Wednesday, December 1, 2010

How Do Organisms Interactions in Nose Hill’s Forest by Caryna, Sarah, Livia, Eric, Kassy and Erin

Nose Hill Park is the second largest environmental park in Calgary, Alberta, with over 198 wildlife species identified on the hill. It is located in the northwest quadrant of Calgary. This park contains three ecosystems, ranging from a shallow pond to a populated forest area, as well as thick grassland. Plants and animals living on this land interact and compete amongst each other for food and habitat. They engage in both interspecific competition (competition between members of different species for resources needed to survive) and intraspecific competition (competition between members of the same species for resources needed to survive). Intraspecific competition generally occurs within a specific trophic level (a group of organisms that occupy the same position in a food chain) with organisms of the same species, while interspecific competition occurs within an entire food chain (the sequence of transfers of matter and energy from organism to organism in the form of food) as well as a specific trophic level – as long as the organisms in the trophic level are not of the same species.. Parasitism (a symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host), mutualism (a symbiotic relationship where both organisms of different species rely on one another for nutrients, protection, and other life functions), and commensalism (a symbiotic relationship between members of two different species of organisms in which one individual is usually only slightly benefited, while the other member is not affected at all by the relationship) also come into play. In the forest, animals interact with animals, plants interact with plants, and animals and plants both interact with each other in many different ways for many different purposes.
Figure 1.  Spider crawling on a sapling.

In the forest ecosystem at Nose Hill, there are many animals of different species with varying sizes. There are large animals, such as deer, smaller animals like ants, and many in between. For example, in an area measuring 0.5m X 0.5m, sixteen ants were crawling on the surface of the grass. Extending that area to a transect of 1m X 10m, one a spider was spotted wrapping a smaller insect in its web. Porcupines and mice have both been seen in the forest at Nose Hill, and for these animals to be able to survive; their food sources must also find a home in Nose Hill. Since all animals of every type of species in any ecosystem have to share food sources amongst their trophic level, this would be interspecific competition. An example of this in a forest would be Black Bears and the Swainson Hawk both vying for squirrels. Intraspecific competition in the forest would include two male Red Deer’s fighting for the attention of a female Red Deer to reproduce with. The Red-billed Oxpecker interacts with deer in a mutually beneficial relationship. The Oxpecker is a bird that eats ticks and other small insects off of the deer’s fur, providing the Oxpecker receives a source of food, and the deer in return gets a clean coat of fur free from ticks and other insects. Birds following army ant raids on a forest floor are an example of commensalism in the forest of Nose Hill. As the army ant colony travels on the forest floor, they stir up various flying insects. As the insects try and escape from the army ants, the birds following the ants catch the insects. In this relationship the birds benefit while the army ants are unaffected. Parasitism in a forest ecosystem is shown with an example of the cuckoo bird. The cuckoo bird does not build its own nest, rather deposits its eggs in the nests of other birds in the forest. The host bird then treats this new egg as its own, since the cuckoo throws an original egg out of the host’s nest so the host will not find a new egg strange. The egg count with remain the same. Once hatched, the newborn cuckoo bird can throw the host’s eggs and newborns from the nest. The cuckoo bird is the parasite in this example, and the bird whose nest the cuckoo is placed in becomes the host, as well as the eggs in the nest.
Figure 2.  A parsitic infection; red fungus on
Plant to plant interactions also occurs frequently in the forest ecosystem at Nose Hill. In an area
measuring 0.5m X 0.5m, two saplings were counted. Extending that area to 1m X 10m, there were seven saplings and ten smaller bushes counted as well as native grass.  These species of plants in forests, as well as many more, all compete for resources. If a tree species in a forest grows taller than surrounding tree species, it is able to absorb more of sunlight. This example of interspecific competition means that less sunlight will reach the trees that are shaded by the taller tree species. Intraspecific competition in the forest can be two trees of the same species growing close together. These two trees will compete for light, water, and nutrients in the soil. Mycorrhizal is a mutulistic association between plant roots and fungi that takes place in 80% of all plant species. The plan proves carbohydrates to the fungus, and the fungus returns the favour by providing the plant with phosphate and nitrogenous compounds. In this interaction, both the fungus and the plant are benefiting from the interaction, defining this as mutualism. Commensalism is also prominent in the forest ecosystem, with examples such as moss growing on trees. Moss is a plant that can have a commensal relationship with trees. The moss grows on the trunks or branches of trees, and receives light as well as nutrients that run down the tree. As long as the moss is not too heavy, the tree is not affected. Parasitism in the forest is closely related to an example of mutualism in the forest. Mycorrahizal is a mutulistic plant-fungi relationship, where as myco-heterotroph is a relationship very similar. However instead of the plant providing resources such as carbon to the fungus, myco-heterotrophs decide to take carbon from a fungus. The fungus becomes the host, and the plant species becomes the parasite. The parasite is benefitting from this relationship, and the host is being harmed and depleted of its carbon supply.
An animal interacting with plants happens frequently in ecosystems, especially in forest ecosystems. In an area measuring 0.5m X 0.5m, small insects, later found identified as mites, were crawling on the bark of a tree. The tree bark was spotted red due to this parasitic interaction. Extending that area to 1m X 10m, one owl was perched on the branch of a sapling tree. Interspecific competition occurs often between plants and animals in the forest, especially when large trees dominate the canopy. This allows little light to reach the animals in the forest, and the animals may have a harder time hunting their food source. Intraspecific competition, however, does not exist between plants and animals, since they are not of the same species. The Whistling Thorn plant and ants coexists in a relationship based on mutualism. The ants live inside the plant's thorns, and in exchange for shelter, the ants reduce competition for light from other plants by trimming back vegetation that would shade the Whistling Thorn from much needed sunlight. Since both the plant and the animal are benefiting from this relationship in the forest, the relationship is classified as mutualism. Commensalism in the forest takes place in many different ways. Plant seeds are moved by animals to other areas of the forest. For example, buts and other stick-tight seeds gather on the fur of animals as they brush past, and when the animal roughly brushes past an obstacle, the seeds fall off and eventually begin to grow into a new plant. Since the animal is not harmed by moving the seed, and the generally seed is moved to a place with little competition for nutrients, light, and water, this relationship is known as commensalism. Mites make a habitat in forests, and seem to find their homes in the bark of trees. The tree bark then begins to have red patchy spots on it, and although the red spots do not seriously harm the tree and leave when the mites leave, this interaction is still classified as parasitism.
Figure 3.  Transect ares measuring
 1 m X 10 m.
                Animals interact with animals while plants interact with plants, and these two different living entities also interact with one other. Nose Hill shows how these organisms interact in different ecosystems, and the in the forest it provides visual examples of the different types of interactions and how they positively or negatively affect the organisms in question. Regardless of the nature of the interaction, a relationship between organisms keeps the forest in Nose Hill consistent with how it has been for decades. Both intraspecific competition and interspecific competition keep the forest from becoming overpopulated, while mutualism, commensalism, and parasitism contribute to the diverse population that is able to thrive in Nose Hill’s forest.
Bio Mini Lab for Nose Hill (Lab in Vodcast)
Problem: What effect does the number of consumers in an ecosystem have on the amount of producers that are consumed?
Hypothesis: If the number of consumers in an ecosystem increases, then the amount of producers that are consumed will decrease, because a higher number of consumers mean that there is a higher need for food.
-3 clear plastic cups
-9 leaves of similar size, and identical species
-20 ants
-1 square foot of saran wrap
-3 rubber bands
1.       Number the cups one, two, and three
2.       Place three leaves in each cup
3.       Cover the opening of cup one with saran wrap and secure it with a rubber band
4.       Poke five small holes in the saran wrap
5.       Place five ants in cup two
6.       Repeat steps 3 to 4 with cup two
7.       Place fifteen ants in cup three
8.       Repeat steps 3 to 4 with cup three
9.       Leave cups indoors for three days
10.   On the third day, observe and record the amount of producers consumed in each cup


