Misplaced Pages

#141858

138-744: After an extensive review of the Act in 2019, the Flora and Fauna Guarantee Amendment Act 2019 modernised and strengthened the provisions of the Act on 1 June 2020. Enforcement of the FFG Act is overseen by the Office of the Conservation Regulator (OCR). The Flora and Fauna Guarantee Act 1988 helps protect and manage the biodiversity of the state of Victoria. It aims to conserve all of Victoria’s native plants and animals. In order to achieve this,

276-591: A biogenic origin. Parts of the Dresser formation preserve hot springs on land, but other regions seem to have been shallow seas. A molecular clock analysis suggests the LUCA emerged prior to the Late Heavy Bombardment (3.9 Gya). All chemical elements except for hydrogen and helium derive from stellar nucleosynthesis. The basic chemical ingredients of life – the carbon-hydrogen molecule (CH),

414-443: A boundary is needed to separate ordered life processes from chaotic non-living matter. Irene Chen and Jack W. Szostak suggest that elementary protocells can give rise to cellular behaviors including primitive forms of differential reproduction, competition, and energy storage. Competition for membrane molecules would favor stabilized membranes, suggesting a selective advantage for the evolution of cross-linked fatty acids and even

552-410: A cell's primary system of energy conversion. The mechanism, now ubiquitous in living cells, powers energy conversion in micro-organisms and in the mitochondria of eukaryotes, making it a likely candidate for early life. Mitochondria produce adenosine triphosphate (ATP), the energy currency of the cell used to drive cellular processes such as chemical syntheses. The mechanism of ATP synthesis involves

690-471: A closed membrane in which the ATP synthase enzyme is embedded. The energy required to release strongly bound ATP has its origin in protons that move across the membrane. In modern cells, those proton movements are caused by the pumping of ions across the membrane, maintaining an electrochemical gradient. In the first organisms, the gradient could have been provided by the difference in chemical composition between

828-501: 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

966-517: 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

1104-530: A diverse array of amino acids. Later work has focused on two other potential reducing environments: outer space and deep-sea hydrothermal vents. Soon after the Big Bang , which occurred roughly 14 Gya, the only chemical elements present in the universe were hydrogen , helium , and lithium , the three lightest atoms in the periodic table. These elements gradually accreted and began orbiting in disks of gas and dust. Gravitational accretion of material at

1242-455: 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

1380-461: A habitable world is formed with a supply of minerals and liquid water. Prebiotic synthesis creates a range of simple organic compounds, which are assembled into polymers such as proteins and RNA. On the other side, the process after the LUCA is readily understood: biological evolution caused the development of a wide range of species with varied forms and biochemical capabilities. However, the derivation of living things such as LUCA from simple components

1518-410: A laboratory setting. Self-assembled vesicles are essential components of primitive cells. The theory of classical irreversible thermodynamics treats self-assembly under a generalized chemical potential within the framework of dissipative systems . The second law of thermodynamics requires that overall entropy increases, yet life is distinguished by its great degree of organization. Therefore,

SECTION 10

#1732791975142

1656-466: A likely constituent of Earth's primordial sea. PAHs have been detected in nebulae , and in the interstellar medium , in comets, and in meteorites. The PAH world hypothesis posits PAHs as precursors to the RNA world. A star, HH 46-IR, resembling the sun early in its life, is surrounded by a disk of material which contains molecules including cyanide compounds, hydrocarbons , and carbon monoxide. PAHs in

1794-460: 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

1932-584: A living organism creates order in some places (e.g. its living body) at the expense of an increase of entropy elsewhere (e.g. heat and waste production). Multiple sources of energy were available for chemical reactions on the early Earth. Heat from geothermal processes is a standard energy source for chemistry. Other examples include sunlight, lightning, atmospheric entries of micro-meteorites, and implosion of bubbles in sea and ocean waves. This has been confirmed by experiments and simulations. Unfavorable reactions can be driven by highly favorable ones, as in

2070-439: A membrane site and a specific compound trapped in the vesicle. Such site/compound pairs are transmissible to the daughter vesicles leading to the emergence of distinct lineages of vesicles, which would have allowed natural selection . A protocell is a self-organized, self-ordered, spherical collection of lipids proposed as a stepping-stone to the origin of life. A functional protocell has (as of 2014) not yet been achieved in

