History of phycology

Vienna Dioscurides illustration, 6th century

Phycology is the study of marine algae (e.g. seaweeds) and history is the study of the past human activities. Man's interest in plants as food goes back into the origins of the species (Homo sapiens) and knowledge of algae can be traced back more than two thousand years. However only in the last three hundred years has that knowledge developed into a rapidly developing science.

Early days

Dioscorides’ De Materia Medica, c. 1334 copy in Arabic, describes medicinal features of cumin and dill.

The study of botany goes back into pre-history as plants were the food of people from the beginning of time. The first attempts at plant cultivation are believed to have been made shortly before 10,000 BC in Western Asia (Morton, 1981) and the first references to algae are to be found in early Chinese literature. Records as far back as 3,000 BC indicate that algae were used by the emperor of China as food. (Huisman, 2000 p.13). The use of Porphyra in China dates back to at least A.D. 533 — 44 (Mumfard and Miura, 1988), there are also references in Roman and Greek literature. The Greek word for algae was "Phycos" whilst in Roman times the name became Fucus. There are early references to the use of algae for manure. The first coralline algae to be recognized as living organisms were probably Corallina, by Pliny the Elder in the first century AD (Irvine and Chamberlain, 1994 p.11).

The classification of plants suffered many changes since Theophrastus (372 - 287 B.C.) and Aristotle (384 - 322 B.C.) grouped them as "trees", "shrubs" and "herbs" (Smith, 1955 p.1).

Little is known of botany during the Middle Ages - it was the dark ages of botany.

The development of the study of phycology runs in a pattern comparable with, and parallel to, other biological fields but at a different rate. After the invention of the printing-press in the 15th century (with the publication of the first printed book: Gutenberg's Bible of 1488) education enabled people to read and knowledge to spread. Interest in algae then increased speedily.

The exploration of the world and the advance of knowledge

Written accounts of the algae of South Africa were made by the Portuguese explorers of the 15th and 16th centuries, however it is not clear to which species reference was being made (Huisman, 2000 p.7).

17th Century

In the 17th Century there was a great awakening of scientific interest all over Europe, and after the invention of the printing-press books on botany were published. Among them was the work of John Ray[1] who wrote in 1660: Catalogus Plantarum circa Cantabrigiam., this initiated a new era in the study of Botany (Smith, 1975 p.4). Ray "influenced both the theory and the practice of botany more decisively than any other single person in the latter half of the seventeenth century" (Morton, 1981).

However no real progress was made in the scientific study of algae until the invention of the microscope - in about 1600. It was Anton van Leeuwenhoek (1632 — 1723) who discovered bacteria and saw the cell structure of plants. His unsystematic glimpses of plant structure, reported to the Royal Society between 1678 and his death in 1723, produced no significant advances (Morton, 1981 p.180).

As adventurers explored the world more species of all animals and plants were discovered, this demanded efforts to bring order out of this quickly accumulating knowledge.

Australia The first Australian marine plant recorded in print was collected from Shark Bay on the Western Australian coast by William Dampier who described many new species of Australian wildlife in the 17th century (Huisman, 2000 p.7).

18th Century

Before Carl von Linné (1707 — 1778) animals and plants, had names, but it took him to arrange the names and group the plants of this Earth in some sort of order. Carolus Linnaeus (Carl von Linné) [2] was a Swedish botanist, the son of a pastor of the Lurtheran church, a physician and zoologist. He laid the foundations of modern biological systematics and nomenclature in his Species Plantarum (1753). He adopted and popularized a binomial (or binary) system of designation (Morton, 1981) using one name as the genus and a second name as the species name both in Latin or Latinised. This specific name he referred to as a trivial name nomen triviale consisting of a single word, normally a Latin adjective, but any single word would suffice, to identify a particular species, but not intended to describe it. He developed a coherent system for naming organisms and divided the plant kingdom into 25 classes (according to Smith p.1 and p.24 according to Dixon, 1973) (Smith, 1955 p.1). one of which, the Cryptogamia, included all plants with concealed reproductive organs. He divided the Cryptogamia into four orders: Filices, Musci (mosses), Algae - which included lichens and liverworts and fungi. (Smith, 1955 p.1) [3]

Examination for the reproductive structures had already started. In 1711, R.A.F de Réaumur gave an account of Fucus in which noted the two types of external openings in the thallus: the non-sexual cryptostromata (sterile surface cavities) and the conceptacles (fertile cavities, immersed but with a surface opening) containing the sexual organs, which he thought were female flowers. With a lens he was able to see the oogonoa (the female sex organs) and the antheridia (the male sex organs) within the conceptacles, but he interpreted these as seeds (Morton, 1981 p.245). Johann Hedwig (1730 — 1799) provided further evidence of the sexual process in algae, and figured conjugation in Spirogyra Hedwig in 1797. He also illustrated Chara (Charales) and identified the antheridia and oogonia as male and female sexual organs (Morton, 1981 p.323 & 357).

During the 18th Century there was a stormy controversy as to whether coralline algae were plants or animals. Up to the mid — 1700s coralline algae (and coral animals) were generally treated as plants. By 1768 many, but by no means all authorities, considered them animal. Five years later, Harvey concluded that they were certainly of vegetable material he noted: "The question of the vegetable nature of Corallines, among which the Melobesia take rank, may now be considered as finally set at rest, by the researches of Kützing, Phillipi and Decaisne." (Harvey,1847, pl. 73).

The first scientific species description of a South African seaweed accepted for most nomenclatural purposes is that of Ecklonia maxima, published in 1757 as Fucus maximus (Stegenga et al, 1997).

Knowledge of North American Pacific algae begins with the 1791 — 95 expedition of Captain George Vancouver (Papenfuss,1976 p.21).

Archibald Menzies (1754 — 1842) was the appointed botanist on the expedition led by Captain George Vancouver in the ships Discovery and Chatham of 1791 — 1795 to the Pacific coast of North America and south-western Australia. The algae collected by Menzies were passed to Dawson Turner (1775 — 1858) who described and illustrated them in a four-volumed work published in 1808 — 1819. However Turner only referred to the taxa referable to Fucus; either Menzies collected very few or he gave only a few to Turner. Three of these species described by Turner later became the types of new genera (Papenfuss, 1976) and (Huisman, 2000) Turner also received plants from Robert Brown (1773 — 1858) the botanist who accompanied Captain Matthew Flinders on the Investigator (1801 - 1805). This collection also included many plants from Australia (Huisman, 2000).

The real awakening of interest in American algae resulted from a visit by William Henry Harvey in 1849 — 1850 when he visited areas from Florida to Nova Scotia and produced three volumes of Nereis Boreali-Americana. These gave an incentive to others to study algae (Taylor, 1972 p.21).

The first collector of marine algae in Greenland waters seems to have been J.M.Vahl who lived in Greenland from 1828 to 1836. Vahl's East Greenland species were not recorded until 1893 when Rosenvinge included them in his work of 1893 together with the species collected by Sylow (Lund, 1959). F.R.Kjellman records only 12 species from East Greenland 4 of which are doubtful, these records are based on Zeller's list (Lund, 1959).

Early 19th Century

Carl Adolph Agardh was one of the most prominent algologists of all time, he was born in Sweden on 23 January 1785 and died on 28th January 1859. He was Professor of Botany at the University of Lund and later Bishop of Karlstad Diocese (Papenfuss, 1976). Many species still show his name as the authority of the scientific name. He traveled widely in Europe visiting Germany, Poland, Denmark, the Netherlands, Belgium, France and Italy and was the first to emphasize the importance of the reproductive characters of algae and use them to distinguish the different genera and families. His son, Jacob Georg Agardh (1813 — 1901), who became Professor of Botany at Lund in 1839, made a study of the life-histories of algae, described many new genera and species. It was to him that many workers sent specimens for determination and as donations. Because of this the herbarium at Lund is the most important algal herbaria in the world (Papenfuss, 1976).

The first records of algae from the Faeröes were made by Jorgen Landt in his book of 1800 where he mentions about 30 species. Following this Hans Christian Lyngbye visited the Faeröes in 1817 and published his work in 1819. In this he described several new genera and species, some 100 new species were listed. E.Rostrup who visited the Faeöes in 1867 listed ten new species and a total not far from 100. In 1895 Herman G. Simmons mentioned 125 species, in that year F. Börgesen (1866 - 1956) started work and in 1902 published his work (Börgesen, 1902 p.399 — 343).

