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98-599: Geologically, the Kitakami Mountains are Paleozoic and Mesozoic formations, divided into northern and southern groups. the southern area has oldest previous Silurian foundation, which was once a shallow sea on the continental margin where the water temperature was high enough for coral growth from the Silurian to the Devonian periods; this region, later collided with the northern Kitakami mountainous area in

196-604: A fossil record extending back about 300 million years to the Paleozoic in the late Carboniferous period; even many of the modern genera are recognizable from fossils 60–120 million years old. Other classes and orders, now long extinct, also occur as fossils, particularly from the late Paleozoic and Mesozoic eras. Fossil conifers included many diverse forms, the most dramatically distinct from modern conifers being some herbaceous conifers with no woody stems. Major fossil orders of conifers or conifer-like plants include

294-697: A sister group to Pinales (the 'gnepine' hypothesis) or as being more derived than Pinales but sister to the rest of the group. Most recent studies favor the 'gnepine' hypothesis. The earliest conifers appear in the fossil record during the Late Carboniferous ( Pennsylvanian ), over 300 million years ago. Conifers are thought to be most closely related to the Cordaitales , a group of extinct Carboniferous-Permian trees and clambering plants whose reproductive structures had some similarities to those of conifers. The most primitive conifers belong to

392-622: A cataclysm known as " The Great Dying ", the third and most severe Phanerozoic mass extinction. The early Cambrian climate was probably moderate at first, becoming warmer over the course of the Cambrian, as the second-greatest sustained sea level rise in the Phanerozoic got underway. However, as if to offset this trend, Gondwana moved south, so that, in Ordovician time, most of West Gondwana (Africa and South America) lay directly over

490-422: A female multicellular gametophyte. The female gametophytes grow to produce two or more archegonia , each of which contains an egg. Upon fertilization, the diploid egg will give rise to the embryo, and a seed is produced. The female cone then opens, releasing the seeds which grow to a young seedling . Conifer reproduction is synchronous with seasonal changes in temperate zones. Reproductive development slows to

588-399: A female cone and are drawn into a tiny opening on the ovule called the micropyle . It is within the ovule that pollen-germination occurs. From here, a pollen tube seeks out the female gametophyte, which contains archegonia each with an egg, and if successful, fertilization occurs. The resulting zygote develops into an embryo , which along with the female gametophyte (nutritional material for

686-445: A foothold on land. These early plants were the forerunners of all plant life on land. During this time, there were four continents: Gondwana (Africa, South America, Australia, Antarctica, Siberia), Laurentia (North America), Baltica (Northern Europe), and Avalonia (Western Europe). The recent rise in sea levels allowed many new species to thrive in water. The Devonian spanned from 419–359 million years ago. Also known as "The Age of

784-665: A halt during each winter season and then resumes each spring. The male strobilus development is completed in a single year. Conifers are classified by three reproductive cycles that refer to the completion of female strobilus development from initiation to seed maturation. All three types of reproductive cycle have a long gap between pollination and fertilization . One year reproductive cycle : The genera include Abies , Picea , Cedrus , Pseudotsuga , Tsuga , Keteleeria ( Pinaceae ) and Cupressus , Thuja , Cryptomeria , Cunninghamia and Sequoia ( Cupressaceae ) . Female strobili are initiated in late summer or fall of

882-413: A maximum of energy from weak sunshine at high latitudes or under forest canopy shade. Conifers from hotter areas with high sunlight levels (e.g. Turkish pine Pinus brutia ) often have yellower-green leaves, while others (e.g. blue spruce , Picea pungens ) may develop blue or silvery leaves to reflect ultraviolet light. In the great majority of genera the leaves are evergreen , usually remaining on

980-880: A needle-like appearance, but others, including most of the Cupressaceae and some of the Podocarpaceae , have flat, triangular scale-like leaves. Some, notably Agathis in Araucariaceae and Nageia in Podocarpaceae, have broad, flat strap-shaped leaves. Others such as Araucaria columnaris have leaves that are awl-shaped. In the majority of conifers, the leaves are arranged spirally, the exceptions being most of Cupressaceae and one genus in Podocarpaceae, where they are arranged in decussate opposite pairs or whorls of 3 (−4). In many species with spirally arranged leaves, such as Abies grandis (pictured),

1078-402: A protective cone called a strobilus . The cones take from four months to three years to reach maturity, and vary in size from 2 to 600 millimetres ( 1 ⁄ 8 to 23 + 5 ⁄ 8  in) long. In Pinaceae , Araucariaceae , Sciadopityaceae and most Cupressaceae , the cones are woody , and when mature the scales usually spread open allowing the seeds to fall out and be dispersed by

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1176-487: A serious environmental issue causing problems for pastoral farming and for conservation . Radiata pine was introduced to Australia in the 1870s. It is "the dominant tree species in the Australian plantation estate" – so much so that many Australians are concerned by the resulting loss of native wildlife habitat. The species is widely regarded as an environmental weed across southeastern and southwestern Australia and

