Pollen
When we think of fossils, we often think of large animals – dinosaurs or mammoths, perhaps. Setting out on a fossil hunt means we go looking for things – using our eyes to spot the remains of animals or plants in rock. Of course, the living world isn’t limited by size and there are many types of important fossil that can only be seen under a microscope. One of these is fossilised pollen.
Pollen has been part of the reproductive process used by plants for a long time. We are all familiar with the association of flower and pollen in flowering plants but gymnosperms such as conifers, ginkgos and cycads also produce pollen as part of their reproduction.
Plant pollen is made up of tiny grains, each with a tough outer shell designed to protect the important reproductive tissues within. The shape of pollen grains varies a lot and is a bit like a fingerprint for plants in that it is often possible to use it to identify the type of plant that the pollen came from. Released in great numbers onto the wind, individual pollen grains do not always fulfil their purpose. Many fall to the ground, into in rivers, lakes or even the sea where they may settle out into mud and sediment, eventually becoming preserved within layers of rock.
Palynologists, scientists who specialise in the study of fossil pollen, are able to extract pollen from sediments using a variety of chemical processes. Examining the extracted grains under a microscope they can identify both the pollen and the plant that produced it. Usually a mixture of pollens is found within a layer, reflecting a community of plants living together in the environment. By comparing the amount and type of pollen found from one layer to the next, we are able to understand not only what these communities may have looked like but also how they have changed over time. The relationship between plant communities and climate makes fossil pollen a powerful tool in understanding ancient environments.
Pollen has been part of the reproductive process used by plants for a long time. We are all familiar with the association of flower and pollen in flowering plants but gymnosperms such as conifers, ginkgos and cycads also produce pollen as part of their reproduction.
Plant pollen is made up of tiny grains, each with a tough outer shell designed to protect the important reproductive tissues within. The shape of pollen grains varies a lot and is a bit like a fingerprint for plants in that it is often possible to use it to identify the type of plant that the pollen came from. Released in great numbers onto the wind, individual pollen grains do not always fulfil their purpose. Many fall to the ground, into in rivers, lakes or even the sea where they may settle out into mud and sediment, eventually becoming preserved within layers of rock.
Palynologists, scientists who specialise in the study of fossil pollen, are able to extract pollen from sediments using a variety of chemical processes. Examining the extracted grains under a microscope they can identify both the pollen and the plant that produced it. Usually a mixture of pollens is found within a layer, reflecting a community of plants living together in the environment. By comparing the amount and type of pollen found from one layer to the next, we are able to understand not only what these communities may have looked like but also how they have changed over time. The relationship between plant communities and climate makes fossil pollen a powerful tool in understanding ancient environments.
