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128-488: Most modern commercial orchards are planted for a single variety of fruit. While the importance of introducing biodiversity is recognized in forest plantations, introducing genetic diversity in orchard plantations by interspersing other trees might offer benefits. Genetic diversity in an orchard would provide resilience to pests and diseases, just as in forests . Orchards are sometimes concentrated near bodies of water where climatic extremes are moderated and blossom time

256-420: A double helix . The two DNA strands are known as polynucleotides since they are composed of simpler units called nucleotides . Each nucleotide is composed of a nitrogen-containing nucleobase —either cytosine (C), guanine (G), adenine (A), or thymine (T)—as well as a sugar called deoxyribose and a phosphate group . The nucleotides are joined to one another in a chain by covalent bonds between

384-420: A living systems theory viewpoint that does not necessarily depend on molecular chemistry. One systemic definition of life is that living things are self-organizing and autopoietic (self-producing). Variations of this include Stuart Kauffman 's definition as an autonomous agent or a multi-agent system capable of reproducing itself, and of completing at least one thermodynamic work cycle . This definition

512-428: A nucleus and other membrane-bound organelles , although they have circular DNA and ribosomes . Bacteria and Archaea are two domains of prokaryotes. The other primary type is the eukaryote cell, which has a distinct nucleus bound by a nuclear membrane and membrane-bound organelles, including mitochondria , chloroplasts , lysosomes , rough and smooth endoplasmic reticulum , and vacuoles . In addition, their DNA

640-403: A universal common ancestor . This evolved into all the species that exist now, by way of many extinct species, some of which have left traces as fossils . Attempts to classify living things, too, began with Aristotle . Modern classification began with Carl Linnaeus 's system of binomial nomenclature in the 1740s. Living things are composed of biochemical molecules , formed mainly from

768-407: A common origin. All life forms require certain core chemical elements for their biochemical functioning. These include carbon , hydrogen , nitrogen , oxygen , phosphorus , and sulfur —the elemental macronutrients for all organisms. Together these make up nucleic acids , proteins and lipids , the bulk of living matter. Five of these six elements comprise the chemical components of DNA,

896-528: A consequence of these microbial activities, the physical-chemical environment on Earth has been changing on a geologic time scale , thereby affecting the path of evolution of subsequent life. For example, the release of molecular oxygen by cyanobacteria as a by-product of photosynthesis induced global changes in the Earth's environment. Because oxygen was toxic to most life on Earth at the time, this posed novel evolutionary challenges, and ultimately resulted in

1024-501: A country, endangered species are initially supported on a national level then internationally. Ecotourism may be utilized to support the economy and encourages tourists to continue to visit and support species and ecosystems they visit, while they enjoy the available amenities provided. International biodiversity impacts global livelihood, food systems, and health. Problematic pollution, over consumption, and climate change can devastate international biodiversity. Nature-based solutions are

1152-517: A critical tool for a global resolution. Many species are in danger of becoming extinct and need world leaders to be proactive with the Kunming-Montreal Global Biodiversity Framework . Terrestrial biodiversity is thought to be up to 25 times greater than ocean biodiversity. Forests harbour most of Earth's terrestrial biodiversity. The conservation of the world's biodiversity is thus utterly dependent on

1280-656: A few core chemical elements . All living things contain two types of large molecule, proteins and nucleic acids , the latter usually both DNA and RNA : these carry the information needed by each species, including the instructions to make each type of protein. The proteins, in turn, serve as the machinery which carries out the many chemical processes of life. The cell is the structural and functional unit of life. Smaller organisms, including prokaryotes (bacteria and archaea ), consist of small single cells. Larger organisms , mainly eukaryotes , can consist of single cells or may be multicellular with more complex structure. Life

1408-455: A first-order positive feedback (more ancestors, more descendants) and/or a negative feedback arising from resource limitation. Hyperbolic model implies a second-order positive feedback. Differences in the strength of the second-order feedback due to different intensities of interspecific competition might explain the faster rediversification of ammonoids in comparison to bivalves after the end-Permian extinction . The hyperbolic pattern of

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1536-442: A host cell to make new products. Virus self-assembly within host cells has implications for the study of the origin of life , as it may support the hypothesis that life could have started as self-assembling organic molecules . Some of the earliest theories of life were materialist, holding that all that exists is matter, and that life is merely a complex form or arrangement of matter. Empedocles (430 BC) argued that everything in

1664-460: A limit would also cap the number of species. While records of life in the sea show a logistic pattern of growth, life on land (insects, plants and tetrapods) shows an exponential rise in diversity. As one author states, "Tetrapods have not yet invaded 64 percent of potentially habitable modes and it could be that without human influence the ecological and taxonomic diversity of tetrapods would continue to increase exponentially until most or all of

1792-472: A matter of debate; viruses lack characteristics of life such as cell membranes, metabolism and the ability to grow or respond to their environments. Viruses have been classed into "species" based on their genetics , but many aspects of such a classification remain controversial. The original Linnaean system has been modified many times, for example as follows: The attempt to organise the Eukaryotes into

1920-535: A month in a simulated Martian environment . Beyond the Solar System, the region around another main-sequence star that could support Earth-like life on an Earth-like planet is known as the habitable zone . The inner and outer radii of this zone vary with the luminosity of the star, as does the time interval during which the zone survives. Stars more massive than the Sun have a larger habitable zone, but remain on

2048-566: A rapid growth in biodiversity via the Cambrian explosion . In this period, the majority of multicellular phyla first appeared. The next 400 million years included repeated, massive biodiversity losses. Those events have been classified as mass extinction events. In the Carboniferous , rainforest collapse may have led to a great loss of plant and animal life. The Permian–Triassic extinction event , 251 million years ago,

2176-452: A resurgence of interest in the work of Russell, Barge and colleagues. Hylomorphism is a theory first expressed by the Greek philosopher Aristotle (322 BC). The application of hylomorphism to biology was important to Aristotle, and biology is extensively covered in his extant writings . In this view, everything in the material universe has both matter and form, and the form of a living thing

