Can you Survive the Interactions?
Grade Level: 6-8
Author: Katie Cartwright, Newport, NC
All living things interact with living and non-living things in order to survive. Interactions
among organisms (living things) can be classified in three different ways: competition,
predation, and symbiosis.
Competition occurs when two organisms require the same sources of
food, water, or shelter when supplies are limited. Both
organisms are harmed due to the competition. Through
evolution, one may eventually die off or adapt to make
use of other sources for food, water, or shelter.
Predation occurs when one organism kills and eats the other organism. The
one that kills and eats is called the predator and the
one that is killed and eaten is called the prey. Predators
have evolved and adapted to their role by using speed,
poison, venom and other lethal forces to kill their
prey. Prey organisms have also adapted to their
role by avoiding predators through mimicry, warning
coloring, camouflage and other deterrents.
The last interaction, symbiosis, can be broken down into
three interactions where at least one organism benefits. Mutualism
is the interaction where both organisms benefit. It's
the classic "you scratch my back and I'll scratch yours". An
example include bees and flowers where bees benefit
from the tasty nectar in the flowers and flowers benefit
from the bees helping them reproduce through pollination. Another
mutual relationship is that of the fig and the fig wasp. Figs
provide a nursery for fig wasps and fig wasps pollinate
figs for reproduction. This interaction is different
because fig wasps only reproduce inside figs and figs
are only pollinated by fig wasps. This is an example
of a special mutualism - obligate mutualism - two organisms
cannot live without each other. Another symbiotic
interaction occurs when one organism benefits and the
other is unaffected - commensalism. Bromeliads
are plants that grow in the crevices of trees. The
trees are unaffected while the bromeliad gains place
to call home. The last symbiotic interaction occurs
when one organism benefits and the other is harmed -
parasitism. An example of parasitic interactions
might involve botfly larvae making its home in the flesh
of a Jaguar. The botfly larvae feed on mammal
flesh and the Jaguar is harmed by pain and soreness. Parasites
do not typically kill their hosts because if the host
dies, the parasite will have to search for a new host.
- One deck of "rainforest" cards
for each pair of students. (These can be
printed out or made by writing on a regular deck
of cards and providing information on a fact sheet.) Rainforest
card backs; Interaction
- Tally sheet for each pair
- Interaction sheet
- Rainforest Video
- The Great Kapok Tree by Cherry
- Art supplies for making rainforest scene, if desired
- Learners will identify 3 different outcomes from interactions between organisms.
- Learners will identify and describe 5 types of interactions between organisms found
in a rainforest.
- Learners will identify at least 14 different organisms in the rainforest ecosystem.
- Learners will recognize and illustrate the 5 different types of interactions using examples
found in North Carolina.
As students enter classroom or as you begin your lesson, pass out cards that have names of
people students might interacted with (Examples: Mother, Father, Sister, Brother, Teacher, Friend,
Bully, Principal, Sales Clerk, etc.)
Ask students to consider their last interaction with the name on the card. Was the
interaction positive, negative, or neutral? Is it possible for an interaction to be different things
for each individual - Could it be positive for one and negative or neutral for the other?
Explain to students that all living organisms interact with other living organisms throughout the
course of their lives, too. Tell them that they are going to play a survival game,
but first they are going to watch a video about these interactions and learn about 5
types of interactions.
Show them a video that depicts interactions in the rainforest and
ask them to note any interactions they notice. They can simply write the two animals
on a line.
After viewing the video ask students for examples of interactions from the video. As each
interaction is suggested explain the type of interaction
by leading them through deciding who benefits, who is
harmed, and who is unaffected. Name the interaction
and have students write it next to the pair in their
notes. Continue until all 5 types are explained (you
may need to suggest any that went unnoticed).
Have students make a chart of the interactions using +, -, and 0 to show a positive, negative
and a neutral effect.
Now they are ready to play the card game.
- After students are paired up, pass out a deck of rainforest cards to each pair, along with
a tally sheet. Each student should have half of the cards.
- The game is played similar to "War" in that they both flip their top card at the same
time and decide the outcome of the interaction between their two animals. Information
given on the cards should help them determine who benefits, who is harmed, and who is unaffected
by the interaction.
- If the student's animal benefited from the interaction, he scores a point,
if he was harmed, he takes a point away, if he was unaffected, he scores a zero.
(For more challenging score keeping students can score +2 for being a
predator and -2 for being prey as well as +2 for being in an obligatory
- After all cards are flipped, students tally their score. A negative score indicates
that you did not survive, a score of zero means you just got by, and a positive score means
that you are thriving!
After scores are tallied students should go back and make sure that all interactions
were labeled on their tally sheet.
Allow students to use their deck of cards to answer questions
about different scenarios involving interactions among
the 14 rainforest organisms in the deck of cards.
- A tree frog is looking for a water source. As it hops along it encounters a
bromeliad. Describe and name the interaction.
- A bromeliad has an interaction that is identified as commensalism. Name
the organism with which it interacted and describe the interaction.
- A Fruit bat helps the Kapok tree reproduce. Describe and name the interaction.
Allow students to research aquatic systems and make a survival card game using aquatic organisms.
Take students for a walk in a park or forest and see how many interactions they can identify
Useful References: websites such as Belize Zoo, field guides