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Gymnospermae

Gymnospermae Cycadophyta Gingkophyta Coniferophyta

Note the location of Gingkophyta

Ginkgo Live Submittal

History

The first Ginkgo leaves were found during the Triassic period. There were many species of Ginkgo during the Jurassic and Cretaceous periods as well (Beck 2017). These periods, known as the Mesozoic era, were when diversity and distribution were at their highest, including in Ginkophytes. The early Cenozoic period was when Ginkgo nearly became extinct, specifically during the early Cretaceous and Tertiary periods. The only remaining Ginkgo was Ginkgo adiantoidses – a polymorphic species. The Chinese were the ones to save Ginkgo, as they grew them in their temple gardens. This is why modern Ginkgo trees are native to China.

Reproduction

Ginkgo trees produce ovulate, pollen-bearing structures. These structures are dioecious, in that male and female structures come from different Ginkgo plants. The pollen organs are very similar to angiospermous catkins. They come from the axils of the bud scales, and the leaves from the Ginkgo tree spur shoots. Pollen is contained in sacs of two to four at the tips of sporophylls on the strobiloid. Ovules of Ginkgo trees come from stalks from leaf axils on the short shoots, each containing two ovules. The ovule is fertilized by the flagellated male gametes, which can move about freely. This fertilization process begins on the tree itself in the spring. The swollen fruit-like ovules, about 2-3 cm diameter, fall from the tree in the fall, and fertilization continues into the winter/spring.  This fruit contains a single large seed, similar to that of a cycad.

Morphology

Ginkgophyte wood

Fossils that appear Ginkgo-like are filed under a morphogenus called Ginkgoxylon, Ginkgomyeloxylon, or Protoginkgoxylon. Fossilized ginkgophyte wood is not commonly found in the record, possibly because it degrades easily, and possibly because it is difficult to tell apart from the much more pervasive conifer samples.^[3] Like conifer wood, it has secondary thin-walled xylem and a primary vascular system composed of eustele and bifacial vascular cambium.  The tracheids in the secondary xylem rays have pitting that occurs only on the walls and is circularly bordered.^[4]

Ginkgophyte foliage

Ginkgophyte foliage has stayed largely consistent since the Mesozoic.  Its historically wide territory makes it an important leaf morphology, and its unique stomata and isotopic profile give it a key role in recreations of the Mesozoic and Cenozoic.  Leaf fossils that resemble the Ginkgophytes are known as Ginkgoites.  There are similar, now extinct, morphogens, such as Sphenobaiera, which describes fan-shaped, deeply divided leaves without clear petioles. 

The distinctive shape of the modern Ginkgo biloba gives the impression of a very narrow leaf morphology, but the group is varied and diverse.  The Ginkgo genus by itself contains a range of morphologies.  Ginkgo digitatta, from the Jurassic, has long, wedge-shaped laminae with the intercostal regions covered in stomata and resin bodies, while G. pluripartita has at most 2cm-long leaves and is intercostally hypostomatic.^[3]

Ginkgo Article

{{Neornithes cladogram}}

Outline for Article

History (Evan)

http://www.accessscience.com/content/289700

Beck, C. B. (n.d.). Ginkgoales. Retrieved April 13, 2017, from http://accessscience.com.ezproxy.wpi.edu/content/289700

First Ginkgo leaves found during Upper Triassic Period

• Had many species during Jurassic, Cretaceous
• Almost died off in Early Cretaceous, Tertiary periods
• Chinese saved Ginkgo, grew them in temple gardens

http://www.ucmp.berkeley.edu/seedplants/ginkgoales/ginkgo.html

Jalalpour, J., Malkin, M., Poon, P., Rehrmann, L., & Yu, J. (1997). Introduction to the Ginkgoales. Retrieved April 13, 2017, from http://www.ucmp.berkeley.edu/seedplants/ginkgoales/ginkgo.html

Increased during the middle Jurassic and achieved max diversity during the Cretaceous, with a sharp retraction during the paleocene. Only the species Ginkgo adiantoidses--a polymorphic species--remained.

Chapter 18: Ginkophytes 'The Biology and Evolution of Fossil Plants

Krings, M., Taylor, T. N., & Taylor, E. L. (2008). Chapter 18: Ginkgophytes. In Paleobotany: The Biology and Evolution of Fossil Plants (2nd ed., pp. 743-756). Academic Press.