2304-809: A set of 355 genes from the last universal common ancestor was tentatively identified. The biosphere is postulated to have developed, from the origin of life onwards, at least some 3.5 billion years ago. The earliest evidence for life on Earth includes biogenic graphite found in 3.7 billion-year-old metasedimentary rocks from Western Greenland and microbial mat fossils found in 3.48 billion-year-old sandstone from Western Australia . More recently, in 2015, "remains of biotic life " were found in 4.1 billion-year-old rocks in Western Australia. In 2017, putative fossilised microorganisms (or microfossils ) were announced to have been discovered in hydrothermal vent precipitates in

2432-619: A short period Linnaeus had classified them in the taxon Vermes in Animalia, but later placed them back in Plantae. Herbert Copeland classified the Fungi in his Protoctista , including them with single-celled organisms and thus partially avoiding the problem but acknowledging their special status. The problem was eventually solved by Whittaker , when he gave them their own kingdom in his five-kingdom system . Evolutionary history shows that

2560-467: A small number of kingdoms has been challenged. The Protozoa do not form a clade or natural grouping, and nor do the Chromista (Chromalveolata). The ability to sequence large numbers of complete genomes has allowed biologists to take a metagenomic view of the phylogeny of the whole tree of life . This has led to the realisation that the majority of living things are bacteria, and that all have

2688-592: A suitable habitat for many animal species that live in a cultured landscape. A notable example is the hoopoe that nests in tree hollows of old fruit trees and, in the absence of alternative nesting sites, is threatened in many parts of Europe because of the destruction of old orchards. Historical orchards have large, mature trees spaced for heavy equipment. Modern commercial apple orchards, by contrast and as one example, are often "high-density" (tree density above 370/ha or 150/acre), and in extreme cases have up to 22,000/ha (9,000/acre). These plants are no longer trees in

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2816-538: A third of the Earth's land mass) and are home to approximately 80% of the world's biodiversity. About 1 billion hectares are covered by primary forests. Over 700 million hectares of the world's woods are officially protected. The biodiversity of forests varies considerably according to factors such as forest type, geography, climate and soils – in addition to human use. Most forest habitats in temperate regions support relatively few animal and plant species and species that tend to have large geographical distributions, while

2944-408: A thousand years. In the late 1740s, Carl Linnaeus introduced his system of binomial nomenclature for the classification of species. Linnaeus attempted to improve the composition and reduce the length of the previously used many-worded names by abolishing unnecessary rhetoric, introducing new descriptive terms and precisely defining their meaning. The fungi were originally treated as plants. For

3072-949: Is 'planned' diversity or 'associated' diversity. This is a functional classification that we impose and not an intrinsic feature of life or diversity. Planned diversity includes the crops which a farmer has encouraged, planted or raised (e.g. crops, covers, symbionts, and livestock, among others), which can be contrasted with the associated diversity that arrives among the crops, uninvited (e.g. herbivores, weed species and pathogens, among others). Associated biodiversity can be damaging or beneficial. The beneficial associated biodiversity include for instance wild pollinators such as wild bees and syrphid flies that pollinate crops and natural enemies and antagonists to pests and pathogens. Beneficial associated biodiversity occurs abundantly in crop fields and provide multiple ecosystem services such as pest control, nutrient cycling and pollination that support crop production. Life Life on Earth: Life

3200-473: Is a mechanistic explanation for the origin of species by means of natural selection . At the beginning of the 20th century Stéphane Leduc (1853–1939) promoted the idea that biological processes could be understood in terms of physics and chemistry, and that their growth resembled that of inorganic crystals immersed in solutions of sodium silicate. His ideas, set out in his book La biologie synthétique , were widely dismissed during his lifetime, but has incurred

3328-610: Is a quality that distinguishes matter that has biological processes , such as signaling and self-sustaining processes, from matter that does not. It is defined descriptively by the capacity for homeostasis , organisation , metabolism , growth , adaptation , response to stimuli , and reproduction . All life over time eventually reaches a state of death , and none is immortal . Many philosophical definitions of living systems have been proposed, such as self-organizing systems. Viruses in particular make definition difficult as they replicate only in host cells. Life exists all over

3456-561: Is about 4.54 billion years . Life on Earth has existed for at least 3.5 billion years, with the oldest physical traces of life dating back 3.7 billion years. Estimates from molecular clocks, as summarised in the TimeTree public database, place the origin of life around 4.0 billion years ago. Hypotheses on the origin of life attempt to explain the formation of a universal common ancestor from simple organic molecules via pre-cellular life to protocells and metabolism. In 2016,

3584-405: Is an increase in biodiversity from the poles to the tropics . Thus localities at lower latitudes have more species than localities at higher latitudes . This is often referred to as the latitudinal gradient in species diversity. Several ecological factors may contribute to the gradient, but the ultimate factor behind many of them is the greater mean temperature at the equator compared to that at

3712-558: Is capable of forming the various specialised cells that form the adult organism. This specialisation allows multicellular organisms to exploit resources more efficiently than single cells. About 800 million years ago, a minor genetic change in a single molecule, the enzyme GK-PID , may have allowed organisms to go from a single cell organism to one of many cells. Cells have evolved methods to perceive and respond to their microenvironment, thereby enhancing their adaptability. Cell signalling coordinates cellular activities, and hence governs

3840-422: Is considered the starting point of modern organic chemistry . It is of historical significance because for the first time an organic compound was produced in inorganic reactions. During the 1850s Hermann von Helmholtz , anticipated by Julius Robert von Mayer , demonstrated that no energy is lost in muscle movement, suggesting that there were no "vital forces" necessary to move a muscle. These results led to

3968-475: Is decreasing today. Climate change also plays a role. This can be seen for example in the effects of climate change on biomes . This anthropogenic extinction may have started toward the end of the Pleistocene , as some studies suggest that the megafaunal extinction event that took place around the end of the last ice age partly resulted from overhunting. Biologists most often define biodiversity as

