Final exam - Community Ecology - Lectures 11 & 12 - Fill in the Blanks Flashcards Preview

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Flashcards in Final exam - Community Ecology - Lectures 11 & 12 - Fill in the Blanks Deck (49):

An interaction that is beneficial for species 1 and neutral for species 2 is _______.



Commensalism is also referred to as __________.



An interaction that is beneficial to both species involved is referred to as _________.



What is the definition of mutualism?

Reciprocal positive interactions between two species.


Mutualism is often across _______ _______ _______.

Multiple trophic levels


What are the three symbiotic relationships and how do they affect each of the two species involved?

1) Commensalism/facilitation: +/0
2) Mutualism: +/+
3) Parasitism: +/-


What is the difference between the LV model for competition and the LV model for facilitation?

Instead of it being a negative interaction, it is one of facilitation.
dN/dt = r1N1 ([k1-N1 + aN2]/K1)
(instead of being - aN1)


Mycorrhizhae increase the yield of several species.
The fungus invades cortical cells of the roots of vascular plants:
This benefits the plants by ______ (sentence)
This benefits the fungus as well. _____ (sentence).

- increasing surface area helps plant absorb water and nutrients from soil

- Fungus gains carbohydrates


Mycorrhizal fungi: in most plants
- fungi that live intermingled with plant roots
- fungi uptake ______ _____ _____ for plants
- plants provide __________ to the fungi
- important where _________ ____ ________

1) Fungi uptake nutrients from soil for the plant
2) Plants provide carbohydrates to the fungi
3) Important where nutrients are limited


In Juncus and border zones, the presence of Juncus _______ _______.
At high elevations, soil salinities were _____ and _______ _ _____ _____.

1) lowered salinities
2) low and unaffected by plant cover


Mutualism and competition (Juncus and Iva species): both species were _________ by neighbours at lower elevations, but _________ by neighbours at high elevation.

1) enhanced
2) Suppressed


Regarding the nutritional mutualism that occurs between leaf-cutter ants and fungi.
- ants harvest plant material and take it to the nest
- plants are used as a substrate for the _______ of a _______
- The _______ produces _______ _____ on its ________ that ants use for food

1) Plants are used as a substrate for the culture of a fungus
2) The fungus produces swollen tips on its hyphae that ants use for food


What is facultative mutualism?

An interaction which benefits both species, but does not necessitate the survival of either species


In facultative mutualism, in the presence of species 1, the per capita _______ growth rate of species 2 is _______ and _____-_____.

1) Population growth rate
2) Increased and vice versa


What is an example of facultative mutualism?

Honeyguide birds and the honeybadger


What is obligate mutualism?

A highly co-evolved interaction in which both species cannot persist without the other


In obligate mutualism:
In the absence of species 1, the per capita population growth rate of species 2 is ____, and _____-______.

- zero and vice-versa


What is an example of obligate mutualism?

Acacia plant and ants in central america


In the Acacia plant and ants in central america example, what do the ants provide the plant?

Ants chew on all vegetation that might shade out the Acacia and removed other herbivorous insects


In the Acacia plant and ants in central america example, how do ants benefit?

Ants feed on leaflet tips called Beltian bodies, which are the primary source of protein and oil for the ants


What would occur to the Acacia if ants were removed?

The tree would be quickly destroyed by herbivores and crowded out by other plants


Pollination is beneficial to whom?

Both the plant and pollinator


Pollination allowed the evolution of flowering plants and the diversification of plants.
This also lead to what?

Co-evolution of pollinators and specialization of pollinators and flower structures.


What are the different methods in which plants attract pollinators?

1) Food sources (amino acids and various sugars)
2) Odors (mimic insect pheromones)
3) Colours
4) Flower shape blooming habits


In pollination, what are the benefits for the pollinator?

1) Nutrition
2) Refuge or shelter
3) Reproduction


What are the benefits for plants?

Increase in genetic variation
reproduction sexually rather than asexually


What are common pollinators?

Insects, bats, birds


Pollination of the Yucca plant depends on what?

The female yucca moth collecting pollen and transferring it to a stigma.


The female yucca moth ______ a few _____ into the plant ovary.

oviposits a few eggs


The female yucca moth stuffs the _____ on the ______, sending many pollen tubules down to the ovary to fertilize the plant & seeds will be available for offspring.

pollen on the stigma


Pollination by the moth ensures _____ ________ in the yucca plant, some of which is _____ for the ______ ______.

Ensures seed production in the yucca plant, some of which is food for the hatched larvae.


The yucca larva feeds on only a _____ % of the ______/

Small percentage of the seeds


The yucca plant and yucca mother are obligate pollination/seed predation mutualism but....(what? - i.e. what is the caveat to this)

The yucca plant cheats


How does the yucca plant cheat?

Takes advantage of resources (pollinating moths), but doesn't provide resources (food) for oviposited moth egg


Which fruit from the yucca plant are inviable?

Not the Bulbous fruit but the narrow fruit.


Natural selection can be expected to favour individuals that obtain what they can from their partners while _____ (sentence).
For the reason stated above, mutualisms can be thought of as "_________ __________".

1) Investing as little as possible in them
2) Reciprocal parasitisms


What is facilitation?

An interaction where the presence of one species alters the environment to enhance growth, survival and reproduction of another species.


What are foundation species?

Provide structure habitat for others


What are ecosystem engineers?

Modify environment to make it suitable for others.


Blow flies function as ecosystem engineers. How? (2)

1) Aggregated oviposition
2) Dry out resource for other species


Bark beetles function as a foundation species. How?
(Hint: facilitation and mutualism)

- Facilitation of conspecifics with aggregated oviposition.
- Mutualism between bark beetles and fungus
- Facilitate other species by creating tree snags for birds and other animals


How do Bark Beetles also function as ecosystem engineers?

Make openings for succession of new trees.


We tend to think of facilitation and mutualism in positive terms. Why?

It is positive for the species involved and we often assume it is positive for the ecosystem.


Stress Gradient hypothesis:
- relative important of ________ interaction among plant species along a gradient of _________ _______

1) competitive
2) Environmental harshness


What was the assumption of the RNE (relative neighbour effect)?

High elevation is harsher than low elevation.


How was the RNE tested?

Recorded the responses of alpine plant species to removal of neighbouring plants at high and low elevations at 11 sites.


- Removal of neighbouring plants has __________ effects on plants in harsh environments but ____ in mild environments

1) detrimental
2) not


- The interaction changed from ________ to _______ when the harshness of the environment decreased.

facilitation to competition


Neighbour removal had a _______ effect on focal plant survival & reproduction in high elevation plots and a _________ effect on low elevation plots.

1) Negative
2) positive