1.
Munich
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Munich is the capital and largest city of the German state of Bavaria, on the banks of River Isar north of the Bavarian Alps. Munich is the third largest city in Germany, after Berlin and Hamburg, the Munich Metropolitan Region is home to 5.8 million people. According to the Globalization and World Rankings Research Institute Munich is considered an alpha-world city, the name of the city is derived from the Old/Middle High German term Munichen, meaning by the monks. It derives from the monks of the Benedictine order who ran a monastery at the place that was later to become the Old Town of Munich, Munich was first mentioned in 1158. From 1255 the city was seat of the Bavarian Dukes, black and gold—the colours of the Holy Roman Empire—have been the citys official colours since the time of Ludwig the Bavarian, when it was an imperial residence. Following a final reunification of the Wittelsbachian Duchy of Bavaria, previously divided and sub-divided for more than 200 years, like wide parts of the Holy Roman Empire, the area recovered slowly economically. In 1918, during the German Revolution, the house of Wittelsbach, which governed Bavaria since 1180, was forced to abdicate in Munich. In the 1920s, Munich became home to political factions, among them the NSDAP. During World War II, Munich was heavily bombed and more than 50% of the entire city, the postwar period was characterised by American occupation until 1949 and a strong increase of population and economic power during the years of the Wirtschaftswunder after 1949. The city is home to corporations like BMW, Siemens, MAN, Linde, Allianz and MunichRE as well as many small. Munich is home to national and international authorities, major universities, major museums. Its numerous architectural attractions, international events, exhibitions and conferences. Munich is one of the most prosperous and fastest growing cities in Germany and it is a top-ranked destination for migration and expatriate location, despite being the municipality with the highest density of population in Germany. Munich nowadays hosts more than 530,000 people of foreign background, the year 1158 is assumed to be the foundation date, which is the earliest date the city is mentioned in a document. The document was signed in Augsburg, by that time the Guelph Henry the Lion, Duke of Saxony and Bavaria, had built a bridge over the river Isar next to a settlement of Benedictine monks—this was on the Old Salt Route and a toll bridge. In 1175, Munich was officially granted city status and received fortification, in 1180, with the trial of Henry the Lion, Otto I Wittelsbach became Duke of Bavaria and Munich was handed over to the Bishop of Freising. In 1240, Munich was transferred to Otto II Wittelsbach and in 1255, Duke Louis IV, a native of Munich, was elected German king in 1314 and crowned as Holy Roman Emperor in 1328. He strengthened the position by granting it the salt monopoly
2.
Germany
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Germany, officially the Federal Republic of Germany, is a federal parliamentary republic in central-western Europe. It includes 16 constituent states, covers an area of 357,021 square kilometres, with about 82 million inhabitants, Germany is the most populous member state of the European Union. After the United States, it is the second most popular destination in the world. Germanys capital and largest metropolis is Berlin, while its largest conurbation is the Ruhr, other major cities include Hamburg, Munich, Cologne, Frankfurt, Stuttgart, Düsseldorf and Leipzig. Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity, a region named Germania was documented before 100 AD. During the Migration Period the Germanic tribes expanded southward, beginning in the 10th century, German territories formed a central part of the Holy Roman Empire. During the 16th century, northern German regions became the centre of the Protestant Reformation, in 1871, Germany became a nation state when most of the German states unified into the Prussian-dominated German Empire. After World War I and the German Revolution of 1918–1919, the Empire was replaced by the parliamentary Weimar Republic, the establishment of the national socialist dictatorship in 1933 led to World War II and the Holocaust. After a period of Allied occupation, two German states were founded, the Federal Republic of Germany and the German Democratic Republic, in 1990, the country was reunified. In the 21st century, Germany is a power and has the worlds fourth-largest economy by nominal GDP. As a global leader in industrial and technological sectors, it is both the worlds third-largest exporter and importer of goods. Germany is a country with a very high standard of living sustained by a skilled. It upholds a social security and universal health system, environmental protection. Germany was a member of the European Economic Community in 1957. It is part of the Schengen Area, and became a co-founder of the Eurozone in 1999, Germany is a member of the United Nations, NATO, the G8, the G20, and the OECD. The national military expenditure is the 9th highest in the world, the English word Germany derives from the Latin Germania, which came into use after Julius Caesar adopted it for the peoples east of the Rhine. This in turn descends from Proto-Germanic *þiudiskaz popular, derived from *þeudō, descended from Proto-Indo-European *tewtéh₂- people, the discovery of the Mauer 1 mandible shows that ancient humans were present in Germany at least 600,000 years ago. The oldest complete hunting weapons found anywhere in the world were discovered in a mine in Schöningen where three 380, 000-year-old wooden javelins were unearthed
3.