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4096-491: Is estimated at 5.0 x 10 and weighs 50 billion tonnes . In comparison, the total mass of the biosphere has been estimated to be as much as four trillion tons of carbon . In July 2016, scientists reported identifying a set of 355 genes from the last universal common ancestor (LUCA) of all organisms living on Earth. The age of Earth is about 4.54 billion years. The earliest undisputed evidence of life dates at least from 3.7 billion years ago, during

4224-421: Is extended by the evolution of novel functions over time. Death is the termination of all vital functions or life processes in an organism or cell. One of the challenges in defining death is in distinguishing it from life. Death would seem to refer to either the moment life ends, or when the state that follows life begins. However, determining when death has occurred is difficult, as cessation of life functions

4352-572: Is in eastern Washington state, with a lesser but significant apple orchard area in most of Upstate New York . Extensive orange orchards are found in Florida and southern California , where they are more widely known as "groves". In eastern North America , many orchards are along the shores of Lake Michigan (such as the Fruit Ridge Region ), Lake Erie , and Lake Ontario . In Canada , apple and other fruit orchards are widespread on

4480-425: Is its soul (Greek psyche , Latin anima ). There are three kinds of souls: the vegetative soul of plants, which causes them to grow and decay and nourish themselves, but does not cause motion and sensation; the animal soul , which causes animals to move and feel; and the rational soul , which is the source of consciousness and reasoning, which (Aristotle believed) is found only in man. Each higher soul has all of

4608-427: Is local biodiversity, which directly impacts daily life, affecting the availability of fresh water, food choices, and fuel sources for humans. Regional biodiversity includes habitats and ecosystems that synergizes and either overlaps or differs on a regional scale. National biodiversity within a country determines the ability for a country to thrive according to its habitats and ecosystems on a national scale. Also, within

4736-407: Is most likely to exist, within wide bounds of uncertainty. A "Confidence of Life Detection" scale (CoLD) for reporting evidence of life beyond Earth has been proposed. Artificial life is the simulation of any aspect of life, as through computers, robotics , or biochemistry . Synthetic biology is a new area of biotechnology that combines science and biological engineering . The common goal

4864-476: Is not only plausible, but probable or inevitable, possibly resulting in a biophysical cosmology instead of a mere physical cosmology . Other planets and moons in the Solar System and other planetary systems are being examined for evidence of having once supported simple life, and projects such as SETI are trying to detect radio transmissions from possible alien civilisations. Other locations within

4992-428: Is often not simultaneous across organ systems. Such determination, therefore, requires drawing conceptual lines between life and death. This is problematic because there is little consensus over how to define life. The nature of death has for millennia been a central concern of the world's religious traditions and of philosophical inquiry. Many religions maintain faith in either a kind of afterlife or reincarnation for

5120-580: Is only known to exist on Earth but extraterrestrial life is thought probable . Artificial life is being simulated and explored by scientists and engineers. The definition of life has long been a challenge for scientists and philosophers. This is partially because life is a process, not a substance. This is complicated by a lack of knowledge of the characteristics of living entities, if any, that may have developed outside Earth. Philosophical definitions of life have also been put forward, with similar difficulties on how to distinguish living things from

5248-485: Is organised into chromosomes . All species of large complex organisms are eukaryotes, including animals, plants and fungi, though with a wide diversity of protist microorganisms . The conventional model is that eukaryotes evolved from prokaryotes, with the main organelles of the eukaryotes forming through endosymbiosis between bacteria and the progenitor eukaryotic cell. The molecular mechanisms of cell biology are based on proteins . Most of these are synthesised by

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5376-401: Is possible to build fractal hyper volumes, whose fractal dimension rises to three moving towards the equator . A biodiversity hotspot is a region with a high level of endemic species that have experienced great habitat loss . The term hotspot was introduced in 1988 by Norman Myers . While hotspots are spread all over the world, the majority are forest areas and most are located in

5504-529: Is retarded until frost danger is past. An orchard's layout is the technique of planting the crops in a proper system. There are different methods of planting and thus different layouts. Some of these layout types are: For different varieties, these systems may vary to some extent. The most extensive orchards in the United States are apple and orange orchards, although citrus orchards are more commonly called groves. The most extensive apple orchard area

5632-561: Is so full, that that district produces the most variety which is the most examined." Biodiversity is the result of 3.5 billion years of evolution . The origin of life has not been established by science, however, some evidence suggests that life may already have been well-established only a few hundred million years after the formation of the Earth . Until approximately 2.5 billion years ago, all life consisted of microorganisms – archaea , bacteria , and single-celled protozoans and protists . Biodiversity grew fast during

5760-417: Is the design and construction of new biological functions and systems not found in nature. Synthetic biology includes the broad redefinition and expansion of biotechnology, with the ultimate goals of being able to design and build engineered biological systems that process information, manipulate chemicals, fabricate materials and structures, produce energy, provide food, and maintain and enhance human health and

5888-434: Is to define life as "a self-sustained chemical system capable of undergoing Darwinian evolution ", a definition adopted by a NASA committee attempting to define life for the purposes of exobiology , based on a suggestion by Carl Sagan . This definition, however, has been widely criticised because according to it, a single sexually reproducing individual is not alive as it is incapable of evolving on its own. Others take

6016-405: Is uncertainty as to how strongly the fossil record is biased by the greater availability and preservation of recent geologic sections. Some scientists believe that corrected for sampling artifacts, modern biodiversity may not be much different from biodiversity 300 million years ago, whereas others consider the fossil record reasonably reflective of the diversification of life. Estimates of

6144-509: Is unlikely or impossible. Organisms that have a wide range of tolerance are more widely distributed than organisms with a narrow range of tolerance. To survive, some microorganisms have evolved to withstand freezing , complete desiccation , starvation , high levels of radiation exposure , and other physical or chemical challenges. These extremophile microorganisms may survive exposure to such conditions for long periods. They excel at exploiting uncommon sources of energy. Characterization of

