The Evolution of Grasses and the Species That Preceded Them
Grasses, an ecosystem dominator in today's world, have a relatively short but fascinating evolutionary history. Did you know that grasses only began to exist around 60 million years ago, after the non-avian dinosaurs had gone extinct? In the vast timeframe of Earth's history, when precisely did grasses make their appearance, and what did the landscape look like before their emergence? Let's delve into the timeline and underpinning evolution of grasses and the species that preceded them.
From Ancient Prokaryotes to Modern Grasses
Grasses are angiosperms, or flowering plants, a group that first appeared during the early Cretaceous period, approximately 125 million years ago. However, it was only about 60 million years ago that grasses started to diversify and expand into their current dominant role in many ecosystems. Research suggests (Nature, 2016) that grasses evolved from a common ancestor that lived between 67 and 55 million years ago. This makes them a relatively recent addition to Earth's flora.
The Prehistoric Landscape Before Grasses
Before the emergence of grasses, the ground was covered with a diverse array of plants. This included Cycadeoida, which are closely related to cycads, and Archaeopteris, a giant conifer that contributed to the establishment of forests with complex vegetation. But let's focus specifically on ferns, the plant species that flourished during this period.
Ferns: The Predominant Vegetation
Ferns are among the oldest land plants, dating back to around 360 million years ago. One of the most notable ferns is the Coontie (Zamioclava flav Augusta), which is a cycad-like plant that predates the dinosaurs and remains in existence today. Coontie is an example of how ferns have survived significant climatic and evolutionary changes. Marie Selby Botanical Gardens conserves this fascinating species, showcasing its importance in preserving prehistoric plant life.
South African Landscapes: A Showcase of Prehistoric Plant Life
For a closer look at how prehistoric plants established themselves, one must venture to southern Africa. The landscape here is rich with areas that have retained their prehistoric plant life. From the big puddles on Table Mountain National Park to the diverse Fynbos biome, these regions are prime examples of the resilience and persistence of ancient plant life. Table Mountain National Park and the Fynbos Biome are testament to the enduring legacy of prehistoric plants.
The Southern African Desert and Namaqualand Daisies
Even in more challenging landscapes, such as the Karoo Desert, prehistoric plant life still manages to thrive. Namaqualand Daisies and other similar species can be found in the Karoo Desert National Botanical Garden. These daisies have adapted to the arid conditions and continue to bloom during the spring season, much like their prehistoric predecessors.
The Legacy of Prehistoric Plants
Understanding the evolution of grasses and the plants that preceded them provides a valuable insight into the natural history of our planet. From the ancestors of cycads to the enduring resilience of ferns, these plants have left an indelible mark on the landscape. As we continue to study and preserve these plants, we gain a deeper appreciation for the dynamic and ever-evolving nature of life on Earth.