Pollen producing plants

Gymnosperms  Have long thin needle like leaves – to conserve water.  Largest group are the conifers – “Christmas” trees  Are “evergreens” – retain their leaves all year long.  Seeds are on the cone – exposed, not protected.  Have “male” and “female” cones.  Female cones contain ovules  Male cones produce pollen, in large quantities  Pollen is dispersed by the wind  Why do you think these plants produce such a LARGE amount of pollen??

Angiosperms  Develop flowers for the purpose of reproduction  This is an evolutionary advantage because flowers attract insects which can then transport pollen from one flower to another  Can produce less pollen  There is an ovary in each flower that protects the seed  After pollination, the ovary develops into a fruit which protects the seed and aids in its dispersal.  In comparison with Gymnosperms, where is the effort placed in angiosperms? (Flower? Pollen? Fruit?)

World global diet  What percent of the global diet comes from plants?  Hint: you may need to add some pies slices together here.  What about the 13.5% that is not plant based… is it also dependent upon plants in any way?

Pollination vs Fertilization  What’s the difference?

Seed dispersal  Seeds can be dispersed by wind, water, animals…

Spore producers Bacillus anthracis (anthrax) Algae Fungi Ferns

Spores  Understanding spore production and the different organisms that produce spores can help create a spore profile for an area.  Spore producers include protists (algae), fungi, and plants.  Bacteria produce endospores. Endospores are not used in reproduction, they are a dormant capsule of the bacteria.  Some endospores cause disease – Anthrax & botulism are examples.  Spores are dispersed by wind or water.  Spores have widespread coverage in certain geographic areas, just like pollen.  Spores are able to be grown to identify the species exactly.

Pollen and Spore Identification  The hard outer layer of a pollen grain and spore is called the exine.  Exines have a unique structure when viewed under a microscope.  Size, shape, wall thickness, & surface texture  Wind dispersed pollen grains have thinner walls  Animal dispersed pollen are larger, “stickier”, and thick- walled.  Spores are much smaller than pollen grains and produced in greater quantities.  Spores are more difficult to identify than pollen, but they can be grown into a full sized organism for identification.

Pollen and Spores in Forensics  If the pollen or spores found on the victim are not native to the crime scene, it may indicate the body was moved.  Pollen and spores are difficult to remove and/or get rid of.  Pollen and spores are drought resistant and are very hardy.  Pollen and spores can give investigators a timeline for the crime.  Criminals may pick up pollen or spores on their clothing from a crime scene without knowing or thinking of it.

Pollen and Spores in Forensics

Collecting Pollen and Spores  Control and evidence samples must be collected.  Contamination is a major problem with collection and a good defense lawyer will target this to look for holes in the prosecution’s case.  Pollen and spores can be found everywhere, some areas to look are:  Hair, fur, rope, feathers, clothing, mucus membranes, & sticky surfaces  When collecting samples:  Wear clean gloves  Place samples in a sterile container  Use clean or new sampling instruments

Analyzing Pollen and Spore Samples  Pollen and spores are chemically extracted from samples in a lab  Tools specialists use to examine and identify include:  compound light microscope  scanning electron microscope (SEM)  reference collections (photos, illustrations, dried specimens)  Pollen and spore evidence—collected, analyzed, and interpreted—can be presented in court

Making a wet mount  Materials  Microscope slide  Cover slip  Water  Dropper  Specimen  Stain (if required)  Procedure  Place a drop of water on the center of a clean dry slide (if the specimen you plan to observe is already in a liquid environment, you can skip this step).  Next, place your specimen in the middle of the drop.  Carefully place one edge of the cover slip next to the water, holding the cover slip at a 45 degree angle to the microscope slide.  Slowly lower the cover slip onto the water, trying to minimize the number of air bubbles that can form under the cover slip.  Lastly, you may want to use a paper towel, placed at the edge of the cover slip, to draw out some of the extra water.  If using a stain, place a drop of stain at one side of the cover slip while holding a paper towel at the other side. This will draw the stain across the specimen.

Calculating size of an object in micrometers  Determine the size of the field of view in millimeters using a ruler at 100x (that’s your medium power).  Now convert to micrometers: 1mm = 1000μm.  You now know what the size of your field of view is in μm.  Estimate the size of your pollen (or cell, hair, fiber, etc.) with respect to how many can fit across the field of view.  Then calculate the size of the object: Field of view (in μm)= size of object Number of objects across field