Jean Vincent Félix Lamouroux (1779 — 1825) was the first, in 1813, to separate the algae into groups on the basis of colour (Dixon and Irvine, 1977 p.59). At this time all coralline algae were considered animals, it was R. Philippi who in 1837 published his paper in which he finally recognized that coralline algae were not animals and he proposed the generic names Lithophyllum and Lithothamnion (Irvine and Chamberlain, 1994 p.11).

Freshwater algae are commonly treated separately from marine algae and may be considered not correctly placed in phycology. Lewis Weston Dillwyn (1778 — 1855) "British Confervae" (1809) was one of the earliest attempts to bring together all that was then known on the British Freshwater algae .

Specimens of Anne E. Ball (1808 - 1872) have been found in both the Herbarium of the Irish National Botanic Gardens, Dublin [4] and the Ulster Museum (BEL). A.E.Ball was an Irish algologist who corresponded with W.H. Harvey and whose records appear in his Phycologia Britannica. The specimens in Dublin do not contain any unusual or rare items. However, they are well documented.

W.H. Harvey

Willian Henry Harvey (1811 — 1866) was Keeper of the Herbarium and Professor in Botany at Trinity College, Dublin, and was one of the most distinguished algologists of his time (Papenfuss, 1976 p.26). Apart from Ireland he visited South Africa, the Atlantic seaboard of America as far south as the Florida Keys on the east coast of North America and Australia (1854 — 1856). Between 1853 to 1856 he visited Ceylon, Australia and New Zealand and various parts of the South Pacific (Huisman, 2000 & Papenfuss, 1976). His collection in Australia resulted in one of the most extensive collections of marine plants and it inspired others (Huisman, 2000). He published: Nereis Australis Or Algae of the Southern Ocean in 1847 - 1849 and in 1846 — 51 his Phycologia Britannica appeared. His Nereis Boreali-Americana was published in three parts (1852 — 1858) this was the first, and still is (1976)is the only marine algal flora of North America as it includes taxa from the Pacific coast (Papenfuss, 1976 p.27). His five-volume Phycologia Australica was published in 1858 to 1863. These volumes remain to this day a most important reference to Australian algae (Huisman, 2000). His primary herbarium is in Trinity College, Dublin (TCD). However large collections of Harvey material are to be found in the Ulster Museum (BEL) (Morton, 1977 & Morton, 1981); University of St Andrews (STA) and National Herbarium of Victoria (MEL), Melbourne, Australia (May, 1977). Many of the collectors of this period sent, and exchanged, specimens freely one to another, as a result Harvey's books show a remarkable knowledge of the distribution of algae elsewhere in the world. His Phycologia Britannica lists species recorded and collected from various parts of the British Isles. For example he notes William Thompson (1805 — 1852), W. McCalla (c.1814 — 1849), John Templeton (1766 — 1825) and D. Landsborough (1779 — 1854) who collected, as he did, from distinct sites in Ireland. The collections of these botanists, and many others, are represented separately by collections in the Ulster Museum (BEL).

Sir William Jackson Hooker (1785 — 1865) was a life-long friend of Harvey (Papenfuss, 1976 p.26), he was appointed Professor of Botany at Glasgow University in 1820 and became Director in Kew 1841 — 1865. Hooker recognized the talent in Harvey and lent him books, encouraged and invited him to write the section on algae in his British Flora. as well as the section on algae for The Botany of Captain Beechey's Voyage (Papenfuss, 1976). Margaret Gatty (1809 — 1873) (née Margaret Scott) (author of British Seaweeds, 1863), and others, corresponded with William Henry Harvey (Desmond, 1977 and Evans, 2003).

Late 19th century

Much work was done in this period by many workers and the many specimens became very valuable. Harvey's specimens, are to be found in at least several herbaria as well as those of other phycologists whose names are to be found in historic publications. In the same period Friedrich Traugott Kützing (1807-1893) in Germany described more new genera than anyone either before or after (Chapman, 1968 p.13). His publications span the period 1841 to 1869 and added materially to knowledge of algae of cold waters of the Arctic seas. Some of his specimend are stored in the Ulster Museum Herbarium (BEL) catalogued: F1171; F10281 — F10318. In 1883 Frans Reinhold Kjellman, Professor of Botany at Uppsala University, published The Algae of the Arctic Sea. He divided the "Arctic Sea" into different regions which surround the North Pole (Kjellman, 1883). Further research work on the marine algae of the world included: Charles Lewis Anderson (1827 — 1910) who collaborated with William Gilson Farlow and with Professor Daniel Cady Eaton to produce on the first exsiccatae of North American Algae (Papenfuss, 1976). Edward Morell Holmes (1843 - 1930), was an expert on seaweeds, mosses, liverworts and lichens, specimens were sent to him from all over the British Isles, as well as from Norway, Sweden, Florida, Tasmania, France, Cape of Good Hope, Cylon and Australia. He also exchanged specimens (Furley, 1989). and some are in the herbarium of the Ulster Museum (BEL). George Clifton (1823- 1913) an Australian phycologist is mentioned in Harvey's Memoirs, as the Superintendent of the Water Police in Perth, West Australia sent algal specimens to Harvey (Blackler, H.1977). In these years there were many workers in this field: W.G. Farlow, mentioned above, who was appointed in 1879 Professor of Cryptogamic Botany at University of Harvard (U.S.A.) in 1879 and published, among other works, the Marine algae of New England and Adjacent Coasts.; in 1876 John Erhard Areschoug, a Swedish Professor of Botany at Upsalla University, reported on some brown algae collected in California by Gustavus A. Eisen (Papenfuss. 1976). George W.Traill (1836 — 1897) was a clerk in the Standard Life Company in Edinburgh where he worked long hours, yet he was one of the greatest authorities on Scottish algae. Despite bad health he was an indefatigable collector. In 1892 he gave his collection to the Herbarium of the Edinburgh Botanic Gardens (Furley, 1989).

Mikael Heggelund Foslie (M.Foslie) (1855 — 1905) published 69 papers between 1887 — 1909. During this time he increased the number of species and forms (of corallines) from 175 to 650 (Irvine and Chamberlain, 1994). After his death his collection of specimens was purchased by the Museum of the Royal Norwegian Society for Sciences and Letters (Thor et al, 2005) and there is a small collection of his in the Ulster Museum Herbarium: (Collection No. 42) entitled: Algae Norvegicae (Ulster Museum Herbarium catalogue (BEL): F10319 — F10334). F.Heydrich also described 84 taxa and was a bitter foe of Foslie. This left a legacy of complicated and still unresolved problems.

It was in the 19th Century that the true nature of lichens [5], as organisms consisting of an alga and a fungus in specific association, was demonstrated by Schwendener in 1867. This removed a source of confusion in morphology and classification (Morton, 1981 p.432). It was in this period (1859) that Charles Darwin (1809 — 1882) published his book on evolution:On the Origin of Species by Means of Natural Selection,....

20th century

In 1895 Börgesen started his study of the Faeröes and published his work in 1902 (Börgesen, 1902). Later between 1920 and 1936 he published his research on the algae of the Canary Islands.

In 1935 and 1945 Felix Eugen Fritsch (1879 — 1954) published in two volumes his treatise: The Structure and Reproduction of the Algae. These two volumes detail virtually all that was then known about the morphology and reproduction of the algae. However knowledge of algae has so greatly increased since then it would be impossible for these to be to bring to be brought up-to-date, nevertheless reference is often made to them. Other valuable works published in the 1950s include Cryptogamic Botany. written by Gilbert Morgan Smith (1885 — 1959), the algal volume (no.1) was published in 1955. In the following year (1956), Die Gattungen der Rhodophyceen. by Herald Johann Kylin (1879 — 1949) was published posthumously. Other phycologists who contributed massively to the knowledge of algae include: Elmer Yale Dawson (1918 — 1966) who published over 60 papers on the algae of the North American Pacific seas (Papenfuss, 1976).

The development of public awareness

The number of books published in the mid to late 1800s shows how interest in the natural world developed. Books on algae were written by: Isabella Gifford (1853) The Marine Botanist..., some of her specimens are in the Ulster Museum; D. Landsborough (c.1779 — 1854) A Popular History of British Seaweeds,... third edition published in 1857; Louisa Lane Clarke (c.1812 - 1883) The Common Seaweeds of the British Coast and Channel Islands;... in 1865; S.O.Gray (1828 — 1902) British Sea-weeds:... published 1867 and W.H.Grattann British Marine Algae:...published about 1874. These books were for the common people.

