Cyanobacterial Image Gallery
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Disclaimer and Acknowledgements
The images in this gallery are uncopyrighted freeware and are provided for educational purposes. Please contact the webmaster before using any of these images in a published work. A policy for image usage has been established. Images from Cyanosite have appeared in many publications including textbooks, review articles, and news reports. The images also have been used for presentations and museum exhibits worldwide.
Many of these images were taken from field samples. The measurements are approximate and not reliable for taxonomic use. It is hoped that the images will provide field technicians with some help in recognizing the creatures in the samples they have collected. Many of these pictures illustrate certain characteristics that are important in the ongoing discussion of morphological determination of cyanobacteria. Beggiatoa and "Chloroflexus" are not cyanobacteria, but they are included here because they are found in the same habitats as cyanobacteria, and because they could be confused with cyanobacteria. If you disagree with the taxonomic designations given here please submit your comments for inclusion.
The Webspinner is very grateful to those that have provided images to Cyanosite. Submission of additional images is always welcome. A policy for image usage is also available.
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Video Images
The Great Escape - A cyanobacterium defending itself from a ciliate predator.
Spirulina on the Move - Spirulina gyrating in solution.
Woodruffia grazing on Phormidium - Four separate video clips demonstrating avoidance mechanisms.
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Still Images
A full image can be obtained by clicking on a thumbnail sketch
Anabaena affinis, 640X
Anabaena circinalis - Measurement unavailable. probably 400x
Anabaena doliolum
Anabaena flos-aquae enlarged 2500X
Anabaena "laxa" - ID for this complex is of course tenuous--see next entry. Measurement unavailable. probably 400x
Anabaena "laxa" - From the same sample as above, a few weeks later. Note that the akinete is now adjacent the heterocyst. It now keys out to Anabaena "cylindrica". 400x
Anabaena scheremetievi - 400x phase contrast
Anabaena scheremetievi - A slight hint of a sheath is visible. 400x
Anabaena scheremetievi - 400x
Anabaena sperica, 1600X
Anabaena spherica - 400x
Anabaena spiroides - The line is 20 microns. 200x
Anabaena torulosa - 400x
Anabaena torulosa - Is it Synecococcus? No, it is Anabaena torulosa akinetes. 400x
Anabaena variabilis
Anabaena sp. - (Unidentified) No speculations upon the species. 400x
Anabaena sp. - (Unidentified) No speculations upon the species. 400x
Anabaena sp. - (Unidentified) No speculations upon the species. 400x
Anabaena sp. - (Unusual and contorted) Akinetes are round, so it is probably not A. circinalis. Could be A. spiroides in an unusual state. 200x.
Anabaena sp. - (Unusual and contorted) The same specimen as above at 100x.
Anabaena sp. - Probably A. scheremetievi, but akinetes were absent. A hint of a sheath is barely visible. 400x
Anabaena sp. - Probably A. circinalis, but akinetes were absent. 1000x
Anabaena sp. - Possibly A. viguieri, but the akinetes are too broad. 400x.
Anabaena sp., from freshwater lake in Oregon, 100X
Anabaena sp., from freshwater lake in Oregon, 100X
Anabaena sp., from freshwater lake in Oregon, 200X
Anabaena sp., from freshwater lake in Oregon, 100X. Note the fabulous germinating akinetes.
Anabaena sp.
Anabaena sp.
Anabaena sp.
Anabaena sp.
Anabaena sp. with symbiont bacteria (possibly Zoogloea) around heterocysts
Anabaenopsis circularis - The central pair of heterocysts is clearly visible. 200x
Anabaenopsis circularis - A developing pair of heterocysts is visible in the center of the trichome. Note the bacteria attached to it. 400x (phase contrast)
Anabaenopsis circularis - Same as above without phase contrast. 400x
Anabaenopsis sp. bloom in Bedetti Lake, Santo Tome, Santa Fe, Argentina
Anabaenopsis sp. bloom in Bedetti Lake, Santo Tome, Santa Fe, Argentina
Anabaenopsis sp. bloom in Bedetti Lake, Santo Tome, Santa Fe, Argentina
Anacystis nidulans TEM of semi-thin section (200 nm). See protocol.
Anacystis nidulans TEM of semi-thin section (200 nm) See protocol.
Anacystis nidulans TEM of semi-thin section (300 nm) See protocol.
Anacystis nidulans TEM of semi-thin section (300 nm) See protocol.
Anacystis nidulans TEM of semi-thin section (500 nm) See protocol.
Anacystis nidulans TEM of semi-thin section (500 nm) See protocol.
Aphanizomenon flos-aquae - Akinetes and heterocyst clearly visible. Measurement unavailable. probably 400x
Aphanizomenon flos-aquae - Colony. Measurement unavailable. probably 100x
Aphanizomenon flos-aquae - Colony. Akinetes absent. 400x
Aphanizomenon flos-aquae strain 1401/5. Autofluorescence image.
Aphanizomenon flos-aquae strain 1401/5. Autofluorescence image.
Aphanizomenon flos-aquae strain 1401/5. Autofluorescence image.
Arthrospira jenneri - Cross-walls obscured by cytoplasmic granules (sorry). 400x
Beggiatoa alba - 400x
Beggiatoa alba - Cropped portion of image above at higher resolution.
Bloom in waters at the Hartebeespoort dam in South Africa
Bloom of Microcystis aeruginosa and Anabaena circinalis on the St. Johns River, FL
Bloom of Aphanizomenon flos aquae in a lake in Surrey, UK
Bloom
Bloom of Microcystis in Crescent Lake, FL
Bloom in Doctor's Lake
Bloom in Lake Ponchartrain, LA, an oligohaline estuary
Bloom of Microcystis aeruginosa and Anabaena circinalis contaminated by a boat on the St. Johns River, FL
Bloom in agricultural setting in Missouri
Bloom in agricultural setting in Missouri
Bloom in agricultural setting in Missouri
Bloom in agricultural setting in Missouri
Bloom in agricultural setting in Missouri
Borzia sp.
Calothrix sp. PCC 7103
Calothrix sp.
Calothrix sp. showing terminal heterocysts
Chloroflexus sp. - Unknown phytoplankton from a fish pond. Speculation: Chloroflexus. 400x
Chloroflexus sp. - Wider view higher resolution image of specimen above.
Chroococcus sp.