2208-837: A number of possible routes. Some center on high temperature/concentration conditions in which condensation becomes energetically favorable, while others focus on the availability of plausible prebiotic condensing agents. Experimental evidence for the formation of peptides in uniquely concentrated environments is bolstered by work suggesting that wet-dry cycles and the presence of specific salts can greatly increase spontaneous condensation of glycine into poly-glycine chains. Other work suggests that while mineral surfaces, such as those of pyrite, calcite, and rutile catalyze peptide condensation, they also catalyze their hydrolysis. The authors suggest that additional chemical activation or coupling would be necessary to produce peptides at sufficient concentrations. Thus, mineral surface catalysis, while important,

2346-566: 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,

2484-423: A replicator molecule. Possible precursors to protein synthesis include the synthesis of short peptide cofactors or the self-catalysing duplication of RNA. It is likely that the ancestral ribosome was composed entirely of RNA, although some roles have since been taken over by proteins. Major remaining questions on this topic include identifying the selective force for the evolution of the ribosome and determining how

2622-521: A result of the warm climate and high primary productivity in 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

2760-472: A review of the act in 2002, and found a lack of resources to enforce the act, a lack of government transparency and accountability, that the act may be and is ignored in government decisionmaking, and that the act is generally unenforceable. The review identified the following factors: As well as a general review, the review considers the impact of the Act on the Leadbeater's possum , the powerful owl and

2898-473: A sapphire substrate with a web of thin cracks under a heat flow, similar to the environment of deep-ocean vents , as a mechanism to separate and concentrate prebiotically relevant building blocks from a dilute mixture, purifying their concentration by up to three orders of magnitude. The authors propose this as a plausible model for the origin of complex biopolymers. This presents another physical process that allows for concentrated peptide precursors to combine in

SECTION 20

#1732791975142

3036-418: A sugar molecule and RNA precursor, has been detected in regions of space including around protostars and on meteorites. As early as the 1860s, experiments demonstrated that biologically relevant molecules can be produced from interaction of simple carbon sources with abundant inorganic catalysts. The spontaneous formation of complex polymers from abiotically generated monomers under the conditions posited by

3174-826: A synthesis of many sciences. Life functions through the specialized chemistry of carbon and water, and builds largely upon four key families of chemicals: lipids for cell membranes, carbohydrates such as sugars, amino acids for protein metabolism, and nucleic acid DNA and RNA for the mechanisms of heredity. Any successful theory of abiogenesis must explain the origins and interactions of these classes of molecules. Many approaches to abiogenesis investigate how self-replicating molecules, or their components, came into existence. Researchers generally think that current life descends from an RNA world , although other self-replicating and self-catalyzing molecules may have preceded RNA. Other approaches ( "metabolism-first" hypotheses ) focus on understanding how catalysis in chemical systems on

3312-590: 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

3450-476: A turbulent atmosphere, and a hydrosphere subject to intense ultraviolet light from a T Tauri stage Sun , from cosmic radiation , and from continued asteroid and comet impacts. Despite all this, niche environments likely existed conducive to life on Earth in the Late-Hadean to Early-Archaean. The Late Heavy Bombardment hypothesis posits that a period of intense impact occurred at ~3.9 Gya during

3588-410: A urea solution to freeze-thaw cycles under a reductive atmosphere, with spark discharges as an energy source. The explanation given for the unusual speed of these reactions at such a low temperature is eutectic freezing , which crowds impurities in microscopic pockets of liquid within the ice, causing the molecules to collide more often. Prebiotic peptide synthesis is proposed to have occurred through

3726-946: 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. Abiogenesis Abiogenesis

3864-405: 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

4002-456: Is available, an explanation is needed for why the set used is so small. Formamide is attractive as a medium that potentially provided a source of amino acid derivatives from simple aldehyde and nitrile feedstocks. Alexander Butlerov showed in 1861 that the formose reaction created sugars including tetroses, pentoses, and hexoses when formaldehyde is heated under basic conditions with divalent metal ions like calcium. R. Breslow proposed that

4140-475: 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

4278-491: 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

Flora and Fauna Guarantee Act 1988 - Misplaced Pages Continue

4416-498: Is estimated that during the Late Heavy Bombardment, meteorites may have delivered up to five million tons of organic prebiotic elements to Earth per year. Polycyclic aromatic hydrocarbons (PAH) are the most common and abundant polyatomic molecules in the observable universe , and are a major store of carbon. They seem to have formed shortly after the Big Bang, and are associated with new stars and exoplanets . They are