6272-792: The Eoarchean era after a geological crust started to solidify following the earlier molten Hadean eon. There are microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia . Other early physical evidence of a biogenic substance is graphite in 3.7 billion-year-old meta-sedimentary rocks discovered in Western Greenland .. More recently, in 2015, "remains of biotic life " were found in 4.1 billion-year-old rocks in Western Australia . According to one of

6400-714: The International Ocean Discovery Program found unicellular life in 120 °C sediment 1.2 km below seafloor in the Nankai Trough subduction zone. According to one researcher, "You can find microbes everywhere—they're extremely adaptable to conditions, and survive wherever they are." The inert components of an ecosystem are the physical and chemical factors necessary for life—energy (sunlight or chemical energy ), water, heat, atmosphere , gravity , nutrients , and ultraviolet solar radiation protection . In most ecosystems,

6528-633: The Niagara Peninsula , south of Lake Ontario. This region is known as Canada Fruitbelt and, in addition to large-scale commercial fruit marketing, it encourages "pick-your-own" activities in the harvest season. In Spain , Murcia is a major orchard area (or la huerta) in Europe, with citrus crops. New Zealand, China, Argentina, and Chile also have extensive apple orchards. Tenbury Wells in Worcestershire has been called The Town in

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6656-504: The Nuvvuagittuq Belt of Quebec, Canada that were as old as 4.28 billion years, the oldest record of life on Earth, suggesting "an almost instantaneous emergence of life" after ocean formation 4.4 billion years ago , and not long after the formation of the Earth 4.54 billion years ago. Evolution is the change in heritable characteristics of biological populations over successive generations. It results in

6784-713: The Phanerozoic (the last 540 million years), especially during the so-called Cambrian explosion —a period during which nearly every phylum of multicellular organisms first appeared. However, recent studies suggest that this diversification had started earlier, at least in the Ediacaran , and that it continued in the Ordovician . Over the next 400 million years or so, invertebrate diversity showed little overall trend and vertebrate diversity shows an overall exponential trend. This dramatic rise in diversity

6912-458: The Solar System that may host microbial life include the subsurface of Mars , the upper atmosphere of Venus , and subsurface oceans on some of the moons of the giant planets . Investigation of the tenacity and versatility of life on Earth, as well as an understanding of the molecular systems that some organisms utilise to survive such extremes, is important for the search for extraterrestrial life. For example, lichen could survive for

7040-461: The Stone Age , species loss has accelerated above the average basal rate, driven by human activity. Estimates of species losses are at a rate 100–10,000 times as fast as is typical in the fossil record. Loss of biodiversity results in the loss of natural capital that supplies ecosystem goods and services . Species today are being wiped out at a rate 100 to 1,000 times higher than baseline, and

7168-480: The soul , or resurrection of the body at a later date. Whether or not viruses should be considered as alive is controversial. They are most often considered as just gene coding replicators rather than forms of life. They have been described as "organisms at the edge of life" because they possess genes , evolve by natural selection, and replicate by making multiple copies of themselves through self-assembly. However, viruses do not metabolise and they require

7296-467: The structure and metabolic diversity of microbial communities in such extreme environments is ongoing. The first classification of organisms was made by the Greek philosopher Aristotle (384–322 BC), who grouped living things as either plants or animals, based mainly on their ability to move. He distinguished animals with blood from animals without blood, which can be compared with the concepts of vertebrates and invertebrates respectively, and divided

7424-504: The tropics . Brazil 's Atlantic Forest is considered one such hotspot, containing roughly 20,000 plant species, 1,350 vertebrates and millions of insects, about half of which occur nowhere else. The island of Madagascar and India are also particularly notable. Colombia is characterized by high biodiversity, with the highest rate of species by area unit worldwide and it has the largest number of endemics (species that are not found naturally anywhere else) of any country. About 10% of

7552-417: The world population growth arises from a second-order positive feedback between the population size and the rate of technological growth. The hyperbolic character of biodiversity growth can be similarly accounted for by a feedback between diversity and community structure complexity. The similarity between the curves of biodiversity and human population probably comes from the fact that both are derived from

7680-752: The "totality of genes , species and ecosystems of a region". An advantage of this definition is that it presents a unified view of the traditional types of biological variety previously identified: Biodiversity is most commonly used to replace the more clearly-defined and long-established terms, species diversity and species richness . However, there is no concrete definition for biodiversity, as its definition continues to be defined. Other definitions include (in chronological order): According to estimates by Mora et al. (2011), there are approximately 8.7 million terrestrial species and 2.2 million oceanic species. The authors note that these estimates are strongest for eukaryotic organisms and likely represent

7808-402: The 19th and early 20th centuries, Streuobstwiesen were a kind of a rural community orchard that were intended for the productive cultivation of stone fruit . In recent years, ecologists have successfully lobbied for state subsidies to valuable habitats , biodiversity and natural landscapes , which are also used to preserve old meadow orchards. Both conventional and meadow orchards provide

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7936-488: The Earth in air, water, and soil , with many ecosystems forming the biosphere . Some of these are harsh environments occupied only by extremophiles . Life has been studied since ancient times, with theories such as Empedocles 's materialism asserting that it was composed of four eternal elements , and Aristotle 's hylomorphism asserting that living things have souls and embody both form and matter. Life originated at least 3.5 billion years ago, resulting in

8064-606: The IUCN's critically endangered . Numerous scientists and the IPBES Global Assessment Report on Biodiversity and Ecosystem Services assert that human population growth and overconsumption are the primary factors in this decline. However, other scientists have criticized this finding and say that loss of habitat caused by "the growth of commodities for export" is the main driver. Some studies have however pointed out that habitat destruction for

8192-501: The Orchard , since the 19th century, because it was surrounded by extensive orchards. Today, this heritage is celebrated through an annual Applefest . Streuobstwiese (pl. Streuobstwiesen ) is a German word that means a meadow with scattered fruit trees or fruit trees that are planted in a field. Streuobstwiese , or a meadow orchard, is a traditional landscape in the temperate, maritime climate of continental Western Europe. In