In 1902 Edward Arthur Lionel Batters (1860 — 1907) published "A catalogue of the British Marine algae." (Batters, 1902). In this he detailed records of algae found on the shores of the British Isles with the localities. This was the start of a new approach, the bringing together of records, detailed keys, checklists and mapping schemes.

The process accelerated in the 20th century. Lilly Newton (née Batten) (1893 — 1981) Professor in Botany at the University College of Wales, Aberystwyth and Professor Emeritus in 1931 wrote: A Handbook of the British Seaweeds. This was the first, and for quite a time, the only book for identification of seaweeds in the British Isles using a botanical key. In 1962 Eifion Jones published: A key to the genera of the British seaweeds. This small booklet provided a valuable source bridging the period before the valuable series Seaweeds of the British Isles was produced by the British Museum (Natural History) or The Natural History Museum.

Research advanced so quickly that the need for an up-to-date checklist became apparent. Mary Parke (1902 — 1981), who was a founder member of the British Phycological Society, produced a preliminary checklist of British marine algae in 1953, corrections and additions of this were published in 1956, 1957 and 1959. In 1964 M.Parke and Peter Stanley Dixon (1929 — 1993) published a revised check-list, a second revision of this was produced in 1968 and a third revision in 1976. Distribution was added to the checklist in 1986 with G.R.South and I.Tittley's A Checklist and Distributional Index of the Benthic Marine Algae of the North Atlantic Ocean. In 2003 A Check-list and Atlas of the Seaweeds of Britain and Ireland was published by Gavin Hardy and Michael Guiry with a revised edition in 2006 . This shows how rapidly knowledge of algae, at least in the British Isles, advanced. First efforts had been made by interested biologists and people capable of identifying the algae, this required books using the botanical names. Botanical keys to identify the plants then developed, followed by checklists. As more information was brought to light by interested workers, some volunteers, the checklists were improved and eventually a mapping scheme brought together all this information. The same pattern of knowledge developed with birds, mammals and flowering plants, though to a different time-scale and knowledge in other parts of the world has developed to this degree.

Numbers and checklists

As records were collected the need to draw all the information together advanced. Checklists and annotated checklists were produced and updated so the actual numbers of different species became more precise. At first this was quite local. Threlkeld, in 1726, produced the first attempt at an enumeration of Irish Algae and in 1802 William Tighe published his "Marine plants observed at the County of Wexford," it included 58 marine and 2 freshwater species. In 1804 Wade published Plantae Rariores in Hibernia Inventae, in which 51 species of marine and 4 species of freshwater algae were enumerated. In the north of Ireland John Templeton (Botanist) and William Thompson were at work publishing on the algae of Ireland. In 1836 Mackay published his Flora Hibernica including 296 species. Adams, in his synopsis of 1908, listed a total of marine species reaching 843.

In more localised lists Adams (in 1907) listed the species of County Antrim noted that of the 747 species included in "Batter's List" he recorded 211 species from the Co. Antrim coast. In 1907 a list of marine aslgae from Lambay Island (County Dublin) was published by Batters. In 1960 A preliminary list of the marine algae of Galloway coast was published.

At the international level there are well over 3,000 species of alga in Australia.

Identification

As the study and identification of the different species, became more extensive it became clear that identification was not at all easy. Harvey's 1846 - 51 Phycologia Britannica. along with his other publications makes no effort to provide "keys" to help in the identification. In 1931 Newton's Handbook which gave the first key to assist in the identification of algae of the British Isles, in the same year Knight and Park gave a key in their "Manx Algae." Eifion Jones in 1962, wrote a key to the genera of British seaweeds. Others soon followed: Dickinson wrote one entitled British Seaweeds. and Adey and Adey (1973) gave keys to the identification of the Corallinaceae of the British Isles. Abott and Hollenberg, in 1976, published keys to the identification of algae of California.

The evolution of classification in the algae

Linnaeus's "sexual system" (Linnaeus, 1754) in which he grouped plants according to the number of stamens and carepels in the flowers, although wholly artificial was advantageous in that a newly discovered plant could be fitted in amongst those already known. He divided the plant kingdom into 25 classes, one of which was the Cryptogamia - plants with "concealed reproductive organs" (see above) (Smith, 1955). Linnaeus accepted 14 genera of algae of which only four, Conferva, Ulva, Fucus and Chara, contained organisms now regarded as algae (Dixon, 1973 p.231). As a consequence of the great increase in the number of species the artificiality of the Linnaean system was appreciated so that during the 18th Century and early 19th Century considerable numbers of new genera were described. J.V.F.Lamouroux in 1813 was the first to separate the groups on the basis of colour, however this was not taken up by other botanists and it was Harvey, who in 1836, divided the algae into four major devisions solely on the basis of their pigmentation: Rhodospermae (red algae), Melanospermae (brown algae), Chlorospermae (green algae) and Diatomaceae (Dixon,1973 p.232).

In 1883 and 1897 Schmitz separated the Rhodophyceae into two main groups. The first contained the Bangiales and the second the Nemoniales, Cryptonemiales, Gigartinales and Rhodymeniales (Newton, 1931). The Rhodophyta are now arranged in the Orders: Porphyridiales, Goniotrichales, Erythropeltidales, Bangiales, Acrochaetiales, Colaconematales, Palmariales, Ahnfeltiales, Nemaliales, Gelidiales, Gracilariales, Bonnemaisoniales, Cryptonemiales, Hildenbrandiales, Corallinales, Gigartinales, Plocamiales, Rhodymeniales and Ceramiales. The Chlorophyta are arranged in the Orders: Chlorococcales, Microsporales, Chaetophorales, Phaeophilales, Ulvales, Prasiolales, Acrosiphoniales, Cladiphorales, Bryopsidales, Chlorocystidales, Klebsormidiales and Ulotrichales. The Heterokontophyta: Sphacelariales, Dictyotales, Ectocarpales, Ralfsiales, Utleriales, Sporochniales, Tilopteridales, Desmarestiales, Laminariales and the Fucales (Hardy and Guiry, 2006).

Recently (1990s) The Kingdom: Protoctista has been recommended however this has not been accepted by many authors.

Obituaries, memoria and appreciations of distinguished Phycologists:-

• Elsie M. Burrows (Dr.) (1913 — 1986) Norton, T.A. 1987. Obituary: Br.phycol.J. 22: 317 — 319.

• Blackler, Margaret Constance Helen (1902 — 1981) Irvine, D.E.G. and Russell, G. 1982. Obituary: Br. phycol. J. 17: 343 — 346.

• Elsie Conway (née) Phillips) (1902 — 1992) Visited University of British Columbia in 1969 — 1970 and researched there in 1972 — 1974. She was president of the British Phycological Society 1965 — 1967. Retired in 1969. Boney, A.D. 1993 An appreciation. The Phycologist 35: 3.

• de Váléra, Máirin (1912 — 1984). Guiry, M.D. and Dixon, P.S. 1985. Obituary: Br. Phycol. J. 20: 81 — 84.

• Dixon, Peter Stanley (1929 — 1993). Murray, S.N. and Scott, J.L. 1995. In Memoriam Peter Stanley Dixon (1929 - 1993) Phycologia 34: 538 — 543.

• Eifion Jones, Willian (1925 — 2004). Fogg, T. 2004. 2004 In memoriam.; The Phycologist. 67: 19.

• Irvine, David Edward Guthrie (1924 — 1995). Fletcher, R.L. 1996: Obituary : The Phycologist 4: 3 — 7.

• Manton, Irene. (1904 — 1988). Leedale, G. 1989. Obituary: Br phycol. J. 24 :103 — 109.

• Newton, Lilly (née Batten) (1893 — 1981). Jones, G. 1982. Obituary: Br. phycol. J. 17: 1 — 4.

• Papenfuss, George Frederik (1903 — 1981). Abbott, I.A. 1982. Obituary: Br. phycol. J. 17: 347 — 349.

• Parke, Mary (1908 — 1989). Green, J.C. 1990. Obituary: Br. phycol. J. 25: 211 — 216.

• Taylor, William Randolph. (1895 — 1990). Hillis, L. 1992. Obituary: Br. phycol. J. 27: 1 — 2.

