Ch. 16: Competition

Question 1

Competition is a…

Answer 1

(–)/(–) interaction when individuals use the same limited resources

Question 2

Resource

Answer 2

anything an organism consumes or uses that causes an increase in population growth rate when it becomes more available
- must be consumable

Question 3

resources for animals include:

Answer 3

food, water, space

Question 4

resources for plants include:

Answer 4

sunlight, water, and soil nutrients

Question 5

T/F: temperature is considered a resource

Answer 5

FALSE
- any ecological factors that cannot be consumed are NOT considered resources

Question 6

Liebig’s law of the minimum

Answer 6

law stating that a population increases until the supply of the most limiting resource prevents it from increasing further
- not all resources limit consumer populations.

Question 7

When two species compete for a single limiting resource, the species that persists is the one that can…

Answer 7

drive down the abundance of that resource to the lowest level

Question 8

An increase in one resource can have a much larger effect on a population when there is also an…

Answer 8

increase in a second resource

Question 9

Intraspecific competition occurs between…

Answer 9

members of the SAME species

Question 10

Negative density dependence is a common type of __________, where an increase in a population’s density causes a decline in the growth rate of the population.

Answer 10

intraspecific competition

Question 11

Interspecific competition occurs between…

Answer 11

members of two DIFFERENT species

Question 12

Interspecific competition occurs when…

Answer 12

the niches of two species overlap
- you can’t have 2 species occupy the same niche, they will move a little away so they don’t have to compete

Question 13

habitat

Answer 13

place/set of environmental conditions where particular organism lives

Question 14

ecological niche

Answer 14

• role species plays in biological community
• total set of environmental factors species can tolerate
• ex: autotroph (producers, herbivores), heterotrophs (consumers)

Question 15

generalists

Answer 15

occupy a broad niche

Question 16

specialists

Answer 16

occupy a narrow niche

Question 17

when generalists and specialists collide _____ usually win

Answer 17

generalists

Question 18

Species interactions may affect ___ and ___ of a particular species.

Answer 18

the distribution and abundance

Question 19

Interspecific competition can cause the population of one species to…

Answer 19

decline and eventually die out

Question 20

competitive exclusion principle:

Answer 20

it is not possible for species within the same niche to coexist
- one will “win” out and other will move or die off

Question 21

Law of Competitive Exclusion:

Answer 21

• No 2 species will occupy the same niche and compete for exactly the same resources for an extended period of time.
• 1 will either migrate, become extinct, or partition the resource and utilize a sub-set of the same resource.

Question 22

competitive exclusion occurs when…

Answer 22

competition is asymmetric and niches overlap completely

Question 23

the consequences of competition (“niche differentiation”)

Answer 23

• weaker species will retreat to an area of non-overlap

Question 24

Darwin suggested that competition is most intense between….

Answer 24

related species because they have similar traits and consume similar resources.

Question 25

For related species that compete strongly, natural selection should favor...

Answer 25

differences in habitat use

Question 26

if niches don't overlap completely, weaker competitors use....

Answer 26

non-overlapping resources

Question 27

Competition can also be intense among...

Answer 27

distantly related species that consume a common resource

Question 28

Competition can also be intense among...

Answer 28

distantly related species that consume a common resource

Question 29

Population dynamics of two competing species can be modeled by using ______

Answer 29

the logistic growth equation

Question 30

Zero population growth isocline:

Answer 30

population sizes at which a population experiences zero growth

Question 31

Two species may be able to coexist when...

Answer 31

each is better at persisting at low levels of DIFFERENT resources - they're all relying on multiple, slightly different resources

Question 32

The outcome of competition can be altered by...

Answer 32

abiotic conditions, disturbances, and interactions with other species

Question 33

the most competitive organisms are often the most....

Answer 33

susceptible to predation or herbivory

Question 34

Predators can reverse...

Answer 34

the outcome of competition

Question 35

Herbivores can alter...

Answer 35

the outcome of competition

Question 36

Types of competition

Answer 36

1. consumptive competition 2. preemptive competition 3. overgrowth competition 4. chemical competition 5. territorial competition 6. encounter competition 7. apparent competition

Question 37

Consumptive competition (Exploitative competition):

Answer 37

- competition in which individuals consume and decrease the abundance of a resource to a point that other individuals cannot persist

Question 38

consumptive (exploitative) competition is considered ____ competition because it occurs through ____.

Answer 38

- indirect - a shared resource.

Question 39

preemptive competition

Answer 39

competition for space (and access to resources)

Question 40

overgrowth competition

Answer 40

one organism grows over another

Question 41

Interference competition:

Answer 41

when competitors do not immediately consume resources but defend them - direct competition

Question 42

4 types of interference competition

Answer 42

chemical, territorial, encounter, apparent

Question 43

Allelopathy (chemical interference)

Answer 43

type of interference competition when organisms use chemicals to harm their competitors - effective strategy for invasive plants

Question 44

territorial competition

Answer 44

mobile organisms protect a feeding or breeding territory

Question 45

aggressive interactions are a type of..

Answer 45

interference competition

Question 46

encounter competition

Answer 46

organisms interfere directly for access to specific resources

Question 47

apparent competition

Answer 47

form of competition b/w species indirectly competing with another species (or group of organisms) - both of them serve as prey, parasite or herbivore

Question 48

apparent competition occurs when...

Answer 48

the first group of species increases in number - this results in the increase in number of predators in the area - increase in number of predators (all different types of predators trying to eat 1 type of prey)

Question 49

_____ competition could be generated if one species facilitates the enemy of another species.

Answer 49

Apparent

Question 50

organisms are able to use a combination of...

Answer 50

competition and competition types

Question 51

Chi-square test

Answer 51

a statistical test that determines whether the number of observed events in different categories differs from an expected number of events, based on a particular hypothesis; useful when data are counts