Plants & Human Affairs
Cherries.wmf (7140 bytes) Plants & Human Affairs (BIOL106)  -  Stephen G. Saupe, Ph.D.; Biology Department, College of St. Benedict/St. John's University, Collegeville, MN 56321;;

Private Lives of Plants #5:  Living Together

Overview:   Plants, as do all organisms, interact with organisms.  These interactions can take a variety of forms and may be very beneficial to the plant way of life.  This video highlights some of these relationships.


  1. Corals are invertebrate animals that have a branched or dendritic appearance, just like plants.  Explain why coral and plants have a similar structure.  What is the advantage?


  2. Explain why are corals found in relatively shallow, clear water.


  3. Give three examples of algae that live in association with animals.

Acacia's.  Acacia's are leguminous trees that have swollen stipular spines that provide a home for ants.  This is often cited as an example of coevolution in which both partners benefit from their mutual association. 

  1. The plant provides the ants with a home and food.  Identify the two major food sources for the ants.


  2. Identify two ways that the ants benefit the plants.


Fungi.   (prounounced "fun ji" - North America or "fun guy" or "fun - ge," European) 

  1. Fungi interact in many ways with plants.  Identify at least three ways fungi benefit plants (hints - wood rotting, roots, orchids)


  2. What is a lichen?


Parasitic Plants Matching.  Parasitic plants obtain nutrients (carbohydrates) and/or water and minerals from another (called the host) plant.  Holo-parasites are completely parasitic obtaining all of their nutrients (organics, water, minerals) from a host.  Thus, theses plants lack chlorophyll and are unable to photosynthesize.  Hemi-parasites are green and can make their own food through photosynthesis.  However, they rely on a host for support and water/minerals. 

a. Dodder b. Mistletoe c. Rafflesia
1.   Produces the largest single flower

sticky seeds, adheres to bird beaks



4.   hemiparasite
5. a.
holoparasite (2 answers)
6.   Spends entire life, except for flowering, completely within a host plant
7.   main part of plant body is made of hair-like filaments
8.   associated with Christmas
9.   parasite on herbaceous plants
10.   weedy parasite

Bonus:  What was your favorite plant or section of today's video? 



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Last updated:  03/02/2005 / � Copyright  by SG Saupe