Miscellaneous Notes

• Máirin de Valéra (1912 — 1984). Professor Emerita of Botany at University College, Galway.

Publications:-

De Valéra, M. 1958. A topographical guide to the seaweed of Co. Galway Bay with some brief notes on other districts on the west coast coast of Ireland. Institute for Industrial Standards and Rersearch Dublin, Dublin.

De Valéra, M. 1959. The Third International Seaweed Symposium at University College, Galway. 1958, Irish Naturalists' Journal 13: 18 - 19.

De Valéra, M. 1960. Interesting seaweeds from the shores of the Burren. Irish Naturalists' Journal. 13: 168.

De Valéra, M. * Cooke, P.J. 1979. Seaweed in Burren grykes. Irish Naturalists' Journal. 19: 435 - 436.

De Valéra, M., Pybus, C., Casley, B. & Webster, A. 1979. 1979. Littoral and benthic investigations on the west coast of Ireland.X. Marine algae of the northern shores of the Burren, C. Clare. Proceedings of the Royal Irish Academy. 79B: 259 - 269.

• Edward Batters (1860 — 1907). B.A.; FLS 1883

• Elmer Yale Dawson (1918 — 1966).

• Kathleen M. Drew Baker (...1925 — 1927...). University of Manchester. President of the British Phycological Society 1953.

• Margaret Constance Helen Blackler (1902 — 1981). Assistant Keeper of Botany, Liverpool Museum (1933 — 1945). In 1947 joined staff University St Andrews.

• Peter Stanley Dixon (1929 — 1993). Professor Emeritus of Biology at University of California.

• William Dwyn Isaac (1905 — 1995).

• Harald Kylin (...1906 — 1949...). Author: Die Gattengen der Rhodophyceen. 1956 CWK Gleerups Förlag,Lund. Specimens in Ulster Museum....

• George Russell (...1983 — 1984...). President of British Phycological Society 1983 - 1984.

Further Reading

Darwin, C. R. 1859. On the Origin of Species by means of Natural Selection,... London: John Murray, London.

Farlow, W.G. 1881. The marine algae of New England. Report of U.S. Fish Commission 1879 :Appendix A-1, 1 — 210.

Fritsch, F.E. 1935. The Structure and Reproduction of the Algae. Vol. 1. Cambridge University Press, Cambridge.

Fritsch, F.E. 1945. The Structure and Reproduction of the Algae. Vol. 2. Cambridge University Press, Cambridge.

Gatty, M. 1863. British Seaweeds. London.

Gifford, I. 1853. The Marine Botanist;... Longman and Co., London.

Grattan, W.H. (1874?) British Marine Algae: London.

Gray, S.O. 1867. British Sea-weeds:... London.

Hardy, F.G. and Guiry, M.D. 2003. A Checklist and Atlas of the Seaweeds of Britain and Ireland. British Phycological, London.

Hardy, F.G. and Guiry, M.D. 2006. A Checklist and Atlas of the Seaweeds of Britain and Ireland - Revised Edition. British Phycological, London. ISBN 3-906166-35-X

Harvey, W.H. 1833. Algae, in W.J.Hooker and G.A.W.Arnott, The Botany of Captain Beechey's Voyage... London. pp. 163 - 165.

Harvey, W.H. 1846 - 1851. Phycologia Britannica,... London.

Harvey, W.H. 1847 - 1849. Nereis Australis Or Algae Of the Southern Ocean. Reeve, London.

Harvey, W.H. 1852- 1858. Pt 1 - 111 ... Nereis boreali-americana... Smithsonian Contr. to Knoweledge.

Hooker, W.J. 1833. Cryptomaia Algae [pp.264 - 322] in. Hooker, W.J. The English Flora of Sir James Edward Smith. Class xxiv, Cryptogamia. Vol V, Part 1.

Landsborough, D. 1857. A Popular History of British Seaweeds,... London: Reeve, Benham & Reeve.

Parke, M. 1953. A preliminary check-list of British marine algae. J.Mar. Biol. Assoc. U.K. 32: 497 - 520.

Parke, M. and Dixon, P.S. 1964. A revised check-list of British marine algae. J. mar. biol. Ass. U.K. 44: 499 - 542.

Parke, M. and Dixon, P.S. 1968. Check-list of British marine algae - second revision. J. Mar. Biol. Ass. U.K. 48: 783- 832.

Parke, M. and Dixon, P.S. 1976. Check-list of British marine algae - third revision. J. Mar. Biol. Assoc. U.K. 56: 527 - 594.

Ross, H.C.G. and Nash, R. 1985. The development of natural history in early nineteenth century Ireland. From Linnaeus to Darwin: commentaries on the history of biology and geology. Society of Natural History, London. 1985.

South, G.R. and Tittley, I. 1986. A Checklist and Distributional Index of the Benthic Marine Algae of the North Atlantic Ocean. St Andrews and London.

Internal links

• http://en.wikipedia.org/wiki/List_of_botanists - List of Botanists

External links

• http://users.ugent.be/phycology/harvey/ W.H.H. Phycologia Australica

• http://www.botanicgardens.ie/ National Botanic Gardens of Ireland.

• http://www2.nrm.se/fbo/hist/linnaeus/linnaeus.html.en Carl Linnaeus Botanical History

• http://www.ucmp.berkeley.edu/history/linnaeus.html Carl Linnaeus

• http://www.algaebase.org/ listing the world's algae

• http://www.seaweed.ie/ Seaweed Site

• http://www.mba.ac.uk/ Marine Biological Assoc. of UK

• http://www.brphycsoc.org/ British Phycological Society

• http://www.intphycsoc.org/ International Phycological Society

• http://www.schweizerbart.de/j/algological-studies/ Algological Studies is an international journal of phycological

• http://www.psaalgae.org/ Phycological Society of America

• http://www.phycology.net/ The Phycology.Net

See also

• Algae
• Botany

The frontispiece to Erasmus Darwin's evolution-themed poem The Temple of Nature shows a goddess pulling back the veil from nature (in the person of Artemis). Allegory and metaphor have often played an important role in the history of biology.

The history of biology traces the study of the living world from ancient to modern times. Although the concept of biology as a single coherent field arose in the 19th century, the biological sciences emerged from traditions of medicine and natural history reaching back to Galen and Aristotle in ancient Greece. During the Renaissance and early modern period, biological thought was revolutionized by a renewed interest in empiricism and the discovery of many novel organisms. Prominent in this movement were Vesalius and Harvey, who used experimentation and careful observation in physiology, and naturalists such as Linnaeus and Buffon who began to classify the diversity of life and the fossil record, as well as the development and behavior of organisms. Microscopy revealed the previously unknown world of microorganisms, laying the groundwork for cell theory. The growing importance of natural theology, partly a response to the rise of mechanical philosophy, encouraged the growth of natural history (although it entrenched the argument from design).

Over the 18th and 19th centuries, biological sciences such as botany and zoology became increasingly professional scientific disciplines. Lavoisier and other physical scientists began to connect the animate and inanimate worlds through physics and chemistry. Explorer-naturalists such as Alexander von Humboldt investigated the interaction between organisms and their environment, and the ways this relationship depends on geography—laying the foundations for biogeography, ecology and ethology. Naturalists began to reject essentialism and consider the importance of extinction and the mutability of species. Cell theory provided a new perspective on the fundamental basis of life. These developments, as well as the results from embryology and paleontology, were synthesized in Template:Apss theory of evolution by natural selection. The end of the 19th century saw the fall of spontaneous generation and the rise of the germ theory of disease, though the mechanism of inheritance remained a mystery.

In the early 20th century, the rediscovery of Mendel's work led to the rapid development of genetics by Thomas Hunt Morgan and his students, and by the 1930s the combination of population genetics and natural selection in the "neo-Darwinian synthesis". New disciplines developed rapidly, especially after Watson and Crick proposed the structure of DNA. Following the establishment of the Central Dogma and the cracking of the genetic code, biology was largely split between organismal biology—the fields that deal with whole organisms and groups of organisms—and the fields related to cellular and molecular biology. By the late 20th century, new fields like genomics and proteomics were reversing this trend, with organismal biologists using molecular techniques, and molecular and cell biologists investigating the interplay between genes and the environment, as well as the genetics of natural populations of organisms.