8320-459: The Sun-like "main sequence" of stellar evolution for a shorter time interval. Small red dwarfs have the opposite problem, with a smaller habitable zone that is subject to higher levels of magnetic activity and the effects of tidal locking from close orbits. Hence, stars in the intermediate mass range such as the Sun may have a greater likelihood for Earth-like life to develop. The location of

8448-403: The abandonment of scientific interest in vitalistic theories, especially after Eduard Buchner 's demonstration that alcoholic fermentation could occur in cell-free extracts of yeast. Nonetheless, belief still exists in pseudoscientific theories such as homoeopathy , which interprets diseases and sickness as caused by disturbances in a hypothetical vital force or life force. The age of Earth

8576-466: The appearance of new species and often the disappearance of old ones. Evolution occurs when evolutionary processes such as natural selection (including sexual selection ) and genetic drift act on genetic variation, resulting in certain characteristics increasing or decreasing in frequency within a population over successive generations. The process of evolution has given rise to biodiversity at every level of biological organisation . Fossils are

8704-450: The attributes of the lower ones. Aristotle believed that while matter can exist without form, form cannot exist without matter, and that therefore the soul cannot exist without the body. This account is consistent with teleological explanations of life , which account for phenomena in terms of purpose or goal-directedness. Thus, the whiteness of the polar bear's coat is explained by its purpose of camouflage. The direction of causality (from

8832-461: The available eco-space is filled." It also appears that the diversity continues to increase over time, especially after mass extinctions. On the other hand, changes through the Phanerozoic correlate much better with the hyperbolic model (widely used in population biology , demography and macrosociology , as well as fossil biodiversity) than with exponential and logistic models. The latter models imply that changes in diversity are guided by

8960-399: The basic functions of multicellular organisms. Signaling between cells can occur through direct cell contact using juxtacrine signalling , or indirectly through the exchange of agents as in the endocrine system . In more complex organisms, coordination of activities can occur through a dedicated nervous system . Though life is confirmed only on Earth, many think that extraterrestrial life

9088-436: The biosphere, including soil , hot springs , inside rocks at least 19 km (12 mi) deep underground, the deepest parts of the ocean, and at least 64 km (40 mi) high in the atmosphere. For example, spores of Aspergillus niger have been detected in the mesosphere at an altitude of 48 to 77 km. Under test conditions, life forms have been observed to survive in the vacuum of space. Life forms thrive in

9216-457: The blooded animals into five groups: viviparous quadrupeds ( mammals ), oviparous quadrupeds (reptiles and amphibians ), birds, fishes and whales . The bloodless animals were divided into five groups: cephalopods , crustaceans , insects (which included the spiders, scorpions , and centipedes ), shelled animals (such as most molluscs and echinoderms ), and " zoophytes " (animals that resemble plants). This theory remained dominant for more than

9344-412: The conditions vary during the day and from one season to the next. To live in most ecosystems, then, organisms must be able to survive a range of conditions, called the "range of tolerance". Outside that are the "zones of physiological stress", where the survival and reproduction are possible but not optimal. Beyond these zones are the "zones of intolerance", where survival and reproduction of that organism

9472-540: The current sixth mass extinction match or exceed rates of loss in the five previous mass extinction events in the fossil record . Biodiversity loss is in fact "one of the most critical manifestations of the Anthropocene " (since around the 1950s); the continued decline of biodiversity constitutes "an unprecedented threat" to the continued existence of human civilization. The reduction is caused primarily by human impacts , particularly habitat destruction . Since

9600-422: The deep Mariana Trench , and inside rocks up to 580 m (1,900 ft; 0.36 mi) below the sea floor under 2,590 m (8,500 ft; 1.61 mi) of ocean off the coast of the northwestern United States, and 2,400 m (7,900 ft; 1.5 mi) beneath the seabed off Japan. In 2014, life forms were found living 800 m (2,600 ft; 0.50 mi) below the ice of Antarctica. Expeditions of

9728-704: The ecological resources of low-income countries, which was explained as a result of a process whereby wealthy nations are outsourcing resource depletion to poorer nations, which are suffering the greatest ecosystem losses. A 2017 study published in PLOS One found that the biomass of insect life in Germany had declined by three-quarters in the last 25 years. Dave Goulson of Sussex University stated that their study suggested that humans "appear to be making vast tracts of land inhospitable to most forms of life, and are currently on course for ecological Armageddon. If we lose

9856-512: The end of the Maastrichtian , just before that extinction event. However, many other taxa were affected by this crisis, which affected even marine taxa, such as ammonites , which also became extinct around that time. The biodiversity of the past is called Paleobiodiversity. The fossil record suggests that the last few million years featured the greatest biodiversity in history . However, not all scientists support this view, since there

9984-451: The estimated global value of ecosystem services (not captured in traditional markets) at an average of $ 33 trillion annually. With regards to provisioning services, greater species diversity has the following benefits: With regards to regulating services, greater species diversity has the following benefits: Greater species diversity Agricultural diversity can be divided into two categories: intraspecific diversity , which includes

10112-523: The exception being sulfur. The latter is a component of the amino acids cysteine and methionine . The most abundant of these elements in organisms is carbon, which has the desirable attribute of forming multiple, stable covalent bonds . This allows carbon-based (organic) molecules to form the immense variety of chemical arrangements described in organic chemistry . Alternative hypothetical types of biochemistry have been proposed that eliminate one or more of these elements, swap out an element for one not on

10240-428: The expansion of agriculture and the overexploitation of wildlife are the more significant drivers of contemporary biodiversity loss, not climate change . Biodiversity is not evenly distributed, rather it varies greatly across the globe as well as within regions and seasons. Among other factors, the diversity of all living things ( biota ) depends on temperature , precipitation , altitude , soils , geography and

10368-409: The formation of colonies of identical cells. These cells can form group organisms through cell adhesion . The individual members of a colony are capable of surviving on their own, whereas the members of a true multi-cellular organism have developed specialisations, making them dependent on the remainder of the organism for survival. Such organisms are formed clonally or from a single germ cell that