1274-438: A single extant class , Pinopsida . All extant conifers are perennial woody plants with secondary growth . The great majority are trees , though a few are shrubs . Examples include cedars , Douglas-firs , cypresses , firs , junipers , kauri , larches , pines , hemlocks , redwoods , spruces , and yews . As of 2002, Pinophyta contained seven families, 60 to 65 genera, and more than 600 living species. Although

1372-406: A single white spruce tree from 1926 to 1961. Apical growth of the stem was slow from 1926 through 1936 when the tree was competing with herbs and shrubs and probably shaded by larger trees. Lateral branches began to show reduced growth and some were no longer in evidence on the 36-year-old tree. Apical growth totaling about 340 m, 370 m, 420 m, 450 m, 500 m, 600 m, and 600 m was made by the tree in

1470-469: A useful guide by which to assess the adequacy of particular nutrients, and the ratios among the major nutrients are helpful guides to nutritional imbalances. The softwood derived from conifers is of great economic value, providing about 45% of the world's annual lumber production. Other uses of the timber include the production of paper and plastic from chemically treated wood pulp. Some conifers also provide foods such as pine nuts and juniper berries ,

1568-450: A wide range of sediments and environments, which aids correlation between different sites around the world. Trace fossils reflect the complexity of the body plan of the organism that made them. Ediacaran trace fossils are simple, sub-horizontal feeding traces. As more complex organisms evolved, their more complex behaviour was reflected in greater diversity and complexity of the trace fossils they left behind. After two decades of deliberation,

1666-591: A year, then they overwinter. Female strobili emerge followed by pollination in the following spring. Fertilization takes place in summer of the following year, only 3–4 months after pollination. Cones mature and seeds are then shed by the end of that same year. Pollination and fertilization occur in a single growing season. Two-year reproductive cycle : The genera includes Widdringtonia , Sequoiadendron ( Cupressaceae ) and most species of Pinus . Female strobilus initials are formed in late summer or fall then overwinter. Female strobili emerge and receive pollen in

1764-446: Is a coast redwood ( Sequoia sempervirens ), with a height of 115.55 metres (although one mountain ash, Eucalyptus regnans , allegedly grew to a height of 140 metres, the tallest living angiosperms are significantly smaller at around 100 metres. ) The thickest (that is, the tree with the greatest trunk diameter ) is a Montezuma cypress ( Taxodium mucronatum ), 11.42 metres in diameter. The largest tree by three-dimensional volume

1862-418: Is a giant sequoia ( Sequoiadendron giganteum ), with a volume 1486.9 cubic metres. The smallest is the pygmy pine ( Lepidothamnus laxifolius ) of New Zealand, which is seldom taller than 30 cm when mature. The oldest non-clonal living tree is a Great Basin bristlecone pine ( Pinus longaeva ), 4,700 years old. Since most conifers are evergreens, the leaves of many conifers are long, thin and have

1960-663: Is considered the first Phanerozoic mass extinction event, and the second deadliest. The Silurian spanned from 444–419 million years ago. The Silurian saw the rejuvenation of life as the Earth recovered from the previous glaciation. This period saw the mass evolution of fish, as jawless fish became more numerous, jawed fish evolved, and the first freshwater fish evolved, though arthropods, such as sea scorpions , were still apex predators . Fully terrestrial life evolved, including early arachnids, fungi, and centipedes. The evolution of vascular plants ( Cooksonia ) allowed plants to gain

2058-567: Is derived from the Greek palaiós (παλαιός, "old") and zōḗ (ζωή, "life") meaning "ancient life". The Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian witnessed the most rapid and widespread diversification of life in Earth's history, known as the Cambrian explosion , in which most modern phyla first appeared. Arthropods , molluscs , fish , amphibians , reptiles , and synapsids all evolved during

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2156-402: Is probably: first to apical growth and new needle formation, then to buds for the next year's growth, with the cambium in the older parts of the branches receiving sustenance last. In the white spruce studied by Fraser et al. (1964), the needles constituted 17.5% of the over-day weight. Undoubtedly, the proportions change with time. Wind and animal dispersals are two major mechanisms involved in

2254-432: Is the whitespotted sawyer ( Monochamus scutellatus ). Adults are found in summer on newly fallen or recently felled trees chewing tiny slits in the bark in which they lay eggs. The eggs hatch in about two weeks and the tiny larvae tunnel to the wood and score its surface with their feeding channels. With the onset of cooler weather, they bore into the wood, making oval entrance holes and tunnelling deeply. Feeding continues

2352-683: Is the first of three geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma at the start of the Mesozoic Era. The Paleozoic is subdivided into six geologic periods (from oldest to youngest), Cambrian , Ordovician , Silurian , Devonian , Carboniferous and Permian . Some geological timescales divide