Etymology of "biology"

The word biology is formed by combining the Greek βίος (bios), meaning "life", and the suffix '-logy', meaning "science of", "knowledge of", "study of", based on the Greek verb λεγειν, 'legein' = "to select", "to gather" (cf. the noun λόγος, 'logos' = "word"). The term biology in its modern sense appears to have been introduced independently by Karl Friedrich Burdach (in 1800), Gottfried Reinhold Treviranus (Biologie oder Philosophie der lebenden Natur, 1802) and Jean-Baptiste Lamarck (Hydrogéologie, 1802). The word itself appears in the title of Volume 3 of Template:Apss Philosophiae naturalis sive physicae dogmaticae: Geologia, biologia, phytologia generalis et dendrologia, published in 1766.

Before biology, there were several terms used for the study of animals and plants. Natural history referred to the descriptive aspects of biology, though it also included mineralogy and other non-biological fields; from the Middle Ages through the Renaissance, the unifying framework of natural history was the scala naturae or Great Chain of Being. Natural philosophy and natural theology encompassed the conceptual and metaphysical basis of plant and animal life, dealing with problems of why organisms exist and behave the way they do, though these subjects also included what is now geology, physics, chemistry, and astronomy. Physiology and (botanical) pharmacology were the province of medicine. Botany, zoology, and (in the case of fossils) geology replaced natural history and natural philosophy in the 18th and 19th centuries before biology was widely adopted.

Ancient and medieval knowledge

Biological knowledge in early cultures

Template:See also The earliest humans must have had and passed on knowledge about plants and animals to increase their chances of survival. This may have included knowledge of human and animal anatomy and aspects of animal behavior (such as migration patterns). However, the first major turning point in biological knowledge came with the Neolithic Revolution about 10,000 years ago. Humans first domesticated plants for farming, then livestock animals to accompany the resulting sedentary societies.

The ancient cultures of Mesopotamia, Egypt, the Indian subcontinent, and China (among others) had sophisticated systems of philosophical, religious, and technical knowledge that encompassed the living world, and creation myths often centered on some aspect of life. However, the roots of modern biology are usually traced back to the secular tradition of ancient Greek philosophy.

Frontispiece to a 1644 version of the expanded and illustrated edition of Historia Plantarum (ca. 1200), which was originally written around 200 BC

Ancient Greek biological traditions

Template:See also The Pre-Socratic philosophers asked many questions about life but produced little systematic knowledge of specifically biological interest—though the attempts of the atomists to explain life in purely physical terms would recur periodically through the history of biology. However, the medical theories of Hippocrates and his followers, especially humorism, had a lasting impact.

The philosopher Aristotle was the most influential scholar of the living world from antiquity. Though his early work in natural philosophy was speculative, Aristotle's later biological writings were more empirical, focusing on biological causation and the diversity of life. He made countless observations of nature, especially the habits and attributes of plants and animals in the world around him, which he devoted considerable attention to categorizing. In all, Aristotle classified 540 animal species, and dissected at least 50. He believed that intellectual purposes, formal causes, guided all natural processes.

Aristotle, and nearly all scholars after him until the 18th century, believed that creatures were arranged in a graded scale of perfection rising from plants on up to humans: the scala naturae or Great Chain of Being. Aristotle's successor at the Lyceum, Theophrastus, wrote a series of books on botany—the History of Plants—which survived as the most important contribution of antiquity to botany, even into the Middle Ages. Many of Theophrastus' names survive into modern times, such as carpos for fruit, and pericarpion for seed vessel. Pliny the Elder was also known for his knowledge of plants and nature, and was the most prolific compiler of zoological descriptions.

A few scholars in the Hellenistic period under the Ptolemies—particularly Herophilus of Chalcedon and Erasistratus of Chios—amended Aristotle's physiological work, even performing experimental dissections and vivisections. Claudius Galen became the most important authority on medicine and anatomy. Though a few ancient atomists such as Lucretius challenged the teleological Aristotelian viewpoint that all aspects of life are the result of design or purpose, teleology (and after the rise of Christianity, natural theology) would remain central to biological thought essentially until the 18th and 19th centuries. In the words of Ernst Mayr, "Nothing of any real consequence happened in biology after Lucretius and Galen until the Renaissance." The ideas of the Greek traditions of natural history and medicine survived, but they were generally taken unquestioningly.

Medieval knowledge

De arte venandi, by Frederick II, Holy Roman Emperor, was an influential medieval natural history text that explored bird morphology.

The decline of the Roman Empire led to the disappearance or destruction of much knowledge, though physicians still incorporated many aspects of the Greek tradition into training and practice. In Byzantium and the Islamic world, many of the Greek works were translated into Arabic and many of the works of Aristotle were preserved. During the High Middle Ages, a few European scholars such as Hildegard of Bingen, Albertus Magnus, and Frederick II expanded the natural history canon. The rise of European universities, though important for the development of physics and philosophy, had little impact on biological scholarship.

Renaissance and early modern developments

Template:See also The European Renaissance brought expanded interest in both empirical natural history and physiology. In 1543, Andreas Vesalius inaugurated the modern era of Western medicine with his seminal human anatomy treatise De humani corporis fabrica, which was based on dissection of corpses. Vesalius was the first in a series of anatomists who gradually replaced scholasticism with empiricism in physiology and medicine, relying on first-hand experience rather than authority and abstract reasoning. Via herbalism, medicine was also indirectly the source of renewed empiricism in the study of plants. Otto Brunfels, Hieronymus Bock and Leonhart Fuchs wrote extensively on wild plants, the beginning of a nature-based approach to the full range of plant life. Bestiaries—a genre that combines both the natural and figurative knowledge of animals—also became more sophisticated, especially with the work of William Turner, Pierre Belon, Guillaume Rondelet, Conrad Gessner, and Ulisse Aldrovandi.

Artists such as Albrecht Dürer and Leonardo da Vinci, often working with naturalists, were also interested in the bodies of animals and humans, studying physiology in detail and contributing to the growth of anatomical knowledge. The traditions of alchemy and natural magic, especially in the work of Paracelsus, also laid claim to knowledge of the living world. Alchemists subjected organic matter to chemical analysis and experimented liberally with both biological and mineral pharmacology. This was part of a larger transition in world views (the rise of the mechanical philosophy) that continued into the 17th century, as the traditional metaphor of nature as organism was replaced by the nature as machine metaphor.

Seventeenth and eighteenth centuries

Cabinets of curiosities, such as that of Ole Worm, were centers of biological knowledge in the early modern period, bringing organisms from across the world together in one place. Before the Age of Exploration, naturalists had little idea of the sheer scale of biological diversity.

Extending the work of Vesalius into experiments on still living bodies (of both humans and animals), William Harvey and other natural philosophers investigated the roles of blood, veins and arteries. Harvey's De motu cordis in 1628 was the beginning of the end for Galenic theory, and alongside Santorio Santorio's studies of metabolism, it served as an influential model of quantitative approaches to physiology.

In the early 17th century, the micro-world of biology was just beginning to open up. A few lensmakers and natural philosophers had been creating crude microscopes since the late 16th century, and Robert Hooke published the seminal Micrographia based on observations with his own compound microscope in 1665. But it was not until Antony van Leeuwenhoek's dramatic improvements in lensmaking beginning in the 1670s—ultimately producing up to 200-fold magnification with a single lens—that scholars discovered spermatozoa, bacteria, infusoria and the sheer strangeness and diversity of microscopic life. Similar investigations by Jan Swammerdam led to new interest in entomology and built the basic techniques of microscopic dissection and staining.

File:Hooke's cork.png

In Micrographia, Robert Hooke had applied the word cell to biological structures such as this piece of cork, but it was not until the 19th century that scientists considered cells the universal basis of life.

As the microscopic world was expanding, the macroscopic world was shrinking. Botanists such as John Ray worked to incorporate the flood of newly discovered organisms shipped from across the globe into a coherent taxonomy, and a coherent theology (natural theology). Debate over another flood, the Noachian, catalyzed the development of paleontology; in 1669 Nicholas Steno published an essay on how the remains of living organisms could be trapped in layers of sediment and mineralized to produce fossils. Although Steno's ideas about fossilization were well known and much debated among natural philosophers, an organic origin for all fossils would not be accepted by all naturalists until the end of the 18th century due to philosophical and theological debate about issues such as the age of the earth and extinction.

