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Topic Review
Evolutionary History of Life
The evolutionary history of life on Earth traces the processes by which living and fossil organisms evolved, from the earliest emergence of life to the present. Earth formed about 4.5 billion years (Ga) ago and evidence suggests life emerged prior to 3.7 Ga. (Although there is some evidence of life as early as 4.1 to 4.28 Ga, it remains controversial due to the possible non-biological formation of the purported fossils.) The similarities among all known present-day species indicate that they have diverged through the process of evolution from a common ancestor. Approximately 1 trillion species currently live on Earth of which only 1.75–1.8 million have been named and 1.6 million documented in a central database. These currently living species represent less than one percent of all species that have ever lived on earth. The earliest evidence of life comes from biogenic carbon signatures and stromatolite fossils discovered in 3.7 billion-year-old metasedimentary rocks from western Greenland. In 2015, possible "remains of biotic life" were found in 4.1 billion-year-old rocks in Western Australia. In March 2017, putative evidence of possibly the oldest forms of life on Earth was reported in the form of fossilized microorganisms discovered in hydrothermal vent precipitates in the Nuvvuagittuq Belt of Quebec, Canada, that may have lived as early as 4.28 billion years ago, not long after the oceans formed 4.4 billion years ago, and not long after the formation of the Earth 4.54 billion years ago. Microbial mats of coexisting bacteria and archaea were the dominant form of life in the early Archean Epoch and many of the major steps in early evolution are thought to have taken place in this environment. The evolution of photosynthesis, around 3.5 Ga, eventually led to a buildup of its waste product, oxygen, in the atmosphere, leading to the great oxygenation event, beginning around 2.4 Ga. The earliest evidence of eukaryotes (complex cells with organelles) dates from 1.85 Ga, and while they may have been present earlier, their diversification accelerated when they started using oxygen in their metabolism. Later, around 1.7 Ga, multicellular organisms began to appear, with differentiated cells performing specialised functions. Sexual reproduction, which involves the fusion of male and female reproductive cells (gametes) to create a zygote in a process called fertilization is, in contrast to asexual reproduction, the primary method of reproduction for the vast majority of macroscopic organisms, including almost all eukaryotes (which includes animals and plants). However the origin and evolution of sexual reproduction remain a puzzle for biologists though it did evolve from a common ancestor that was a single celled eukaryotic species. Bilateria, animals having a left and a right side that are mirror images of each other, appeared by 555 Ma (million years ago). The earliest complex land plants date back to around 850 Ma, from carbon isotopes in Precambrian rocks, while algae-like multicellular land plants are dated back even to about 1 billion years ago, although evidence suggests that microorganisms formed the earliest terrestrial ecosystems, at least 2.7 Ga. Microorganisms are thought to have paved the way for the inception of land plants in the Ordovician. Land plants were so successful that they are thought to have contributed to the Late Devonian extinction event. (The long causal chain implied seems to involve the success of early tree archaeopteris (1) drew down CO2 levels, leading to global cooling and lowered sea levels, (2) roots of archeopteris fostered soil development which increased rock weathering, and the subsequent nutrient run-off may have triggered algal blooms resulting in anoxic events which caused marine-life die-offs. Marine species were the primary victims of the Late Devonian extinction.) Ediacara biota appear during the Ediacaran period, while vertebrates, along with most other modern phyla originated about 525 Ma during the Cambrian explosion. During the Permian period, synapsids, including the ancestors of mammals, dominated the land, but most of this group became extinct in the Permian–Triassic extinction event 252 Ma. During the recovery from this catastrophe, archosaurs became the most abundant land vertebrates; one archosaur group, the dinosaurs, dominated the Jurassic and Cretaceous periods. After the Cretaceous–Paleogene extinction event 66 Ma killed off the non-avian dinosaurs, mammals increased rapidly in size and diversity. Such mass extinctions may have accelerated evolution by providing opportunities for new groups of organisms to diversify.
  • 1.5K
  • 24 Nov 2022
Topic Review
Exposure Routes of Micro and Nanoplastics to Human
Microplastics (MPs) are plastic particles that range from 1 μm to less than 5 mm, while nanoplastics (NPs) are plastic particles smaller than 1 μm. MNPLs are mainly classified in two ways—primary or secondary—taking into account their origin. Primary MNPLs are plastic particles intentionally manufactured to have a small size (1 μm to less than 5 mm), e.g., pellet beads, which are used as raw material for the production of cosmetics, such as toothpastes, exfoliating treatments, body wash, and other personal care products.
  • 548
  • 22 Jun 2022
Topic Review
Extreme Points of Earth
This is a list of extreme points of Earth, the geographical locations that are farther north or south than, higher or lower in elevation than, or farthest inland or out to sea from, any other locations on the landmasses, continents or countries. For other lists of extreme points on Earth, including places that hold temperature and weather records, see Extremes on Earth, Lists of extreme points, and List of weather records.
