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

Question 1

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

Answer 1

Commensalism

Question 2

Commensalism is also referred to as __________.

Answer 2

Facilitation

Question 3

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

Answer 3

Mutualism

Question 4

What is the definition of mutualism?

Answer 4

Reciprocal positive interactions between two species.

Question 5

Mutualism is often across _______ _______ _______.

Answer 5

Multiple trophic levels

Question 6

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

Answer 6

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

Question 7

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

Answer 7

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

Question 8

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

Answer 8

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

Fungus:
- Fungus gains carbohydrates

Question 9

Mycorrhizal fungi: in most plants

• fungi that live intermingled with plant roots
• fungi uptake ______ _____ _____ for plants
• plants provide __________ to the fungi
• important where _________ ____ ________

Answer 9

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

Question 10

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

Answer 10

1) lowered salinities

2) low and unaffected by plant cover

Question 11

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

Answer 11

1) enhanced

2) Suppressed

Question 12

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

Answer 12

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

Question 13

What is facultative mutualism?

Answer 13

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

Question 14

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

Answer 14

1) Population growth rate

2) Increased and vice versa

Question 15

What is an example of facultative mutualism?

Answer 15

Honeyguide birds and the honeybadger

Question 16

What is obligate mutualism?

Answer 16

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

Question 17

In obligate mutualism:

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

Answer 17

• zero and vice-versa

Question 18

What is an example of obligate mutualism?

Answer 18

Acacia plant and ants in central america

Question 19

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

Answer 19

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

Question 20

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

Answer 20

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

Question 21

What would occur to the Acacia if ants were removed?

Answer 21

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

Question 22

Pollination is beneficial to whom?

Answer 22

Both the plant and pollinator

Question 23

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

Answer 23

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

Question 24

What are the different methods in which plants attract pollinators?

Answer 24

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

Question 25

In pollination, what are the benefits for the pollinator?

Answer 25

1) Nutrition
2) Refuge or shelter
3) Reproduction

Question 26

What are the benefits for plants?

Answer 26

Increase in genetic variation

reproduction sexually rather than asexually

Question 27

What are common pollinators?

Answer 27

Insects, bats, birds

Question 28

Pollination of the Yucca plant depends on what?

Answer 28

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

Question 29

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

Answer 29

oviposits a few eggs

Question 30

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.

Answer 30

pollen on the stigma

Question 31

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

Answer 31

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

Question 32

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

Answer 32

Small percentage of the seeds

Question 33

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

Answer 33

The yucca plant cheats

Question 34

How does the yucca plant cheat?

Answer 34

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

Question 35

Which fruit from the yucca plant are inviable?

Answer 35

Not the Bulbous fruit but the narrow fruit.

Question 36

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 “_________ __________”.

Answer 36

1) Investing as little as possible in them

2) Reciprocal parasitisms

Question 37

What is facilitation?

Answer 37

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

Question 38

What are foundation species?

Answer 38

Provide structure habitat for others

Question 39

What are ecosystem engineers?

Answer 39

Modify environment to make it suitable for others.

Question 40

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

Answer 40

1) Aggregated oviposition

2) Dry out resource for other species

Question 41

Bark beetles function as a foundation species. How?

Hint: facilitation and mutualism

Answer 41

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

Question 42

How do Bark Beetles also function as ecosystem engineers?

Answer 42

Make openings for succession of new trees.

Question 43

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

Answer 43

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

Question 44

Stress Gradient hypothesis:

- relative important of ________ interaction among plant species along a gradient of _________ _______

Answer 44

1) competitive

2) Environmental harshness

Question 45

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

Answer 45

High elevation is harsher than low elevation.

Question 46

How was the RNE tested?

Answer 46

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

Question 47

RNE:

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

Answer 47

1) detrimental

2) not

Question 48

RNE:

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

Answer 48

facilitation to competition

Question 49

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

Answer 49

1) Negative

2) positive