10496-474: The formation of Earth's major animal and plant species. This interplay between organisms and their environment is an inherent feature of living systems. The biosphere is the global sum of all ecosystems. It can also be termed as the zone of life on Earth, a closed system (apart from solar and cosmic radiation and heat from the interior of the Earth), and largely self-regulating. Organisms exist in every part of

10624-406: The fungi are more closely related to animals than to plants. As advances in microscopy enabled detailed study of cells and microorganisms, new groups of life were revealed, and the fields of cell biology and microbiology were created. These new organisms were originally described separately in protozoa as animals and protophyta/thallophyta as plants, but were united by Ernst Haeckel in

10752-480: The future to the past) is in contradiction with the scientific evidence for natural selection, which explains the consequence in terms of a prior cause. Biological features are explained not by looking at future optimal results, but by looking at the past evolutionary history of a species, which led to the natural selection of the features in question. Spontaneous generation was the belief that living organisms can form without descent from similar organisms. Typically,

10880-491: The genetic variation within a single species, like the potato ( Solanum tuberosum ) that is composed of many different forms and types (e.g. in the U.S. they might compare russet potatoes with new potatoes or purple potatoes, all different, but all part of the same species, S. tuberosum ). The other category of agricultural diversity is called interspecific diversity and refers to the number and types of different species. Agricultural diversity can also be divided by whether it

11008-426: The given environment. This implies all or most of the following traits: From a physics perspective, an organism is a thermodynamic system with an organised molecular structure that can reproduce itself and evolve as survival dictates. Thermodynamically, life has been described as an open system which makes use of gradients in its surroundings to create imperfect copies of itself. Another way of putting this

11136-434: The idea was that certain forms such as fleas could arise from inanimate matter such as dust or the supposed seasonal generation of mice and insects from mud or garbage. The theory of spontaneous generation was proposed by Aristotle , who compiled and expanded the work of prior natural philosophers and the various ancient explanations of the appearance of organisms; it was considered the best explanation for two millennia. It

11264-496: The information to be preserved during reproduction and cell division. Within cells, DNA is organised into long structures called chromosomes . During cell division these chromosomes are duplicated in the process of DNA replication , providing each cell its own complete set of chromosomes. Eukaryotes store most of their DNA inside the cell nucleus . Cells are the basic unit of structure in every living thing, and all cells arise from pre-existing cells by division . Cell theory

11392-587: The insects then everything is going to collapse." In 2020 the World Wildlife Foundation published a report saying that "biodiversity is being destroyed at a rate unprecedented in human history". The report claims that 68% of the population of the examined species were destroyed in the years 1970 – 2016. Of 70,000 monitored species, around 48% are experiencing population declines from human activity (in 2023), whereas only 3% have increasing populations. Rates of decline in biodiversity in

11520-596: The interactions between other species. The study of the spatial distribution of organisms , species and ecosystems , is the science of biogeography . Diversity consistently measures higher in the tropics and in other localized regions such as the Cape Floristic Region and lower in polar regions generally. Rain forests that have had wet climates for a long time, such as Yasuní National Park in Ecuador , have particularly high biodiversity. There

11648-737: The interference of the hyperbolic trend with cyclical and stochastic dynamics. Most biologists agree however that the period since human emergence is part of a new mass extinction, named the Holocene extinction event , caused primarily by the impact humans are having on the environment. It has been argued that the present rate of extinction is sufficient to eliminate most species on the planet Earth within 100 years. New species are regularly discovered (on average between 5–10,000 new species each year, most of them insects ) and many, though discovered, are not yet classified (estimates are that nearly 90% of all arthropods are not yet classified). Most of

11776-642: The kingdom Protista ; later, the prokaryotes were split off in the kingdom Monera , which would eventually be divided into two separate groups, the Bacteria and the Archaea . This led to the six-kingdom system and eventually to the current three-domain system , which is based on evolutionary relationships. However, the classification of eukaryotes, especially of protists, is still controversial. As microbiology developed, viruses, which are non-cellular, were discovered. Whether these are considered alive has been

11904-563: The list, or change required chiralities or other chemical properties. Deoxyribonucleic acid or DNA is a molecule that carries most of the genetic instructions used in the growth, development, functioning and reproduction of all known living organisms and many viruses. DNA and RNA are nucleic acids ; alongside proteins and complex carbohydrates , they are one of the three major types of macromolecule that are essential for all known forms of life. Most DNA molecules consist of two biopolymer strands coiled around each other to form

12032-430: The lower bound of prokaryote diversity. Other estimates include: Since the rate of extinction has increased, many extant species may become extinct before they are described. Not surprisingly, in the animalia the most studied groups are birds and mammals , whereas fishes and arthropods are the least studied animals groups. During the last century, decreases in biodiversity have been increasingly observed. It

12160-508: The middle of the 19th century. It appealed to philosophers such as Henri Bergson , Friedrich Nietzsche , and Wilhelm Dilthey , anatomists like Xavier Bichat , and chemists like Justus von Liebig . Vitalism included the idea that there was a fundamental difference between organic and inorganic material, and the belief that organic material can only be derived from living things. This was disproved in 1828, when Friedrich Wöhler prepared urea from inorganic materials. This Wöhler synthesis

12288-877: The montane forests of Africa, South America and Southeast Asia and lowland forests of Australia, coastal Brazil, the Caribbean islands, Central America and insular Southeast Asia have many species with small geographical distributions. Areas with dense human populations and intense agricultural land use, such as Europe , parts of Bangladesh, China, India and North America, are less intact in terms of their biodiversity. Northern Africa, southern Australia, coastal Brazil, Madagascar and South Africa, are also identified as areas with striking losses in biodiversity intactness. European forests in EU and non-EU nations comprise more than 30% of Europe's land mass (around 227 million hectares), representing an almost 10% growth since 1990. Generally, there