Scientist
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A scientist is a person engaging in a systematic activity to acquire knowledge that describes and predicts the natural world. In a more restricted sense, a scientist may refer to an individual who uses the scientific method, the person may be an expert in one or more areas of science. The term scientist was coined by the theologian, philosopher and historian of science William Whewell and this article focuses on the more restricted use of the word. Scientists perform research toward a comprehensive understanding of nature, including physical, mathematical and social realms. Philosophers aim to provide an understanding of fundamental aspects of reality and experience, often pursuing inquiries with conceptual, rather than empirical. When science is done with a goal toward practical utility, it is called applied science, an applied scientist may not be designing something in particular, but rather is conducting research with the aim of developing new technologies and practical methods. When science seeks to answer questions about aspects of reality it is sometimes called natural philosophy. Science and technology have continually modified human existence through the engineering process, as a profession the scientist of today is widely recognized. Jurisprudence and mathematics are often grouped with the sciences, some of the greatest physicists have also been creative mathematicians and lawyers. There is a continuum from the most theoretical to the most empirical scientists with no distinct boundaries, in terms of personality, interests, training and professional activity, there is little difference between applied mathematicians and theoretical physicists. Scientists can be motivated in several ways, many have a desire to understand why the world is as we see it and how it came to be. They exhibit a strong curiosity about reality, other motivations are recognition by their peers and prestige, or the desire to apply scientific knowledge for the benefit of peoples health, the nations, the world, nature or industries. Scientists tend to be motivated by direct financial reward for their work than other careers. As a result, scientific researchers often accept lower average salaries when compared with other professions which require a similar amount of training. The number of scientists is vastly different from country to country, for instance, there are only 4 full-time scientists per 10,000 workers in India while this number is 79 for the United Kingdom and the United States. According to the US National Science Foundation 4.7 million people with science degrees worked in the United States in 2015, across all disciplines, the figure included twice as many men as women. Of that total, 17% worked in academia, that is, at universities and undergraduate institutions, 5% of scientists worked for the federal government and about 3. 5% were self-employed. Of the latter two groups, two-thirds were men, 59% of US scientists were employed in industry or business, and another 6% worked in non-profit positions
4.
Engineer
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Engineers design materials, structures, and systems while considering the limitations imposed by practicality, regulation, safety, and cost. The word engineer is derived from the Latin words ingeniare and ingenium, the work of engineers forms the link between scientific discoveries and their subsequent applications to human and business needs and quality of life. His/her work is predominantly intellectual and varied and not of a mental or physical character. It requires the exercise of original thought and judgement and the ability to supervise the technical, he/she is thus placed in a position to make contributions to the development of engineering science or its applications. In due time he/she will be able to give authoritative technical advice, much of an engineers time is spent on researching, locating, applying, and transferring information. Indeed, research suggests engineers spend 56% of their time engaged in various information behaviours, Engineers must weigh different design choices on their merits and choose the solution that best matches the requirements. Their crucial and unique task is to identify, understand, Engineers apply techniques of engineering analysis in testing, production, or maintenance. Analytical engineers may supervise production in factories and elsewhere, determine the causes of a process failure and they also estimate the time and cost required to complete projects. Supervisory engineers are responsible for major components or entire projects, Engineering analysis involves the application of scientific analytic principles and processes to reveal the properties and state of the system, device or mechanism under study. Most engineers specialize in one or more engineering disciplines, numerous specialties are recognized by professional societies, and each of the major branches of engineering has numerous subdivisions. Civil engineering, for example, includes structural and transportation engineering and materials engineering include ceramic, metallurgical, mechanical engineering cuts across just about every discipline since its core essence is applied physics. Engineers also may specialize in one industry, such as vehicles, or in one type of technology. Several recent studies have investigated how engineers spend their time, that is, research suggests that there are several key themes present in engineers’ work, technical work, social work, computer-based work, information behaviours. Amongst other more detailed findings, a recent work sampling study found that engineers spend 62. 92% of their time engaged in work,40. 37% in social work. The time engineers spend engaged in activities is also reflected in the competencies required in engineering roles. There are many branches of engineering, each of which specializes in specific technologies, typically engineers will have deep knowledge in one area and basic knowledge in related areas. When developing a product, engineers work in interdisciplinary teams. For example, when building robots an engineering team will typically have at least three types of engineers, a mechanical engineer would design the body and actuators
5.
