Case Study on Relationships in Ecosystems:

An observant 11 th grade biology student was doing a study on the relationships between organisms. One June, the student wandered through a Sweet Clover field and observed the following organisms and their activities :

The main producers were Sweet Clover plants, Wild Oats, Canada Thistle and Blue Burr. These species were growing and photosynthesizing, intermingled in the same field.

1. Which two of the following best describe the relationships that exist between the plants?  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition

Upon digging up a clover plant, the student observed an average of 8 nodules on the roots of each clover plant (Nodules contain bacteria which have the ability to convert atmospheric nitrogen into nitrates and release them into the soil. Plants utilize nitrates to manufacture proteins.)

2. Which of the following best describes the ecological relationship that exists between the bacteria and the clover plant?  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition

Small green aphids were sucking the juices from clover stems. Further investigation found some aphids being eaten by an army of ants.

3. What type of ecological relationship exists between the aphids and the clover?  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition

4. What type of ecological relationship exists between the ants and the aphids?  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition

A considerable number of clover and wild oat plants had been cut down and partially eaten by a colony of lined squirrels that made their home in an adjacent pasture.

5. Which of the following describes the relationship between the squirrels and the clover plants?  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition

6. What is the ecological relationship that exists between the squirrels?  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition

The squirrels had lice.

. What ecological relationship exists between the lice and the squirrels?  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition

Some clover plants had withered and died. A white fungus was found on the roots and lower stems, which was identified as root rot.

8. Which of the following best describes the ecological relationship between the clover plant and the fungus?  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition

A colony of Leaf Cutters bees was feeding on the nectar and pollinating flowers.

9. What ecological relationship exists between the flowers and the bees  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition

A bee keeper was setting out a hive of honey bees.

10. What ecological relationship exists between the bee keeper and the bees?  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition

Several butterflies and moths were flitting over the field. Some could be observed landing on flowers, others were landing on leaf axils, and the students thought they were laying eggs.

11. What ecological relationship exists between the butterflies and the leaves?  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition

Nearby, a Red Fox was dozing in the sun, contented after his recent kill, a Jack Rabbit. Several Blue Burr seeds were stuck in his coat.

12. What ecological relationship exists between the fox and the rabbit?  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition

13. What is the relationship between the seeds and the fox?  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition

Hundreds of soil insects were burrowing in and out of the soil, pausing to feed on dead plant leaves. Several species of insects were involved.

14. Which of the following best describes the ecological relationship that exists between the various species of insects?  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition

A Mallard hen brooded her clutch, hidden from the watchful eyes by the dense clover foliage.

15. What is the ecological relationship between the hen and the foliage?  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition

Prairie birds from a nearby slough picked caterpillars from clover stems.

16. What is the ecological relationship between the blackbirds and the caterpillars?  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition

17. What is the ecological relationship between the blackbirds and the clover stems?  mutualism  parasitism  commensalism  predation  competition  mutualism  parasitism  commensalism  predation  competition