4554-451: Is far from understood. Although Earth remains the only place where life is known, the science of astrobiology seeks evidence of life on other planets. The 2015 NASA strategy on the origin of life aimed to solve the puzzle by identifying interactions, intermediary structures and functions, energy sources, and environmental factors that contributed to the diversity, selection, and replication of evolvable macromolecular systems, and mapping

4692-427: 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

4830-405: Is not sufficient alone for peptide synthesis. Many prebiotically plausible condensing/activating agents have been identified, including the following: cyanamide, dicyanamide, dicyandiamide, diaminomaleonitrile, urea, trimetaphosphate, NaCl, CuCl 2, (Ni,Fe)S, CO, carbonyl sulfide (COS), carbon disulfide (CS 2 ) , SO 2, and diammonium phosphate (DAP). An experiment reported in 2024 used

4968-714: Is poisonous only to aerobic organisms ( eukaryotes and aerobic bacteria), which did not yet exist. It can play roles in other chemical processes such as the synthesis of the amino acid glycine. DNA and RNA components including uracil, cytosine and thymine can be synthesized under outer space conditions, using starting chemicals such as pyrimidine found in meteorites. Pyrimidine may have been formed in red giant stars or in interstellar dust and gas clouds. All four RNA-bases may be synthesized from formamide in high-energy density events like extraterrestrial impacts. Other pathways for synthesizing bases from inorganic materials have been reported. Freezing temperatures are advantageous for

5106-401: 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

5244-561: 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

5382-399: Is that life is not required to have formed on each planet it occurs on, but rather in a more limited set of locations, or even a single location, and then spread about the galaxy to other star systems via cometary or meteorite impact. Panspermia did not get much scientific support because it was largely used to deflect the need of an answer instead of explaining observable phenomena. Although

5520-441: Is the natural process by which life arises from non-living matter , such as simple organic compounds . The prevailing scientific hypothesis is that the transition from non-living to living entities on Earth was not a single event, but a process of increasing complexity involving the formation of a habitable planet , the prebiotic synthesis of organic molecules, molecular self-replication , self-assembly , autocatalysis , and

5658-465: Is to explain how such a complex and tightly interlinked system could develop by evolutionary steps, as at first sight all its parts are necessary to enable it to function. For example, a cell, whether the LUCA or in a modern organism, copies its DNA with the DNA polymerase enzyme, which is in turn produced by translating the DNA polymerase gene in the DNA. Neither the enzyme nor the DNA can be produced without

Flora and Fauna Guarantee Act 1988 - Misplaced Pages Continue

5796-405: 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

5934-465: Is universal today. That in turn implies a suite of cellular machinery including messenger RNA , transfer RNA , and ribosomes to translate the code into proteins . Those proteins included enzymes to operate its anaerobic respiration via the Wood–Ljungdahl metabolic pathway , and a DNA polymerase to replicate its genetic material. The challenge for abiogenesis (origin of life) researchers

6072-515: Is unknown. Minimum age estimates are based on evidence from the geologic rock record . The earliest physical evidence of life so far found consists of microbialites in the Nuvvuagittuq Greenstone Belt of Northern Quebec, in banded iron formation rocks at least 3.77 and possibly as old as 4.32 Gya. The micro-organisms lived within hydrothermal vent precipitates, soon after the 4.4 Gya formation of oceans during

6210-551: The Earth is 4.54 Gya as found by radiometric dating of calcium-aluminium-rich inclusions in carbonaceous chrondrite meteorites, the oldest material in the Solar System. The Hadean Earth (from its formation until 4 Gya) was at first inhospitable to any living organisms. During its formation, the Earth lost a significant part of its initial mass, and consequentially lacked the gravity to hold molecular hydrogen and

6348-409: The Earth's crust , pressure cycling leads to the periodic formation of vesicles. Under the same conditions, random peptide chains are being formed, which are being continuously selected for their ability to integrate into the vesicle membrane. A further selection of the vesicles for their stability potentially leads to the development of functional peptide structures, associated with an increase in

6486-792: 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

6624-513: The Hadean . Life consists of reproduction with (heritable) variations. NASA defines life as "a self-sustaining chemical system capable of Darwinian [i.e., biological] evolution ." Such a system is complex; the last universal common ancestor (LUCA), presumably a single-celled organism which lived some 4 billion years ago, already had hundreds of genes encoded in the DNA genetic code that