Collecting cyanobacteria from a large bloom
Cyanobacterial bloom
Cyanosarcina sp. from a pulp and paper waste-treatment system in Brazil
Cylindrospermopsis raciborskii - Heterocysts and akinetes visible. 400x
Cylindrospermopsis raciborskii - 400x phase contrast
Cylindrospermopsis raciborskii - Heterocyst visible. 400x
Cylindrospermopsis raciborskii - Akinetes (only) visible. 400x phase contrast
Cylindrospermopsis raciborskii - Heterocyst visible. 400x phase contrast
Cylindrospermum muscicola - 400x
Cylindrospermum muscicola - Surprise! It is not Pseudanabaena, but C. muscicola, without akinetes, but with a developing heterocyst. 400x phase contrast
Cylindrospermum sp. str. PCC 7417
Cylindrospermum sp.
Cylindrospermum sp., 1600X
Cylindrospermum sp., 1600X
Eubacterium - Unidentified bacterium pays Euglena a visit. 1000x
Fischerella sp. str. PCC 7414
Fischerella sp.
Geitlerinema sp. from a pulp and paper waste-treatment system in Idaho
Girvanella sp. in algae oncolites from the Lower Cambrian Mule Spring Limestone, Waucoba Spring, Death Valley National Park
Gloeobacter sp. str. PCC 8105
Gloeobacter sp.
Gloeocapsa sp. together with two algae
"Gloeotrichia" - Akinete and heterocyst clearly visible. Measurement unavailable. 400x
"Gloeotrichia" - Colony. Measurement unavailable. 100x
Leptolyngbya africana
Leptolyngbya foveolarum f maior
Leptolyngbya foveolarum
Leptolyngbya fragilis
Leptolyngbya sp.
Lyngbya aestuarii
Lyngbya majuscula
Lyngbya sp.
Lyngbya sp. showing classical sheath and terminal differentiation in the lower filament
Lyngbya sp. showing formation of a coil at the end of a "hairpin" formation
Lyngbya sp. - (Unidentified) No speculations upon the species. 200x
Lyngbya sp. - (Unidentified) No speculations upon the species. Note that one has no visible sheath. 200x
Lyngbya sp. - Same specimen as above. 400x phase contrast
Lyngbya sp. - (Unidentified) Possibly birgei. 200x
Lyngbya sp. - Social gathering of the above species. 200x
Lyngbya sp.
Lyngbya sp.
Lyngbya sp., two cells are leaving the shell
Lyngbya sp.
Lyngbya sp. at 100 X.
Mat Community Knit strings of cyanobacteria from green layer of a microbial mat from Great Sippewissett Saltmarsh, Falmouth, MA
Mat Community Cross-section of a microbial mat from Great Sippewissett Saltmarsh, Falmouth, MA
Merismopedia - Colony of Merismopedia (Agmenellum [Drouet], Synechocystis Low GC cluster [Waterbury and Rippka]). 200x
Merismopedia elegans, 640X
Microcoleus chthonoplastes
Microcoleus vaginatus
Microcoleus sp. - One of those in the anomalous Microcoleus/Symploca/Lyngbya/Take-a-guess range. 400x
Microcrust on soil
Microcystis aeruginosa enlarged 2500X
Microcystis aeruginosa strain PCC 7806. Autofluorescence image.
Microcystis aeruginosa strain PCC 7806. Autofluorescence image.
Microcystis aeruginosa strain PCC 7806. Autofluorescence image.
Microcystis aeruginosa strain PCC 7806. Autofluorescence image.
Microcystis aeruginosa strain PCC 7806. Autofluorescence image.
Microcystis aerogenosa strain 1450/10 in very old (6 month) stationary phase cultures imaged with autofluoresence. 1000X
Microcystis aerogenosa strain 7806 in very old stationary phase cultures imaged with autofluoresence. Note transient "bright strike" feature. 1000X
Microcystis aerogenosa strain 7806 in very old (100 d) stationary phase cultures imaged with phase contrast. Note multi-planar division. 1000X
Microcystis aerogenosa strain 7806 in very old (100 d) stationary phase cultures imaged with phase contrast. Note narrow sheath. 1000X
Microcystis aerogenosa. 100X
Microcystis sp. bloom
Microcystis sp. - Becoming confluent. 200x
Microcystis sp. bloom from bird's eye view
Microcystis aeruginosa bloom, Lake Mokoan, Victoria, Australia.
Microcystis sp.
Microcystis sp. - Separate colonies. 200x
Microcystis sp. bloom, Balgavies Loch, Dundee, Scotland, 1981.
Microcystis sp., bloom, Grandview Garden Park, Beijing
Mixture - Oscillatoria cf. chalybea, Planktothrix agardhii, and Anabaena spiroides. 200x
Mixture - Oscillatoria cf. chalybea, Planktothrix agardhii, and Arthrospira jenneri. 200x
Mixture, including Thiothrix and Oscillatoria sp.
Mixture, including Spirulina and Microcoleus sp. and diatoms together with Thiopediasp.
Mixture of cyanobacteria from microbial mat community
Mystery Bug - Truly strange. Spirulina major inside a bundle. 400x
Mystery Bug - Unidentified filament. Is it made of diatoms, desmids, cyanobacteria, or the unknown? 400x
Mystery Bug A - Planktothrix agardhii with a swollen terminal cell. 200x. For Mystery Bugs A through E, it has been suggested that the swollen terminal cells are fungal (chytrid) fruiting bodies (sporangia) as hyphae have been observed running the length of similar trichomes.
Mystery Bug B - Planktothrix agardhii with a double swollen terminal cell. 200x. See Mystery Bug A.
Mystery Bug C - Another odd Planktothrix agardhii. 400x phase contrast. See Mystery Bug A.
Mystery Bug D - Another odd Planktothrix agardhii. 400x phase contrast. See Mystery Bug A.
Mystery Bug E - Same as above without phase contrast. 400x. See Mystery Bug A.
Mystery wavy cyanobacteria
Mystery cyanobacteria in a colony
Mystery cyanobacteria showing vessicles
Mystery 13
Mystery 14
Mystery 15
Mystery 16
Nodularia spumigena enlarged 1250X
Nodularia sp. bloom in situ from an undersea porthole in the Baltic Proper
Nostoc (Anabaena) azollae - Heterocyst clearly visible. 400x
Nostoc (Anabaena) azollae - Numerous akinetes visible. 400x
Nostoc sp. - Possible germling. 400x
Nostoc sp. - Possible colony or is it a strange type of Anabaena spherica?. The only thing for sure is that nothing is for sure. 200x
Nostoc sp., 130X
Nostoc sp. at 10X
Nostoc sp.
