Plants > Plant History
[Editor's Note: We welcome your collaboration if you want to help us research, write, or edit any part of this article, a work in progress. We need paleobotanical or archaeoloical evidence for the period 6,000 - 100 BP, especially in Broward or SE Florida. We need to document our sources throughout. If statements are not good science, let us know. Thank you. Write to: Richard@Brownscombe.net]
Our story begins a very, very long time ago, about 3.8 billion years. Tough, single-cell bacteria and archaea, were early life forms. Perhaps as early as 3.5 billion years ago, blue-green algae formed into some of our earliest photosynthetic organisms, stromatolites. Close to South Floridia, in the Bahamas National Trust, Exuma Cays Land and Sea Park you can see living stromatolites thriving today.
Since these early times and over eons oxygen increased and the continents drifted and shifted. Most scientists mark the beginning of vascular plants at around 410 million years ago. Among the first vascular flora were mosses, quillwarts, and scale trees. In Broward, Lycopodiella cernua (Nodding Clubmoss), Lycopodiella appressa (Southern Clubmoss), and Selaginella arenicola (Sand Spikemoss) are related to those ancient species. Other South Florida species with this ancient geneaology include: Isoetes flaccida (Florida Quillwart) and Selaginella armata eatonii (Eaton's Spikemoss).
Since vascular plants first appeared, countless species have come and gone, of course. The fossil record sometimes provides beautifully preserved specimen of these early plants. In South Florida the fossil record is relatively recent, since the beginning of the Holocene 12,000 years ago. Very little paleontological research has been done tell us how plants evolved in South Florida. However, microscopic research, pollen research, DNA, and even trace chemical research is increasing capable of identifying older and older species even where no intact fossils are found. This gives us hope of better understanding the environmental evolution of the Florida peninsula in the future.
[Cite Florida peninsula paleontological discoveries here.]
Locally, most of the the surviving native species migrated naturally to South Florida from temperated North American, the Carbbean, Mexico, Central and South America. They then either evolved and adapted to the Florida peninsula or remained much as they were.
An important point of comparison is that Florida's historic evolution occurred over thousands of years, giving plants a chance to adapt, evolve, and be replaced. Plants don't live in isolation, but as part of complex plant communities intertwined with microbioltic forms, insects, wildlife, weather, sifting substrates and water levels. The current climate change is taking place over hundreds of years, even decades, so will be drastically different and more impactful. Already, there is evidence that plants seasons are coming earlier. [Cite evidence.]
During the early Holocene, the seas rose and fell as the planet's water was trapped and released from massive glaciers slowly over cycles of thousands of years. When the seas fell (and the glasiers were large) the peninsula was three times the land mass of today. During the last ice age, the Florida peninsula was a wide dry Savanna, home to mega fauna. As the planet warmed the rising seas shrank peninsular Florida. Broward County was probably entirely inundated for the last time between 4,000 - 6,000 years ago. This process of repeated inundation is described in a University of Florida fact sheet by Ginger M. Allen and Martin B. Main, Florida's Geological History:
"Many of Florida's modern topographic features and surficial sediments were created or deposited during periods when sea levels were high. Waves and currents in these ancient seas eroded the exposed formations of previous epochs, reshaping earlier landforms and redistributing eroded sediments over a wide area. Florida's central ridge system represents ancient dunes that are relic habitats from periods of higher sea levels. Beneath the sea, the Florida platform acted as a marine shelf. As sea levels rose and fell, the calcium carbonate remains of sea creatures and algae formed sedimentary limestone bedrock.
"Erosion of the limestone bedrock causes karst development. Karst is a terrain or type of topography underlain by soluble rocks, such as limestone. The karst landscape is largely shaped by the dissolving action of groundwater made weakly acidic as rain collects carbon dioxide from the air and from decomposing organic matter on the ground. Given many thousands of years, this geological process results in unusual surface-subsurface features ranging from sinkholes, vertical shafts, disappearing streams, and springs to complex underground drainage systems and caves."
Worldwide scientists estimate more than 300,000 plant species (with perhaps another 80,000 yet undiscovered) on planet earth. In Rare Plants of South Florida: Their History, Conservation, and Restoration, George D. Gann, et al, state, “South Florida is one of the most biologically diverse regions in North America harboring over 1,400 species of native plants.” In Broward county we count about 733 extant native species.
[Continue here with the history or modern botany, how plants were first documented and preserved and provide a basis for understanding which secies existed before European, Caribbean, and African immigrants began importanting and cultivating plants on a wide scale. John Loomis Blodgett, John Bartram, and William Bartram are among these early botanists.]