2450-519: Is the sudden appearance of nearly all of the invertebrate animal phyla in great abundance at the beginning of the Cambrian. The first vertebrates appeared in the form of primitive fish, which greatly diversified in the Silurian and Devonian Periods. The first animals to venture onto dry land were the arthropods. Some fish had lungs, and powerful bony fins that in the late Devonian, 367.5 million years ago, allowed them to crawl onto land. The bones in their fins eventually evolved into legs and they became

2548-550: The Appalachians , Caledonides , Ural Mountains , and mountains of Tasmania . The Cambrian spanned from 539–485 million years ago and is the first period of the Paleozoic Era of the Phanerozoic. The Cambrian marked a boom in evolution in an event known as the Cambrian explosion in which the largest number of creatures evolved in any single period of the history of the Earth. Creatures like algae evolved, but

2646-531: The Carboniferous Rainforest Collapse . Gondwana was glaciated as much of it was situated around the south pole. The Permian spanned from 299–252 million years ago and was the last period of the Paleozoic Era. At the beginning of this period, all continents joined together to form the supercontinent Pangaea, which was encircled by one ocean called Panthalassa . The land mass was very dry during this time, with harsh seasons, as

2744-623: The Cephalotaxaceae may be better included within the Taxaceae, and some authors additionally recognize Phyllocladaceae as distinct from Podocarpaceae (in which it is included here). The family Taxodiaceae is here included in the family Cupressaceae, but was widely recognized in the past and can still be found in many field guides. A new classification and linear sequence based on molecular data can be found in an article by Christenhusz et al. The conifers are an ancient group, with

2842-583: The Cordaitales , Vojnovskyales , Voltziales and perhaps also the Czekanowskiales (possibly more closely related to the Ginkgophyta ). Pinaceae Araucariaceae Podocarpaceae Sciadopityaceae Cupressaceae Cephalotaxaceae Taxaceae Multiple studies also indicate that the Gnetophyta belong within the conifers despite their distinct appearances, either placing them as

2940-645: The Early Palaeozoic Icehouse , culminating in the Hirnantian glaciation, 445  million years ago at the end of the Ordovician. The middle Paleozoic was a time of considerable stability. Sea levels had dropped coincident with the ice age, but slowly recovered over the course of the Silurian and Devonian. The slow merger of Baltica and Laurentia, and the northward movement of bits and pieces of Gondwana created numerous new regions of relatively warm, shallow sea floor. As plants took hold on

3038-743: The Mesozoic era. Modern groups of conifers emerged from the Voltziales during the Late Permian through Jurassic . Conifers underwent a major decline in the Late Cretaceous corresponding to the explosive adaptive radiation of flowering plants . All living conifers are woody plants, and most are trees, the majority having a monopodial growth form (a single, straight trunk with side branches) with strong apical dominance . Many conifers have distinctly scented resin , secreted to protect

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3136-571: The South Pole . The early Paleozoic climate was strongly zonal, with the result that the "climate", in an abstract sense, became warmer, but the living space of most organisms of the time – the continental shelf marine environment – became steadily colder. However, Baltica (Northern Europe and Russia) and Laurentia (eastern North America and Greenland) remained in the tropical zone, while China and Australia lay in waters which were at least temperate. The early Paleozoic ended, rather abruptly, with

3234-460: The influence of environmental conditions, their anatomical characteristics record growth rate changes produced by these changing conditions. The microscopic structure of conifer wood consists of two types of cells : parenchyma , which have an oval or polyhedral shape with approximately identical dimensions in three directions, and strongly elongated tracheids. Tracheids make up more than 90% of timber volume. The tracheids of earlywood formed at

3332-402: The wind . In some (e.g. firs and cedars ), the cones disintegrate to release the seeds, and in others (e.g. the pines that produce pine nuts ) the nut-like seeds are dispersed by birds (mainly nutcrackers , and jays ), which break up the specially adapted softer cones. Ripe cones may remain on the plant for a varied amount of time before falling to the ground; in some fire-adapted pines,

3430-409: The 16 nutrient elements known to be essential to plants, 13 of which are obtained from the soil, including nitrogen , phosphorus , potassium , calcium , magnesium , and sulfur , all used in relatively large amounts. Nutrient concentrations in conifers also vary with season, age, and kind of tissue sampled, and analytical technique. The ranges of concentrations occurring in well-grown plants provide

3528-593: The Fish", the Devonian featured a huge diversification of fish, including armored fish like Dunkleosteus and lobe-finned fish which eventually evolved into the first tetrapods. On land, plant groups diversified rapidly in an event known as the Devonian explosion when plants made lignin , leading to taller growth and vascular tissue; the first trees and seeds evolved. These new habitats led to greater arthropod diversification. The first amphibians appeared and fish occupied

3626-649: The ICS chose Fortune Head , Burin Peninsula, Newfoundland as the basal Cambrian Global Stratotype Section and Point (GSSP) at the base of the Treptichnus pedum assemblage of trace fossils and immediately above the last occurrence of the Ediacaran problematica fossils Harlaniella podolica and Palaeopsacichnus . The base of the Phanerozoic, Paleozoic and Cambrian is dated at 538.8+/-0.2 Ma and now lies below both