Nostochopsis sp., cell and branching
Nostochopsis sp., gross structure
Nostochopsis sp., detailed image
Nostochopsis sp., pediellate heterocyst
Nostochopsis sp., intercalary heterocyst
Oscillatoria agardhii - Autofluorescence image.
Oscillatoria cf. chalybea - With Planktothrix agardhii, and possible Raphidiopsis sp. 200x
Oscillatoria "chlorina" - Quotes represent the contributor's resentment at identifying cyanobacteria using color. 400x
Oscillatoria geminata - 400x
Oscillatoria limnetica
Oscillatoria limosa, 640X
Oscillatoria margaritifera
Oscillatoria princeps - 200x
Oscillatoria princeps - 100x
Oscillatoria princeps - Social gathering with some friends. 200x
Oscillatoria splendida - 400x phase contrast
Oscillatoria subuliformis
Oscillatoria sp. - The famous "big Oscillatoria". Species not known. It may be undescribed. 200x
Oscillatoria sp. - Note the granules in the terminal cell, along with its thickened membrane. 400x
Oscillatoria sp. - With the bright light rendering its striking granules more visible. Note the spiral arrangement of the granules. 100x
Oscillatoria sp. - The same specimen as above. 200x
Oscillatoria sp. - At low magnification. 40x
Oscillatoria sp. together with a Synechocystis microcolony. Note the numerous bacteria in the background.
Oscillatoria sp.
Oscillatoria sp., 640X
Oscillatoria sp., likely a hormogonium, from a pulp and paper waste-treatment system in Brazil
Phormidium jenkelianum
Phormidium retzii - Tentative identification. 200x
Phormidium sp.
Phormidium sp.
Phormidium uncinatum - Tentative identification. 400x phase contrast
Phormidium uncinatum - Same as above without phase contrast. 200x
Phycobilisome diagram Each disk in the phycobilisome structure represents a hexameric aggregate, (alpha-beta)66, of a phycobiliprotein complexed with a linker protein: Phycoerythrin = red, Phycocyanin = blue, Allophycocyanin = light blue. The green elements are the two PSII reaction centers that associate with each phycobilisome.
Planktothrix (Oscillatoria) agardhii - With visible pseudovacuoles. 400x phase contrast
Planktothrix rubescens. 100x.
Pleurocapsa sp. str. PCC 7440
Raphidiopsis curvata - Mixed with some straight chains that are either more Raphidiopsis or Cylndrospermopsis raciborskii without akinetes or heterocysts. 400x
Raphidiopsis curvata - Same as above with phase contrast
Raphidiopsis cf. mediterranea - Could be R. brookii. 400x
Raphidiopsis cf. mediterranea - 100x
Raphidiopsis curvata - 200x
Raphidiopsis cf. mediterranea - Pseudovacuoles clearly visible. 400x phase contrast
Schizothrix lenormandiana
Scytonema cf. Crustaceum
Scytonema sp.
Spirulina major - 400x phase contrast
Spirulina sp.
Spirulina sp.
Spirulina sp.
Spirulina sp.
Spirulina sp.
Spirulina subsalsa
Spirulina sp. (Arthrospira) culture contaminated by brown swans in South Bend, IN.
Stromatolites
Stromatolites
Stromatolites
Stromatolites
Columnar Stromatolites and Thrombolites from tidal channel at Lee Stocking Island, Bahamas
Stromatolite Cross-section, columnar procaryotic stromatolite grown on Calianassa burrow. Bar = 1 cm.
Stromatolite Photomicrograph, thin section of prokaryotic stromatolite showing alternating layers of dense micrite and coarse detritus.
Stromatolite Photomicrograph, thin section of eukaryotic stromatolite showing undulose laminations formed by a combination of eukaryotic algal and cyanobacterial activities.
Stromatolites found in Middle Proterozoic formations of the Hakatai Shale in Grand Canyon National Park.
Stromatolites found in Middle Proterozoic formations of the Hakatai Shale in Grand Canyon National Park. Lens cap is 55 mm.
Stromatolites found in Middle Proterozoic formations of the Hakatai Shale in Grand Canyon National Park. Lens cap is 55 mm.
Stromatolites found in Middle Proterozoic formations of the Hakatai Shale in Grand Canyon National Park.
Stromatolite crossection
Frozen Stromatolites, Shark's Bay, Australia
Frozen Stromatolites, Shark's Bay, Australia
Frozen Stromatolite Mat, Shark's Bay, Australia
Frozen Stromatolite, Shark's Bay, Australia
Frozen Stromatolites, Shark's Bay, Australia
Living Stromatolites, Salda Lake, Turkey
Living Stromatolites, Salda Lake, Turkey
Living Stromatolites, Salda Lake, Turkey
Living Stromatolites, Salda Lake, Turkey
Living Stromatolites, Salda Lake, Turkey
Living Stromatolites, Salda Lake, Turkey
Living Stromatolites, Salda Lake, Turkey
Living Stromatolites, Salda Lake, Turkey
Stromatoids, dry lake bed near Agaean Sea
Stromatoids, dry lake bed near Agaean Sea
Stromatoids, dry lake bed near Agaean Sea
Synechocystis buzasii
Synechocystis sp.
Thrombolite Heads heavily overgrown by Lee Stocking Island, Bahamas
Thrombolite of modern origin from Lee Stocking Channel, Bahamas. Bar = 1 cm.
Thrombolite Photomicrograph, thin section showing boundary between micritic clot and detritus-rich sediment pocket
Tolypothrix sp. strain A
Tolypothrix sp. strain A
Trichodesmium sp., Nomarski optics, 1000x
Trichodesmium sp., Nomarski optics, 1000x
Trichodesmium sp., Phase contrast, 1000x
Trichodesmium sp., Fluorescence optics, 1000x
Trichodesmium sp., Fluorescence optics, 1000x
Trichodesmium sp., Phase contrast, 1000x
Trichormus sp.