• Diversity and distribution of Ginkgophytes were highest during Mesozoic Period
• Almost lost during Cenozoic

Morphology (Tomas)

http://www.ucmp.berkeley.edu/seedplants/ginkgoales/ginkgomm.html

MORPHOLOGY:

Ginkgophyte Foliage

The extent of differentiation within the leaves of one plant make fossil identification difficult. The leaves are open dichotomous, fanned, and have hypostomatic cuticles with the adaxial side containing a minority of stomata. The last trait reduces water loss. Slender petioles. clustered leaves grow on 3-inch shoots. Drooping branches. Grey bark, yellow wood.

Reproduction (Evan)

http://www.ucmp.berkeley.edu/seedplants/ginkgoales/ginkgomm.html

REPRODUCTION: Dioecious, like cycads and conifers. Spur shoots produce pollen cones and seed structures. A cone has sacs. Motile sperm, not in conifers and angiosperms. Cones appear in spring, ovules appear in fall. Also, asexual reproduction. Burls grow into ground and leaf.

Cladogram (Tomas)

Ginkgo Notes

Sources

http://www.ucmp.berkeley.edu/seedplants/ginkgoales/ginkgo.html

http://www.ucmp.berkeley.edu/seedplants/ginkgoales/ginkgomm.html

http://www.accessscience.com/content/289700

http://www.jstor.org/stable/pdf/27571195.pdf

Notes

UCMP

• Buddhist monks adopted it as a sacred tree
• They are all gymnosperms; closely related to conifers
• Increased during the middle Jurassic and achieved max diversity during the Cretaceous, with a sharp retraction during the paleocene. Only the species Ginkgo adiantoidses--a polymorphic species--remained.

UCMP 2

• MORPHOLOGY: The extent of differentiation within the leaves of one plant make fossil identification difficult. The leaves are open dichotomous, fanned, and have hypostomatic cuticles with the adaxial side containing a minority of stomata. The last trait reduces water loss. Slender petioles. clustered leaves grow on 3-inch shoots. Drooping branches. Grey bark, yellow wood.
• REPRODUCTION: Dioecious, like cycads and conifers. Spur shoots produce pollen cones and seed structures. A cone has sacs. Motile sperm, not in conifers and angiosperms. Cones appear in spring, ovules appear in fall. Also, asexual reproduction. Burls grow into ground and leaf.
• Similar to Conifers: Primitive vascular system, with eustele and bifacial vascular cambium. Secondary xylem made of thin-walled tracheids & narrow vascular rays. Tracheal pitting is circular bordered and restricted to radial walls.

Charles Beck 'Ginkgoales'

• Trees are native to China
• Trees used in cities to aid decreasing impact of disease & air pollution
• First Ginkgo leaves found during Upper Triassic Period
  • Had many species during Jurassic, Cretaceous
  • Almost died off in Early Cretaceous, Tertiary periods
  • Chinese saved Ginkgo, grew them in temple gardens
• Morphology, reproduction label Ginkgo as gymnosperm
• Leaves fan-shaped
• Long shoots (on trees) have alternating leaves
• Short shoots on trees have leaf clusters
  • Come from leaf axils on long shoots
• Leaves = dioecious (male/female on different trees)

Wikipedia Evaluation

Botany

• Were they found in 221 BC, or was China unified then?
• Add link to unification of China
• A chart of where it exists within biology could be helpful
• Honestly, this article seems huge and really good
• It seems odd to end on systematic biology

Cyanobacteria

• There's a citation missing in the first paragraph of nitrogen fixation, but it's flagged
• The section about their effects on water utilities needs citation, probably
• Also, the first sentence under Photosynthesis needs citation
• According to the Talk section, there's some controversy around the word "billion"?
• Also from the Talk section: these people are really smart
• There is no history. There should be history.

Pinophyta

• The taxonomic section in the overview is from 1998. Outdated? Fine?
• "Largest terrestrial carbon sink" could use a citation.
• The shape of Northern Confers helps the shed snow. WHAT. WHAAAT. I NEVER KNEW THAT
• "Economically most important" is a large claim, and I think it might be good to expand on it.
• Now, this may just be me, but I think it would be good to add a section about succession. At least in California, conifers are kind of a problem. They are more successful than the Oak forests, but their allopathic and nonnutritious nature makes them actively harmful to the biome; they simply do not contribute to the same biodiversity.
• Those stats about the redwoods are not cited.