The Holocene ( ) is the current
geological epoch. It began approximately 11,650
cal years
Before Present
Before Present (BP) years, or "years before present", is a time scale used mainly in archaeology, geology and other scientific disciplines to specify when events occurred relative to the origin of practical radiocarbon dating in the 1950s. Becau ...
(), after the
Last Glacial Period, which concluded with the
Holocene glacial retreat
The Holocene glacial retreat is a geographical phenomenon that involved the global retreat of glaciers (deglaciation) that previously had advanced during the Last Glacial Maximum. Ice sheet retreat initiated ca. 19,000 years ago and accelerated ...
.
The Holocene and the preceding
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...
together form the
Quaternary period. The Holocene has been identified with the current warm period, known as
MIS 1. It is considered by some to be an
interglacial period within the Pleistocene Epoch, called the
Flandrian interglacial The Flandrian interglacial or stage is the name given by geologists and archaeologists in the British Isles to the first, and so far only, stage of the Holocene epoch (the present geological period), covering the period from around 12,000 years ago, ...
.
[Oxford University Press – Why Geography Matters: More Than Ever (book) – "Holocene Humanity" section https://books.google.com/books?id=7P0_sWIcBNsC ]
The Holocene corresponds with the rapid proliferation, growth and impacts of the
human species
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, an ...
worldwide, including
all of its written history,
technological revolution
A technological revolution is a period in which one or more technologies is replaced by another novel technology in a short amount of time. It is an era of accelerated technological progress characterized by new innovations whose rapid applic ...
s, development of major
civilization
A civilization (or civilisation) is any complex society characterized by the development of a state, social stratification, urbanization, and symbolic systems of communication beyond natural spoken language (namely, a writing system).
...
s, and overall significant transition towards
urban living in the present. The human impact on modern-era
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
and its
ecosystem
An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...
s may be considered of global significance for the future evolution of living species, including approximately synchronous
lithospheric
A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the portion of the upper mantle that behaves elastically on time scales of up to thousands of years or ...
evidence, or more recently
hydrospheric and
atmospheric evidence of the human impact. In July 2018, the
International Union of Geological Sciences split the Holocene Epoch into three distinct
ages based on the climate,
Greenlandian
In the geologic time scale, the Greenlandian is the earliest age or lowest stage of the Holocene Epoch or Series, part of the Quaternary. Beginning in 11,650 BP (9701 BCE or 300 HE) and ending 8,276 BP (6237 BCE or 3764 HE), it is the earli ...
(11,700 years ago to 8,200 years ago),
Northgrippian
In the geologic time scale, the Northgrippian is the middle one of three ages or stages of the Holocene Epoch or Series. It was officially ratified by the International Commission on Stratigraphy in June 2018 along with the earlier Greenlandi ...
(8,200 years ago to 4,200 years ago) and
Meghalayan
The Meghalayan age is the name given in 2018, by the International Commission on Stratigraphy, to the current age or latest geologic age – or uppermost stage of the Quaternary. It is also the upper, or latest, of three subdivisions of the ...
(4,200 years ago to the present), as proposed by
International Commission on Stratigraphy
The International Commission on Stratigraphy (ICS), sometimes referred to unofficially as the "International Stratigraphic Commission", is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigr ...
.
The oldest age, the Greenlandian was characterized by a warming following the preceding ice age. The Northgrippian Age is known for vast cooling due to a disruption in ocean circulations that was caused by the melting of glaciers. The most recent age of the Holocene is the present Meghalayan, which began with extreme drought that lasted around 200 years.
Etymology
The word is formed from two
Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...
words. ''Holos'' () is the Greek word for "whole". "Cene" comes from the Greek word ''kainos'' (), meaning "new". The concept is that this epoch is "entirely new". The suffix '-cene' is used for all the seven epochs of the
Cenozoic Era.
Overview
It is accepted by the
International Commission on Stratigraphy
The International Commission on Stratigraphy (ICS), sometimes referred to unofficially as the "International Stratigraphic Commission", is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigr ...
that the Holocene started approximately 11,650
cal years
BP (9,700 BCE).
The Subcommission on Quaternary Stratigraphy (SQS) observes the terms ‘recent’ to be an incorrect way of referring to the Holocene, and the term ‘modern’ may be used instead to describe current processes. It also observes the term ‘Flandrian’ may be used as a synonym for Holocene, although it is becoming outdated. The International Commission on Stratigraphy, however, considers the Holocene an epoch following the
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...
and specifically the
last glacial period. Local names for the last glacial period include the
Wisconsinan in North America,
the
Weichselian
The Weichselian glaciation was the last glacial period and its associated glaciation in northern parts of Europe. In the Alpine region it corresponds to the Würm glaciation. It was characterized by a large ice sheet (the Fenno-Scandian ice sheet) ...
in Europe,
the Devensian in Britain,
the
Llanquihue in Chile
and the Otiran in New Zealand.