6762-619: The Isua supracrustal belt in southwestern Greenland, dating to 3.7 Gya, have shown biogenic carbon isotopes . In other parts of the Isua supracrustal belt, graphite inclusions trapped within garnet crystals are connected to the other elements of life: oxygen, nitrogen, and possibly phosphorus in the form of phosphate , providing further evidence for life 3.7 Gya. In the Pilbara region of Western Australia, compelling evidence of early life

6900-713: 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

7038-461: 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

SECTION 50

#1732791975142

7176-467: The fourth most abundant chemical element in the universe (after hydrogen, helium, and oxygen ), was formed mainly in white dwarf stars , particularly those bigger than twice the mass of the sun. As these stars reached the end of their lifecycles , they ejected these heavier elements, among them carbon and oxygen, throughout the universe. These heavier elements allowed for the formation of new objects, including rocky planets and other bodies. According to

7314-402: The last universal common ancestor of all modern organisms (LUCA) is thought to have been quite different from the origin of life, investigations into LUCA can guide research into early universal characteristics. A genomics approach has sought to characterise LUCA by identifying the genes shared by Archaea and Bacteria , members of the two major branches of life (with Eukaryotes included in

7452-516: The nebular hypothesis , the formation and evolution of the Solar System began 4.6 Gya with the gravitational collapse of a small part of a giant molecular cloud . Most of the collapsing mass collected in the center, forming the Sun , while the rest flattened into a protoplanetary disk out of which the planets , moons , asteroids , and other small Solar System bodies formed. The age of

7590-453: The phospholipids of today. Such micro-encapsulation would allow for metabolism within the membrane and the exchange of small molecules, while retaining large biomolecules inside. Such a membrane is needed for a cell to create its own electrochemical gradient to store energy by pumping ions across the membrane. Fatty acid vesicles in conditions relevant to alkaline hydrothermal vents can be stabilized by isoprenoids which are synthesized by

7728-426: The tiger quoll , as well as on a threatened community and a threatening process. For example, it considers the concern of environmentalists for the small and poorly placed Special Protection and Management Zones for the tiger quoll, the continuing clear-fell logging followed by slash burns in their management zones, and the failure to stop the use of 1080 poison , which is a threat to the species. LFF recommended that

7866-504: 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

8004-417: 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

8142-471: The "soup" theory is not straightforward. Besides the necessary basic organic monomers, compounds that would have prohibited the formation of polymers were also formed in high concentration during the Miller–Urey and Joan Oró experiments. Biology uses essentially 20 amino acids for its coded protein enzymes, representing a very small subset of the structurally possible products. Since life tends to use whatever

8280-752: 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

8418-436: The Act enables a number of mechanisms, such as listing threatened species, communities and threats to native species; the establishment of a statewide biodiversity management strategy; declaring certain areas as critical habitat; requiring public authorities to take the Act into account in their operations; and requiring permits for certain activities which may affect native plants and animals. Lawyers for Forests (LFF) published

SECTION 60

#1732791975142

8556-622: The Common Assessment Method, consistent with the national method for assessment and listing of threatened species (as per the EPBC Act ); setting up a reporting requirement on the implementation of the statewide Biodiversity Strategy. It also improved powers for enforcement and increased penalties for breaches of the legislation. Other significant reforms included the introduction of a set of principles to guide decision making (including consultation with traditional owners and

8694-472: The Earth may have been a predominantly water world between 4.4 and 4.3 Gya. It is debated whether or not crust was exposed above this ocean due to uncertainties of what early plate tectonics looked like. For early life to have developed, it is generally thought that a land setting is required, so this question is essential to determining when in Earth's history life evolved. The post-Moon-forming impact Earth likely existed with little if any continental crust,

8832-542: The FFG Act" was noted by the Victorian Rainforest Network in 2003. A major review was undertaken in 2019, resulting in the enactment of the Flora and Fauna Guarantee Amendment Act 2019 , by which amendments to the FFG Act took effect from 1 June 2020. The amendments modernised and strengthened some of the provisions of the Act, such as action preventing species from becoming threatened; adopting

8970-558: The Hadean. A cataclysmic impact event would have had the potential to sterilise all life on Earth by volatilising liquid oceans and blocking the Sun needed for photosynthesising primary producers, pushing back the earliest possible emergence of life to after Late Heavy Bombardment. Recent research questions both the intensity of the Late Heavy Bombardment as well as its potential for sterilisation. Uncertainties as to whether Late Heavy Bombardment

