A Little Bit More
The term “pollen” gets used by both hayfever sufferers and those not affected, but how many of us have ever really thought about what pollen is? The name “pollen” means dust and this is a good description; there are literally hundreds of thousands of microscopic pollen grains in the least smudge of pollen. Each species of flowering plant has its own distinctive pollen grain, by the way. The study of pollen is called palynology and is a specialized branch of botany that is particularly helpful for identifying fossilized pollen grains. Botanists can identify the plant life that was growing in a prehistoric site by simply observing the pollen grains found at the location. Of course, this assumes that the same plants growing prehistorically are closely related to those growing today!
The earliest form of pollination was wind pollination. Most pollen grains are small enough to float for long periods in the air and enough pollen grains are produced that some eventually reach their goal. The most primitive seed-producing plants, as one would expect, are all wind pollinated (cycads, maidenhair trees, and conifers). Later in the history of the earth, some plants developed true flowers. For flowering plants to reproduce, pollen from one flower must reach the pistil, or female part, of another, and to this end many varied and beautiful pollen grains have evolved. Unfortunately, some of the particular shapes and compositions of pollen grains bother some particular noses. Humans vary a great deal and you may be allergic to some conifer pollen, for example, but not to grasses, while another person is just the reverse. And then there are some of us who are not allergic to any at all – doesn’t seem fair!
Activities
Science – Who’s Allergic?
Objectives: A better sense of the number of people who are allergic
Materials: none
In casual conversation, people often remark that they’re allergic to this or to that. Not all of the material that humans are allergic to is pollen - the list can be an enormous one at that.
I think it would be interesting to have students share their own allergies and/or those of immediate family. It should be interesting to note the variety of foods and products that can cause problems.
Although an individual could be allergic to any food, such as fruits, vegetables, and meats, there are eight foods that account for 90% of all food-allergic reactions. These are: milk, egg, peanut, tree nuts (walnut, cashew, almond, etc.), fish, shellfish, soy, and wheat.
- Airborne particles (hay fever)
- grass
- weeds
- timothy grass
- birch trees
- Mold spores
- nuts (2 separate cases)
- peanuts
- Tree nuts
- sesame
- seafood
- eggs (typically albumen, the white)
- peas, beans, peanuts, soybeans and other legumes
- celery
- soy
- milk
- wheat
- corn or maize
- bee sting venom
- wasp sting venom
- Animal hair and dander
- dust mite excretion
Key Concepts
Environmental Issues, Life Cycles, Structures and Functions
Questions
Do you have a question for a naturalist? Go ahead and ask!
It's easy -- just fill out this form, submit your question and you'll receive an answer shortly.