Systematizing, naming and classifying dominated natural history throughout much of the 17th and 18th centuries. Carolus Linnaeus published a basic taxonomy for the natural world in 1735 (variations of which have been in use ever since), and in the 1750s introduced scientific names for all his species. While Linnaeus conceived of species as unchanging parts of a designed hierarchy, the other great naturalist of the 18th century, Georges-Louis Leclerc, Comte de Buffon, treated species as artificial categories and living forms as malleable—even suggesting the possibility of common descent. Though he was opposed to evolution, Buffon is a key figure in the history of evolutionary thought; his work would influence the evolutionary theories of both Lamarck and Darwin.

The discovery and description of new species and the collection of specimens became a passion of scientific gentlemen and a lucrative enterprise for entrepreneurs; many naturalists traveled the globe in search of scientific knowledge and adventure.

Nineteenth century: the emergence of biological disciplines

Up through the nineteenth century, the scope of biology was largely divided between medicine, which investigated questions of form and function (i.e., physiology), and natural history, which was concerned with the diversity of life and interactions among different forms of life and between life and non-life. By 1900, much of these domains overlapped, while natural history and (and its counterpart natural philosophy) had largely given way to more specialized scientific disciplines—cytology, bacteriology, morphology, embryology, geography, and geology.

In the course of his travels, Alexander von Humboldt mapped the distribution of plants across landscapes and recorded a variety of physical conditions such as pressure and temperature.

Natural history and natural philosophy

Template:See also Widespread travel by naturalists in the early- to mid-nineteenth century resulted in a wealth of new information about the diversity and distribution of living organisms. Of particular importance was the work of Alexander von Humboldt, which analyzed the relationship between organisms and their environment (i.e., the domain of natural history) using the quantitative approaches of natural philosophy (i.e., physics and chemistry). Humboldt's work laid the foundations of biogeography and inspired several generations of scientists.

Geology and paleontology

Template:See also The emerging discipline of geology also brought natural history and natural philosophy closer together; the establishment of the stratigraphic column linked the spacial distribution of organisms to their temporal distribution, a key precursor to concepts of evolution. Georges Cuvier and others made great strides in comparative anatomy and paleontology in the late 1790s and early 1800s. In a series of lectures and papers that made detailed comparisons between living mammals and fossil remains Cuvier was able to establish that the fossils were remains of species that had become extinct—rather than being remains of species still alive elsewhere in the world, as had been widely believed. Fossils discovered and described by Gideon Mantell, William Buckland, Mary Anning, and Richard Owen among others helped establish that there had been an 'age of reptiles' that had preceded even the prehistoric mammals. These discoveries captured the public imagination and focused attention on the history of life on earth. Most of these geologists held to catastrophism, but Charles Lyell's influential Principles of Geology (1830) popularised Hutton's uniformitarianism, a theory that explained the geological past and present on equal terms.

Evolution and biogeography

Charles Darwin's first sketch of an evolutionary tree from his First Notebook on Transmutation of Species (1837)

Template:See also The most significant evolutionary theory before Darwin's was that of Jean-Baptiste Lamarck; based on the inheritance of acquired characteristics (an inheritance mechanism that was widely accepted until the 20th century), it described a chain of development stretching from the lowliest microbe to humans. The British naturalist Charles Darwin, combining the biogeographical approach of Humboldt, the uniformitarian geology of Lyell, Thomas Malthus's writings on population growth, and his own morphological expertise, created a more successful evolutionary theory based on natural selection; similar evidence lead Alfred Russel Wallace to independently reach the same conclusions.

The 1859 publication of Darwin's theory in On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life is often considered the central event in the history of modern biology. Darwin's established credibility as a naturalist, the sober tone of the work, and most of all the sheer strength and volume of evidence presented, allowed Origin to succeed where previous evolutionary works such as the anonymous Vestiges of Creation had failed. Most scientists were convinced of evolution and common descent by the end of the 19th century. However, natural selection would not be accepted as the primary mechanism of evolution until well into the 20th century, as most contemporary theories of heredity seemed incompatible with the inheritance of random variation.

Wallace, building on earlier work by Humbolt and Darwin, made major contributions to biogeography by focusing on the distribution of closely allied species with particular attention to the effects of geographical barriers during his research in the Amazon basin and the Malay archipelago. He discovered the Wallace line dividing the fauna of the Malay archipelago between a zone allied with Asia and a zone allied with Australia. The ornithologist Philip Sclater, drawing on the work of Wallace and others, proposed a system of 6 major geographical regions to describe the distribution of bird species in the world. Wallace and others would in turn extend Sclater's system from birds to animals of all kinds.

The scientific study of heredity grew rapidly in the wake of Darwin's Origin of Species with the work of Francis Galton and the biometricians. The origin of genetics is usually traced to the 1866 work of the monk Gregor Mendel, who would later be credited with the laws of inheritance. However, his work was not recognized as significant until 35 years afterward. In the meantime, a variety of theories of inheritance (based on pangenesis, orthogenesis, or other mechanisms) were debated and investigated vigorously. Embryology and ecology also became central biological fields, especially as linked to evolution and popularized in the work of Ernst Haeckel. Most of the 19th century work on heredity, however, was not in the realm of natural history, but that of experimental physiology.

Physiology

Over the course of the 19th century, the scope of physiology expanded greatly, from a primarily medically-oriented field to a wide-ranging investigation of the physical and chemical processes of life—including plants, animals, and even microorganisms in addition to man. Living things as machines became a dominant metaphor in biological (and social) thinking.

Innovative laboratory glassware and experimental methods developed by Louis Pasteur and other biologists contributed to the young field of bacteriology in the late 19th century.

Cell theory, embryology and germ theory

Advances in microscopy also had a profound impact on biological thinking. In the early 19th century, a number of pointed to the central importance of the cell. In 1838 and 1839, Schleiden and Schwann began promoting the ideas that (1) the basic unit of organisms is the cell and (2) that individual cells have all the characteristics of life, though they opposed the idea that (3) all cells come from the division of other cells. Thanks to the work of Robert Remak and Rudolf Virchow, however, by the 1860s most biologists accepted all three tenets of what came to be known as cell theory.

Cell theory led biologists to re-envision individual organisms as interdependent assemblages of individual cells. Scientists in the rising field of cytology, armed with increasingly powerful microscopes and new staining methods, soon found that even single cells were far more complex than the homogeneous fluid-filled chambers of described by earlier microscopists. Robert Brown had described the nucleus in 1831, and by the end of the 19th century cytologists identified many of the key cell components: chromosomes, centrosomes mitochondria, chloroplasts, and other structures made visible through staining. Between 1874 and 1884 Walther Flemming described the discrete stages of mitosis, showing that they were not artifacts of staining but occurred in living cells, and moreover, that chromosomes doubled in number just before the cell divided and a daughter cell was produced. Much of the research on cell reproduction came together in August Weismann's theory of heredity: he identified the nucleus (in particular chromosomes) as the hereditary material, proposed the distinction between somatic cells and germ cells (arguing that chromosome number must be halved for germ cells, a precursor to the concept of meiosis), and adopted Hugo de Vries's theory of pangenes. Weismannism was extremely influential, especially in the new field of experimental embryology.

By the mid 1850s the miasma theory of disease was largely superseded by the germ theory of disease, creating extensive interest in microorganisms and their interactions with other forms of life. By the 1880s, bacteriology was becoming a coherent discipline, especially through the work of Robert Koch, who introduced methods for growing pure cultures on agar gels containing specific nutrients in Petri dishes. The long-held idea that living organisms could easily originate from nonliving matter (spontaneous generation) was attacked in a series of experiments carried out by Louis Pasteur, while debates over vitalism vs. mechanism (a perennial issue since the time of Aristotle and the Greek atomists) continued apace.

Rise of organic chemistry and experimental physiology

In chemistry, one central issue was the distinction between organic and inorganic substances, especially in the context of organic transformations such as fermentation and putrefaction. Since Aristotle these had been considered essentially biological (vital) processes. However, Friedrich Wöhler, Justus Liebig and other pioneers of the rising field of organic chemistry—building on the work of Lavoisier—showed that the organic world could often be analyzed by physical and chemical methods. In 1828 Wöhler showed that the organic substance urea could be created by chemical means that do not involve life, providing a powerful argument against vitalism. Cell extracts ("ferments") that could effect chemical transformations were discovered, beginning with diastase in 1833, and by the end of the 19th century the concept of enzymes was well established, though equations of chemical kinetics would not be applied to enzymatic reactions until the early 20th century.