Thursday, August 16, 2007
A Webserver for Cyanobacterial Research
Features Resources Announcements Submissions
A Webserver for Cyanobacterial Research
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Features
Cyanobacteria Image Gallery presenting over 200 beautiful images or videos of cyanobacteria. With thumbnails (longer download).
Or Without thumbnails (shorter download).
Cyanobacteria Bibliography CyBib v5 The most extensive cyanobacterial bibliography on-line. It contains nearly 25,000 references and can be imported into reference managing programs on any platform. Now searchable on-line.
Cyanobacteria Links Library to cyanobacterial sites on the WWW.
CyanoNews has been discontinued. A few back issues can be obtained here
The Toxic Cyanobacteria Homepage now resides on Cyanosite with information about cyanobacterial toxins.
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Resources
Media Recipes for Culturing Cyanobacteria
Experimental Protocols
CyanoBase at Kazusa DNA Research Institute provides the entire sequence of several cyanobacteria.
Taxonomy of Cyanobacteria
Directory of Cyanobacteriologist. This list is from 2001 and likely will not be updated.
Cyanobacteriologist Email Directory (with tables) and without tables (smaller file). This list is from 2001 and likely will not be updated.
Cyanosite Mailing List. This list is only for announcements about Cyanosite.
History of Cyanosite including the first on-line version of Cyanosite from 1995
--------------------------------------------------------------------------------
Announcements
Great website on toxic cyanobacterial blooms; loaded with practical information for the general public.
The International Society for Applied Phycology (ISAP) has been formed. You are invited to become a member of this new society. You can learn more here.
Cyanosite was awarded a two-year grant from the The Waksman Foundation for Microbiology to support an undergraduate stipend. The work-study student helped to maintain CyBib and weblinks while adding useful information to the site. We are most appreciative of this opportunity for substantial practical improvement of the site.
--------------------------------------------------------------------------------
Awards
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Submissions
Cyanosite is dedicated to information transfer within the cyanobacterial research community. This site will work to maintain archives of experimental protocols, taxonomic information, comprehensive bibliographic information, educational resources for college and secondary school teachers, general information about blue-green algae, and links to other cyanobacterial, prochlorophyte, and cyanelle sites on the web. What you can do to help Cyanosite grow.
--------------------------------------------------------------------------------
Questions and comments can be directed to: Dr. Mark A. Schneegurt, mark.schneegurt@wichita.edu
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Two words from the Webspinner and Friends
Homepage image provided by Dave Krogmann, Purdue University
Cyanosite receives support from the Department of Biological Sciences at Purdue University
--------------------------------------------------------------------------------
The counter reflects the number of machines that have downloaded the counter image since July 3, 1997.
220,000 Plus
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A Webserver for Cyanobacterial Research
--------------------------------------------------------------------------------
Features
Cyanobacteria Image Gallery presenting over 200 beautiful images or videos of cyanobacteria. With thumbnails (longer download).
Or Without thumbnails (shorter download).
Cyanobacteria Bibliography CyBib v5 The most extensive cyanobacterial bibliography on-line. It contains nearly 25,000 references and can be imported into reference managing programs on any platform. Now searchable on-line.
Cyanobacteria Links Library to cyanobacterial sites on the WWW.
CyanoNews has been discontinued. A few back issues can be obtained here
The Toxic Cyanobacteria Homepage now resides on Cyanosite with information about cyanobacterial toxins.
--------------------------------------------------------------------------------
Resources
Media Recipes for Culturing Cyanobacteria
Experimental Protocols
CyanoBase at Kazusa DNA Research Institute provides the entire sequence of several cyanobacteria.
Taxonomy of Cyanobacteria
Directory of Cyanobacteriologist. This list is from 2001 and likely will not be updated.
Cyanobacteriologist Email Directory (with tables) and without tables (smaller file). This list is from 2001 and likely will not be updated.
Cyanosite Mailing List. This list is only for announcements about Cyanosite.
History of Cyanosite including the first on-line version of Cyanosite from 1995
--------------------------------------------------------------------------------
Announcements
Great website on toxic cyanobacterial blooms; loaded with practical information for the general public.
The International Society for Applied Phycology (ISAP) has been formed. You are invited to become a member of this new society. You can learn more here.
Cyanosite was awarded a two-year grant from the The Waksman Foundation for Microbiology to support an undergraduate stipend. The work-study student helped to maintain CyBib and weblinks while adding useful information to the site. We are most appreciative of this opportunity for substantial practical improvement of the site.
--------------------------------------------------------------------------------
Awards
--------------------------------------------------------------------------------
Submissions
Cyanosite is dedicated to information transfer within the cyanobacterial research community. This site will work to maintain archives of experimental protocols, taxonomic information, comprehensive bibliographic information, educational resources for college and secondary school teachers, general information about blue-green algae, and links to other cyanobacterial, prochlorophyte, and cyanelle sites on the web. What you can do to help Cyanosite grow.
--------------------------------------------------------------------------------
Questions and comments can be directed to: Dr. Mark A. Schneegurt, mark.schneegurt@wichita.edu
--------------------------------------------------------------------------------
Two words from the Webspinner and Friends
Homepage image provided by Dave Krogmann, Purdue University
Cyanosite receives support from the Department of Biological Sciences at Purdue University
--------------------------------------------------------------------------------
The counter reflects the number of machines that have downloaded the counter image since July 3, 1997.
220,000 Plus
--------------------------------------------------------------------------------
Introduction to the Cyanobacteria
Introduction to the Cyanobacteria
Architects of earth's atmosphere
Cyanobacteria are aquatic and photosynthetic, that is, they live in the water, and can manufacture their own food. Because they are bacteria, they are quite small and usually unicellular, though they often grow in colonies large enough to see. They have the distinction of being the oldest known fossils, more than 3.5 billion years old, in fact! It may surprise you then to know that the cyanobacteria are still around; they are one of the largest and most important groups of bacteria on earth.
Many Proterozoic oil deposits are attributed to the activity of cyanobacteria. They are also important providers of nitrogen fertilizer in the cultivation of rice and beans. The cyanobacteria have also been tremendously important in shaping the course of evolution and ecological change throughout earth's history. The oxygen atmosphere that we depend on was generated by numerous cyanobacteria during the Archaean and Proterozoic Eras. Before that time, the atmosphere had a very different chemistry, unsuitable for life as we know it today.
