Gymnosperm Case Study

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II. Nature is not a Museum
The gymnosperms are often called ‘Living Fossils’, or are dismissed as being primitive. Gymnosperms are indeed ancient: originating in the carboniferous period (Bowe, Coat, & dePamphilis, 2000). They can be divided into four monophyletic groups: ginkophytes, gnetophytes, cycads, and the largest of the four (with more than 600 extant species), conifers. Conifers account for the greatest diversity amongst the gymnosperms. This diversity might pale in comparison to that of the angiosperms, but a group can have biological importance without being speciose. From an ecological point of view, gymnosperm success is in fact comparable to angiosperms, as gymnosperms are thriving in important niches across latitudes. This is
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Though specific geographical distributions of gymnosperms are poorly documented, some broad conclusions have been made. For instance, Bond (1989), Coomes et al. (2005), and Lusk (2011) found that competition with angiosperms has limited all living gymnosperms to areas of high latitude and high elevation. This has also been documented in a recent meta-analysis by Fragniere et al. (2015). Gymnosperms hence exhibit the inverse of the general latitudinal diversity gradient: in species richness from the equator to the poles, and decreasing at equatorial latitudes. The observed pattern is apparent when considering gymnosperms as a group and when the group is split into separate lineages. One downfall of their analysis is, however, that the varying availability of land approaching the equator was not taken into account, which would perhaps be a confounding factor. While this needs to be corrected for, the study nevertheless pinpoints an underlying pattern that would likely be retained when standardized by land area …show more content…
In regards to future research, it would be useful to ascertain the proportion of total plants that gymnosperms account for in these environments (i.e. (Number of gymnosperms)/(Number of gymnosperms + angiosperms)) in a given area, for ease of comparability and to remove any size effects. Linking biogeography with quantitative measures of abundance can give an indication of how gymnosperms stack up against angiosperms, and the more quantitative information obtained, the greater our understanding. For example, in the analysis by Fragniere et al. (2015) it was ascertained that the mean conservation threat level of gymnosperms decreases in equatorial latitudes. These areas, where they are least threatened, are productive areas in which they are increasingly in contact with angiosperms. We would therefore expect that under Bond’s (1989) hypothesis, they should be experiencing considerable competition, facing extinction: but they are not. Thus, the competitive superiority of angiosperms does not appear to fully explain global distributions of

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