Physiologists such as Claude Bernard explored (through vivisection and other experimental methods) the chemical and physical functions of living bodies to an unprecedented degree, laying the groundwork for endocrinology (a field that developed quickly after the discovery of the first hormone, secretin, in 1902), biomechanics, and the study of nutrition and digestion. The importance and diversity of experimental physiology methods, within both medicine and biology, grew dramatically over the second half of the 19th century. The control and manipulation of life processes became a central concern, and experiment was placed at the center of biological education.

Twentieth century biological sciences

At the beginning of the 20th century, biological research was largely a professional endeavour. However, most work was still done in the natural history mode, which emphasized morhphological and phylogenetic analysis over experiment-based causal explanations. However, anti-vitalist experimental physiologists and embryologists, especially in Europe, were increasingly influential. The tremendous success of experimental approaches to development, heredity, and metabolism in the 1900s and 1910s demonstrated the power of experimentation in biology. In the following decades, experimental work replaced natural history as the dominant mode of research.

Ecology and environmental science

In the early 20th century, naturalists were faced with increasing pressure to add rigor and preferably experimentation to their methods, as the newly prominent laboratory-based biological disciplines had done. Ecology had emerged as a combination of biogeography with the biogeochemical cycle concept pioneered by chemists; field biologists developed quantitative methods such as the quadrat and adapted laboratory instruments and cameras for the field to further set their work apart from traditional natural history. Zoologists and botanists did what they could to mitigate the unpredictability of the living world, performing laboratory experiments and studying semi-controlled natural environments such as gardens; new institutions like the Carnegie Station for Experimental Evolution and the Marine Biological Laboratory provided more controlled environments for studying organisms through their entire life cycles.

The ecological succession concept, pioneered in the 1900s and 1910s by Henry Chandler Cowles and Frederic Clements, was important in early plant ecology. Alfred Lotka's predator-prey equations, G. Evelyn Hutchinson's studies of the biogeography and biogeochemical structure of lakes and rivers (limnology) and Charles Elton's studies of animal food chains were pioneers among the succession of quantitative methods that colonized the developing ecological specialties. Ecology became an independent discipline in the 1940s and 1950s after Eugene P. Odum synthesized many of the concepts of ecosystem ecology, placing relationships between groups of organisms (especially material and energy relationships) at the center of the field.

In the 1960s, as evolutionary theorists explored the possibility of multiple units of selection, ecologists turned to evolutionary approaches. In population ecology, debate over group selection was brief but vigorous; by 1970, most biologists agreed that natural selection was rarely effective above the level of individual organisms. The evolution of ecosystems, however, became a lasting research focus. Ecology expanded rapidly with the rise of the environmental movement; the International Biological Program attempted to apply the methods of big science (which had been so successful in the physical sciences) to ecosystem ecology and pressing environmental issues, while smaller-scale independent efforts such as island biogeography and the Hubbard Brook Experimental Forest helped redefine the scope of an increasingly diverse discipline.

Classical genetics, the modern synthesis, and evolutionary theory

Thomas Hunt Morgan's illustration of crossing over, part of the Mendelian-chromosome theory of heredity

1900 marked the so-called rediscovery of Mendel: Hugo de Vries, Carl Correns, and Erich von Tschermak independently arrived at Mendel's laws (which were not actually present in Mendel's work). Soon after, cytologists (cell biologists) proposed that chromosomes were the hereditary material. Between 1910 and 1915, Thomas Hunt Morgan and the "Drosophilists" in his fly lab forged these two ideas—both controversial—into the "Mendelian-chromosome theory" of heredity. They quantified the phenomenon of genetic linkage and postulated that genes reside on chromosomes like beads on string; they hypothesized crossing over to explain linkage and constructed genetic maps of the fruit fly Drosophila melanogaster, which became a widely used model organism.

Hugo de Vries tried to link the new genetics with evolution; building on his work with heredity and hybridization, he proposed a theory of mutationism, which was widely accepted in the early 20th century. Lamarckism also had many adherents. Darwinism was seen as incompatible with the continuously variable traits studied by biometricians, which seemed only partially heritable. In the 1920s and 1930s—following the acceptance of the Mendelian-chromosome theory— the emergence of the discipline of population genetics, with the work of R.A. Fisher, J.B.S. Haldane and Sewall Wright, unified the idea of evolution by natural selection with Mendelian genetics, producing the modern synthesis. The inheritance of acquired characters was rejected, while mutationism gave way as genetic theories matured.

In the second half of the century the ideas of population genetics began to be applied in the new discipline of the genetics of behavior, sociobiology, and, especially in humans, evolutionary psychology. In the 1960s W.D. Hamilton and others developed game theory approaches to explain altruism from an evolutionary perspective through kin selection. The possible origin of higher organisms through endosymbiosis, and contrasting approaches to molecular evolution in the gene-centered view (which held selection as the predominant cause of evolution) and the neutral theory (which made genetic drift a key factor) spawned perennial debates over the proper balance of adaptationism and contingency in evolutionary theory.

In the 1970s Stephen Jay Gould and Niles Eldredge proposed the theory of punctuated equilibrium which holds that stasis is the most prominent feature of the fossil record, and that most evolutionary changes occur rapidly over relatively short periods of time. In 1980 Luis Alvarez and Walter Alvarez proposed the hypothesis that an impact event was responsible for the Cretaceous-Tertiary extinction event. Also in the early 1980s, statistical analysis of the fossil record of marine organisms published by Jack Sepkoski and David M. Raup lead to a better appreciation of the importance of mass extinction events to the history of life on earth.

Biochemistry, microbiology, and molecular biology

By the end of the 19th century all of the major pathways of drug metabolism had been discovered, along with the outlines of protein and fatty acid metabolism and urea synthesis. In the early decades of the twentieth century, the minor components of foods in human nutrition, the vitamins, began to be isolated and synthesized. Improved laboratory techniques such as chromatography and electrophoresis led to rapid advances in physiological chemistry, which—as biochemistry—began to achieve independence from its medical origins. In the 1920s and 1930s, biochemists—led by Hans Krebs and Carl and Gerty Cori—began to work out many of the central metabolic pathways of life: the citric acid cycle, glycogenesis and glycolysis, and the synthesis of steroids and porphyrins. Between the 1930s and 1950s, Fritz Lipmann and others established the role of ATP as the universal carrier of energy in the cell, and mitochondria as the powerhouse of the cell. Such traditionally biochemical work continued to be very actively pursued throughout the 20th century and into the 21st.

Origins of molecular biology

Following the rise of classical genetics, many biologists—including a new wave of physical scientists in biology—pursued the question of the gene and its physical nature. Warren Weaver—head of the science division of the Rockefeller Foundation—issued grants to promote research that applied the methods of physics and chemistry to basic biological problems, coining the term molecular biology for this approach in 1938; many of the significant biological breakthroughs of the 1930s and 1940s were funded by the Rockefeller Foundation.

Wendell Stanley's crystallization of tobacco mosaic virus as a pure nucleoprotein in 1935 convinced many scientists that heredity might be explained purely through physics and chemistry.

Like biochemistry, the overlapping disciplines of bacteriology and virology (later combined as microbiology), situated between science and medicine, developed rapidly in the early 20th century. Félix d'Herelle's isolation of bacteriophage during World War I initiated a long line of research focused of phage viruses and the bacteria they infect.

The development of standard, genetically uniform organisms that could produce repeatable experimental results was essential for the development of molecular genetics. After early work with Drosophila and maize, the adoption of simpler model systems like the bread mold Neurospora crassa made it possible to connect genetics to biochemistry, most importantly with Beadle and Tatum's "one gene, one enzyme" hypothesis in 1941. Genetics experiments on even simpler systems like tobacco mosaic virus and bacteriophage, aided by the new technologies of electron microscopy and ultracentrifugation, forced scientists to re-evaluate the literal meaning of life; virus heredity and reproducing nucleoprotein cell structures outside the nucleus ("plasmagenes") complicated the accepted Mendelian-chromosome theory.

The "central dogma of molecular biology" (originally a "dogma" only in jest) was proposed by Francis Crick in 1958. This is Crick's reconstruction of how he conceived of the central dogma at the time. The solid lines represent (as it seemed in 1958) known modes of information transfer, and the dashed lines represent postulated ones.

