One scientific approach used by archeologists is pollen analysis. Archeologists use pollen data and historical research to answer questions about previous environmental conditions and human behaviors, as well as the impact one had on the other. Pollen is microscopic particles of plants' bodies, or vegetative cells. Each species of plant has its own unique set of pollen that can be transported by wind or water. Scientists can use this information to determine what types of plants were growing in different areas at different times. Pollen analysis has many applications in archaeology.
Pollen analysis has been used for years by botanists to study past vegetation changes over time. However, recent advances in molecular biology have brought this type of research to a new level. Today, scientists can extract DNA from pollen samples to identify and compare whole genomes from different plants species. This allows them to build up a picture of how our world changed over time through examination of the plants that grew where and when using only small samples of material. For example, pollen from a single tree could be collected over several years to see how the composition of the forest changed due to natural events (such as fire) or human activity (such as logging). The same technique could also reveal whether some trees are genetically more resistant to pests or diseases than others. Finally, pollen analysis has been used to study migration patterns of humans and animals into new environments.
Pollen analysis is a scientific approach that can disclose evidence of past ecological and climatic changes by combining stratigraphic principles with observations of existing (today) pollen-vegetation connections to reconstruct past terrestrial vegetation. Pollen is the seed or fruit body of a plant species; it is made up of small particles containing sperm cells and ovules (female organs of plants). Pollen is released into the air when plants die and decompose, and it falls to the ground where it is swept away by wind or water. In general, older pollen is found in higher concentrations in organic soil layers because it decays more quickly than newer pollen. Pollen analysis can also reveal information about human activity during specific time periods by comparing samples collected before construction of a road or building project with those collected after the project was completed.
For example, archaeologists use pollen data to: identify and date plants present at sites where no other clues exist about what kinds of vegetation were growing there; understand how environments have changed over time by comparing results from different areas or sites within a single location; and explore how humans have influenced certain regions or ecosystems by analyzing how much pollen comes from trees, grasses, and other plants that we know were affected by human actions (e.g., deforestation, agricultural development).
Pollen analyzers (or palynologists) collect pollen from soil excavated or extracted from the earth using auger-cores. Each soil stratum is examined independently. Radiocarbon dating is routinely employed to date these strata in order to evaluate the changing pollen presence through time. Pollen is very small and light, and so is able to travel long distances on wind currents from source regions to central locations such as lakes or sea coasts where it can be washed up by waves or deposited by rain.
Pollen provides essential information about plant species present during different time periods in past climates. It has been used for this purpose since the early 1900s, when William Joseph Cook published one of the first books on the subject: The Pollen Record: Its Significance for Plant Geography.
Since then, many more books and articles have been written about pollen analysis, and its importance has been recognized by scientists all over the world. Pollen is a unique resource because no other type of fossil remains exist that allows us to follow changes in vegetation throughout geologic time.
Pollen comes in several shapes and sizes, but they all share certain features that allow scientists to identify them. All pollen consists of two parts: an outer shell or coat called the exine wall, which is produced by cells in the flower's pistil; and the nucleus, which contains the sperm cells that will become seeds.
Fossil pollen is a valuable source of information for reconstructing previous vegetation. Because vegetation is climate-sensitive, ancient pollen is a critical type of proxy data for reconstructing past climates. In insect-pollinated plants, pollen is transported from one bloom to the next by insects, often bees. As pollen falls into honeypots or other protected places, it germinates and grows into a seedling before flowering again. Thus, the pollen found in honey comes from flowers that are recently pollinated, usually within the last few weeks.
Pollen is made up of two parts: sperm cells and egg cells. The sperm cells are very small, with only 9 out of 100,000 being viable. The remaining 91% are non-viable and will eventually disintegrate. The egg cells are even smaller, with only 1 out of 100,000 being viable. The remaining 99% are non-viable and will also eventually disintegrate.
When pollen is buried in sediments, the survival of its components depends on how well-preserved the sediment is. If pollen is preserved in silica deposits called spherules, then spores will emerge from these structures when exposed to air conditions suitable for spore growth. The spore capsules will contain the intact pollen grain inside. However, if the pollen is trapped in organic material such as wood, fungus, or animal dung, then it will not survive over time.
When scientists examine sediment cores, they may discover that pollen from various species predominated in different epochs. And, because plants survive best in specific temperatures and circumstances, researchers may utilize pollen mix to estimate an era's environment. For example, if pine trees are rarely found in the core samples, then the area probably wasn't warm enough for pine trees.
Pollen is also used as a climate indicator today. Because plants only produce pollen when conditions are right, their absence or low numbers in a sample can be an indication of poor growing seasons or even natural disasters. For example, after a heavy rain or earthquake, some species of plant will produce no pollen at all for several months while they recover from the damage.
Finally, scientists can date pollen by measuring how many times it has divided itself during its lifetime. Each time a pollen grain divides, it creates two new cells with the same genetic make-up as the original. By counting these cells, scientists can tell how long ago the pollen was produced which in turn gives them information about the age of the plant it came from.
Pollen has many different applications within archaeology and geology. It can help scientists learn about past environments and guide them to potential sites worthy of further investigation.
This is a very specialized ability, and only a few professionals are capable of identifying plant species based on the size, shape, and color of pollen grains. Pollen analysis can be useful in criminal investigations to determine the presence of certain plants at a crime scene that may not be readily apparent to the naked eye.
Pollen analysis has also been used as evidence in civil lawsuits. For example, if a person alleges they were exposed to toxic chemicals at their place of employment, their employer could potentially argue that pollution was the cause of any resulting illness. The employer would then need to prove that its facilities are not contaminated to avoid liability. Pollen data could be introduced to show that polluted materials were present at the workplace at levels high enough to be harmful.
In conclusion, pollen analysis is an important tool in forensic science that assists investigators in determining the presence of certain plants at a crime scene- often something that wouldn't be evident to the naked eye.