The other great contribution of the cyanobacteria is the origin of plants. The chloroplast with which plants make food for themselves is actually a cyanobacterium living within the plant's cells. Sometime in the late Proterozoic, or in the early Cambrian, cyanobacteria began to take up residence within certain eukaryote cells, making food for the eukaryote host in return for a home. This event is known as endosymbiosis, and is also the origin of the eukaryotic mitochondrion.
Because they are photosynthetic and aquatic, cyanobacteria are often called "blue-green algae". This name is convenient for talking about organisms in the water that make their own food, but does not reflect any relationship between the cyanobacteria and other organisms called algae. Cyanobacteria are relatives of the bacteria, not eukaryotes, and it is only the chloroplast in eukaryotic algae to which the cyanobacteria are related.
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Click on the buttons below to find out more about the Cyanobacteria.
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Images of Nostoc and Oscillatoria provided by the University of Wisconsin Botanical Images Collection.
For more information about cyanobacteria on the web, visit Cyanosite, a webserver dedicated to cyanobacterial research.
Information about the ecology of fresh-water cyanobacteria is available from the Soil and Water Conservation Society of Metro Halifax.
The Tree of Life has a preliminary page on the Cyanobacteria, with some very nice pictures.
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Architects of earth's atmosphere
Cyanobacteria are aquatic and photosynthetic, that is, they live in the water, and can manufacture their own food. Because they are bacteria, they are quite small and usually unicellular, though they often grow in colonies large enough to see. They have the distinction of being the oldest known fossils, more than 3.5 billion years old, in fact! It may surprise you then to know that the cyanobacteria are still around; they are one of the largest and most important groups of bacteria on earth.
Many Proterozoic oil deposits are attributed to the activity of cyanobacteria. They are also important providers of nitrogen fertilizer in the cultivation of rice and beans. The cyanobacteria have also been tremendously important in shaping the course of evolution and ecological change throughout earth's history. The oxygen atmosphere that we depend on was generated by numerous cyanobacteria during the Archaean and Proterozoic Eras. Before that time, the atmosphere had a very different chemistry, unsuitable for life as we know it today.
The other great contribution of the cyanobacteria is the origin of plants. The chloroplast with which plants make food for themselves is actually a cyanobacterium living within the plant's cells. Sometime in the late Proterozoic, or in the early Cambrian, cyanobacteria began to take up residence within certain eukaryote cells, making food for the eukaryote host in return for a home. This event is known as endosymbiosis, and is also the origin of the eukaryotic mitochondrion.
Because they are photosynthetic and aquatic, cyanobacteria are often called "blue-green algae". This name is convenient for talking about organisms in the water that make their own food, but does not reflect any relationship between the cyanobacteria and other organisms called algae. Cyanobacteria are relatives of the bacteria, not eukaryotes, and it is only the chloroplast in eukaryotic algae to which the cyanobacteria are related.
--------------------------------------------------------------------------------
Click on the buttons below to find out more about the Cyanobacteria.
--------------------------------------------------------------------------------
Images of Nostoc and Oscillatoria provided by the University of Wisconsin Botanical Images Collection.
For more information about cyanobacteria on the web, visit Cyanosite, a webserver dedicated to cyanobacterial research.
Information about the ecology of fresh-water cyanobacteria is available from the Soil and Water Conservation Society of Metro Halifax.
The Tree of Life has a preliminary page on the Cyanobacteria, with some very nice pictures.
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Photosynthetic Pigments
Photosynthetic Pigments
Pigments are colorful compounds.
Pigments are chemical compounds which reflect only certain wavelengths of visible light. This makes them appear "colorful". Flowers, corals, and even animal skin contain pigments which give them their colors. More important than their reflection of light is the ability of pigments to absorb certain wavelengths.
Because they interact with light to absorb only certain wavelengths, pigments are useful to plants and other autotrophs --organisms which make their own food using photosynthesis. In plants, algae, and cyanobacteria, pigments are the means by which the energy of sunlight is captured for photosynthesis. However, since each pigment reacts with only a narrow range of the spectrum, there is usually a need to produce several kinds of pigments, each of a different color, to capture more of the sun's energy.
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There are three basic classes of pigments.
Chlorophylls are greenish pigments which contain a porphyrin ring. This is a stable ring-shaped molecule around which electrons are free to migrate. Because the electrons move freely, the ring has the potential to gain or lose electrons easily, and thus the potential to provide energized electrons to other molecules. This is the fundamental process by which chlorophyll "captures" the energy of sunlight.
There are several kinds of chlorophyll, the most important being chlorophyll "a". This is the molecule which makes photosynthesis possible, by passing its energized electrons on to molecules which will manufacture sugars. All plants, algae, and cyanobacteria which photosynthesize contain chlorophyll "a". A second kind of chlorophyll is chlorophyll "b", which occurs only in "green algae" and in the plants. A third form of chlorophyll which is common is (not surprisingly) called chlorophyll "c", and is found only in the photosynthetic members of the Chromista as well as the dinoflagellates. The differences between the chlorophylls of these major groups was one of the first clues that they were not as closely related as previously thought.
Carotenoids are usually red, orange, or yellow pigments, and include the familiar compound carotene, which gives carrots their color. These compounds are composed of two small six-carbon rings connected by a "chain" of carbon atoms. As a result, they do not dissolve in water, and must be attached to membranes within the cell. Carotenoids cannot transfer sunlight energy directly to the photosynthetic pathway, but must pass their absorbed energy to chlorophyll. For this reason, they are called accessory pigments. One very visible accessory pigment is fucoxanthin the brown pigment which colors kelps and other brown algae as well as the diatoms.
Phycobilins are water-soluble pigments, and are therefore found in the cytoplasm, or in the stroma of the chloroplast. They occur only in Cyanobacteria and Rhodophyta.
The picture at the right shows the two classes of phycobilins which may be extracted from these "algae". The vial on the left contains the bluish pigment phycocyanin, which gives the Cyanobacteria their name. The vial on the right contains the reddish pigment phycoerythrin, which gives the red algae their common name.