The Holocene can be subdivided into five time intervals, or
chronozones, based on climatic fluctuations:
*
Preboreal (10 ka–9 ka BP),
*
Boreal (9 ka–8 ka BP),
*
Atlantic
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...
(8 ka–5 ka BP),
*
Subboreal (5 ka–2.5 ka BP) and
*
Subatlantic
The Subatlantic is the current climatic age of the Holocene epoch. It started about 2,500 years BP and is still ongoing. Its average temperatures are slightly lower than during the preceding Subboreal and Atlantic. During its course, the tempe ...
(2.5 ka BP–present).
: ''Note: "
ka BP" means "kilo-annum
Before Present
Before Present (BP) years, or "years before present", is a time scale used mainly in archaeology, geology and other scientific disciplines to specify when events occurred relative to the origin of practical radiocarbon dating in the 1950s. Becau ...
", i.e. 1,000 years before 1950 (non-calibrated
C14 dates)''
Geologists working in different regions are studying sea levels, peat bogs and
ice core samples by a variety of methods, with a view toward further verifying and refining the
Blytt–Sernander sequence. This is a classification of climatic periods initially defined by plant remains in
peat moss
''Sphagnum'' is a genus of approximately 380 accepted species of mosses, commonly known as sphagnum moss, peat moss, also bog moss and quacker moss (although that term is also sometimes used for peat). Accumulations of ''Sphagnum'' can store wa ...
es. Though the method was once thought to be of little interest, based on
14C dating of peats that was inconsistent with the claimed chronozones, investigators have found a general correspondence across
Eurasia
Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago ...
and
North America. The scheme was defined for
Northern Europe, but the
climate changes were claimed to occur more widely. The periods of the scheme include a few of the final pre-Holocene oscillations of the last glacial period and then classify climates of more recent
prehistory
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use ...
.
Paleontologists
Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of foss ...
have not defined any
faunal stage
In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convent ...
s for the Holocene. If subdivision is necessary, periods of human technological development, such as the
Mesolithic,
Neolithic
The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several p ...
, and
Bronze Age
The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second prin ...
, are usually used. However, the time periods referenced by these terms vary with the emergence of those technologies in different parts of the world.
According to some scholars, a third division, the
Anthropocene
The Anthropocene ( ) is a proposed geological epoch dating from the commencement of significant human impact on Earth's geology and ecosystems, including, but not limited to, anthropogenic climate change.
, neither the International Commissio ...
, has now begun. This term is used to denote the present time interval in which many geologically significant conditions and processes have been profoundly altered by human activities.
The 'Anthropocene' (a term coined by
Paul J. Crutzen and Eugene Stoermer in 2000) is not a formally defined geological unit. The Subcommission on Quaternary Stratigraphy of the
International Commission on Stratigraphy
The International Commission on Stratigraphy (ICS), sometimes referred to unofficially as the "International Stratigraphic Commission", is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigr ...
has a working group to determine whether it should be.
In May 2019, members of the working group voted in favour of recognizing the Anthropocene as formal chrono-stratigraphic unit, with stratigraphic signals around the mid-twentieth century CE as its base. The exact criteria have still to be decided upon, after which the recommendation also has to be approved by the working group's parent bodies (ultimately the International Union of Geological Sciences).
Geology
The Holocene is a geologic epoch that follows directly after the Pleistocene. Continental motions due to
plate tectonics
Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large ...
are less than a kilometre over a span of only 10,000 years. However, ice melt caused world
sea levels to rise about in the early part of the Holocene and another 30 m in the later part of the Holocene. In addition, many areas above about
40 degrees north latitude had been depressed by the weight of the Pleistocene glaciers and rose as much as due to
post-glacial rebound
Post-glacial rebound (also called isostatic rebound or crustal rebound) is the rise of land masses after the removal of the huge weight of ice sheets during the last glacial period, which had caused isostatic depression. Post-glacial rebound ...
over the late Pleistocene and Holocene, and are still rising today.
The sea-level rise and temporary
land depression allowed temporary marine incursions into areas that are now far from the sea. For example, marine fossils from the Holocene epoch have been found in locations such as
Vermont
Vermont () is a state in the northeast New England region of the United States. Vermont is bordered by the states of Massachusetts to the south, New Hampshire to the east, and New York to the west, and the Canadian province of Quebec to ...
and
Michigan
Michigan () is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the List of U.S. states and ...
