Unit 2: Ecological Organization
Module 1: Ecosystems and Ecology
Learning Objectives: 2.6
Lesson 7: Ecological Relationships
Lesson Objectives:
Evaluation:
Relationships in Ecosystems
In previous lessons you examined relationships between organisms through the passage of energy (food) from one organism to the next. It is also important to look at direct relationships between individual organisms within ecological communities. These relationships can generally be classified as one of three types. Symbiotic relationships exist where one or more organisms live in close contact or live with one another. Predator – prey relationships or predation exist when one organisms consumes a second organism. Competitive relationships exist where organisms compete for an important resource such as food, shelter or possibly mates.
The following are the names for three types of symbiotic relationships. Using a biology text book, a web search, or another suitable resource, define each of the following types of relationships and describe an example for each.
Using your own knowledge or a suitable resource, desribe two examples for the following type of relationship:
The following are the names for the two types of competitive relationships that can exist between organisms. Using a suitable resource define and provide an example for each type of relationship.
Ecological Relationships – Quick Quiz
Case Study on Relationships in Ecosystems:
An observant Grade 11 Biology student was doing a study of the relationship between organisms. One June, the student wandered through a Sweet Clover field and observed the following organisms and their activities:
Read each of the following descriptions of an interaction within the ecological community and answer each of the questions in order to identify the types of ecological relationship(s) that exist within the community.
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.
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.)
Small green aphids were sucking the juices from clover stems. Further investigation found some aphids being eaten by an army of ants.
4. What type of ecological relationship exists between
the ants and the aphids?
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.
The squirrels had lice.
Some clover plants had withered and died. A white fungus was found on the roots and lower stems, which was identified as root rot.
A colony of Leaf Cutters bees was feeding on the nectar and pollinating flowers.
A bee keeper was setting out a hive of honey bees.
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.
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.
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.
A Mallard hen brooded her clutch, hidden from the watchful eyes by the dense clover foliage.
Blackbirds from a nearby slough picked caterpillars from clover stems.