States of Germany
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Germany is a federal republic consisting of sixteen federal states. Since todays Germany was formed from a collection of several states, it has a federal constitution. The remaining 13 states are called Flächenländer, the creation of the Federal Republic of Germany in 1949 was through the unification of the western states created in the aftermath of World War II. West Berlin, while not part of the Federal Republic, was largely integrated and considered as a de facto state. In 1952, following a referendum, Baden, Württemberg-Baden, in 1957, the Saar Protectorate rejoined the Federal Republic as the Saarland. Federalism is one of the constitutional principles of Germany. After 1945, new states were constituted in all four zones of occupation, in 1949, the states in the three western zones formed the Federal Republic of Germany. This is in contrast to the development in Austria, where the Bund was constituted first. The use of the term Länder dates back to the Weimar Constitution of 1919, before this time, the constituent states of the German Empire were called Staaten. Today, it is common to use the term Bundesland. However, this term is not used officially, neither by the constitution of 1919 nor by the Basic Law of 1949, three Länder call themselves Freistaaten, Bavaria, Saxony, and Thuringia. He summarizes the arguments for boundary reform in Germany. The German system of dual federalism requires strong Länder that have the administrative and fiscal capacity to implement legislation, too many Länder also make coordination among them and with the federation more complicated. But several proposals have failed so far, territorial reform remains a topic in German politics. Federalism has a tradition in German history. The Holy Roman Empire comprised many petty states numbering more than 300 around 1796, the number of territories was greatly reduced during the Napoleonic Wars. After the Congress of Vienna,39 states formed the German Confederation, the new German Empire included 25 states and the imperial territory of Alsace-Lorraine. The empire was dominated by Prussia, which controlled 65% of the territory, after the territorial losses of the Treaty of Versailles, the remaining states continued as republics of a new German federation
6.
Biomedical engineering
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Biomedical engineering is the application of engineering principles and design concepts to medicine and biology for healthcare purposes. Biomedical engineering has recently emerged as its own study, compared to many other engineering fields. Such an evolution is common as a new field transitions from being an interdisciplinary specialization among already-established fields, much of the work in biomedical engineering consists of research and development, spanning a broad array of subfields. Biomedical engineering has existed for centuries,1895, Wilhelm Roentgen accidentally discovered that a cathode-ray tube could make a sheet of paper coated with barium platinocyanide glow, even when the tube and the paper were in separate rooms. Roentgen decided the tube must be emitting some kind of penetrating rays,1791, Luigi Galvani invented the frog galvanoscope. 1851, Hermann von Helmholtz invented the ophthalmoscope,1881, Samuel von Basch invented the blood pressure meter. 1895, Conrad Roentgen discovered the X-ray using gas discharged tubes,1896, Henry Becquerel discovered X-rays were emitted from uranium ore. 1901, Roentgen received the Nobel Prize for discovery of X-rays,1903, Willem Einthoven invented the electrocardiogram. 1921, First formal training in engineering was started at Oswalt Institute for Physics in Medicine, Frankfurt. 1927, Invention of the Drinker respirator,1929, Hans Berger invents the electroencephalogram. 1930, X-rays were being used to visualize most organ systems using radio-opaque materials, refrigeration, mid 1930s – early 1940s, Antibiotics, sulfanilamide and pencillin reduced cross-infection in hospitals. 1943, The International Bio-Physical Society was formed,1948, The first conference of Engineering in Medicine & Biology was held in the United States. 1950s – early 1960s, Nuclear medicine,1969, Case Western Reserve created a MD/PhD program 1970, computer tomography and magnetic resonance imaging. 1980, Gamma camera, positron emission tomography and SPECT,1997, First Indigenous endovascular coronary stent was developed by the Care Foundation. Biomedical engineering has provided advances in technology to improve human health. As per the statistics of the National Academy of Engineering, about 32000 biomedical engineers are working in various areas of health care technology. Bioinformatics is a field that develops methods and software tools for understanding biological data. As an interdisciplinary field of science, bioinformatics combines computer science, statistics, mathematics, common uses of bioinformatics include the identification of candidate genes and nucleotides
7.