. Other than higher-latitude temporary marine incursions associated with glacial depression, Holocene fossils are found primarily in lakebed,
floodplain
A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...
, and
cave deposits. Holocene marine deposits along low-latitude coastlines are rare because the rise in sea levels during the period exceeds any likely
tectonic uplift
Tectonic uplift is the geologic uplift of Earth's surface that is attributed to plate tectonics. While isostatic response is important, an increase in the mean elevation of a region can only occur in response to tectonic processes of crustal th ...
of non-glacial origin.
Post-glacial rebound in the
Scandinavia
Scandinavia; Sámi languages: /. ( ) is a subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, Norway, and Swe ...
region resulted in a shrinking
Baltic Sea
The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain.
The sea stretches from 53°N to 66°N latitude and ...
. The region continues to rise, still causing weak
earthquake
An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, fr ...
s across Northern Europe. An equivalent event in North America was the rebound of
Hudson Bay, as it shrank from its larger, immediate post-glacial
Tyrrell Sea phase, to its present boundaries.
Climate
![Journal](https://upload.wikimedia.org/wikipedia/commons/5/54/Journal.pone.0076514.g004.png)
The climate throughout the Holocene has shown significant variability despite ice core records from Greenland suggesting a more stable climate following the preceding ice age. Marine chemical fluxes during the Holocene were lower than during the Younger Dryas, but were still considerable enough to imply notable changes in the climate. The Greenland ice core records indicate that climate changes became more regional and had a larger effect on the mid-to-low latitudes and mid-to-high latitudes after ~5600 B.P. During the transition from the last glacial to the Holocene, the
Huelmo–Mascardi Cold Reversal in the
Southern Hemisphere began before the Younger Dryas, and the maximum warmth flowed south to north from 11,000 to 7,000 years ago. It appears that this was influenced by the residual glacial ice remaining in the
Northern Hemisphere until the later date.
The
Holocene climatic optimum (HCO) was a period of warming throughout the globe. It has been suggested that the warming was not uniform across the world. Ice core measurements imply that the sea surface temperature (SST) gradient east of New Zealand, across the subtropical front (STF), was around 2 degrees Celsius. This temperature gradient is significantly less than modern times, which is around 6 degrees Celsius. A study utilizing five SST proxies from 37°S to 60°S latitude confirmed that the strong temperature gradient was confined to the area immediately south of the STF, and is correlated with reduced westerly winds near New Zealand. From the 10th-14th century, the climate was similar to that of modern times during a period known as the Medieval climate optimum, or the Medieval warm period (MWP). It was found that the warming that is taking place in current years is both more frequent and more spatially homogeneous than what was experienced during the MWP. A warming of +1 degree Celsius occurs 5-40 times more frequently in modern years than during the MWP. The major forcing during the MWP was due to greater solar activity, which led to heterogeneity compared to the greenhouse gas forcing of modern years that leads to more homogeneous warming. This was followed by the
Little Ice Age, from the 13th or 14th century to the mid-19th century.
The temporal and spatial extent of climate change during the Holocene is an area of considerable uncertainty, with
radiative forcing
Radiative forcing (or climate forcing) is the change in energy flux in the atmosphere caused by natural or anthropogenic factors of climate change as measured by watts / metre2. It is a scientific concept used to quantify and compare the extern ...
recently proposed to be the origin of cycles identified in the North Atlantic region. Climate cyclicity through the Holocene (
Bond events) has been observed in or near marine settings and is strongly controlled by glacial input to the North Atlantic.
Periodicities of ≈2500, ≈1500, and ≈1000 years are generally observed in the North Atlantic. At the same time spectral analyses of the continental record, which is remote from oceanic influence, reveal persistent periodicities of 1,000 and 500 years that may correspond to solar activity variations during the Holocene Epoch.
A 1,500-year cycle corresponding to the North Atlantic oceanic circulation may have had widespread global distribution in the Late Holocene.
