Study Questions Flashcards
What is the competitive exclusion principle? What are the conditions necessary for it to exist?
Two species can’t have the same niche and coexist stably
We have to have two or more species that use the same resources, inhabit the same habitat at the same time, etc
What is ecological character displacement? How does this result in low niche overlap? Think of the niche curve graphs and what happens when there is too much overlap.
When species live in the same geographic area, their differentiating characteristics are enhanced so as to reduce niche overlap
How can trade offs allow species that use the same resources to coexist? Provide an example.
A trait can come at a deficit to another trait strong enough that it keeps the populations’ numbers to a steady amount enough to let the species coexist.
For example, if a species can reproduce very quickly, then intraspecific competition will have more of an impact on their numbers then interspecific competition
What is the difference between exploitative and interference competition? Give an example of each.
The indirect competition that comes from the interaction of mutual resources between species. For example, when two birds inhabit the same area and eat the same insects. One bird might take more insects, leaving the other to die off.
Interference competition is when two individuals compete directly for resources. For example, when two males compete to be head male for a group of females during mating season.
Using the lynx-hare example, explain how changes in predator density is directly linked to the abundance of prey? How does low prey density increase or decrease predator abundance? How is this a consequence to predator numbers? What would we see in a graph of this over time?
The graph of predator-prey numbers would have the prey density going up and down with predator numbers following in the wake.
We see this because, the more prey there are, the more resources predators have, the more they can reproduce. But, there comes a point when there are too many predators and so prey numbers start to dwindle. This leads to fewer resources for predators, and the predators start dying out following the decline in prey numbers. Once there are few enough predators, prey are able to go out and reproduce at higher rates, leading to another increase in their numbers. This cycle continues in perpetuity as long as conditions stay the same, totally caused by the predators
How does intraspecific competition stabilize predator-prey cycles? How could this competition prevent prey from going extinct?
Intraspecific competition can reduce numbers within the predator population without prey numbers declining. If there is competition within the prey numbers, we see the prey reach carrying capacity. This keeps their numbers at a certain level, which should be reflected in predator numbers.
What is a functional response (between predator and prey)? What are the three main types and what causes these types? Think of the graph that was shown in class. There are three different types of curves, one being not a curve. They all exhibit curves found in biology (___, chemical equilibrium graph, hit a ceiling). How would changing from a type 1 to a type 3 impact the oscillations of predator and prey response?
A function of prey density to how many prey consumed. It shows predator response to prey density.
1- linear increase in food intake as prey density increases. This is found when prey are increasing at a consistent rate, and predators are eating them at a consistent rate.
2- reach an asymptote. This is found when prey and predator interact and reproduce at a consistent rate, but there’s a finite amount of food and resources available that make them plateau.
3- logistical graph, like the one we see with population density. This can be found when a carrying capacity is reached for either the prey, predator, or both.
In type 1, we’d see not too much oscillation
When do we see k selected species colonize an area? Why?
We see them colonize later than r selected as k selected typically do better when the area is reaching or at carrying capacity. They produce fewer stronger offspring that can do well in competition
When do we see r selected species come into an area? Why?
At the beginning as they do better when the environment is harsh and there are bountiful resources
What are keystone species?
Species that have a big impact compared to their biomass.
Example- sea otters, top predators
What are foundational species?
Species that support all other species in an area; their impact is proportional to their biomass
Example: kelp
What are the differences between these terms; define them:
-Facultative and obligate mutualism
-commensalism
-positive interactions
In Facultative, you don’t need to have both organisms actively participating to have mutualism. In obligate, both actively need to participate
One benefits and the other is unharmed, but no benefit.
Any sort of interaction that is beneficial to both species
Explain why positive interactions play an important role in stressful conditions. How do interactions that benefit both species aid in stressful conditions? Draw a graph depicting this along some increasing stress
They help by lessening the impacts of some stress on each other. For example, a sea anemone provides shelter to a clownfish, and the clownfish protects the sea anemone
What is a fundamental niche and how does it differ from a realized niche?
Fundamental is what in theory the animal can use as a set of conditions that that species can use. Realized niche is what they actually use when we take into account interactions with other species.
What is the intermediate disturbance hypothesis? How can we use this to predict what areas will look like in terms of kinds of species?
Most diversity in the middle of time of area (between carrying capacity and initial colonization)
The longer it’s been since disturbance, the more k selected species
A shorter time since disturbance, the more r selected species