3724-610: The Middle Carboniferous). An important evolutionary development of the time was the evolution of amniotic eggs , which allowed amphibians to move farther inland and remain the dominant vertebrates for the duration of this period. Also, the first reptiles and synapsids evolved in the swamps. Throughout the Carboniferous, there was a cooling trend, which led to the Permo-Carboniferous glaciation or

3822-743: The North American Forest Tree Nursery Soils Workshop at Syracuse in 1980 provided strong contrary evidence: Bob Eastman, President of the Western Maine Forest Nursery Co. stated that for 15 years he has been successful in avoiding winter “burn” to Norway spruce and white spruce in his nursery operation by fertilizing with 50–80 lb/ac (56–90 kg/ha) nitrogen in September, whereas previously winter burn had been experienced annually, often severely. Eastman also stated that

3920-629: The Palaeozoic had very few facultatively motile animals that could easily adjust to disturbance, with such creatures composing 1% of its assemblages in contrast to 50% in Cenozoic faunal assemblages. Non-motile animals untethered to the substrate, extremely rare in the Cenozoic, were abundant in the Palaeozoic. Palaeozoic phytoplankton overall were both nutrient-poor themselves and adapted to nutrient-poor environmental conditions. This phytoplankton nutrient poverty has been cited as an explanation for

4018-421: The Palaeozoic's relatively low biodiversity. Conifers Conifers are a group of cone-bearing seed plants , a subset of gymnosperms . Scientifically, they make up the division Pinophyta ( / p ɪ ˈ n ɒ f ɪ t ə , ˈ p aɪ n oʊ f aɪ t ə / ), also known as Coniferophyta ( / ˌ k ɒ n ɪ f ə ˈ r ɒ f ɪ t ə , - oʊ f aɪ t ə / ) or Coniferae . The division contains

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4116-614: The Paleozoic and Neoproterozoic eras and the Ediacaran and Cambrian periods. When Adam Sedgwick named the Paleozoic in 1835, he defined the base as the first appearance of complex life in the rock record as shown by the presence of trilobite -dominated fauna. Since then evidence of complex life in older rock sequences has increased and by the second half of the 20th century, the first appearance of small shelly fauna (SSF), also known as early skeletal fossils, were considered markers for

4214-560: The Paleozoic informally into early and late sub-eras: the Early Paleozoic consisting of the Cambrian, Ordovician and Silurian; the Late Paleozoic consisting of the Devonian, Carboniferous and Permian. The name Paleozoic was first used by Adam Sedgwick (1785–1873) in 1838 to describe the Cambrian and Ordovician periods. It was redefined by John Phillips (1800–1874) in 1840 to cover the Cambrian to Permian periods. It

4312-410: The Paleozoic. Life began in the ocean but eventually transitioned onto land, and by the late Paleozoic, great forests of primitive plants covered the continents, many of which formed the coal beds of Europe and eastern North America . Towards the end of the era, large, sophisticated synapsids and diapsids were dominant and the first modern plants ( conifers ) appeared. The Paleozoic Era ended with

4410-464: The Pinales without Taxales as paraphyletic , and the latter order is no longer considered distinct. A more accurate subdivision would be to split the class into three orders, Pinales containing only Pinaceae, Araucariales containing Araucariaceae and Podocarpaceae, and Cupressales containing the remaining families (including Taxaceae), but there has not been any significant support for such a split, with

4508-529: The Silurian Period, about 420 million years ago, when they began to transition onto dry land. Terrestrial flora reached its climax in the Carboniferous, when towering lycopsid rainforests dominated the tropical belt of Euramerica . Climate change caused the Carboniferous Rainforest Collapse which fragmented this habitat, diminishing the diversity of plant life in the late Carboniferous and Permian periods. A noteworthy feature of Paleozoic life

4606-498: The base of the Paleozoic. However, whilst SSF are well preserved in carbonate sediments, the majority of Ediacaran to Cambrian rock sequences are composed of siliciclastic rocks where skeletal fossils are rarely preserved. This led the International Commission on Stratigraphy (ICS) to use trace fossils as an indicator of complex life. Unlike later in the fossil record, Cambrian trace fossils are preserved in

4704-558: The beginning of a growing season have large radial sizes and smaller, thinner cell walls . Then, the first tracheids of the transition zone are formed, where the radial size of cells and the thickness of their cell walls changes considerably. Finally, latewood tracheids are formed, with small radial sizes and greater cell wall thickness. This is the basic pattern of the internal cell structure of conifer tree rings. Most conifers are monoecious , but some are subdioecious or dioecious ; all are wind-pollinated . Conifer seeds develop inside

4802-516: The boundary confine its age to a narrow range of 251.902+/-0.024 Ma. The beginning of the Paleozoic Era witnessed the breakup of the supercontinent of Pannotia and ended while the supercontinent Pangaea was assembling. The breakup of Pannotia began with the opening of the Iapetus Ocean and other Cambrian seas and coincided with a dramatic rise in sea level. Paleoclimatic studies and evidence of glaciers indicate that Central Africa

