BIOTIC INTERACTIONS

Question 1

Relationship between two species which interact but do not affect each other

Interactions are INCIDENTAL or INDIRECT

Example:
Cacti and tarantulas living in the desert

Answer 1

NEUTRALISM

Question 2

One species causes harm to another organism without any cost or benefit to itself

• Cogon & bermuda grass
• Lantana & blue sweet pea
• Penicillium & gram + bacteria

Answer 2

AMENSALISM

Question 3

NEGATIVE effect due to SUBSTANCES released

Answer 3

ALLELOPATHY

Question 4

Beneficial to one but no effect on the other

Small commensal & larger host

Examples:
Fern/orchid & dipterocarp
Diatom & green algae
Various epiphytes & seagrass

Answer 4

COMMENSALISM

Question 5

Two or more individuals or species utilize the same limited resources

Reduces species dominance

Answer 5

COMPETITION

Question 6

Types of Competition:

Answer 6

Intraspecific vs. Interspecific competition

Scramble vs. Exploitative vs. Contest competition

Question 7

All competing individuals garner such a SMALL SHARE of the resources that NON SURVIVE

Answer 7

SCRAMBLE

Question 8

Occurs indirectly when both organisms use a common limiting resource or shared food item

Each individual is affected by the amount of shared resource remaining

Scramble-like but LESS SEVERE

Answer 8

EXPLOITATIVE

Question 9

Species interact directly by fighting for scarce resources

Only a fraction of the population obtains all the resources it needs while the others get less and produce no offspring or die

Answer 9

CONTEST / INTERFERENCE

Question 10

Possible Outcomes of Competition

Answer 10

Species 1 or 2 may become extinct. (EXCLUSION)

Both species live. (COEXISTENCE)

Question 11

“No two species completely needing the same resources will live together in the same area. The better competitor will eventually survive and the other will ultimately die or be excluded.” – G. F. Gause (1934)

Answer 11

Gause Exclusion Principle:

Question 12

Coexistence Mechanisms:

Answer 12

1. RESOURCE PARTITIONING
2. NICHE SPECIALIZATION
3. CHARACTER DISPLACEMENT

Question 13

Sympatric species consume slightly different resources or use resources in slightly different ways

Answer 13

1. RESOURCE PARTITIONING

Question 14

Species become better adapted, by natural selection, to the specific characteristics of a particular habitat

Answer 14

2. NICHE SPECIALIZATION

Question 15

Characters or parts become more varied (divergence of characteristics) to promote coexistence

Answer 15

3. CHARACTER DISPLACEMENT

Question 16

PREDATION is also called as

Predator eats prey

Answer 16

ANTAGONISM

Question 16

Types of Predator Response

Answer 16

FUNCTIONAL
NUMERICAL

Question 17

As prey density increases, each predator may take more prey or take them sooner

Answer 17

FUNCTIONAL RESPONSE

Question 18

Predators become more numerous through increased reproduction and/or immigration

Answer 18

NUMERICAL RESPONSE

Question 19

TYPES OF FUNC RESPONSE

Answer 19

TYPE I
TYPE II
TYPE III

Question 20

Linear increase in intake rate with food density until saturation

Answer 20

TYPE I

Question 21

Decelerating intake rate; limited by consumer’s capacity to process food

Answer 21

TYPE II

Question 22

Similar to Type II; at high prey density, saturation occurs

Answer 22

TYPE III

Question 23

COMPONENTS OF NUMERICAL RESPONSE

Answer 23

IMMIGRATION (↑i)
AGGREGATION
INCREASED BIRTH (↑b)

Question 24

Predation on Autotrophs

Answer 24

HERBIVORY

Question 25

EFFECTS OF HERBIVORY ON PREY

Answer 25

- Reduce fitness - Stimulate biomass production

Question 26

TYPE OF HERBIVORY

Answer 26

GRAZING BROWSING

Question 27

Plant Defenses Against Herbivores:

Answer 27

1. CHEMICAL DEFENSE 2. MECHANICAL / STRUCTURAL DEFENSE 3. MIMICRY 4. Herbivores have evolved ways of BREACHING plant defenses

Question 28

Predation on Heterotrophs

Answer 28

CARNIVORY

Question 29

Prey Defense Mechanisms:

Answer 29

1. Chemical defense 2. Mechanical defense 3. Behavioral defense

Question 30

Predator Offense Mechanisms:

Answer 30

1. Tactics 2. Aggressive mimicry 3. Cryptic coloration 4. Other adaptations for hunting

Question 31

Animal Defenses

Answer 31

1. Mechanical defense 2. Chemical defense 3. Behavioral defense 4. Cryptic coloration 5. Warning / aposematic coloration 6. Camouflage

Question 32

when organisms resemble natural objects

Answer 32

MIMICRY

Question 33

TYPES OF MIMICRY

Answer 33

BATESIAN MüLLERIAN

Question 34

a harmless and palatable species mimics a harmful and unpalatable one

Answer 34

BATESIAN

Question 35

two or more harmful species resemble each other

Answer 35

MüLLERIAN

Question 36

Parasites draw nutrients from live hosts

Answer 36

PARASITISM

Question 37

Types of Parasites:

Answer 37

Full-time vs. Part-time Microparasites vs. Macroparasites Ectoparasites vs. Endoparasites