropogenic change. While funds to protect biodiversity are essential, the best way to conserve the world's biodiversity is to empower more people in developing nations with the knowledge they need to act locally and promote conservation.

Phylogeny

A phylogeny, also called an evolutionary tree, shows the relationships between various groups of organisms. Scientists can construct a phylogenetic chart that shows the evolution of taxonomic groups using molecular data and morphological differences or similarities. Phylogeny plays a crucial role in understanding genetics, biodiversity and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 ) identifies the relationships between organicies they should 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 central theme in evolution is that organisms change over time as a result of their interactions with their environment. Several theories of evolutionary change have been proposed by a wide variety of scientists, including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing slowly according to its requirements and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that the use or misuse of traits can cause changes that can be passed on to offspring.

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

Recent discoveries in the field of evolutionary developmental biology have demonstrated the ways in which variation can be introduced to a species via genetic drift, mutations or reshuffling of genes in sexual reproduction, and even migration between populations. These processes, 에볼루션 바카라 as well as other ones like directional selection and genetic erosion (changes in the frequency of a genotype over time) can result in evolution, which is defined by change in the genome of the species over time, and also the change in phenotype as time passes (the expression of the genotype within the 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 example, showed that teaching about the evidence for evolution increased students' understanding of evolution in a college 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 에볼루션 카지노 Infusing the Concept of Evolution into Life Sciences Education.

Evolution in Action

Scientists have looked at evolution through the past--analyzing fossils and comparing species. They also study living organisms. But evolution isn't just something that happened in the past; it's an ongoing process that is taking place today. Viruses evolve to stay away from new drugs and bacteria evolve to resist antibiotics. Animals alter their behavior in the wake of a changing world. The results are often apparent.

It wasn't until late 1980s when biologists began to realize that natural selection was also at work. The key is that different traits have different rates of survival and reproduction (differential fitness) and are passed from one generation to the next.

In the past when one particular allele - the genetic sequence that controls coloration - was present in a group of interbreeding species, it could quickly become more common than other alleles. As time passes, that could mean the number of black moths in the population could increase. The same is true for many other characteristics--including morphology and fwme.eu behavior--that vary among populations of organisms.

Monitoring evolutionary changes in action is much easier when a species has a rapid turnover of its generation like bacteria. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that are descended from one strain. The samples of each population have been collected regularly and more than 500.000 generations of E.coli have passed.

Lenski's research has revealed that mutations can alter the rate at which change occurs and the efficiency at which a population reproduces. It also proves that evolution takes time, a fact that many find hard to accept.

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

The speed at which evolution can take place has led to an increasing recognition of its importance in a world shaped by human activity, including climate change, pollution, and the loss of habitats that hinder many species from adjusting. Understanding the evolution process can help us make better decisions regarding the future of our planet as well as the lives of its inhabitants.