Allopatric speciationAllopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow. Various geographic changes can arise such as the movement of continents, and the formation of mountains, islands, bodies of water, or glaciers. Human activity such as agriculture or developments can also change the distribution of species populations.
GenomeIn the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as regulatory sequences (see non-coding DNA), and often a substantial fraction of junk DNA with no evident function. Almost all eukaryotes have mitochondria and a small mitochondrial genome.
Evolutionary capacitanceEvolutionary capacitance is the storage and release of variation, just as electric capacitors store and release charge. Living systems are robust to mutations. This means that living systems accumulate genetic variation without the variation having a phenotypic effect. But when the system is disturbed (perhaps by stress), robustness breaks down, and the variation has phenotypic effects and is subject to the full force of natural selection. An evolutionary capacitor is a molecular switch mechanism that can "toggle" genetic variation between hidden and revealed states.
EthambutolEthambutol (EMB, E) is a medication primarily used to treat tuberculosis. It is usually given in combination with other tuberculosis medications, such as isoniazid, rifampicin and pyrazinamide. It may also be used to treat Mycobacterium avium complex, and Mycobacterium kansasii. It is taken by mouth. Common side effects include problems with vision, joint pain, nausea, headaches, and feeling tired. Other side effects include liver problems and allergic reactions.
History of BeijingThe city of Beijing has a long and rich history that dates back over 3,000 years. Prior to the unification of China by the First Emperor in 221 BC, Beijing had been for centuries the capital of the ancient states of Ji and Yan. It was a provincial center in the earliest unified empires of China, Qin and Han. The northern border of ancient China ran close to the present city of Beijing, and northern nomadic tribes frequently broke in from across the border.
Beijing city fortificationsThe Beijing city fortifications were series of walls with towers and gates constructed in the city of Beijing, China in the early 1400s until they were partially demolished in 1965 for the construction of the 2nd Ring Road and Line 2 of the Beijing Subway. The original walls were preserved in the southeastern part of the city, just south of the Beijing railway station. The entire perimeter of the Inner and Outer city walls stretched for approximately .
OsteomyelitisOsteomyelitis (OM) is an infection of bone. Symptoms may include pain in a specific bone with overlying redness, fever, and weakness. The long bones of the arms and legs are most commonly involved in children e.g. the femur and humerus, while the feet, spine, and hips are most commonly involved in adults. The cause is usually a bacterial infection, but rarely can be a fungal infection. It may occur by spread from the blood or from surrounding tissue.