Computer graphics
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Computer graphics are pictures and films created using computers. Usually, the term refers to computer-generated image data created with help from specialized hardware and software. It is a vast and recent area in computer science, the phrase was coined in 1960, by computer graphics researchers Verne Hudson and William Fetter of Boeing. It is often abbreviated as CG, though sometimes referred to as CGI. The overall methodology depends heavily on the sciences of geometry, optics. Computer graphics is responsible for displaying art and image data effectively and meaningfully to the user and it is also used for processing image data received from the physical world. Computer graphic development has had a significant impact on many types of media and has revolutionized animation, movies, advertising, video games, the term computer graphics has been used a broad sense to describe almost everything on computers that is not text or sound. Such imagery is found in and on television, newspapers, weather reports, a well-constructed graph can present complex statistics in a form that is easier to understand and interpret. In the media such graphs are used to illustrate papers, reports, thesis, many tools have been developed to visualize data. Computer generated imagery can be categorized into different types, two dimensional, three dimensional, and animated graphics. As technology has improved, 3D computer graphics have become more common, Computer graphics has emerged as a sub-field of computer science which studies methods for digitally synthesizing and manipulating visual content. Screens could display art since the Lumiere brothers use of mattes to create effects for the earliest films dating from 1895. New kinds of displays were needed to process the wealth of information resulting from such projects, early projects like the Whirlwind and SAGE Projects introduced the CRT as a viable display and interaction interface and introduced the light pen as an input device. Douglas T. Ross of the Whirlwind SAGE system performed an experiment in 1954 in which a small program he wrote captured the movement of his finger. Electronics pioneer Hewlett-Packard went public in 1957 after incorporating the decade prior, and established ties with Stanford University through its founders. This began the transformation of the southern San Francisco Bay Area into the worlds leading computer technology hub - now known as Silicon Valley. The field of computer graphics developed with the emergence of computer graphics hardware, further advances in computing led to greater advancements in interactive computer graphics. In 1959, the TX-2 computer was developed at MITs Lincoln Laboratory, the TX-2 integrated a number of new man-machine interfaces
8.
Laser
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A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term laser originated as an acronym for light amplification by stimulated emission of radiation, the first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light coherently, spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances, Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum, i. e. they can emit a single color of light. Temporal coherence can be used to produce pulses of light as short as a femtosecond, Lasers are distinguished from other light sources by their coherence. Spatial coherence is typically expressed through the output being a narrow beam, Laser beams can be focused to very tiny spots, achieving a very high irradiance, or they can have very low divergence in order to concentrate their power at a great distance. Temporal coherence implies a polarized wave at a single frequency whose phase is correlated over a great distance along the beam. A beam produced by a thermal or other incoherent light source has an amplitude and phase that vary randomly with respect to time and position. Lasers are characterized according to their wavelength in a vacuum, most single wavelength lasers actually produce radiation in several modes having slightly differing frequencies, often not in a single polarization. Although temporal coherence implies monochromaticity, there are lasers that emit a broad spectrum of light or emit different wavelengths of light simultaneously, there are some lasers that are not single spatial mode and consequently have light beams that diverge more than is required by the diffraction limit. However, all devices are classified as lasers based on their method of producing light. Lasers are employed in applications where light of the spatial or temporal coherence could not be produced using simpler technologies. The word laser started as an acronym for light amplification by stimulated emission of radiation, in the early technical literature, especially at Bell Telephone Laboratories, the laser was called an optical maser, this term is now obsolete. A laser that produces light by itself is technically an optical rather than an optical amplifier as suggested by the acronym. It has been noted that the acronym LOSER, for light oscillation by stimulated emission of radiation. With the widespread use of the acronym as a common noun, optical amplifiers have come to be referred to as laser amplifiers. The back-formed verb to lase is frequently used in the field, meaning to produce light, especially in reference to the gain medium of a laser. Further use of the laser and maser in an extended sense, not referring to laser technology or devices, can be seen in usages such as astrophysical maser
9.