9108-408: The Hadean. The microbes resembled modern hydrothermal vent bacteria, supporting the view that abiogenesis began in such an environment. Biogenic graphite has been found in 3.7 Gya metasedimentary rocks from southwestern Greenland and in microbial mat fossils from 3.49 Gya cherts in the Pilbara region of Western Australia . Evidence of early life in rocks from Akilia Island, near

9246-606: 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

9384-529: The Miller–Urey experiment that "it is not enough to explain the formation of such molecules, what is necessary, is a physical-chemical explanation of the origins of these molecules that suggests the presence of suitable sources and sinks for free energy." However, current scientific consensus describes the primitive atmosphere as weakly reducing or neutral, diminishing the amount and variety of amino acids that could be produced. The addition of iron and carbonate minerals, present in early oceans, however, produces

9522-584: The Moon-forming impact. This scenario has found support from the dating of 4.404 Gya zircon crystals with high δ O values from metamorphosed quartzite of Mount Narryer in Western Australia. The Hadean atmosphere has been characterized as a "gigantic, productive outdoor chemical laboratory," similar to volcanic gases today which still support some abiotic chemistry. Despite the likely increased volcanism from early plate tectonics,

9660-548: The Murchison meteorite suggest that the RNA component uracil and related molecules, including xanthine , were formed extraterrestrially. NASA studies of meteorites suggest that all four DNA nucleobases (adenine, guanine and related organic molecules) have been formed in outer space. The cosmic dust permeating the universe contains complex organics ("amorphous organic solids with a mixed aromatic – aliphatic structure") that could be created rapidly by stars. Glycolaldehyde ,

9798-486: The NRE should receive appropriate funding to fully implement the FFG Act, and the government commit to NRE fulfilling its obligations under the Act. The group further recommended that the Act should be enforceable, and NRE should be accountable in its efforts to fulfil its obligations under the Act. Other environmental groups have echoed the review; for example, the "delays or lack of implementation of key documents required under

9936-412: The Office of the Conservation Regulator (OCR), established in 2019. Related acts include: 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

10074-450: The archaean branch in the two-domain system ). It appears there are 60 proteins common to all life and 355 prokaryotic genes that trace to LUCA; their functions imply that the LUCA was anaerobic with the Wood–Ljungdahl pathway , deriving energy by chemiosmosis , and maintaining its hereditary material with DNA, the genetic code , and ribosomes . Although the LUCA lived over 4 billion years ago (4  Gya ), researchers believe it

10212-461: 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

10350-484: The bulk of the original inert gases. Soon after initial accretion of Earth at 4.48 Ga, its collision with Theia , a hypothesised impactor, is thought to have created the ejected debris that would eventually form the Moon. This impact would have removed the Earth's primary atmosphere, leaving behind clouds of viscous silicates and carbon dioxide. This unstable atmosphere was short-lived and condensed shortly after to form

10488-401: The bulk silicate Earth, leaving behind an atmosphere largely consisting of water vapor, nitrogen , and carbon dioxide , with smaller amounts of carbon monoxide , hydrogen, and sulfur compounds. The solution of carbon dioxide in water is thought to have made the seas slightly acidic , with a pH of about 5.5. Condensation to form liquid oceans is theorised to have occurred as early as

10626-573: The carbon-hydrogen positive ion (CH+) and the carbon ion (C+) – were produced by ultraviolet light from stars. Complex molecules, including organic molecules, form naturally both in space and on planets. Organic molecules on the early Earth could have had either terrestrial origins, with organic molecule synthesis driven by impact shocks or by other energy sources, such as ultraviolet light, redox coupling, or electrical discharges; or extraterrestrial origins ( pseudo-panspermia ), with organic molecules formed in interstellar dust clouds raining down on to

10764-436: The case of iron-sulfur chemistry. For example, this was probably important for carbon fixation . Carbon fixation by reaction of CO 2 with H 2 S via iron-sulfur chemistry is favorable, and occurs at neutral pH and 100 °C. Iron-sulfur surfaces, which are abundant near hydrothermal vents, can drive the production of small amounts of amino acids and other biomolecules. In 1961, Peter Mitchell proposed chemiosmosis as

10902-448: The chemical landscape of potential primordial informational polymers . The advent of polymers that could replicate, store genetic information, and exhibit properties subject to selection was, it suggested, most likely a critical step in the emergence of prebiotic chemical evolution. Those polymers derived, in turn, from simple organic compounds such as nucleobases , amino acids , and sugars that could have been formed by reactions in

