Forensic palynology is the study of pollen and powdered minerals, their identification, and where and when they occur, to ascertain that a body or other object was in a certain place at a certain time.
Pollen can tell a lot about where a person or object has been, because regions of the world, or even more particular locations such a certain set of bushes, will have a distinctive collection of pollen species. Pollen evidence can also reveal the season in which a particular object picked up the pollen. Pollen has been used to trace activity at mass graves in Bosnia, catch a burglar who brushed against a Hypericum bush during a crime, and has even been proposed as an additive for bullets to enable tracking them.
For instance, a dead body may be found in a wood, and the clothes may contain pollen that was released after death (the time of death can be determined by forensic entomology), but in a place other than where it was found. That indicates that the body was moved.
Palynology is the study of pollen, spores and other microscopic plant bodies such as dinoflagellates (marine algal cysts). Pollen carries the male sex cells of flowering plants and plants that produce cones (e.g. pine trees). Spores are asexual reproductive bodies of ferns, mosses and fungi. There are four major characteristics of pollen that make it a useful scientific tool:
- (1) Microscopic size - most pollen grains are 10-70 um in diameter (there are 1,000 um in a mm).
- (2) Abundance - Pollen is produced in the anthers of flowers. Most flowers use wind or insects and small animals to help transport their pollen to the female part of a flower on another plant of the same species, so they must produce enormous amounts of pollen (100-100,000 grains per anther) to make sure some of it reaches its intended destination. BUT – most pollen ends up as particulate components of soil, dirt, dust and rocks. Therefore, pollen is everywhere.
- (3) Resistance to degradation - Pollen and spore walls are so resistant to degradation that if they are deposited in the right conditions they can be preserved in rocks for millions of years.
- (4) Complexity – most plant species produce pollen or spores that are different from pollen of other plant species. This enables palynologists to link dispersed pollen and spores found in rocks, soil, dust etc, with the plants that produced them.
Palynology is used by geologists to help date rocks for petroleum, mining and water exploration and to help unravel the history of plants on Earth; by geographers to investigate climatic and environmental change: by botanists for plant taxonomy and phylogeny; by immunologist to investigate allergenic pollen; by archaeologists to study the customs, rituals and agricultural practices of ancient peoples; by zoologists and environmental scientists to understand foraging habits of insects, birds and mammals and to investigate past native vegetation and habitats in order to preserve the present and protect endangered species.
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