  • 6.4K
  • 30 Sep 2022
Topic Review
Festive Ecology
Festive ecology explores the relationships between the symbolism and the ecology of the plants, fungi and animals associated with cultural events such as festivals, processions, and special occasions. Examples of topics are given below.
  • 279
  • 20 Nov 2022
Topic Review
Field-Effect Transistor-Based Biosensors for Environmental Monitoring
The precise monitoring of environmental contaminants and agricultural plant stress factors, respectively responsible for damages to our ecosystems and crop losses, has become nowadays a topic of uttermost importance. This is also highlighted by the recent introduction of the so-called "Sustainable Development Goals" of the United Nations, which aim at reducing pollutants while implementing more sustainable food production practices leading to a reduced impact on all ecosystems. In this context, the standard methods currently used in these fields represent a sub-optimal solution, being expensive, laboratory-based techniques, and typically requiring trained personnel with high expertise. Recent advances in both biotechnology and material science, have led to the emergence of new sensing (and biosensing) technologies, enabling low-cost, precise, and real-time detection. An especially interesting category of biosensors is represented by field-effect transistor-based biosensors (bio-FETs), which enable the possibility of performing in-situ, continuous, selective, and sensitive measurements of a wide palette of different parameters of interest. Furthermore, bio-FETs offer the possibility of being fabricated using innovative and sustainable materials, employing various device configurations, each customized for a specific application. In the specific field of environmental and agricultural monitoring, the exploitation of these devices is particularly attractive as it paves the way to early detection and intervention strategies useful to limit, or even to completely avoid negative outcomes (such as diseases to animals or ecosystems losses). 
  • 942
  • 08 Jun 2022
Topic Review
Finn River (County Fermanagh and County Monaghan)
The Finn River (Irish: An Fhinn or Abhainn na Finne), also known as the River Finn, is a small river that flows through parts of County Fermanagh and County Monaghan in the south of Ulster, the northern province in Ireland. Part of the river forms the boundary between County Fermanagh and County Monaghan, thus forming a short part of the border between Northern Ireland and the Republic of Ireland. Two very short stretches of the river, just north of Redhills and at Castle Saunderson, near Belturbet, also form part of the boundary between County Fermanagh and County Cavan. Parts of the river flow entirely within County Fermanagh, while other parts of the river flow entirely within County Monaghan. The Finn River should not be confused with the better known and much longer River Finn in County Donegal in the west of Ulster. The Finn River rises on the slopes of Slieve Beagh in the south-east of County Fermanagh, rising to the north of Roslea, a village also located in south-east Fermanagh. It initially flows in a southerly direction, meandering around both Rough Hill and Gola, two neighbouring townlands in the north-west of County Monaghan that are a short distance north-east of Roslea. The river then flows back into Fermanagh, skirting around the north-western, western and southern edges of Roslea and along the western edge of Spring Grove Forest, crossing back into County Monaghan beside New Bridge. At a place between New Bridge and Aghafin House, the river meanders around a sharp bend, flowing in a south-easterly direction for almost two miles, entirely within County Monaghan, between the townland of Aghafin, just north-east of Clones, and the townland of Nook, just south-east of Stonebridge. Thereafter, the river mainly flows in a south-westerly direction, all the way to its mouth on Upper Lough Erne. The river flows through Stonebridge and Analore, two hamlets in West Monaghan. It flows very close to Ballynure House, a now ruined Late Georgian residence just outside Analore. The Finn flows to the east, and then to the south, of Clones, the main town in West Monaghan. The river flows just to the north and north-west of the Hilton Park Demesne, near the village of Scotshouse, also in West Monaghan. The Finn flows through Wattlebridge, a hamlet in the south-east of County Fermanagh, then enters Upper Lough Erne nearby, entering the lough directly opposite Derrykerrib (Irish: Doire Ceirbe), an island and townland also in the south-east of County Fermanagh. The river flows into a narrow channel of the lough at this place, where the townland of Edergool in County Fermanagh meets the townland of Castlesaunderson Demesne, where Castle Saunderson is located, in County Cavan. Thus, half of the river's mouth is in County Fermanagh, while the other half is in County Cavan. The river's mouth, which is at the edge of the Castle Saunderson Demesne, is also very near the Lanesborough Demesne, a former demesne in the townland of Quivvy on the County Cavan shore of Upper Lough Erne. The Lanesborough Demesne, near Belturbet, is directly opposite the north-western shore of Derrykerrib Island. Traditionally, the Finn River was considered navigable for most of the year by certain types of river boat, from its mouth upstream as far as Cumber Bridge in the townland of Coolnalong (Irish: Cúil na Long), a bridge located between Scotshouse and Clones. The river meanders significantly throughout most of its course.