11040-540: 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

11178-522: The early Earth might have provided the precursor molecules necessary for self-replication. The classic 1952 Miller–Urey experiment demonstrated that most amino acids, the chemical constituents of proteins , can be synthesized from inorganic compounds under conditions intended to replicate those of the early Earth . External sources of energy may have triggered these reactions, including lightning , radiation , atmospheric entries of micro-meteorites and implosion of bubbles in sea and ocean waves. While

11316-438: The early Earth, which were very different from those that prevail today. The structure of the ribosome has been called the "smoking gun", with a central core of RNA and no amino acid side chains within 18 Å of the active site that catalyzes peptide bond formation. The concept of the RNA world was proposed in 1962 by Alexander Rich , and the term was coined by Walter Gilbert in 1986. There were initial difficulties in

11454-704: 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

11592-439: The emergence of cell membranes . The transition from non-life to life has never been observed experimentally, but many proposals have been made for different stages of the process. The study of abiogenesis aims to determine how pre-life chemical reactions gave rise to life under conditions strikingly different from those on Earth today. It primarily uses tools from biology and chemistry , with more recent approaches attempting

11730-512: 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

11868-505: The environment. A successful theory of the origin of life must explain how all these chemicals came into being. One ancient view of the origin of life, from Aristotle until the 19th century, is of spontaneous generation . This theory held that "lower" animals such as insects were generated by decaying organic substances, and that life arose by chance. This was questioned from the 17th century, in works like Thomas Browne 's Pseudodoxia Epidemica . In 1665, Robert Hooke published

12006-451: 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

12144-441: The evolution and preservation of polymers like RNA that store information. Only one or two types of amphiphiles have been studied which might have led to the development of vesicles. There is an enormous number of possible arrangements of lipid bilayer membranes, and those with the best reproductive characteristics would have converged toward a hypercycle reaction, a positive feedback composed of two mutual catalysts represented by

12282-428: 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

12420-513: The explanation of the abiotic synthesis of the nucleotides cytosine and uracil. Subsequent research has shown possible routes of synthesis; for example, formamide produces all four ribonucleotides and other biological molecules when warmed in the presence of various terrestrial minerals. RNA replicase can function as both code and catalyst for further RNA replication, i.e. it can be autocatalytic. Jack Szostak has shown that certain catalytic RNAs can join smaller RNA sequences together, creating

12558-492: The first drawings of a microorganism . In 1676, Antonie van Leeuwenhoek drew and described microorganisms, probably protozoa and bacteria . Van Leeuwenhoek disagreed with spontaneous generation, and by the 1680s convinced himself, using experiments ranging from sealed and open meat incubation and the close study of insect reproduction, that the theory was incorrect. In 1668 Francesco Redi showed that no maggots appeared in meat when flies were prevented from laying eggs. By

12696-511: The first molecules constituting the earliest cells slowly self-organized from a primordial soup , and this theory is called the Oparin–Haldane hypothesis . Haldane suggested that the Earth's prebiotic oceans consisted of a "hot dilute soup" in which organic compounds could have formed. J. D. Bernal showed that such mechanisms could form most of the necessary molecules for life from inorganic precursors. In 1967, he suggested three "stages":

12834-417: The first to exist. Another model echoes Darwin's "warm little pond" with cycles of wetting and drying. RNA is central to the translation process. Small RNAs can catalyze all the chemical groups and information transfers required for life. RNA both expresses and maintains genetic information in modern organisms; and the chemical components of RNA are easily synthesized under the conditions that approximated

12972-526: The flow from a hydrothermal vent and the surrounding seawater, or perhaps meteoric quinones that were conducive to the development of chemiosmotic energy across lipid membranes if at a terrestrial origin. The RNA world hypothesis describes an early Earth with self-replicating and catalytic RNA but no DNA or proteins. Many researchers concur that an RNA world must have preceded the DNA-based life that now dominates. However, RNA-based life may not have been

13110-609: The following generation, thus initiating the evolution of life. The lipid world theory postulates that the first self-replicating object was lipid -like. Phospholipids form lipid bilayers in water while under agitation—the same structure as in cell membranes. These molecules were not present on early Earth, but other amphiphilic long-chain molecules also form membranes. These bodies may expand by insertion of additional lipids, and may spontaneously split into two offspring of similar size and composition. Lipid bodies may have provided sheltering envelopes for information storage, allowing