Phycobilins are not only useful to the organisms which use them for soaking up light energy; they have also found use as research tools. Both pycocyanin and phycoerythrin fluoresce at a particular wavelength. That is, when they are exposed to strong light, they absorb the light energy, and release it by emitting light of a very narrow range of wavelengths. The light produced by this fluorescence is so distinctive and reliable, that phycobilins may be used as chemical "tags". The pigments are chemically bonded to antibodies, which are then put into a solution of cells. When the solution is sprayed as a stream of fine droplets past a laser and computer sensor, a machine can identify whether the cells in the droplets have been "tagged" by the antibodies. This has found extensive use in cancer research, for "tagging" tumor cells.
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Pigments are colorful compounds.
Pigments are chemical compounds which reflect only certain wavelengths of visible light. This makes them appear "colorful". Flowers, corals, and even animal skin contain pigments which give them their colors. More important than their reflection of light is the ability of pigments to absorb certain wavelengths.
Because they interact with light to absorb only certain wavelengths, pigments are useful to plants and other autotrophs --organisms which make their own food using photosynthesis. In plants, algae, and cyanobacteria, pigments are the means by which the energy of sunlight is captured for photosynthesis. However, since each pigment reacts with only a narrow range of the spectrum, there is usually a need to produce several kinds of pigments, each of a different color, to capture more of the sun's energy.
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There are three basic classes of pigments.
Chlorophylls are greenish pigments which contain a porphyrin ring. This is a stable ring-shaped molecule around which electrons are free to migrate. Because the electrons move freely, the ring has the potential to gain or lose electrons easily, and thus the potential to provide energized electrons to other molecules. This is the fundamental process by which chlorophyll "captures" the energy of sunlight.
There are several kinds of chlorophyll, the most important being chlorophyll "a". This is the molecule which makes photosynthesis possible, by passing its energized electrons on to molecules which will manufacture sugars. All plants, algae, and cyanobacteria which photosynthesize contain chlorophyll "a". A second kind of chlorophyll is chlorophyll "b", which occurs only in "green algae" and in the plants. A third form of chlorophyll which is common is (not surprisingly) called chlorophyll "c", and is found only in the photosynthetic members of the Chromista as well as the dinoflagellates. The differences between the chlorophylls of these major groups was one of the first clues that they were not as closely related as previously thought.
Carotenoids are usually red, orange, or yellow pigments, and include the familiar compound carotene, which gives carrots their color. These compounds are composed of two small six-carbon rings connected by a "chain" of carbon atoms. As a result, they do not dissolve in water, and must be attached to membranes within the cell. Carotenoids cannot transfer sunlight energy directly to the photosynthetic pathway, but must pass their absorbed energy to chlorophyll. For this reason, they are called accessory pigments. One very visible accessory pigment is fucoxanthin the brown pigment which colors kelps and other brown algae as well as the diatoms.
Phycobilins are water-soluble pigments, and are therefore found in the cytoplasm, or in the stroma of the chloroplast. They occur only in Cyanobacteria and Rhodophyta.
The picture at the right shows the two classes of phycobilins which may be extracted from these "algae". The vial on the left contains the bluish pigment phycocyanin, which gives the Cyanobacteria their name. The vial on the right contains the reddish pigment phycoerythrin, which gives the red algae their common name.
Phycobilins are not only useful to the organisms which use them for soaking up light energy; they have also found use as research tools. Both pycocyanin and phycoerythrin fluoresce at a particular wavelength. That is, when they are exposed to strong light, they absorb the light energy, and release it by emitting light of a very narrow range of wavelengths. The light produced by this fluorescence is so distinctive and reliable, that phycobilins may be used as chemical "tags". The pigments are chemically bonded to antibodies, which are then put into a solution of cells. When the solution is sprayed as a stream of fine droplets past a laser and computer sensor, a machine can identify whether the cells in the droplets have been "tagged" by the antibodies. This has found extensive use in cancer research, for "tagging" tumor cells.
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Introduction to the Rhodophyta
Introduction to the Rhodophyta
The red "algae"
Red algae are red because of the presence of the pigment phycoerythrin; this pigment reflects red light and absorbs blue light. Because blue light penetrates water to a greater depth than light of longer wavelengths, these pigments allow red algae to photosynthesize and live at somewhat greater depths than most other "algae". Some rhodophytes have very little phycoerythrin, and may appear green or bluish from the chlorophyll and other pigments present in them.
In Asia, rhodophytes are important sources of food, such as nori. The high vitamin and protein content of this food makes it attractive, as does the relative simplicity of cultivation, which began in Japan more than 300 years ago.
Some rhodophytes are also important in the formation of tropical reefs, an activity with which they have been involved for millions of years; in some Pacific atolls, red algae have contributed far more to reef structure than other organisms, even more than corals. These reef-building rhodophytes are called coralline algae, because they secrete a hard shell of carbonate around themselves, in much the same way that corals do.
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Click on the buttons below to learn more about the Rhodophyta.
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For more information:
Algae: The Forgotten Treasure of Tidepools is an excellent exhibit at Sonoma State on California tidepool algae, including red algae.
Visit Michael Rasser's pages on FOSSIL CORALLINE ALGAE (Corallinaceae: Rhodophyta).
For more on the biology and economic uses of seaweeds, including rhodophytes, visit the marine plants database of the DELTA Project, or the Seaweed Information Server maintained at University College Galway, Ireland. Or go to the exhibit on Porphyra, a typical red alga, from the Protist Image Database at the University of Montreal.
Derek Keats at the University of Western Cape, South Africa, has put extensive information about the nongeniculate coralline algae on-line. David Hills has a page on Pleistocene crustose coralline algae.
For a fuller listing of on-line phycological collections resources, try our Phycological Collection Catalogs Listings.
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The image of Porphyra is one of several images of Rhodophyta available from the excellent Virtual Foliage Page image collection of the University of Wisconsin-La Crosse. Image used with permission.
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The red "algae"
Red algae are red because of the presence of the pigment phycoerythrin; this pigment reflects red light and absorbs blue light. Because blue light penetrates water to a greater depth than light of longer wavelengths, these pigments allow red algae to photosynthesize and live at somewhat greater depths than most other "algae". Some rhodophytes have very little phycoerythrin, and may appear green or bluish from the chlorophyll and other pigments present in them.
In Asia, rhodophytes are important sources of food, such as nori. The high vitamin and protein content of this food makes it attractive, as does the relative simplicity of cultivation, which began in Japan more than 300 years ago.
Some rhodophytes are also important in the formation of tropical reefs, an activity with which they have been involved for millions of years; in some Pacific atolls, red algae have contributed far more to reef structure than other organisms, even more than corals. These reef-building rhodophytes are called coralline algae, because they secrete a hard shell of carbonate around themselves, in much the same way that corals do.