Cup 1 (No ants)
Cup 2 (5 ants)
Cup 3 (20 ants)
After 3 days
No change
No change
Small amounts nibbled off from the sides of the leaves.
After 7 days
No change
Small amounts nibbled off from the sides of the leaves.
Approximately a quarter of the leaves were consumed.

Sources of Error:
-Sizes of leaves may be inconsistent.
-Ant’s appetite size and preference may differ
From our data collected, we have observed that the higher amount of consumers there are in an ecosystem, the more producers will be consumed.
Blog References
1.       EverythingBio. Life Science Glossary. 2005. Web. 23 Oct. 2010. <>.
2.       " Trees: Diseases." - Tree Care Made Easy. Web. 23 Oct. 2010. <>.
3.       Copyright, Inc. "Nearctica - Ecology - Population Ecology - Commensalism." Commensalism. 2004. Web. 23 Oct. 2010. <>.
4.       "Symbiosis in the Forest." Web. 23 Oct. 2010. <>.
5.       "Competition." Marietta College. 2008. Web. 23 Oct. 2010. <>.
6.       The City of Calgary. "The City of Calgary: Nose Hill Park." 2010. Web. 23 Oct. 2010. <;/ Living/Facilities and Programs/Parks/Natural Environment Parks/Locations/Natural Areas in NW Calgary/Nose Hill Park/Nose Hill Park.htm>.
Vodcast References

1.       Learn Science at Scitable." Nature Publishing Group : Science Journals and Information. Web. 26 Oct. 2010. <>.
2.       "Mutualism." Encyclopedia of Earth. Web. 26 Oct. 2010. <>.
3. | Find the Meanings and Definitions of Words at Web. 26 Oct. 2010. <>.
4.       "Interactions of Organisms." Oracle ThinkQuest Library. Web. 26 Oct. 2010. < Station/How living things interact with their environment/interactions of organisms.htm>.
5.       "Predator-Prey Relationships." The Global Change Program at the University of Michigan. Web. 26 Oct. 2010. <>.
6.       "Tree Infections -" EHow | How To Do Just About Everything! | How To Videos & Articles. Web. 26 Oct. 2010. <>.
7.       "Commensalism." The Department of Biodiversity & Conservation Biology - UWC. Web. 26 Oct. 2010. <>.
Podcast References
1.       " Trees: Diseases." - Tree Care Made Easy. Web. 23 Oct. 2010. <>.
2.       Malmstrom, Carolyn M. "Ecologists Study the Interactions of Organisms and Their Environment | Learn Science at Scitable." Nature Publishing Group : Science Journals, Jobs, and Information. 2010. Web. 23 Oct. 2010. <>.
3.       Advameg, Inc. "Competition - Biology Encyclopedia - Body, Examples, Different, Organisms, Specific, Types, Water, Produce, Role." Biology Reference. 2010. Web. 23 Oct. 2010. <>.
4.       "Behaviour - How Does Interspecific Competition Affect Organisms?" Biology Revision Online. Web. 23 Oct. 2010. <>.
5.       TurorVista. "Interactions Among Organisms |" - Online Tutoring, Homework Help for Math, Science, English from Best Online Tutor. 2010. Web. 23 Oct. 2010. <>.

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