13248-405: The formose reaction; the advantages and disadvantages of isoprenoids incorporated within the lipid bilayer in different microenvironments might have led to the divergence of the membranes of archaea and bacteria. Laboratory experiments have shown that vesicles can undergo an evolutionary process under pressure cycling conditions. Simulating the systemic environment in tectonic fault zones within

13386-491: 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

13524-407: The hot and dense centers of these protoplanetary disks formed stars by the fusion of hydrogen. Early stars were massive and short-lived, producing all the heavier elements through stellar nucleosynthesis . Element formation through stellar nucleosynthesis proceeds to its most stable element Iron- 56 . Heavier elements were formed during supernovae at the end of a stars lifecycle. Carbon , currently

13662-587: 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

13800-596: 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

13938-685: The interest in panspermia grew when the study of meteorites found traces of organic materials in them, it is currently accepted that life started locally on Earth. The idea that life originated from non-living matter in slow stages appeared in Herbert Spencer 's 1864–1867 book Principles of Biology , and in William Turner Thiselton-Dyer 's 1879 paper "On spontaneous generation and evolution". On 1 February 1871 Charles Darwin wrote about these publications to Joseph Hooker , and set out his own speculation, suggesting that

14076-737: 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

14214-453: The interstellar medium can be transformed through hydrogenation , oxygenation , and hydroxylation to more complex organic compounds used in living cells. The majority of organic compounds introduced on Earth by interstellar dust particles have helped to form complex molecules, thanks to their peculiar surface-catalytic activities. Studies of the C/ C isotopic ratios of organic compounds in

14352-430: 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

14490-433: The materials for DNA and RNA to form on the early Earth . The amino acid glycine was found in material ejected from comet Wild 2 ; it had earlier been detected in meteorites. Comets are encrusted with dark material, thought to be a tar -like organic substance formed from simple carbon compounds under ionizing radiation. A rain of material from comets could have brought such complex organic molecules to Earth. It

14628-440: The middle of the 19th century, spontaneous generation was considered disproven. Another ancient idea dating back to Anaxagoras in the 5th century BC is panspermia , the idea that life exists throughout the universe , distributed by meteoroids , asteroids , comets and planetoids . It does not attempt to explain how life originated in itself, but shifts the origin of life on Earth to another heavenly body. The advantage

14766-877: 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

14904-629: The origin of biological monomers ; the origin of biological polymers ; and the evolution from molecules to cells. In 1952, Stanley Miller and Harold Urey carried out a chemical experiment to demonstrate how organic molecules could have formed spontaneously from inorganic precursors under prebiotic conditions like those posited by the Oparin–Haldane hypothesis. It used a highly reducing (lacking oxygen) mixture of gases— methane , ammonia , and hydrogen , as well as water vapor —to form simple organic monomers such as amino acids . Bernal said of

15042-508: The original spark of life may have begun in a "warm little pond, with all sorts of ammonia and phosphoric salts , light, heat, electricity, &c., present, that a proteine compound was chemically formed ready to undergo still more complex changes." Darwin went on to explain that "at the present day such matter would be instantly devoured or absorbed, which would not have been the case before living creatures were formed." Alexander Oparin in 1924 and J. B. S. Haldane in 1929 proposed that

15180-442: The other. The evolutionary process could have involved molecular self-replication , self-assembly such as of cell membranes , and autocatalysis via RNA ribozymes . Nonetheless, the transition of non-life to life has never been observed experimentally, nor has there been a satisfactory chemical explanation. The preconditions to the development of a living cell like the LUCA are clear enough, though disputed in their details:

15318-468: 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

15456-588: The planet. An organic compound is a chemical whose molecules contain carbon. Carbon is abundant in the Sun, stars, comets, and in the atmospheres of most planets. Organic compounds are relatively common in space, formed by "factories of complex molecular synthesis" which occur in molecular clouds and circumstellar envelopes , and chemically evolve after reactions are initiated mostly by ionizing radiation . Purine and pyrimidine nucleobases including guanine , adenine , cytosine , uracil , and thymine have been found in meteorites . These could have provided

15594-546: 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")

15732-575: The potential for self-replication. The RNA replication systems, which include two ribozymes that catalyze each other's synthesis, showed a doubling time of the product of about one hour, and were subject to natural selection under the experimental conditions. If such conditions were present on early Earth, then natural selection would favor the proliferation of such autocatalytic sets , to which further functionalities could be added. Self-assembly of RNA may occur spontaneously in hydrothermal vents. A preliminary form of tRNA could have assembled into such