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Click on the buttons below to learn more about the Rhodophyta.
--------------------------------------------------------------------------------
For more information:
Algae: The Forgotten Treasure of Tidepools is an excellent exhibit at Sonoma State on California tidepool algae, including red algae.
Visit Michael Rasser's pages on FOSSIL CORALLINE ALGAE (Corallinaceae: Rhodophyta).
For more on the biology and economic uses of seaweeds, including rhodophytes, visit the marine plants database of the DELTA Project, or the Seaweed Information Server maintained at University College Galway, Ireland. Or go to the exhibit on Porphyra, a typical red alga, from the Protist Image Database at the University of Montreal.
Derek Keats at the University of Western Cape, South Africa, has put extensive information about the nongeniculate coralline algae on-line. David Hills has a page on Pleistocene crustose coralline algae.
For a fuller listing of on-line phycological collections resources, try our Phycological Collection Catalogs Listings.
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The image of Porphyra is one of several images of Rhodophyta available from the excellent Virtual Foliage Page image collection of the University of Wisconsin-La Crosse. Image used with permission.
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Introduction to the Psilotales
Introduction to the Psilotales
the whisk ferns
The Psilotales are the least complex of all terrestrial vascular plants, and were once believed to be remnants of an otherwise extinct Devonian flora. This is primarily because psilophytes are the only living vascular plants to lack both roots and leaves. Though they have been considered “primitive,” recent developmental and molecular evidence suggests that the group may actually be reduced from fern-like ancestors. There is not universal agreement on this, but we here treat them with the ferns for that reason. Despite the uncertainty of their relationships, psilophytes do structurally resemble certain early vascular plants, and are used as a model for understanding the ecology of these plants.
This is a small group with only two genera, Psilotum, shown above left, and Tmesipteris, above right, neither with many species. Both genera grow in tropical or subtropical regions, where they occur on rich soil or as epiphytes. Psilotum occurs in North America in the Caribbean, and along the Gulf and Atlantic Coasts to as far north as North Carolina, and has been reported from one locality in Arizona. It may also be found in tropical Asia and on Pacific islands. Tmesipteris grows in New Caledonia and nearby areas of the South Pacific, including Australia and New Zealand.
In addition to its natural distribution, Psilotum is also found as a common weed in greenhouses, and sometimes escapes cultivation in regions with mild climate. It occasionally becomes a nuisance, but is still very popular for its unusual growth form. In Japan, more than 100 unusual breeds have been produced, some of them highly prized by cultivators.
The Psilotales have no fossil record at all.
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Morphology and Life History of Psilotales
The psilophyte stem lacks roots; it is anchored instead by a horizontally creeping stem called a rhizome. The erect portion of the stem bears paired enations, outgrowths which look like miniature leaves, but unlike true leaves, the enations have no vascular tissue. These paired outgrowths lie immediately below the spore-producing synangia, which produce the spores. The synangia appear to be the product of three sporangia which became fused over the course of evolution, and are borne on the tip of a short lateral branch. This is another feature in which the psilophytes differ from other living vascular plants; all other such plants produce their sporangia on their leaves. You can click on the picture of the synangia of Psilotum at right, for a better look at these structures.
When the synangia mature, they open to release yellow to whitish spores, from which the gametophyte plants will later emerge, like the one shown at left. The gametophytes are very small, usually less than two millimeters long. They are subterranean and saprophytic, getting their nutrition by absorbing substances dissolved in the environment. This is often aided by the presence of fungi which grow into the tissues of the gametophyte and through the surrounding soil.
Eventually, the gametophyte reaches sexual maturity, producing both egg and sperm cells. The multiflagellate sperm swim to the egg cells, where they unite to begin the sporophyte generation. Psilophyte gametophytes may even self-fertilize to produce a sporophyte plant. The resulting sporophyte begins its life as a dependent on its parent gametophyte, as in other seedless plants. But unlike the “bryophytes,” the sporophyte eventually gains independence from its parent, and establishes itself in the environment.
The mature sporophyte of Psilotum will often grow to 30 cm tall, and may grow even taller. It has no true leaves, and instead the stem is green and photosynthetic, being covered with stomates to allow gas exchange. As the cross-section at right shows, the stem has a central core of vascular tissue (protostele) which is usually lobed. The thick-walled cells in the center of this core are sometimes considered to be pith, in which case the vascular arrangement would actually be a siphonostele. Surrounding the vascular tissue is a layer called the endodermis, which has specially packed cells to regulate flow of water and nutrients.
Tmesipteris has similar reproductive structures and life history to that of Psilotum, but by contrast it has broad leaf-like extensions of its stem, each with a single vascular bundle. These extensions may lie to either side of the stem, forming a flat growth, or they may be radially arranged. In any case, they are not considered leaves by most botanists, though this interpretation has been challenged by some workers.
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There is a nice collection of Psilotum images at the University of Wisconsin; the image of the Psilotum gametophyte on this page was made available through them.
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the whisk ferns
The Psilotales are the least complex of all terrestrial vascular plants, and were once believed to be remnants of an otherwise extinct Devonian flora. This is primarily because psilophytes are the only living vascular plants to lack both roots and leaves. Though they have been considered “primitive,” recent developmental and molecular evidence suggests that the group may actually be reduced from fern-like ancestors. There is not universal agreement on this, but we here treat them with the ferns for that reason. Despite the uncertainty of their relationships, psilophytes do structurally resemble certain early vascular plants, and are used as a model for understanding the ecology of these plants.
This is a small group with only two genera, Psilotum, shown above left, and Tmesipteris, above right, neither with many species. Both genera grow in tropical or subtropical regions, where they occur on rich soil or as epiphytes. Psilotum occurs in North America in the Caribbean, and along the Gulf and Atlantic Coasts to as far north as North Carolina, and has been reported from one locality in Arizona. It may also be found in tropical Asia and on Pacific islands. Tmesipteris grows in New Caledonia and nearby areas of the South Pacific, including Australia and New Zealand.
In addition to its natural distribution, Psilotum is also found as a common weed in greenhouses, and sometimes escapes cultivation in regions with mild climate. It occasionally becomes a nuisance, but is still very popular for its unusual growth form. In Japan, more than 100 unusual breeds have been produced, some of them highly prized by cultivators.