4900-509: The center of the range, is the highest peak at 1,917 metres (6,289 ft), and supports endemic alpine vegetation. Notable caves within the Kitakami Mountains include Akkadō and Ryūsendō . The peaks of the Kitakami mountains include the following: Paleozoic The Paleozoic ( / ˌ p æ l i . ə ˈ z oʊ . ɪ k , - i . oʊ -, ˌ p eɪ -/ PAL-ee-ə-ZOH-ik , -⁠ee-oh- , PAY- ; or Palaeozoic ) Era

4998-566: The climate of the interior of Pangaea was not regulated by large bodies of water. Diapsids and synapsids flourished in the new dry climate. Creatures such as Dimetrodon and Edaphosaurus ruled the new continent. The first conifers evolved, and dominated the terrestrial landscape. Near the end of the Permian, however, Pangaea grew drier. The interior was desert, and new taxa such as Scutosaurus and Gorgonopsids filled it. Eventually they disappeared, along with 95% of all life on Earth, in

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5096-587: The cone consists of several fused scales, while in others (e.g. Taxaceae), the cone is reduced to just one seed scale or (e.g. Cephalotaxaceae) the several scales of a cone develop into individual arils, giving the appearance of a cluster of berries. The male cones have structures called microsporangia that produce yellowish pollen through meiosis. Pollen is released and carried by the wind to female cones. Pollen grains from living pinophyte species produce pollen tubes, much like those of angiosperms. The gymnosperm male gametophytes (pollen grains) are carried by wind to

5194-561: The continental margins, oxygen levels increased and carbon dioxide dropped, although much less dramatically. The north–south temperature gradient also seems to have moderated, or metazoan life simply became hardier, or both. At any event, the far southern continental margins of Antarctica and West Gondwana became increasingly less barren. The Devonian ended with a series of turnover pulses which killed off much of middle Paleozoic vertebrate life, without noticeably reducing species diversity overall. There are many unanswered questions about

5292-402: The dispersal of conifer seeds. Wind-born seed dispersal involves two processes, namely; local neighborhood dispersal and long-distance dispersal. Long-distance dispersal distances range from 11.9–33.7 kilometres (7.4–20.9 mi) from the source. Birds of the crow family, Corvidae , are the primary distributor of the conifer seeds. These birds are known to cache 32,000 pine seeds and transport

5390-517: The early Cretaceous period, and the whole was penetrated by the granite in various places. Until the Paleogene , the Kitakami Mountains were geologically part of Primorsky region of Siberia . About 30 million years to 15 million years ago, the Japanese archipelago separated from the continent and moved to its present position. The Kitakami Mountains around that time was an island, the west side

5488-507: The empty continent of Gondwana. By the end of the Ordovician, Gondwana was at the south pole, early North America had collided with Europe, closing the intervening ocean. Glaciation of Africa resulted in a major drop in sea level, killing off all life that had established along coastal Gondwana. Glaciation may have caused the Ordovician–Silurian extinction events , in which 60% of marine invertebrates and 25% of families became extinct, and

5586-560: The end of the Permian period. In late middle Permian the pareiasaurs originated, successful herbivores and the only sauropsids that could reach sizes comparable to some of the largest synapsids. The Palaeozoic marine fauna was notably lacking in predators relative to the present day. Predators made up about 4% of the fauna in Palaeozoic assemblages while making up 17% of temperate Cenozoic assemblages and 31% of tropical ones. Infaunal animals made up 4% of soft substrate Palaeozoic communities but about 47% of Cenozoic communities. Additionally,

5684-715: The equivalent level is marked by the disappearance of the Permian Dicynodon tetrapods . This means events previously considered to mark the Permian-Triassic boundary, such as the eruption of the Siberian Traps flood basalts , the onset of greenhouse climate, ocean anoxia and acidification and the resulting mass extinction are now regarded as being of latest Permian in age. The GSSP is near Meishan , Zhejiang Province, southern China. Radiometric dating of volcanic clay layers just above and below

5782-567: The female cone is termed fruit , which undergoes ripening (maturation). It was found recently that the pollen of conifers transfers the mitochondrial organelles to the embryo , a sort of meiotic drive that perhaps explains why Pinus and other conifers are so productive, and perhaps also has bearing on observed sex-ratio bias. Conifers are heterosporous , generating two different types of spores: male microspores and female megaspores . These spores develop on separate male and female sporophylls on separate male and female cones. In

5880-418: The first appearance of trilobites and SSF. The boundary between the Paleozoic and Mesozoic eras and the Permian and Triassic periods is marked by the first occurrence of the conodont Hindeodus parvus . This is the first biostratigraphic event found worldwide that is associated with the beginning of the recovery following the end- Permian mass extinctions and environmental changes. In non-marine strata,

