9.1 Ecosystems & The Stabilty Of Populations

Question 0

What is a population?

Answer 0

A group of individuals of the same species living in a certain defined area

Question 1

What is a community?

Answer 1

All the living organisms in an ecosystem at any given time

Question 2

What is meant by biotic?

Answer 2

An ecological factor that makes up part of the living environment of an organism (competition/predation)

Question 3

What is meant by abiotic ?

Answer 3

An ecological factor that makes up part of the non-biological environment of an organism (pH/temperature)

Question 4

What is a niche?

Answer 4

The role, activities and location of a population within a habitat

Question 5

What is a habitat ?

Answer 5

The place where an organism normally lives, which is characterised by physical conditions and the types of other organisms present

Question 6

What is an ecosystem?

Answer 6

The community of living organisms and the biotic factors that affect them

Question 7

What is biodiversity?

Answer 7

The variety of different organisms in a particular area

Question 8

Ecosystems are dynamic as the organisms within them :

Answer 8

Interact with one another and the ever changing environment

Question 9

Energy and nutrients usually flow between the organisms in an?

Answer 9

Ecosystem

Question 10

All organisms affect?

Answer 10

One another, e.g. Competition or energy source

Question 11

Abiotic factors also affect the?

Answer 11

Ecosystem (climate/light level)

Question 12

Some abiotic factors can be altered due to?

Answer 12

The presence of organisms

Question 13

A niche is often described as an?

Answer 13

Organism’s role within its ecosystem; it encompasses it’s food source, habitat, physiology and behaviour

Question 14

Natural selection ensure that organisms are adapted to a?

Answer 14

Specific niche

Question 15

Overlap between the niches of the 2 species in the same ecosystem results in:

Answer 15

Interspecific competition

Question 16

Primary succession occurs when organisms ?

Answer 16

Colonise a lifeless habitat

Question 17

Secondary succession occurs when organisms?

Answer 17

Re-colonise a devastated ecosystem

Question 18

Nitrogen fixed helps to improve the soil quality allowing?

Answer 18

Colonisation of new species

Question 19

Each serial stage of succession has distinct biotic and abiotic characteristics. In order to conserve unique species?

Answer 19

Halting the process of succession may be necessary

Question 20

Population is :

Answer 20

Individuals of the same species in a given area

Question 21

What 2 factors act as an indicator of its ecosystem’s condition?

Answer 21

Size

Health

Question 22

A decline in population is likely to be caused by a ?

Answer 22

Change in its ecosystem

Question 23

Size of population is influenced by both

Answer 23

Abiotic and biotic factors

Question 24

Populations are dynamic responding to:

Answer 24

Variations in their environment

Question 25

Populations can be measured in a number of ways:

Answer 25

Size Density Growth rate

Question 26

Size is:

Answer 26

Number of individuals in a population

Question 27

Density is:

Answer 27

Number of individuals per unit area

Question 28

Growth rate is:

Answer 28

Change in the number of individuals per unit of time

Question 29

Population's size and distribution in both space and time is only apparent when:

Answer 29

Each of these measures is known

Question 30

Population is affected by:

Answer 30

Birth rate Death rate Immigration rate Emigration rate

Question 31

Population growth =

Answer 31

B+I-D-E

Question 32

Lag phase is:

Answer 32

Pop. Growth is initially low Few widely dispersed individuals Limits sexual reproduction as mates are difficult to locate

Question 33

Exponential growth is:

Answer 33

Population grows at it's max. Possible rate its biotic potential Birth rate is higher than death rate and there is little competition (predators, food, sunlight space)

Question 34

Transitional phase:

Answer 34

As population grows, environmental resistance increases. Increased competition for resources increases death rate Growth rate slows as pop. Increases

Question 35

Plateau phase is:

Answer 35

The population reaches the maximum size that its ecosystem can sustain. This is the carrying capacity (k) The population remains roughly stable in a constant environment

Question 36

Availability of resources depends on :

Answer 36

Population size

Question 37

Factors whose effect upon a population depends on the population's size are:

Answer 37

Density dependant - often cause intraspecific competition and ate important for determining a population's carrying capacity

Question 38

Density independent factors are:

Answer 38

Not reliant upon a population's size and remain constant regardless (temperature, rainfall and salinity)

Question 39

Interspecies interactions can limit:

Answer 39

A population's size

Question 40

When species compete with each other it can lead to:

Answer 40

Competitive exclusion

Question 41

Competitive exclusion is the:

Answer 41

Inevitable elimination from a habitat of one or two different species with identical needs for resources