Oswald Avery showed in 1943 that DNA was likely the genetic material of the chromosome, not its protein; the issue was settled decisively with the 1952 Hershey-Chase experiment—one of many contribution from the so-called phage group centered around physicist-turned-biologist Max Delbrück. In 1953 James D. Watson and Francis Crick, building on the work of Maurice Wilkins and Rosalind Franklin, suggested that the structure of DNA was a double helix. In their famous paper "Molecular structure of Nucleic Acids", Watson and Crick noted coyly, "It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material." After the 1958 Meselson-Stahl experiment confirmed the semiconservative replication of DNA, it was clear to most biologists that nucleic acid sequence must somehow determine amino acid sequence in proteins; physicist George Gamow proposed that a fixed genetic code connected proteins and DNA. Between 1953 and 1961, there were few known biological sequences—either DNA or protein—but an abundance of proposed code systems, a situation made even more complicated by expanding knowledge of the intermediate role of RNA. To actually decipher the code, it took an extensive series of experiments in biochemistry and bacterial genetics, between 1961 and 1966—most importantly the work of Nirenberg and Khorana.

File:Myoglobindiffraction.png

Myoglobin was used extensively for early crystallographic studies of protein structure, because of its availability from Sperm Whales.

Expansion of molecular biology

In addition to the Division of Biology at Caltech, the Laboratory of Molecular Biology (and its precursors) at Cambridge, and a handful of other institutions, the Pasteur Institute became a major center for molecular biology research in the late 1950s. Scientists at Cambridge, led by Max Perutz and John Kendrew, focused on the rapidly developing field of structural biology, combining X-ray crystallography with molecular modelling and the new computational possibilities of digital computing (benefiting both directly and indirectly from the military funding of science). A number of biochemists led by Fred Sanger later joined the Cambridge lab, bringing together the study of macromolecular structure and function. At the Pasteur Institute, François Jacob and Jacques Monod followed the 1959 PaJaMo experiment with a series of publications regarding the lac operon that established the concept of gene regulation and identified what came to be known as messenger RNA. By the mid-1960s, the intellectual core of molecular biology—a model for the molecular basis of metabolism and reproduction— was largely complete.

The late 1950s to the early 1970s was a period of intense research and institutional expansion for molecular biology, which had only recently become a somewhat coherent discipline. In what organismic biologist E. O. Wilson called "The Molecular Wars", the methods and practitioners of molecular biology spread rapidly, often coming to dominate departments and even entire disciplines. Molecularization was particularly important in genetics, immunology, embryology, and neurobiology, while the idea that life is controlled by a "genetic program"—a metaphor Jacob and Monod introduced from the emerging fields of cybernetics and computer science—became an influential perspective throughout biology. Immunology in particular became linked with molecular biology, with innovation flowing both ways: the clonal selection theory developed by Niels Jerne and Frank Macfarlane Burnet in the mid 1950s helped shed light on the general mechanisms of protein synthesis.

Resistance to the growing influence molecular biology was especially evident in evolutionary biology. Protein sequencing had great potential for the quantitative study of evolution (through the molecular clock hypothesis), but leading evolutionary biologists questioned the relevance of molecular biology for answering the big questions of evolutionary causation. Departments and disciplines fractured as organismic biologists asserted their importance and independence: Theodosius Dobzhansky made the famous statement that "nothing in biology makes sense except in the light of evolution" as a response to the molecular challenge. The issue became even more critical after 1968; Motoo Kimura's neutral theory of molecular evolution suggested that natural selection was not the ubiquitous cause of evolution, at least at the molecular level, and that molecular evolution might be a fundamentally different process from morphological evolution. (Resolving this "molecular/morphological paradox" has been a central focus of molecular evolution research since the 1960s.)

Biotechnology, genetic engineering, and genomics

Biotechnology in the general sense has been an important part of biology since the late 19th century. With the industrialization of brewing and agriculture, chemists and biologists became aware of the great potential of human-controlled biological processes. In particular, fermentation proved a great boon to chemical industries. By the early 1970s, a wide range of biotechnologies were being developed, from drugs like penicillin and steroids to foods like Chlorella and single-cell protein to gasohol—as well as a wide range of hybrid high-yield crops and agricultural technologies, the basis for the Green Revolution.

Carefully engineered strains of the bacterium Escherichia coli are crucial tools in biotechnology as well as many other biological fields.

Recombinant DNA

Biotechnology in the modern sense of genetic engineering began in the 1970s, with the invention of recombinant DNA techniques. Restriction enzymes were discovered and characterized in the late 1960s, following on the heels of the isolation, then duplication, then synthesis of viral genes. Beginning with the lab of Paul Berg in 1972 (aided by EcoRI from Herbert Boyer's lab, building on work with ligase by Arthur Kornberg's lab), molecular biologists put these pieces together to produce the first transgenic organisms. Soon after, others began using plasmid vectors and adding genes for antibiotic resistance, greatly increasing the reach of the recombinant techniques.

Wary of the potential dangers (particularly the possibility of a prolific bacteria with a viral cancer-causing gene), the scientific community as well as a wide range of scientific outsiders reacted to these developments with both enthusiasm and fearful restraint. Prominent molecular biologists led by Berg suggested a temporary moratorium on recombinant DNA research until the dangers could be assessed and policies could be created. This moratorium was largely respected, until the participants in the 1975 Asilomar Conference on Recombinant DNA created policy recommendations and concluded that the technology could be used safely.

Following Asilomar, new genetic engineering techniques and applications developed rapidly. DNA sequencing methods improved greatly (pioneered by Fred Sanger and Walter Gilbert), as did oligonucleotide synthesis and transfection techniques. Researchers learned to control the expression of transgenes, and were soon racing—in both academic and industrial contexts—to create organisms capable of expressing human genes for the production of human hormones. However, this was a more daunting task than molecular biologists had expected; developments between 1977 and 1980 showed that, due to the phenomena of split genes and splicing, higher organisms had a much more complex system of gene expression than the bacteria models of earlier studies. The first such race, for synthesizing human insulin, was won by Genentech. This marked the beginning of the biotech boom (and with it, the era of gene patents), with an unprecedented level of overlap between biology, industry, and law.

Molecular systematics and genomics

Inside of a 48-well thermal cycler, a device used to perform polymerase chain reaction on many samples at once.

By the 1980s, protein sequencing had already transformed methods of scientific classification of organisms (especially cladistics) but biologists soon began to use RNA and DNA sequences as characters; this expanded the significance of molecular evolution within evolutionary biology, as the results of molecular systematics could be compared with traditional evolutionary trees based on morphology. Following the pioneering ideas of Lynn Margulis on endosymbiotic theory, which holds that some of the organelles of eukaryotic cells originated from free living prokaryotic organisms through symbiotic relationships, even the overall division of the tree of life was revised. Into the 1990s, the five domains (Plants, Animals, Fungi, Protists, and Monerans) became three (the Archaea, the Bacteria, and the Eukarya) based on Carl Woese's pioneering molecular systematics work with 16S rRNA sequencing.

The development and popularization of the polymerase chain reaction (PCR) in mid 1980s (by Kary Mullis and others at Cetus Corp.) marked another watershed in the history of modern biotechnology, greatly increasing the ease and speed of genetic analysis. Coupled with the use of expressed sequence tags, PCR led to the discovery of many more genes than could be found through traditional biochemical or genetic methods and opened the possibility of sequencing entire genomes.

The unity of much of the morphogenesis of organisms from fertilized egg to adult began to be unraveled after the discovery of the homeobox genes, first in fruit flies, then in other insects and animals, including humans. These developments led to advances in the field of evolutionary developmental biology towards understanding how the various body plans of the animal phyla have evolved and how they are related to one another.

The Human Genome Project—the largest, most costly single biological study ever undertaken—began in 1988 under the leadership of James D. Watson, after preliminary work with genetically simpler model organisms such as E. coli, S. cerevisiae and C. elegans. Shotgun sequencing and gene discovery methods pioneered by Craig Venter—and fueled by the financial promise of gene patents with Celera Genomics— led to a public-private sequencing competition that ended in compromise with the first draft of the human DNA sequence announced in 2000.

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External links

• International Society for History, Philosophy, and Social Studies of Biology - professional history of biology organization
• History of Biology - Historyworld article
• History of Biology at Bioexplorer.Net - a collection of history of biology links
• Biology - historically-oriented article on Citizendium
• Miall, L. C. (1911) History of biology. Watts & Co. London

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