Ecological developments
Animal and plant life have not evolved much during the relatively short Holocene, but there have been major shifts in the richness and abundance of plants and animals. A
number of large animals including
mammoth
A mammoth is any species of the extinct elephantid genus ''Mammuthus'', one of the many genera that make up the order of trunked mammals called proboscideans. The various species of mammoth were commonly equipped with long, curved tusks an ...
s and
mastodon
A mastodon ( 'breast' + 'tooth') is any proboscidean belonging to the extinct genus ''Mammut'' (family Mammutidae). Mastodons inhabited North and Central America during the late Miocene or late Pliocene up to their extinction at the end of th ...
s,
saber-toothed cat
Machairodontinae is an extinct subfamily of carnivoran mammals of the family Felidae (true cats). They were found in Asia, Africa, North America, South America, and Europe from the Miocene to the Pleistocene, living from about 16 million ...
s like ''
Smilodon
''Smilodon'' is a genus of the extinct machairodont subfamily of the felids. It is one of the most famous prehistoric mammals and the best known saber-toothed cat. Although commonly known as the saber-toothed tiger, it was not closely rela ...
'' and ''
Homotherium
''Homotherium'', also known as the scimitar-toothed cat or scimitar cat, is an extinct genus of machairodontine saber-toothed predator, often termed scimitar-toothed cats, that inhabited North America, South America, Eurasia, and Africa during ...
'', and
giant sloth
Ground sloths are a diverse group of extinct sloths in the mammalian superorder Xenarthra. The term is used to refer to all extinct sloths because of the large size of the earliest forms discovered, compared to existing tree sloths. The Caribbea ...
s went extinct in the late Pleistocene and early Holocene. The extinction of some megafauna in America could be attributed to the Clovis people; this culture was known for "
Clovis points" which were fashioned on spears for hunting animals. Shrubs, herbs, and mosses had also changed in relative abundance from the Pleistocene to Holocene, identified by permafrost core samples.
Throughout the world, ecosystems in cooler climates that were previously regional have been isolated in higher altitude ecological "islands".
The ''
8.2-ka event'', an abrupt cold spell recorded as a negative excursion in the record lasting 400 years, is the most prominent climatic event occurring in the Holocene Epoch, and may have marked a resurgence of ice cover. It has been suggested that this event was caused by the final drainage of
Lake Agassiz
Lake Agassiz was a large glacial lake in central North America. Fed by glacial meltwater at the end of the last glacial period, its area was larger than all of the modern Great Lakes combined.
First postulated in 1823 by William H. Keating, i ...
, which had been confined by the glaciers, disrupting the
thermohaline
Thermohaline circulation (THC) is a part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes. The adjective ''thermohaline'' derives from '' thermo-'' referring to tempe ...
circulation of the
Atlantic
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...
. This disruption was the result of an ice dam over
Hudson Bay collapsing sending cold
lake Agassiz
Lake Agassiz was a large glacial lake in central North America. Fed by glacial meltwater at the end of the last glacial period, its area was larger than all of the modern Great Lakes combined.
First postulated in 1823 by William H. Keating, i ...
water into the
North Atlantic ocean
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe an ...
.
Furthermore, studies show that the melting of
Lake Agassiz
Lake Agassiz was a large glacial lake in central North America. Fed by glacial meltwater at the end of the last glacial period, its area was larger than all of the modern Great Lakes combined.
First postulated in 1823 by William H. Keating, i ...
led to sea-level rise which flooded the North American coastal landscape. The
basal peat plant was then used to determine the resulting local sea-level rise of 0.20-0.56m in the
Mississippi Delta.
Subsequent research, however, suggested that the discharge was probably superimposed upon a longer episode of cooler climate lasting up to 600 years and observed that the extent of the area affected was unclear.
Human developments
![World in 1000 BCE](https://upload.wikimedia.org/wikipedia/commons/a/ad/World_in_1000_BCE.png)
The beginning of the Holocene corresponds with the beginning of the
Mesolithic age in most of
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
. In regions such as the
Middle East
The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...
and
Anatolia
Anatolia, tr, Anadolu Yarımadası), and the Anatolian plateau, also known as Asia Minor, is a large peninsula in Western Asia and the westernmost protrusion of the Asian continent. It constitutes the major part of modern-day Turkey. The ...
, the term
Epipaleolithic is preferred in place of Mesolithic, as they refer to approximately the same time period. Cultures in this period include
Hamburgian,
Federmesser, and the
Natufian culture, during which
the oldest inhabited places still existing on Earth were first settled, such as
Tell es-Sultan
Tell es-Sultan ( ar, تل السلطان, ''lit.'' Sultan's Hill), also known as Tel Jericho ( he, תל יריחו) or Ancient Jericho, is a UNESCO-nominated archaeological site in the West Bank, in the State of Palestine, located adjacent to th ...
(Jericho) in the
Middle East
The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...
. There is also evolving archeological evidence of
proto-religion at locations such as
Göbekli Tepe
Göbekli Tepe (, "Potbelly Hill"; known as ''Girê Mirazan'' or ''Xirabreşkê'' in Kurdish) is a Neolithic archaeological site in the Southeastern Anatolia Region of Turkey. Dated to the Pre-Pottery Neolithic, between 9500 and 8000 BCE, the ...