5978-461: The first tetrapods, 390  million years ago , and began to develop lungs. Amphibians were the dominant tetrapods until the mid-Carboniferous, when climate change greatly reduced their diversity, allowing amniotes to take over. Amniotes would split into two clades shortly after their origin in the Carboniferous; the synapsids, which was the dominant group, and the sauropsids . The synapsids continued to prosper and increase in number and variety till

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6076-449: The first year spring and become conelets. The conelet goes through another winter rest and, in the spring of the second year archegonia form in the conelet. Fertilization of the archegonia occurs by early summer of the second year, so the pollination-fertilization interval exceeds a year. After fertilization, the conelet is considered an immature cone. Maturation occurs by autumn of the second year, at which time seeds are shed. In summary,

6174-466: The following spring. Female strobili emerge then pollination occurs in spring of the second year then the pollinated strobili become conelets in the same year (i.e. the second year). The female gametophytes in the conelet develop so slowly that the megaspore does not go through free-nuclear divisions until autumn of the third year. The conelet then overwinters again in the free-nuclear female gametophyte stage. Fertilization takes place by early summer of

6272-492: The following summer when larvae occasionally return to the surface of the wood and extend the feeding channels generally in a U-shaped configuration. During this time, small piles of frass extruded by the larvae accumulate under logs. Early in the spring of the second year following egg-laying, the larvae, about 30 mm long, pupate in the tunnel enlargement just below the wood surface. The resulting adults chew their way out in early summer, leaving round exit holes, so completing

6370-399: The fourth year and seeds mature in the cones by autumn of the fourth year. The growth and form of a forest tree are the result of activity in the primary and secondary meristems , influenced by the distribution of photosynthate from its needles and the hormonal gradients controlled by the apical meristems. External factors also influence growth and form. Fraser recorded the development of

6468-419: The growing embryo) and its surrounding integument, becomes a seed . Eventually, the seed may fall to the ground and, if conditions permit, grow into a new plant. In forestry , the terminology of flowering plants has commonly though inaccurately been applied to cone-bearing trees as well. The male cone and unfertilized female cone are called male flower and female flower , respectively. After fertilization,

6566-530: The immense conifer forests of the world represent the largest terrestrial carbon sink . Conifers are of great economic value for softwood lumber and paper production. Conifer is a Latin word, a compound of conus (cone) and ferre (to bear), meaning "the one that bears (a) cone(s)". The division name Pinophyta conforms to the rules of the International Code of Nomenclature for algae, fungi, and plants (ICN), which state (Article 16.1) that

6664-679: The largest extinction event of the Phanerozoic Eon , the Permian–Triassic extinction event . The effects of this catastrophe were so devastating that it took life on land 30 million years into the Mesozoic Era to recover. Recovery of life in the sea may have been much faster. The base of the Paleozoic is one of the major divisions in geological time representing the divide between the Proterozoic and Phanerozoic eons,

6762-535: The largest and economically most important component group of gymnosperms, but nevertheless they comprise only one of the four groups. The division Pinophyta consists of just one class, Pinopsida, which includes both living and fossil taxa. Subdivision of the living conifers into two or more orders has been proposed from time to time. The most commonly seen in the past was a split into two orders, Taxales (Taxaceae only) and Pinales (the rest), but recent research into DNA sequences suggests that this interpretation leaves

6860-548: The late Paleozoic. The Mississippian (early Carboniferous Period) began with a spike in atmospheric oxygen, while carbon dioxide plummeted to new lows. This destabilized the climate and led to one, and perhaps two, ice ages during the Carboniferous. These were far more severe than the brief Late Ordovician ice age; but, this time, the effects on world biota were inconsequential. By the Cisuralian Epoch, both oxygen and carbon dioxide had recovered to more normal levels. On

6958-417: The leaf bases are twisted to present the leaves in a very flat plane for maximum light capture. Leaf size varies from 2 mm in many scale-leaved species, up to 400 mm long in the needles of some pines (e.g. Apache pine, Pinus engelmannii ). The stomata are in lines or patches on the leaves and can be closed when it is very dry or cold. The leaves are often dark green in colour, which may help absorb

7056-402: The majority of opinion preferring retention of all the families within a single order Pinales, despite their antiquity and diverse morphology . There were seven families of conifers c.  2011 , with 65–70 genera and over 600 living species ( c.  2002 ). The seven most distinct families are linked in the box above right and phylogenetic diagram left. In other interpretations,

7154-403: The male cones, microspores are produced from microsporocytes by meiosis . The microspores develop into pollen grains, which contain the male gametophytes. Large amounts of pollen are released and carried by the wind. Some pollen grains will land on a female cone for pollination. The generative cell in the pollen grain divides into two haploid sperm cells by mitosis leading to the development of

7252-603: The most ubiquitous of that period were the armored arthropods, like trilobites. Almost all marine phyla evolved in this period. During this time, the supercontinent Pannotia begins to break up, most of which later became the supercontinent Gondwana. The Ordovician spanned from 485–444 million years ago. The Ordovician was a time in Earth's history in which many of the biological classes still prevalent today evolved, such as primitive fish, cephalopods, and coral. The most common forms of life, however, were trilobites, snails and shellfish. The first arthropods went ashore to colonize