Metal foam
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A metal foam is a cellular structure consisting of a solid metal with gas-filled pores comprising a large portion of the volume. The pores can be sealed or interconnected, the defining characteristic of metal foams is a high porosity, typically only 5–25% of the volume is the base metal, making these ultralight materials. The strength of the material is due to the square-cube law, metallic foams typically retain some physical properties of their base material. Foam made from non-flammable metal remains non-flammable and can generally be recycled as the base material and its coefficient of thermal expansion is similar while thermal conductivity is likely reduced. Open celled metal foam, also called metal sponge, can be used in heat exchangers, energy absorption, flow diffusion, the high cost of the material generally limits its use to advanced technology, aerospace, and manufacturing. Fine-scale open-cell foams, with smaller than can be seen unaided, are used as high-temperature filters in the chemical industry. Metallic foams are used in heat exchangers to increase heat transfer at the cost of reduced pressure. However, their use permits substantial reduction in size and fabrication costs. Most models of materials use idealized and periodic structures or averaged macroscopic properties. Metal sponge has very large surface area per unit weight and catalysts are often formed into metal sponge, such as black, platinum sponge. Metals such as osmium and palladium hydride are metaphorically called metal sponges, open cell foams are manufactured by foundry or powder metallurgy. In the powder method, space holders are used, as their name suggests, they occupy the pore spaces, in casting processes, foam is cast with an open-celled polyurethane foam skeleton. Closed-cell metal foam was first reported in 1926 by Meller in a French patent where foaming of light metals, two patents on sponge-like metal were issued to Benjamin Sosnik in 1948 and 1951 who applied mercury vapor to blow liquid aluminium. Closed-cell metal foams were developed in 1956 by John C. Elliott at Bjorksten Research Laboratories, although the first prototypes were available in the 1950s, commercial production began in the 1990s by Shinko Wire company in Japan. Closed-cell metal foams are used as an impact-absorbing material, similarly to the polymer foams in a bicycle helmet. Unlike many polymer foams, metal foams remain deformed after impact and they are light and stiff and are frequently proposed as a lightweight structural material. However, they have not been used for this purpose. Closed-cell foams retain the fire resistance and recycling potential of other metallic foams, foams are commonly made by injecting a gas or mixing a foaming agent into molten metal
10.
Manufacturing engineering
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The manufacturing engineers primary focus is to turn raw materials into a new or updated product in the most economic, efficient, and effective way possible. It is a broad area which includes the design and development of products. Manufacturing engineering is considered to be a subdiscipline of industrial engineering and has very strong overlaps with mechanical engineering. Manufacturing engineers success or failure directly impacts the advancement of technology and this field of manufacturing engineering emerged from tool and die discipline in the early 20th century. It expanded greatly from the 1960s when industrialized countries introduced factories with,1, numerical control machine tools and automated systems of production. Advanced statistical methods of quality control, These factories were pioneered by the American electrical engineer William Edwards Deming, the same methods of quality control later turned Japanese factories into world leaders in cost-effectiveness and production quality. This cut costs and improved production speed, the history of manufacturing engineering can be traced to factories in the mid 19th century USA and 18th century UK. Founded in 1104 in the Republic of Venice several hundred years before the Industrial Revolution, the Venice Arsenal apparently produced nearly one ship every day and, at its height, employed 16,000 people. Many historians regard Matthew Boultons Soho Manufactory as the first modern factory, similar claims can be made for John Lombes silk mill in Derby, or Richard Arkwrights Cromford Mill. The Cromford Mill was purpose-built to accommodate the equipment it held, one historian, Murno Gladst, contends that the first factory was in Potosí. The Potosi factory took advantage of the abundant silver that was mined nearby, british colonies in the 19th century built factories simply as buildings where a large number of workers gathered to perform hand labor, usually in textile production. This proved more efficient for the administration and distribution of materials to individual workers than earlier methods of manufacturing and this experience formed the basis for the later studies of manufacturing engineering. Between 1820 and 1850, non-mechanized factories supplanted traditional artisan shops as the predominant form of manufacturing institution, henry Ford further revolutionized the factory concept and thus manufacturing engineering in the early 20th century with the innovation of mass production. Highly specialized workers situated alongside a series of rolling ramps would build up a product such as an automobile and this concept dramatically decreased production costs for virtually all manufactured goods and brought about the age of consumerism. Modern manufacturing engineering studies include all intermediate processes required for the production and integration of a products components, some industries, such as semiconductor and steel manufacturers use the term fabrication for these processes. Automation is used in different processes of manufacturing such as machining and welding, automated manufacturing refers to the application of automation to produce goods in a factory. Robotics is the application of mechatronics and automation to create robots and these robots may be of any shape and size, but all are preprogrammed and interact physically with the world. To create a robot, an engineer typically employs kinematics and mechanics, robots are used extensively in manufacturing engineering
11.