, as long ago as the
9th millennium BCE.
The preceding period of the Late Pleistocene had already brought advancements such as the bow and arrow, creating more efficient forms of hunting and replacing spear throwers. In Holocene, however, the domestication of plants and animals allowed human civilization to develop villages and towns in centralized locations. Archaeological data shows that between 10,000 to 7,000
BP rapid domestication of plants and animals took place in tropical and subtropical parts of
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
,
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
, and
Central America
Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...
.
The development of farming allowed
human civilization
A civilization (or civilisation) is any complex society characterized by the development of a state, social stratification, urbanization, and symbolic systems of communication beyond natural spoken language (namely, a writing system).
Civi ...
to transition away from
hunter-gatherer nomadic cultures, which did not establish permanent settlements, to a more sustainable sedentary lifestyle. This form of lifestyle change allowed human civilization to develop towns and villages in centralized locations, which gave rise to the world known today. It is believed that the domestication of plants and animals began in the early part of the Holocene in the tropical areas of the planet.
Because these areas had warm, moist temperatures, the climate was perfect for effective farming. Culture development and human population change, specifically in South America, has also been linked to spikes in hydroclimate resulting in climate variability in the mid-Holocene (8.2 - 4.2 k cal BP). Climate change on seasonality and available moisture also allowed for favorable agricultural conditions which promoted human development for Maya and Tiwanaku regions.
Extinction event
The
Holocene extinction, otherwise referred to as the ''sixth mass extinction'' or ''Anthropocene extinction'', is an ongoing
extinction event of
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
during the present Holocene
epoch
In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured.
The moment of epoch is usually decided by ...
(with the more recent time sometimes called Anthropocene) as a result of
human activity
Human behavior is the potential and expressed capacity ( mentally, physically, and socially) of human individuals or groups to respond to internal and external stimuli throughout their life. Kagan, Jerome, Marc H. Bornstein, and Richard M. ...
.
The included
extinctions span numerous families of
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...
,
fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
,
plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclu ...
s and
animal
Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...
s, including
mammals,
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s,
reptiles,
amphibians,
fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...
and
invertebrates
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordat ...
. With widespread degradation of
highly biodiverse habitats such as
coral reef
A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups.
C ...
s and
rainforests, as well as other areas, the vast majority of these extinctions are thought to be undocumented, as the species are undiscovered at the time of their extinction, or no one has yet discovered their extinction. The current rate of extinction of species is estimated at 100 to 1,000 times higher than
natural background extinction rates.
Gallery
See also
* 4.2-kiloyear event
* 8.2-kiloyear event
In climatology, the so-called "8.2-kiloyear event" was a sudden decrease in global temperatures that occurred approximately 8,200 years before the present ( BP), that is, 6,251 BC. It defines the start of the Northgrippian age in the Holocene ...
* 10th millennium BC
The 10th millennium BC spanned the years 10,000 BC to 9001 BC (c. 12 ka to c. 11 ka). It marks the beginning of the transition from the Palaeolithic to the Neolithic via the interim Mesolithic ( Northern Europe and Western Europe) and Epip ...
* Blytt–Sernander system
* Holocene calendar
The Holocene calendar, also known as the Holocene Era or Human Era (HE), is a year numbering system that adds exactly 10,000 years to the currently dominant ( AD/ BC or CE/BCE) numbering scheme, placing its first year near the beginning of the ...
* African humid period
The African humid period (AHP) (also known by other names) is a climate period in Africa during the late Pleistocene and Holocene geologic epochs, when northern Africa was wetter than today. The covering of much of the Sahara desert by grasses, ...
* Older Peron
The Older Peron was the name for a period identified in 1961 as an episode of a global sea-level (i.e. eustatic) high-stand during the Holocene Epoch
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years B ...
* Outburst flood
In geomorphology, an outburst flood—a type of megaflood—is a high-magnitude, low-frequency catastrophic flood involving the sudden release of a large quantity of water. During the last deglaciation, numerous glacial lake outburst floods were ca ...
* Piora Oscillation
* Quaternary extinction event
The Quaternary period (from 2.588 ± 0.005 million years ago to the present) has seen the extinctions of numerous predominantly megafaunal species, which have resulted in a collapse in faunal density and diversity and the extinction of key ecolog ...
References
Further reading
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External links
The Holocene epoch explained by the BBC
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Geological epochs
Quaternary geochronology
Interglacials
Historical eras