15870-412: 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

16008-604: The public); a new definition of "critical habitat" to replace the previous one which was too hard to prove and thus implement; the introduction of habitat conservation orders; setting up a new register; and an obligation for the Commissioner for Environmental Sustainability to report on achievement of targets in the Biodiversity Strategy every five years. Enforcement of the FFG ACT would now be overseen by

16146-584: 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

16284-474: The reaction was autocatalytic in 1959. Nucleobases, such as guanine and adenine, can be synthesized from simple carbon and nitrogen sources, such as hydrogen cyanide (HCN) and ammonia. Formamide produces all four ribonucleotides when warmed with terrestrial minerals. Formamide is ubiquitous in the Universe, produced by the reaction of water and HCN. It can be concentrated by the evaporation of water. HCN

16422-913: 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

16560-472: The right conditions. A similar role of increasing amino acid concentration has been suggested for clays as well. While all of these scenarios involve the condensation of amino acids, the prebiotic synthesis of peptides from simpler molecules such as CO, NH 3 and C, skipping the step of amino acid formation, is very efficient.   The largest unanswered question in evolution is how simple protocells first arose and differed in reproductive contribution to

16698-461: The rock record both before and after the 3.9 Ga marker, suggesting that the early Earth was subject to continuous impacts that would not have had as great an impact on extinction as previously thought. If the Late Heavy Bombardment did not take place, this allows for the emergence of life to have taken place far before 3.9 Ga. If life evolved in the ocean at depths of more than ten meters, it would have been shielded both from late impacts and

16836-693: 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

16974-437: The survival rate of the vesicles. Life requires a loss of entropy, or disorder, as molecules organize themselves into living matter. At the same time, the emergence of life is associated with the formation of structures beyond a certain threshold of complexity . The emergence of life with increasing order and complexity does not contradict the second law of thermodynamics, which states that overall entropy never decreases, since

17112-495: The synthesis of purines, due to the concentrating effect for key precursors such as hydrogen cyanide. However, while adenine and guanine require freezing conditions for synthesis, cytosine and uracil may require boiling temperatures. Seven amino acids and eleven types of nucleobases formed in ice when ammonia and cyanide were left in a freezer for 25 years. S- triazines (alternative nucleobases), pyrimidines including cytosine and uracil, and adenine can be synthesized by subjecting

17250-419: 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

17388-475: The then high levels of ultraviolet radiation from the sun. Geothermically heated oceanic crust could have yielded far more organic compounds through deep hydrothermal vents than the Miller–Urey experiments indicated. The available energy is maximized at 100–150 °C, the temperatures at which hyperthermophilic bacteria and thermoacidophilic archaea live. The exact timing at which life emerged on Earth

17526-479: 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

17664-773: 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

17802-630: 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

17940-482: 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

18078-553: 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

18216-697: Was far from the first form of life. Earlier cells might have had a leaky membrane and been powered by a naturally occurring proton gradient near a deep-sea white smoker hydrothermal vent . Earth remains the only place in the universe known to harbor life. Geochemical and fossil evidence from the Earth informs most studies of abiogenesis. The Earth was formed at 4.54 Gya, and the earliest evidence of life on Earth dates from at least 3.8 Gya from Western Australia . Some studies have suggested that fossil micro-organisms may have lived within hydrothermal vent precipitates dated 3.77 to 4.28 Gya from Quebec , soon after ocean formation 4.4 Gya during

18354-760: Was found in pyrite -bearing sandstone in a fossilized beach, with rounded tubular cells that oxidized sulfur by photosynthesis in the absence of oxygen. Carbon isotope ratios on graphite inclusions from the Jack Hills zircons suggest that life could have existed on Earth from 4.1 Gya. The Pilbara region of Western Australia contains the Dresser Formation with rocks 3.48 Gya, including layered structures called stromatolites . Their modern counterparts are created by photosynthetic micro-organisms including cyanobacteria . These lie within undeformed hydrothermal-sedimentary strata; their texture indicates

18492-483: 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

18630-582: Was one giant impact or a period of greater impact rates greatly changed the implication of its destructive power. The 3.9 Ga date arises from dating of Apollo mission sample returns collected mostly near the Imbrium Basin , biasing the age of recorded impacts. Impact modelling of the lunar surface reveals that rather than a cataclysmic event at 3.9 Ga, multiple small-scale, short-lived periods of bombardment likely occurred. Terrestrial data backs this idea by showing multiple periods of ejecta in

18768-401: 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

18906-567: 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

19044-425: 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

#141858