pollen analysis. pollen and spores objectives distinguish between and explain how pollen and spore...
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Pollen and Spores objectives
• distinguish between and explain how pollen and spore evidence can be used in crime investigation
• define a pollen fingerprint • classify the different organisms that produce
pollen and spores • compare and contrast the female and male
reproductive parts in plants • distinguish between gymnosperms and
angiosperms
Pollen Samples
• Are unique to each species• Vary in appearance, size and
color• Can last unchanged for
extended periods of time
Forensic palynology is a specialized field that studies pollen and spore
evidence
• Since both pollen and spores have resistant structures, they at times can help determine such things as whether a body was moved, a crime’s location, whether it occurred in a city or in the country, or in which season it may have occurred.
Pollen/spore-Producing PlantsPollen/spore-Producing Plants
Forensic palynologists know each pollen-producing plant provides a pollen fingerprint—a specific type of pollen grain. They also know there will be a certain number of grains found in a specific geographical area during particular times of the year. – Examples of non-seed plants (spores) would be
ferns, mosses, liverworts, and horsetails.
– Examples of seed plants would be gymnosperms (cycads, ginkgoes, and conifers like an evergreen) and angiosperms (flowering plants like roses).
Gymnosperms
• Gymnosperms are the oldest seed plants. • Evergreens are conifer gymnosperms. • They produce their seeds in a hard, scaly
structure (cones). • Pollination occurs when pollen is transferred
from the male cones to the female cones. • Which of the two structures shown above
transfers pollen to the other?
Angiosperms
• The most recent plant group to evolve is known as the flowering plant.
• Identify its different parts in the illustration above.
• Plants in this group produce seeds in an enclosed fruit.
• These plants are very diverse and include corn, oaks, maples, and the grasses.
Spore producers
• Spore producers include certain protists (algae), plants, fungi, and the bacteria that produce a unique type of spore.
• Bacterial spores, endospores, can cause diseases such as anthrax and botulism.
• Spore analysis has the advantage that the spores possibly can be grown and the species identified with certainty.
Collection of evidence
• During an investigation, control samples must be collected as well as evidence samples.
• Samples must be collected wearing gloves and with clean tools (such as brushes and cellophane tape) and placed in sterile containers, which then must be sealed and labeled with care.
• Sampling instruments must be cleaned after each use, or new ones must be used.
• Collected evidence must be secured, and the chain of custody must be maintained
Examine evidence
• To identify pollen and spores, specialists can use a compound light microscope, a scanning electronic microscope, reference collections that may consist of photos and illustrations or perhaps even actual dried specimens arranged systematically (herbariums).
• Pollen and spore evidence that has been collected, analyzed, and interpreted can be presented in court.
• These “fingerprints” can be used to confirm certain aspects of a crime.
Match suspect with crime scene
Any residue found to be a matchon clothing, shoes, or personcould place suspect at the scene
Flower
Pine tree