12416-448: The non-living. Legal definitions of life have been debated, though these generally focus on the decision to declare a human dead, and the legal ramifications of this decision. At least 123 definitions of life have been compiled. Since there is no consensus for a definition of life, most current definitions in biology are descriptive. Life is considered a characteristic of something that preserves, furthers or reinforces its existence in

12544-566: The oldest from the Archaean Eon, up to 3.4 billion years old. Extinction is the process by which a species dies out. The moment of extinction is the death of the last individual of that species. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively after a period of apparent absence. Species become extinct when they are no longer able to survive in changing habitat or against superior competition. Over 99% of all

12672-609: The parent cell divides into two or more daughter cells. For prokaryotes, cell division occurs through a process of fission in which the DNA is replicated, then the two copies are attached to parts of the cell membrane. In eukaryotes , a more complex process of mitosis is followed. However, the result is the same; the resulting cell copies are identical to each other and to the original cell (except for mutations ), and both are capable of further division following an interphase period. Multicellular organisms may have first evolved through

12800-468: The planet's species went extinct prior to the evolution of humans. Estimates on the number of Earth's current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86% have not yet been described. However, a May 2016 scientific report estimates that 1 trillion species are currently on Earth, with only one-thousandth of one percent described. The total amount of related DNA base pairs on Earth

12928-546: The poles. Even though terrestrial biodiversity declines from the equator to the poles, some studies claim that this characteristic is unverified in aquatic ecosystems , especially in marine ecosystems . The latitudinal distribution of parasites does not appear to follow this rule. Also, in terrestrial ecosystems the soil bacterial diversity has been shown to be highest in temperate climatic zones, and has been attributed to carbon inputs and habitat connectivity. In 2016, an alternative hypothesis ("the fractal biodiversity")

13056-412: The present global macroscopic species diversity vary from 2 million to 100 million, with a best estimate of somewhere near 9 million, the vast majority arthropods . Diversity appears to increase continually in the absence of natural selection. The existence of a global carrying capacity , limiting the amount of life that can live at once, is debated, as is the question of whether such

13184-473: The preserved remains or traces of organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in layers ( strata ) of sedimentary rock is known as the fossil record . A preserved specimen is called a fossil if it is older than the arbitrary date of 10,000 years ago. Hence, fossils range in age from the youngest at the start of the Holocene Epoch to

13312-584: The rate of extinctions is increasing. This process destroys the resilience and adaptability of life on Earth. In 2006, many species were formally classified as rare or endangered or threatened ; moreover, scientists have estimated that millions more species are at risk which have not been formally recognized. About 40 percent of the 40,177 species assessed using the IUCN Red List criteria are now listed as threatened with extinction —a total of 16,119. As of late 2022 9251 species were considered part of

13440-455: The region near the equator . Tropical forest ecosystems cover less than one-fifth of Earth's terrestrial area and contain about 50% of the world's species. There are latitudinal gradients in species diversity for both marine and terrestrial taxa. Since life began on Earth , six major mass extinctions and several minor events have led to large and sudden drops in biodiversity. The Phanerozoic aeon (the last 540 million years) marked

13568-913: The researchers, "If life arose relatively quickly on Earth...then it could be common in the universe ." There have been many claims about biodiversity's effect on the ecosystem services , especially provisioning and regulating services . Some of those claims have been validated, some are incorrect and some lack enough evidence to draw definitive conclusions. Ecosystem services have been grouped in three types: Experiments with controlled environments have shown that humans cannot easily build ecosystems to support human needs; for example insect pollination cannot be mimicked, though there have been attempts to create artificial pollinators using unmanned aerial vehicles . The economic activity of pollination alone represented between $ 2.1–14.6 billion in 2003. Other sources have reported somewhat conflicting results and in 1997 Robert Costanza and his colleagues reported

13696-460: The ribosomes through an enzyme-catalyzed process called protein biosynthesis . A sequence of amino acids is assembled and joined based upon gene expression of the cell's nucleic acid. In eukaryotic cells, these proteins may then be transported and processed through the Golgi apparatus in preparation for dispatch to their destination. Cells reproduce through a process of cell division in which

13824-435: The soul, like everything else, was composed of fiery atoms. He elaborated on fire because of the apparent connection between life and heat, and because fire moves. Plato , in contrast, held that the world was organised by permanent forms , reflected imperfectly in matter; forms provided direction or intelligence, explaining the regularities observed in the world. The mechanistic materialism that originated in ancient Greece

13952-640: The species of the Earth can be found in Colombia, including over 1,900 species of bird, more than in Europe and North America combined, Colombia has 10% of the world's mammals species, 14% of the amphibian species and 18% of the bird species of the world. Madagascar dry deciduous forests and lowland rainforests possess a high ratio of endemism . Since the island separated from mainland Africa 66 million years ago, many species and ecosystems have evolved independently. Indonesia 's 17,000 islands cover 735,355 square miles (1,904,560 km ) and contain 10% of

14080-493: The species that have ever lived are now extinct. Mass extinctions may have accelerated evolution by providing opportunities for new groups of organisms to diversify. The diversity of life on Earth is a result of the dynamic interplay between genetic opportunity , metabolic capability, environmental challenges, and symbiosis . For most of its existence, Earth's habitable environment has been dominated by microorganisms and subjected to their metabolism and evolution. As

14208-488: The star within a galaxy may also affect the likelihood of life forming. Stars in regions with a greater abundance of heavier elements that can form planets, in combination with a low rate of potentially habitat -damaging supernova events, are predicted to have a higher probability of hosting planets with complex life. The variables of the Drake equation are used to discuss the conditions in planetary systems where civilisation

14336-408: The sugar of one nucleotide and the phosphate of the next, resulting in an alternating sugar-phosphate backbone . According to base pairing rules (A with T, and C with G), hydrogen bonds bind the nitrogenous bases of the two separate polynucleotide strands to make double-stranded DNA. This has the key property that each strand contains all the information needed to recreate the other strand, enabling

