25 Points
Name:
Period:
Symbiosis and Relationships between organisms
1. Parasitism: one species benefits while the other is harmed. Parasites generally attach to a
host as a consistent source of nutrition. Parasites may be endoparasites, existing outside the
host, or endoparasites, existing inside the host.
2. Commensalism: one species benefits from the interaction while the other is neither helped nor
harmed. Until definitive evidence of the benefit served by the anemone is discovered, the clown
fish and the sea anemone described above are an example of this.
3. Mutualism: both species benefit.
4. Competition: based upon a competition for resources.
5. Predation (predator/prey): one species benefits while the other is harmed. Predators obtain
food at the expense of their prey. Predation may be considered herbivory or carnivory.
Write which interaction is taking place below (some may be used more than once, and not all
words may be used):
E. coli is a common rod-shaped intestinal bacterium. It lives in a relationship with humans where
it benefits from the warmth, shelter, and nutrients provided by the colon and in return makes
vitamin K and sodium. It also serves as a competitive inhibitor of pathogenic bacteria. E. coli
does not cause disease or discomfort but does produce 400ml to 500ml of gas per day. Prolonged
treatment with antibiotics may reduce the population of E. coli within the intestines.
1. Interaction __________________________
Remoras, or suckerfish, are elongated brown fish. They grow up to 30-90 cm long (1-3 feet), and
their distinctive first dorsal fin takes the form of a modified oval sucker-like organ with slat-like
structures that open and close to create suction and take a firm hold against the skin of larger
marine animals. Remora commonly attach themselves to sharks and or ride their hydrodynamic
bow wakes. The shark is not affected by the remora attaching themselves it.
2. Interaction __________________________
Lichens are not a single organism but a symbiotic relationship between a fungi and certain
species of bacteria and blue-green algae. The fungus and the bacteria can live independently
when separated in a laboratory but in nature the fungus often never exists on its own while some
of the bacteria do and some don't.
The fungus provides structural support, protection and a relatively stable environment for the
bacteria and blue-green algae that are embedded in its hyphal strands (threadlike structures of all
fungi). It also provides the algae with nutrients absorbed from its environment (ie: from the trees
or rocks they live on as well as the air and water). The bacteria/blue-green algae provides the
fungus with carbohydrates produced during photosynthesis from carbon dioxide and water.
3. Interaction __________________________
Lions usually hunt at night, alone, or in groups. Typically, a lion hunting alone will slowly and
silently stalk its prospective victim, trying not to be seen, until it is about 30 m (about 98 ft)
away. Then with a burst of speed, the lion will run toward the prey, grab it, and throw it to the
ground. The lion kills the prey by biting the back of the animal’s neck with sharp canine teeth or
by holding the prey's throat in its jaws until the animal suffocates. If, during a hunt, the prey
detects the lion's presence and starts to run, the lion gives up. Although lions are capable of high
speed over short distances, they do not have the endurance to chase down an escaping animal.
Their preferred prey are large hoofed mammals, such as zebras and wildebeests, but they will go
after small hares as well as huge giraffes.
4. Interaction __________________________
Adult flukes are purple-gray in color, flat, elongate, oval, and look like "bloodsuckers" or
"leeches". When found while cutting open or slicing liver, they resemble a blood clot and are
surrounded by a thick black-grey discharge. The flukes vary in size from 15-30mm wide by 30100mm long by 2-5mm thick. Animals infected with the adult fluke may be healthy or be in
poor condition, appearing drowsy, depressed, with poor appetite.
5. Interaction __________________________
Now look at the organisms on the other page. Make up a relationship for each category below.
Cut and past the organisms out under the column, then write a brief explanation on what is going
on between your chosen creatures. You can be creative, but it has to make sense.
MUTUALISM
PARASITISM
COMMENSALISM
PREDATOR-PREY
COMPETITION
Explanation
Explanation
Explanation
Explanation
Explanation