Lecture 18: Species Interactions

Question 1

Interactions between two species can…

Answer 1

• benefit (+),
• harm (-), or
• have no effect (0)
…on each of them.

Question 2

Describe the interaction of species in competition.

Answer 2

-/-

Both do worse when together.

Question 3

competition

Answer 3

resource use by ONE individual that reduces its availability for others.

Question 4

Intraspecific competition

Answer 4

individuals of the same species compete.

Question 5

Interspecific competition

Answer 5

individuals of different species compete.

Question 6

Niche

Answer 6

Total range of all abiotic/biotic conditions

tolerated and all resources used

Question 7

Fundamental Niche:

Answer 7

Niche that a species potentially could occupy

Few species actually fill their fundamental niche

Question 8

Realized Niche

Answer 8

subset of the fundamental niche that a species actually occupies

Question 9

Competitive Exclusion Principle

Answer 9

complete competitors cannot coexist

worst competitor would be entirely excluded.

Question 10

Mutualism

Answer 10

positive/positive
+/+

Both species benefit (do better together).

Question 11

Pollination Syndrome

Answer 11

Suites of floral characters associated with different modes of pollination (flower characteristics that relate to pollinator characteristics)

Question 12

pollination

Answer 12

Act of transferring pollen grains from the male part of a flower to the female part of the flower.

• Required before fertilization to take place (i.e., to create a zygote).

Question 13

Plant

Answer 13

provides organic carbon derived from photosynthesis

Question 14

Bacteria

Answer 14

provide fixed nitrogen by forming nodules in plant roots

Question 15

antagonist interaction

Answer 15

negative/positive
-/+
One does worse, one does better when together.

Question 16

Forms of Antagonism

Answer 16

1. Predation
2. Herbivory
3. Parasitism
4. Pathogens

Question 17

Stone plants make themselves less apparent to herbivores by blending in with their environment

Answer 17

Reduced Apparency (Herbivory Resistance)

Question 18

Herbivory Resistance: Structural Defenses

Answer 18

a. modified stems
b. modified leaves
c. extension of the epidermis
d. trichomes (hair)
e. leaf margin

Question 19

Secondary metabolites

Answer 19

specialized compounds not directly related to basic metabolic pathways (e.g., photosynthesis)

Question 20

Herbivory Resistance

Answer 20

• Reduced apparently
• structural defenses
• chemical defenses

Question 21

Give an example of indirect defenses against herbivory

Answer 21

the ants that inject other plants to kill them off and protect the main species plant and also attack other insects trying to eat the plant. In return ants get shelter.

Question 22

commensalism

Answer 22

positive/unaffected
+/0

One does better when together; one is unaffected.

Question 23

ammensalism

Answer 23

negative/unaffected
-/0

One does worse when together; one is
unaffected.

Question 24

Describe the species interaction grid

Answer 24

(+/+) (+/-)
Mutualism Antagonism

(-/+) (-/-)
Antagonism Competition

(0/+) (0/-)
Commensalism Ammensalism