Logistics
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Logistics is generally the detailed organization and implementation of a complex operation. In a general sense, logistics is the management of the flow of things between the point of origin and the point of consumption in order to meet requirements of customers or corporations. The resources managed in logistics can include items such as food, materials, animals, equipment. The logistics of physical items usually involves the integration of information flow, material handling, production, packaging, inventory, transportation, warehousing, and often security. In military science, logistics is concerned with maintaining army supply lines while disrupting those of the enemy, since an armed force without resources and transportation is defenseless. Military logistics was already practiced in the ancient world and as modern military have a significant need for logistics solutions, in military logistics, logistics officers manage how and when to move resources to the places they are needed. The complexity of logistics can be modeled, analyzed, visualized, the minimization of the use of resources is a common motivation in all logistics fields. A professional working in the field of management is called a logistician. The prevalent view is that the term comes from the late 19th century. Others attribute a Greek origin to the word, λόγος, meaning reason or speech, λογιστικός, the Oxford English Dictionary defines logistics as the branch of military science relating to procuring, maintaining and transporting material, personnel and facilities. As such, logistics is commonly seen as a branch of engineering that creates people systems rather than machine systems and that being said, from a modeling perspective, there are similarities between operations management and logistics, and companies sometimes use hybrid professionals, with for ex. Director of Operations or Logistics Officer working on similar problems, furthermore, the term supply chain management originally refers to, among other issues, having an integrated vision in of both production and logistics from point of origin to point of production. All these terms may suffer from semantic change as an effect of advertising. Outbound logistics is the related to the storage and movement of the final product. Advance Logistics consists of the required to set up or establish a plan for logistics activities to occur. Distribution logistics has, as main tasks, the delivery of the products to the customer. It consists of processing, warehousing, and transportation. Distribution logistics is necessary because the time, place, and quantity of production differs with the time, place, disposal logistics has as its main function to reduce logistics cost and enhance service related to the disposal of waste produced during the operation of a business
12.
Ecology
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Ecology is the scientific analysis and study of interactions among organisms and their environment. It is a field that includes biology, geography. Ecology includes the study of interactions that organisms have with other, other organisms. Ecosystems are composed of dynamically interacting parts including organisms, the communities make up. Ecosystem processes, such as production, pedogenesis, nutrient cycling. These processes are sustained by organisms with specific life history traits, biodiversity, which refers to the varieties of species, genes, and ecosystems, enhances certain ecosystem services. Ecology is not synonymous with environment, environmentalism, natural history and it is closely related to evolutionary biology, genetics, and ethology. An important focus for ecologists is to improve the understanding of how biodiversity affects ecological function, Ecology is a human science as well. For example, the Circles of Sustainability approach treats ecology as more than the environment out there and it is not treated as separate from humans. Organisms and resources compose ecosystems which, in turn, maintain biophysical feedback mechanisms that moderate processes acting on living and non-living components of the planet, the word ecology was coined in 1866 by the German scientist Ernst Haeckel. Ecological thought is derivative of established currents in philosophy, particularly from ethics and politics, ancient Greek philosophers such as Hippocrates and Aristotle laid the foundations of ecology in their studies on natural history. Modern ecology became a more rigorous science in the late 19th century. Evolutionary concepts relating to adaptation and natural selection became the cornerstones of modern ecological theory, the scope of ecology contains a wide array of interacting levels of organization spanning micro-level to a planetary scale phenomena. Ecosystems, for example, contain abiotic resources and interacting life forms, an ecosystems area can vary greatly, from tiny to vast. A single tree is of consequence to the classification of a forest ecosystem. Several generations of a population can exist over the lifespan of a single leaf. Each of those aphids, in turn, support diverse bacterial communities, biodiversity describes the diversity of life from genes to ecosystems and spans every level of biological organization. The term has several interpretations, and there are ways to index, measure, characterize