  • 618
  • 06 Oct 2022
Topic Review
Fire-vegetation Feedbacks and Alternative Stable States
The relationship between fire, vegetation, and climate create what is known as a fire regime. Within a fire regime, fire ecologists study the relationship between diverse ecosystems and fire; not only how fire affects vegetation, but also how vegetation affects the behavior of fire. The study of neighboring vegetations types that may be highly flammable and less flammable has provided insight into how these vegetation types can exist side by side, and are maintained by the presence or absence of fire events. Ecologists have studied these boundaries between different vegetation types, such as a closed canopy forest and a grassland, and hypothesized how climate, and soil fertility create these boundaries in vegetation types. Research in the field of pyrogeography shows how fire also plays an important role in the maintenance of dominant vegetation types, and how different vegetation types with distinct relationships to fire can exist side by side in the same climate conditions. These relationships can be described in conceptual models called fire-vegetation feedbacks, and alternative stable states.
  • 466
  • 29 Sep 2022
Topic Review
Firestorm
A firestorm is a conflagration which attains such intensity that it creates and sustains its own wind system. It is most commonly a natural phenomenon, created during some of the largest bushfires and wildfires. Although the term has been used to describe certain large fires, the phenomenon's determining characteristic is a fire with its own storm-force winds from every point of the compass. The Black Saturday bushfires and the Great Peshtigo Fire are possible examples of forest fires with some portion of combustion due to a firestorm, as is the Great Hinckley Fire. Firestorms have also occurred in cities, usually due to targeted explosives, such as in the aerial firebombings of Hamburg, Dresden, and Tokyo, and the atomic bombings of Hiroshima and Nagasaki.
  • 455
  • 19 Oct 2022
Topic Review
First Bulgarian Empire
The First Bulgarian Empire (Old Bulgarian: ц︢рьство бл︢гарское, ts'rstvo bl'garskoe) was a medieval Bulgarian state that existed in Southeastern Europe between the 7th and 11th centuries AD. It was founded in 681 when Bulgar tribes led by Asparuh moved to the northeastern Balkans. There they secured Byzantine recognition of their right to settle south of the Danube by defeating – possibly with the help of local South Slavic tribes – the Byzantine army led by Constantine IV. At the height of its power, Bulgaria spread from the Danube Bend to the Black Sea and from the Dnieper River to the Adriatic Sea. As the state solidified its position in the Balkans, it entered into a centuries-long interaction, sometimes friendly and sometimes hostile, with the Byzantine Empire. Bulgaria emerged as Byzantium's chief antagonist to its north, resulting in several wars. The two powers also enjoyed periods of peace and alliance, most notably during the Second Arab siege of Constantinople, where the Bulgarian army broke the siege and destroyed the Arab army, thus preventing an Arab invasion of Southeastern Europe. Byzantium had a strong cultural influence on Bulgaria, which also led to the eventual adoption of Christianity in 864. After the disintegration of the Avar Khaganate, the country expanded its territory northwest to the Pannonian Plain. Later the Bulgarians confronted the advance of the Pechenegs and Cumans, and achieved a decisive victory over the Magyars, forcing them to establish themselves permanently in Pannonia. During the late 9th and early 10th centuries, Simeon I achieved a string of victories over the Byzantines. Thereafter, he was recognized with the title of Emperor, and proceeded to expand the state to its greatest extent. After the annihilation of the Byzantine army in the battle of Anchialus in 917, the Bulgarians laid siege to Constantinople in 923 and 924. The Byzantines, however, eventually recovered, and in 1014, under Basil II, inflicted a crushing defeat on the Bulgarians at the Battle of Kleidion. By 1018, the last Bulgarian strongholds had surrendered to the Byzantine Empire, and the First Bulgarian Empire had ceased to exist. It was succeeded by the Second Bulgarian Empire in 1185. After the adoption of Christianity, Bulgaria became the cultural center of Slavic Europe. Its leading cultural position was further consolidated with the invention of the Glagolitic and Early Cyrillic alphabets shortly after in the capital Preslav, and literature produced in Old Bulgarian soon began spreading north. Old Bulgarian became the lingua franca of much of Eastern Europe and it came to be known as Old Church Slavonic. In 927, the fully independent Bulgarian Patriarchate was officially recognized. The ruling Bulgars and other non-Slavic tribes in the empire gradually mixed and adopted the prevailing Slavic language, thus gradually forming the Bulgarian nation from the 7th century to the 9th century. Since the late 9th century, the names Bulgarians and Bulgarian gained prevalence and became permanent designations for the local population, both in literature and in common parlance. The development of Old Church Slavonic literacy had the effect of preventing the assimilation of the South Slavs into neighbouring cultures, while stimulating the formation of a distinct Bulgarian identity.
  • 3.5K
  • 25 Oct 2022
Topic Review
First Grinnell Expedition
The First Grinnell Expedition of 1850 was the first American effort, financed by Henry Grinnell, to determine the fate of the lost Franklin Polar Expedition. Led by Lieutenant Edwin De Haven, the team explored the accessible areas along Franklin's proposed route. In coordination with British expeditions, they identified the remains of Franklin's Beechy Island winter camp, providing the first solid clues to Franklin's activities during the winter of 1845 before becoming icebound themselves.
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  • 02 Dec 2022
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