The Psilotales have no fossil record at all.
--------------------------------------------------------------------------------
Morphology and Life History of Psilotales
The psilophyte stem lacks roots; it is anchored instead by a horizontally creeping stem called a rhizome. The erect portion of the stem bears paired enations, outgrowths which look like miniature leaves, but unlike true leaves, the enations have no vascular tissue. These paired outgrowths lie immediately below the spore-producing synangia, which produce the spores. The synangia appear to be the product of three sporangia which became fused over the course of evolution, and are borne on the tip of a short lateral branch. This is another feature in which the psilophytes differ from other living vascular plants; all other such plants produce their sporangia on their leaves. You can click on the picture of the synangia of Psilotum at right, for a better look at these structures.
When the synangia mature, they open to release yellow to whitish spores, from which the gametophyte plants will later emerge, like the one shown at left. The gametophytes are very small, usually less than two millimeters long. They are subterranean and saprophytic, getting their nutrition by absorbing substances dissolved in the environment. This is often aided by the presence of fungi which grow into the tissues of the gametophyte and through the surrounding soil.
Eventually, the gametophyte reaches sexual maturity, producing both egg and sperm cells. The multiflagellate sperm swim to the egg cells, where they unite to begin the sporophyte generation. Psilophyte gametophytes may even self-fertilize to produce a sporophyte plant. The resulting sporophyte begins its life as a dependent on its parent gametophyte, as in other seedless plants. But unlike the “bryophytes,” the sporophyte eventually gains independence from its parent, and establishes itself in the environment.
The mature sporophyte of Psilotum will often grow to 30 cm tall, and may grow even taller. It has no true leaves, and instead the stem is green and photosynthetic, being covered with stomates to allow gas exchange. As the cross-section at right shows, the stem has a central core of vascular tissue (protostele) which is usually lobed. The thick-walled cells in the center of this core are sometimes considered to be pith, in which case the vascular arrangement would actually be a siphonostele. Surrounding the vascular tissue is a layer called the endodermis, which has specially packed cells to regulate flow of water and nutrients.
Tmesipteris has similar reproductive structures and life history to that of Psilotum, but by contrast it has broad leaf-like extensions of its stem, each with a single vascular bundle. These extensions may lie to either side of the stem, forming a flat growth, or they may be radially arranged. In any case, they are not considered leaves by most botanists, though this interpretation has been challenged by some workers.
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There is a nice collection of Psilotum images at the University of Wisconsin; the image of the Psilotum gametophyte on this page was made available through them.
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The Devonian
The Devonian
417 to 354 Million Years Ago
The Rhynie Chert in Scotland is a Devonian age deposit containing fossils of both Zosterophyllophytes and Trimerophytes, the two major lines of vascular plants. This indicates that prior to the start of the Devonian, the first major radiations of the plants had already happened. The oldest known vascular plants in the Northern Hemisphere are Devonian.
The vegetation of the early Devonian consisted primarily of small plants, the tallest being only a meter tall. By the end of the Devonian, ferns, horsetails and seed plants had also appeared, producing the first trees and the first forests. Archaeopteris, shown below left, is one of these first trees.
Also during the Devonian, two major animal groups colonized the land. The first tetrapods, or land-living vertebrates, appeared during the Devonian, as did the first terrestrial arthropods, including wingless insects and the earliest arachnids. In the oceans, brachiopods flourished, like the beautifully pyritized brachiopod Paraspirifer bownockeri from Ohio, pictured above and to the right. Crinoids and other echinoderms, tabulate and rugose corals, and ammonites were also common. Many new kinds of fish appeared.
During the Devonian, there were three major continental masses: North America and Europe sat together near the equator, much of their current land underneath seas. To the north lay a portion of modern Siberia. A composite continent of South America, Africa, Antarctica, India, and Australia dominated the southern hemisphere.
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Click on the buttons below to learn more about the Devonian.
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Subdivisions of the
Devonian:
The chart at left shows the major subdivisions of the Devonian Period. This image is mapped to take you back to the Silurian, or forward in time to the Carboniferous Period.
The Devonian Period is part of the Paleozoic Era.
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One of the best places to learn more about the Devonian is the Devonian Times site.
Tour Devonian Fossil Gorge near Iowa City.
Visit Karl Wilson's site on New York Paleontology, which includes a nice section on New York in the Devonian.
Find out more about the Devonian paleontology and geology of North America at the Paleontology Portal.
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417 to 354 Million Years Ago
The Rhynie Chert in Scotland is a Devonian age deposit containing fossils of both Zosterophyllophytes and Trimerophytes, the two major lines of vascular plants. This indicates that prior to the start of the Devonian, the first major radiations of the plants had already happened. The oldest known vascular plants in the Northern Hemisphere are Devonian.
The vegetation of the early Devonian consisted primarily of small plants, the tallest being only a meter tall. By the end of the Devonian, ferns, horsetails and seed plants had also appeared, producing the first trees and the first forests. Archaeopteris, shown below left, is one of these first trees.
Also during the Devonian, two major animal groups colonized the land. The first tetrapods, or land-living vertebrates, appeared during the Devonian, as did the first terrestrial arthropods, including wingless insects and the earliest arachnids. In the oceans, brachiopods flourished, like the beautifully pyritized brachiopod Paraspirifer bownockeri from Ohio, pictured above and to the right. Crinoids and other echinoderms, tabulate and rugose corals, and ammonites were also common. Many new kinds of fish appeared.
During the Devonian, there were three major continental masses: North America and Europe sat together near the equator, much of their current land underneath seas. To the north lay a portion of modern Siberia. A composite continent of South America, Africa, Antarctica, India, and Australia dominated the southern hemisphere.
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Click on the buttons below to learn more about the Devonian.
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Subdivisions of the
Devonian:
The chart at left shows the major subdivisions of the Devonian Period. This image is mapped to take you back to the Silurian, or forward in time to the Carboniferous Period.
The Devonian Period is part of the Paleozoic Era.
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One of the best places to learn more about the Devonian is the Devonian Times site.
Tour Devonian Fossil Gorge near Iowa City.
Visit Karl Wilson's site on New York Paleontology, which includes a nice section on New York in the Devonian.
Find out more about the Devonian paleontology and geology of North America at the Paleontology Portal.
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