Ch.13- Interactions among organisms: Competition

Question 0

Indirect interaction

Answer 0

Organism A affects organism B indirectly by affecting organism C
-interactions that are mediated by a third species/ individual

Question 1

Direct interaction

Answer 1

organism A directly affects organism B

Question 2

Competition

Answer 2

Organisms compete for resources (a feature of the environment required for growth, survival or reproduction and which can be consumed or used to the point of depletion)
Ex: water, food, space, mates, ect.

Question 3

Interspecific Competition

Answer 3

Between individuals of different species

-> organisms with similar niches tend to compete

Question 4

Intraspecific Competition

Answer 4

Between individuals of the same species

-> organisms with similar niches tend to compete

Question 5

3 mechanisms for competition

Answer 5

1: Interference competition
2: Exploitation
3: Apparent Competition

Question 6

Interference Competition

Answer 6

-Direct interaction
-Occurs between two or more individuals
-can happen physically
~ex: Bucks fighting over access to females

Question 7

Exploitation (Indirect Competition)

Answer 7

-Indirect interaction
-Use of a resource by one individual affects all other individuals that use that resource
~Ex: plants taking nutrients from the soil, aleopathy (releasing toxic chemicals

Question 8

Apparent competition

Answer 8

• Indirect interaction
• presence of one species increases the predator population of another
• In this type of competition, organisms are NOT competing for resources

Question 9

Asymmetrical competition

Answer 9

competition has a negative influence on both species/individuals
~But, one is often a better competitor than the other, so one suffers more than the other

Question 10

Competitive exclustion

Answer 10

-If niches for two competing species are very similar they will not coexist
~the superior competitor will outcompete the lesser competitor

Question 11

Competition coefficients

Answer 11

alpha: the effect of one idividual of species 2 on the population growth rate of species 1

Beta: the effect of one idividual of species 1 on the population growth rate of species 2

Question 12

Lotka-Volterra competition Equation (Species 1)

Answer 12

dN/dt= rN((K-N- alpha N)/K)

Question 13

Lotka-Volterra Competition Equation(species 2)

Answer 13

dN/dt= r N((K-N- beta N)/K)

Question 14

Factors that facilitate coexistence

Answer 14

• Abundance of resources (not limiting)
• Environmental changes
• Interaction with other organisms
• Immigration form other location
• character displacement
• recruitment