14464-419: The terrestrial diversity is found in tropical forests and in general, the land has more species than the ocean; some 8.7 million species may exist on Earth, of which some 2.1 million live in the ocean. It is estimated that 5 to 50 billion species have existed on the planet. Assuming that there may be a maximum of about 50 million species currently alive, it stands to reason that greater than 99% of

14592-515: The traditional sense, but instead resemble vines on dwarf stock and require trellises to support them. Now new "Smart Orchards" are being set up throughout the world. The first examples of such orchards are the Smart Orchard at Washington , United States of America by Innov8 and Washington State University and Samriti Bagh orchard created in Maraog, India by Tejasvi Dogra that incorporates

14720-413: The universe is made up of a combination of four eternal "elements" or "roots of all": earth, water, air, and fire. All change is explained by the arrangement and rearrangement of these four elements. The various forms of life are caused by an appropriate mixture of elements. Democritus (460 BC) was an atomist ; he thought that the essential characteristic of life was having a soul ( psyche ), and that

14848-479: The upcoming years. As of 2012, some studies suggest that 25% of all mammal species could be extinct in 20 years. In absolute terms, the planet has lost 58% of its biodiversity since 1970 according to a 2016 study by the World Wildlife Fund. The Living Planet Report 2014 claims that "the number of mammals, birds, reptiles, amphibians, and fish across the globe is, on average, about half the size it

14976-436: The use of various sensors for orchard management. Biodiversity Biodiversity is the variability of life on Earth . It can be measured on various levels. There is for example genetic variability , species diversity , ecosystem diversity and phylogenetic diversity. Diversity is not distributed evenly on Earth . It is greater in the tropics as a result of the warm climate and high primary productivity in

15104-773: The way in which we interact with and use the world's forests. A new method used in 2011, put the total number of species on Earth at 8.7 million, of which 2.1 million were estimated to live in the ocean. However, this estimate seems to under-represent the diversity of microorganisms. Forests provide habitats for 80 percent of amphibian species , 75 percent of bird species and 68 percent of mammal species. About 60 percent of all vascular plants are found in tropical forests. Mangroves provide breeding grounds and nurseries for numerous species of fish and shellfish and help trap sediments that might otherwise adversely affect seagrass beds and coral reefs, which are habitats for many more marine species. Forests span around 4 billion acres (nearly

15232-630: The world's flowering plants , 12% of mammals and 17% of reptiles , amphibians and birds —along with nearly 240 million people. Many regions of high biodiversity and/or endemism arise from specialized habitats which require unusual adaptations, for example, alpine environments in high mountains , or Northern European peat bogs . Accurately measuring differences in biodiversity can be difficult. Selection bias amongst researchers may contribute to biased empirical research for modern estimates of biodiversity. In 1768, Rev. Gilbert White succinctly observed of his Selborne, Hampshire "all nature

15360-482: Was 40 years ago". Of that number, 39% accounts for the terrestrial wildlife gone, 39% for the marine wildlife gone and 76% for the freshwater wildlife gone. Biodiversity took the biggest hit in Latin America , plummeting 83 percent. High-income countries showed a 10% increase in biodiversity, which was canceled out by a loss in low-income countries. This is despite the fact that high-income countries use five times

15488-414: Was decisively dispelled by the experiments of Louis Pasteur in 1859, who expanded upon the investigations of predecessors such as Francesco Redi . Disproof of the traditional ideas of spontaneous generation is no longer controversial among biologists. Vitalism is the belief that there is a non-material life-principle. This originated with Georg Ernst Stahl (17th century), and remained popular until

15616-553: Was estimated in 2007 that up to 30% of all species will be extinct by 2050. Of these, about one eighth of known plant species are threatened with extinction . Estimates reach as high as 140,000 species per year (based on Species-area theory ). This figure indicates unsustainable ecological practices, because few species emerge each year. The rate of species loss is greater now than at any time in human history, with extinctions occurring at rates hundreds of times higher than background extinction rates. and expected to still grow in

15744-495: Was formulated by Henri Dutrochet , Theodor Schwann , Rudolf Virchow and others during the early nineteenth century, and subsequently became widely accepted. The activity of an organism depends on the total activity of its cells, with energy flow occurring within and between them. Cells contain hereditary information that is carried forward as a genetic code during cell division. There are two primary types of cells, reflecting their evolutionary origins. Prokaryote cells lack

15872-483: Was marked by periodic, massive losses of diversity classified as mass extinction events. A significant loss occurred in anamniotic limbed vertebrates when rainforests collapsed in the Carboniferous , but amniotes seem to have been little affected by this event; their diversification slowed down later, around the Asselian / Sakmarian boundary, in the early Cisuralian (Early Permian ), about 293 Ma ago. The worst

16000-401: Was proposed to explain the biodiversity latitudinal gradient. In this study, the species pool size and the fractal nature of ecosystems were combined to clarify some general patterns of this gradient. This hypothesis considers temperature , moisture , and net primary production (NPP) as the main variables of an ecosystem niche and as the axis of the ecological hypervolume . In this way, it

16128-486: Was revived and revised by the French philosopher René Descartes (1596–1650), who held that animals and humans were assemblages of parts that together functioned as a machine. This idea was developed further by Julien Offray de La Mettrie (1709–1750) in his book L'Homme Machine . In the 19th century the advances in cell theory in biological science encouraged this view. The evolutionary theory of Charles Darwin (1859)

16256-567: Was the Permian-Triassic extinction event , 251 million years ago. Vertebrates took 30 million years to recover from this event. The most recent major mass extinction event, the Cretaceous–Paleogene extinction event , occurred 66 million years ago. This period has attracted more attention than others because it resulted in the extinction of the non-avian dinosaurs , which were represented by many lineages at

16384-425: Was the worst; vertebrate recovery took 30 million years. Human activities have led to an ongoing biodiversity loss and an accompanying loss of genetic diversity . This process is often referred to as Holocene extinction , or sixth mass extinction . For example, it was estimated in 2007 that up to 30% of all species will be extinct by 2050. Destroying habitats for farming is a key reason why biodiversity

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