Transcript Chapter 12 Soil & Sand Analysis

Pollen Analysis
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 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.
Evidence
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 match
on clothing, shoes, or person
could place suspect at the scene
Flower
Pine tree
All pollen is unique
You can identify the
type of plant
and maybe its
location by its pollen
Angiosperm structure
Lily pollen