Populations And Communities

Question 1

What is a population

Answer 1

A group of organisms of the same species living in a particular habitat

Question 2

What are the 4 phases of population growth

Answer 2

Lag phase
Exponential phase
Stationary phase
Decline phase

Question 3

What is the lag phase

Answer 3

This is the time for nutrient assimilation or egg production or egg/ larvae development to occur

Question 4

What is the exponential phase

Answer 4

When reproduction creates new members at an exponential rate

Question 5

What is the stationary phase

Answer 5

When the population numbers stay around the same, reaching its carrying capacity

Question 6

What is the decline phase

Answer 6

When the population has exhausted all resources, numbers drop at a high rate

Question 7

What are R-selected species

Answer 7

The populations of species increase rapidly as a resource becomes available and crash as the resource is used up

Question 8

What are K-selected species

Answer 8

The populations of the species remain at the carrying capacity of the environment

Question 9

What are some features of R-selected species

Answer 9

Short lifespan
Short generation time
Many offspring
Highly variable population density
High disperability
Weak competitive ability
Little parental care
Unstable habitat

Question 10

What are some features of K-selected species

Answer 10

Long lifespan
Long generation time
Little offspring
Low variable population density
Low disperability
Strong competitive ability
Considerable parental care
Stable habitat

Question 11

What are the 3 types of interaction

Answer 11

Mutualism (+/+)
Predation (-/+)
Competition (-/-)

Question 12

What is mutualism

Answer 12

When both species benefit from the interaction

Question 13

What is an example of mutualism

Answer 13

Rhizobium and Trifolium

Question 14

What is predation

Answer 14

When the predator gains, the prey losses

Question 15

What is a predator prey interaction

Answer 15

When prey numbers are high, predator numbers increase
When predator numbers increase, prey numbers decrease
When prey numbers decrease, predator numbers decrease
When predator numbers decrease, prey numbers increase

Question 16

What is inter-specific competition

Answer 16

When two species require a common resource in limited supply

Question 17

What are some characteristics of inter-specific competition

Answer 17

Both species tend to do less well
One species is completely eliminated
One species tends to use the resources better
The winner may well be decided by the environmental conditions

Question 18

What is the competitive exclusion principle

Answer 18

That two species cannot share the same niche, without one being completely eliminated

Question 19

What is a pest

Answer 19

An organism that affects the population of plants or animals that is economically beneficial to humans

Question 20

What are some advantages of biological control

Answer 20

They target only the pest species
They don’t negative affect biodiversity
Unlikely to develop pest resistance
They are self-perpetuating over time
It is relatively cheap

Question 21

What is a disadvantage of biological control

Answer 21

It requires a lot of a lot more research

Question 22

What are some features of primary succession

Answer 22

Soil depth and fertility increases
Plant biomass and height increases
Number of food chains increase
As plant height increases, less sunlight reaches the ground, which decreases plant biodiversity

Question 23

What is a climax community

Answer 23

The stable end-stage when a community is in dynamic equilibrium with its environment

Question 24

What is a climatic climax

Answer 24

When the climax community is determined by the environment

Question 25

What is secondary succession

Answer 25

When succession occurs on an already disturbed environment, when happens more quickly that primary succession

Question 26

What is the first stage of primary succession

Answer 26

Lichens take up most of the community