7350-466: The names of higher taxa in plants (above the rank of family) are either formed from the name of an included family (usually the most common and/or representative), in this case Pinaceae (the pine family), or are descriptive. A descriptive name in widespread use for the conifers (at whatever rank is chosen) is Coniferae (Art 16 Ex 2). According to the ICN, it is possible to use a name formed by replacing

7448-486: The one 11 m tall white spruce, Fraser et al. (1964) speculated that if the photosynthate used in making apical growth in 1961 was manufactured the previous year, then the 4 million needles that were produced up to 1960 manufactured food for about 600,000 mm of apical growth or 730 g dry weight, over 12 million mm of wood for the 1961 annual ring, plus 1 million new needles, in addition to new tissue in branches, bark, and roots in 1960. Added to this would be

7546-424: The one-year and the two-year cycles differ mainly in the duration of the pollination-fertilization interval. Three-year reproductive cycle : Three of the conifer species are pine species ( Pinus pinea , Pinus leiophylla , Pinus torreyana ) which have pollination and fertilization events separated by a two-year interval. Female strobili initiated during late summer or autumn of a year, then overwinter until

7644-520: The other hand, the assembly of Pangaea created huge arid inland areas subject to temperature extremes. The Lopingian Epoch is associated with falling sea levels, increased carbon dioxide and general climatic deterioration, culminating in the devastation of the Permian extinction. While macroscopic plant life appeared early in the Paleozoic Era and possibly late in the Neoproterozoic Era of the earlier eon, plants mostly remained aquatic until

7742-425: The overwintering storage capacity of stock thus treated was much improved (Eastman 1980). The concentrations of nutrients in plant tissues depend on many factors, including growing conditions. Interpretation of concentrations determined by analysis is easy only when a nutrient occurs in excessively low or occasionally excessively high concentration. Values are influenced by environmental factors and interactions among

7840-511: The paraphyletic assemblage of " walchian conifers ", which were small trees, and probably originated in dry upland habitats. The range of conifers expanded during the Early Permian ( Cisuralian ) to lowlands due to increasing aridity. Walchian conifers were gradually replaced by more advanced voltzialean or "transition" conifers. Conifers were largely unaffected by the Permian–Triassic extinction event , and were dominant land plants of

7938-429: The photosynthate to produce energy to sustain respiration over this period, an amount estimated to be about 10% of the total annual photosynthate production of a young healthy tree. On this basis, one needle produced food for about 0.19 mg dry weight of apical growth, 3 mm wood, one-quarter of a new needle, plus an unknown amount of branch wood, bark and roots. The order of priority of photosynthate distribution

8036-561: The plant for several (2–40) years before falling, but five genera ( Larix , Pseudolarix , Glyptostrobus , Metasequoia and Taxodium ) are deciduous , shedding their leaves in autumn. The seedlings of many conifers, including most of the Cupressaceae, and Pinus in Pinaceae, have a distinct juvenile foliage period where the leaves are different, often markedly so, from the typical adult leaves. Tree rings are records of

8134-416: The pollen tube. At fertilization, one of the sperm cells unites its haploid nucleus with the haploid nucleus of an egg cell. The female cone develops two ovules, each of which contains haploid megaspores. A megasporocyte is divided by meiosis in each ovule. Each winged pollen grain is a four celled male gametophyte . Three of the four cells break down leaving only a single surviving cell which will develop into

8232-514: The removal of individual plants beyond plantations is encouraged. At least 20 species of roundheaded borers of the family Cerambycidae feed on the wood of spruce , fir , and hemlock (Rose and Lindquist 1985). Borers rarely bore tunnels in living trees, although when populations are high, adult beetles feed on tender twig bark, and may damage young living trees. One of the most common and widely distributed borer species in North America

8330-453: The same effect in 105-day-old white spruce. The general short-term effect of nitrogen fertilization on coniferous seedlings is to stimulate shoot growth more so than root growth (Armson and Carman 1961). Over a longer period, root growth is also stimulated. Many nursery managers were long reluctant to apply nitrogenous fertilizers late in the growing season, for fear of increased danger of frost damage to succulent tissues. A presentation at

8428-927: The seeds as far as 12–22 km (7.5–13.7 mi) from the source. The birds store the seeds in the soil at depths of 2–3 cm ( 3 ⁄ 4 – 1 + 1 ⁄ 4  in) under conditions which favor germination . Conifers are the dominant plants over large areas of land, most notably the taiga of the Northern Hemisphere , but also in similar cool climates in mountains further south. A number of conifers originally introduced for forestry have become invasive species in parts of New Zealand , including radiata pine ( Pinus radiata ), lodgepole pine ( P. contorta ), Douglas fir ( Pseudotsuga mensiezii ) and European larch ( Larix decidua ). In parts of South Africa , maritime pine ( Pinus pinaster ), patula pine ( P. patula ) and radiata pine have been declared invasive species. These wilding conifers are

