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Competition
Predation & Herbivory
Parasitism and Mutualism
Communities & Ecosystems
Large-Scale Ecology
100
What is the difference between interference and exploitative competition?
- -Interference: a direct interaction between competing individuals; - -Exploitative: individuals indirectly compete by taking up resources before others are able to
100
Why does the predator population hit its peaks and troughs after the prey population?
Because the prey must reach higher numbers before the predator population can grow (need abundance of food), and it isn't until after the prey numbers drop that the predators can't sustain large numbers anymore.
100
What are parasitoids and hyperparasitoids?
Parasitoids differ from parasite in that successful development involves killing and/or consuming the host. Hyperparasitoids are parasites of parasites.
100
What was the point of MacArthur's 2nd Warbler study?
With all else being equal, an environment with greater environmental complexity is predicated to display higher species diversity than one that displays lesser environmental complexity.
100
What is a landscape?
An area consisting of distinct, different landscape elements (e.g. forests, mountains, lakes) in a mosaic-like pattern.
200
Why might interspecific competition be more common in plants than in animals?
Plants are competing for the same essential, non-substitutable resources.
200
Why can overfishing lead to shifts in phenotypic traits?
We preferentially fish larger fish to allow juveniles mature, but fish that mature at smaller sizes are more likely to live to reproduce more, leading to a general decrease in body size at maturity.
200
True or false: Unlike definitive hosts, intermediate hosts are not affected by their parasites.
False - recall the interesting behavioural modifications that you were introduced to (ex. parasite causing its intermediate host to venture further up the intertidal zone than usual, where it is more likely to be eaten by definitive host)
200
What is a trophic cascade?
It is an indirect interaction wherein predators in upper trophic levels effect the entire ecosystem from their prey down to the primary producers.
200
What are glacial ages composed of?
Glaciations: very cold periods (60 - 90K years). Interglacials: warm periods (10 - 40K years).
300
How can Chthalamus coexist with Balanus when Balanus is the competitively dominant species?
Chthalamus are able to survive in the upper intertidal zone, where the Balanus cannot, because they are desiccation specialists?
300
Two unpalatable butterfly species are very difficult to tell apart. What type of mimicry is this, and why would this type of mimicry be evolutionarily favoured?
Mullerian mimicry. Evolutionarily favoured because it increases the incidence of the signal - increases predator learning (advantageous to both species).
300
Describe the two gene types involved in gene-for-gene systems. How are they related?
avirulence gene (Avr): present in parasite, gene for virulence; resistance gene (R): present in the host, gene for resistance; hosts with a given R gene are resistant towards parasites that have corresponding Avr gene
300
(See graph) Locate keystone and dominant species on the following graph.
Keystone - low relative biomass, high impact; dominant - high relative biomass, high impact
300
Why does species richness generally decrease with latitude? Provide two possible mechanisms.
- - The Age Argument - the tropics are "older" because they are less affected by glaciations. - - There is more land area at the equator. - - Temperatures are more uniform and warmer, potentially leading to fewer extinctions. - - More solar energy which could potentially support more trophic levels and/or lead to higher mutation rates.
400
What is the Competitive Exclusion Principle and under which conditions can species coexist? Bonus: Who proposed the theory?
No two species can coexist if they use the same resources in the same way. Species can coexist if intraspecific competition>interspecific competition. Bonus: Gause
400
Name and briefly describe the sequence of the prey capture process.
"EDIASC" 1) Encounter (proximity) 2) Detection 3) Identification as prey 4) Approach to capture 5) Subduing prey (gain control or kill) 6) Consumption
400
Myxoma virus is a virus that was used in the past as a pest control for rabbits. The virus is transmitted via mosquitos when they feed on infected rabbits and subsequently feed on healthy rabbits. However, mosquitos only prefer to feed on warm, live rabbits, and do not tend to feed on cold, dead rabbits. Would you expect myxoma virus to have a high or low level of virulence?
Low level of virulence. What would happen if it was a high level of virulence? Once rabbits got the disease, they would die. But since mosquitos do not feed on dead rabbits, then the virus would not be spread from that rabbit to other rabbits.
400
What are the essential nutrients?
Carbon, nitrogen, sulfur, phosphorus and water
400
What is a sky island, and how do they affect the ecosystem?
A glacial refugia that exists because it is higher than the glaciers reach. They are places where organisms can survive glaciations and repopulate an area at the beginning of interglacials.
500
(See figure on board) What will be the trajectory of this population?
Species 1 will be excluded and Species 2 will go to its carrying capacity (K2)
500
Give an example of each of the following defences plants employ: mechanical, biotic, biochemical.
- -mechanical: trichomes (kills herbivorous insects) - -biotic: ant guards (attack herbivores, protecting the plant in exchange for shelter) - -biochemical: resin in plant stems (gums up the mouth parts)
500
Name the 3 categories of mutualisms, and provide an example for each.
1) resource-resource relationships (ex. mycorrhizae) 2) service-resource relationships (ex. pollination, zoochory) 3) service-service relationships (ex. clownfish + anemones - ish)
500
For each of the three cycles discussed in class (phosphorus, carbon and nitrogen), state the element's largest pool and the element's main role in organisms.
Phosphorus: largest pool = mineral deposits; role = energetics and genetics (and in membranes). Carbon: largest pool = oceans; role = found in all organic molecules. Nitrogen: largest pool = oceans; role = amino acids and nucleic acids (and chlorophyll).
500
Name four geological factors can change the landscape, and give an example of how for each.
Glaciation - e.g. eskers, till plains, "U" valleys, drumlins. Volcanism - e.g. mountains, seamounts, hot springs. Erosion - e.g. loss of nutrients from an area. Earthquakes - e.g. mountains, landslides, tsunamis. **This is a non-exhaustive list. Other answers are possible.**