8526-545: The seeds may be stored in closed cones for up to 60–80 years, being released only when a fire kills the parent tree. In the families Podocarpaceae , Cephalotaxaceae , Taxaceae , and one Cupressaceae genus ( Juniperus ), the scales are soft, fleshy, sweet, and brightly colored, and are eaten by fruit-eating birds, which then pass the seeds in their droppings. These fleshy scales are (except in Juniperus ) known as arils . In some of these conifers (e.g. most Podocarpaceae),

8624-479: The short, but apparently severe, late Ordovician ice age. This cold spell caused the second-greatest mass extinction of the Phanerozoic Eon. Over time, the warmer weather moved into the Paleozoic Era. The Ordovician and Silurian were warm greenhouse periods, with the highest sea levels of the Paleozoic (200 m above today's); the warm climate was interrupted only by a 30 million year cool period,

8722-429: The sole source of nitrogen guanidine compounds were less prominent. Durzan and Steward noted that their results, drawn from determinations made in late summer, did not rule out the occurrence of different interim responses at other times of the year. Ammonium nitrogen produced significantly heavier (dry weight) seedlings with a higher nitrogen content after 5 weeks than did the same amount of nitrate nitrogen. Swan found

8820-517: The termination -aceae in the name of an included family, in this case preferably Pinaceae , by the appropriate termination, in the case of this division -ophyta . Alternatively, " descriptive botanical names " may also be used at any rank above family. Both are allowed. This means that if conifers are considered a division, they may be called Pinophyta or Coniferae. As a class, they may be called Pinopsida or Coniferae. As an order they may be called Pinales or Coniferae or Coniferales . Conifers are

8918-554: The top of the food chain. Earth's second Phanerozoic mass extinction event (a group of several smaller extinction events), the Late Devonian extinction , ended 70% of existing species. The Carboniferous is named after the large coal deposits laid down during the period. It spanned from 359–299 million years ago. During this time, average global temperatures were exceedingly high; the early Carboniferous averaged at about 20 degrees Celsius (but cooled to 10 °C during

9016-570: The total number of species is relatively small, conifers are ecologically important. They are the dominant plants over large areas of land, most notably the taiga of the Northern Hemisphere , but also in similar cool climates in mountains further south. Boreal conifers have many wintertime adaptations. The narrow conical shape of northern conifers, and their downward-drooping limbs, help them shed snow. Many of them seasonally alter their biochemistry to make them more resistant to freezing. While tropical rainforests have more biodiversity and turnover,

9114-475: The tree against insect infestation and fungal infection of wounds. Fossilized resin hardens into amber , which has been commercially exploited historically (for example, in New Zealand's 19th-century kauri gum industry). The size of mature conifers varies from less than one metre to over 100 metres in height. The world's tallest, thickest, largest, and oldest living trees are all conifers. The tallest

9212-416: The usual 2-year life cycle. Conifers – notably Abies (fir), Cedrus , Chamaecyparis lawsoniana (Lawson's cypress), Cupressus (cypress), juniper , Picea (spruce), Pinus (pine), Taxus (yew), Thuja (cedar) – have been the subject of selection for ornamental purposes. Plants with unusual growth habits, sizes, and colours are propagated and planted in parks and gardens throughout

9310-468: The world. Conifers can absorb nitrogen in either the ammonium (NH 4 ) or nitrate (NO 3 ) form, but the forms are not physiologically equivalent. Form of nitrogen affected both the total amount and relative composition of the soluble nitrogen in white spruce tissues (Durzan and Steward). Ammonium nitrogen was shown to foster arginine and amides and lead to a large increase of free guanidine compounds, whereas in leaves nourished by nitrate as

9408-403: The years 1955 through 1961, respectively. The total number of needles of all ages present on the 36-year-old tree in 1961 was 5.25 million weighing 14.25 kg. In 1961, needles as old as 13 years remained on the tree. The ash weight of needles increased progressively with age from about 4% in first-year needles in 1961 to about 8% in needles 10 years old. In discussing the data obtained from

9506-538: Was a shallow sea, and the Ōu Mountains were not yet born. The uplift of the Ōu mountain range began in late Miocene and the Kitakami Basin was born. The Kitakami Mountains were exposed to erosion for a long time because they were above water from the Cenozoic onwards. In addition, as a result the glacier effects of the last glacial period , the current gentle topography was created. Mount Hayachine , near

9604-539: Was most likely in the polar regions during the early Paleozoic. The breakup of Pannotia was followed by the assembly of the huge continent Gondwana ( 510  million years ago ). By the mid-Paleozoic, the collision of North America and Europe produced the Acadian-Caledonian uplifts, and a subducting plate uplifted eastern Australia . By the late Paleozoic, continental collisions formed the supercontinent of Pangaea and created great mountain chains, including

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