Investigating Populations

Question 1

What is ecology?

Answer 1

The study of organisms and their interactions with each other and their environment and biotic/abiotic factors

Question 2

What is a species?

Answer 2

A group of closely related individuals with similar characteristics that are able to reproduce together to produce fertile offspring

Question 3

What is a population?

Answer 3

All the individuals of a given species living together in the same area at the same time

Question 4

What is a community?

Answer 4

All the individuals of all species in a community living together in the same area at the same time and the ways in which they interact with each other, their environment and abiotic and biotic factors.

Question 5

What is a habitat?

Answer 5

The place in which an organism lives within an ecosystem, characterised by abiotic and biotic factors

Question 6

What is a niche?

Answer 6

Describes an organisms role within a community. It is what it feeds on and the way in which it interacts with its environment, other organisms and abiotic/biotic factors

Question 7

What is carrying capacity?

Answer 7

• The maximum equilibrium number of organisms of a particular species that can be supported indefinitely by a given stable environment
• Can change in response to changes in abiotic or biotic factors

Question 8

Explain the competitive exclusion principle

Answer 8

No 2 species can occupy the exact same niche for a long period of time.
The better adapted species will always displace the lesser adapted species causing them to become extinct
Reduces interspecific competition so both survive

Question 9

What is an ecosystem?

Answer 9

A community made of living organisms and their interactions with each other and abiotic components such as air, water, mineral salts.

Question 10

What is the difference between interspecific and intraspecific competition?

Answer 10

Interspecific: Occurs between different species within the same/similar niche
Intraspecific: Occurs between organisms of the same species in the same niche

Question 11

What are biotic factors?

Answer 11

Living factors that affect the distribution of an organism

• Competition for food or living space
• Disease
• Parasites
• Predation

Question 12

What are abiotic factors?

Answer 12

Non-living factors that affect the distribution of an organism

• Temperature
• Light Intensity
• Wind speed
• Salinity
• Water
• pH

Question 13

Why do no two species have the exact same niche

Answer 13

It would cause interspecific competition, which can’t occur due to the competitive exclusion principle as the better adapted species would displace the lesser adapted species causing it to become extinct

Question 14

What happens when niches overlap?

Answer 14

Competitive exclusion principle

Question 15

Why is it incorrect to say that no two species share the same niche?

Answer 15

Different organisms occupy the same ecological niche whilst competing until one species displaces the other e.g extinction of migrants

Question 16

Explain the 3R’s for a sample?

Answer 16

Random: To ensure the data collected is not biased
Reliable: If it can be repeated to get the same or similar results
Representative: Must be large enough sample and be able to have statistical tests carried out on it or have a running mean

Question 17

How many quadrats

Answer 17

Running mean
Enough when little change/levels off
Enough for stats test
Large so reliable (20+)
Not too large so that it can be carried out in time available

Question 18

Sytematic sampling

Answer 18

Investigating the effector an environmental gradient (named abiotic factor) on biodiversity

Transect
Belt transect
Interupted belt transet

Question 19

Belt transect

Answer 19

2 parallel lines a meter apart

Record species found between lines

Question 20

Interupted belt transect

Answer 20

Use one line and place quadrat down equally spaced points and record abundance in transect

Question 21

How do you investigate the distribution of marram grass across a dune

Answer 21

Transect from one side to the other
Place quadrats at regular intervals along line
Count plants/percentage cover
Record where they touch transect

Question 22

Mark recapture release

Answer 22

Moving species

Collect ethically
Mark in non harmful way
Released and left to redistribute
After time recapture
Count number caught and how many marked

Question 23

Population size mark recapture release

Answer 23

N1×N2/Nm

N1: number caught the first time
N2 : number caught second time
Nm : number caught second time marked

Question 24

Considerations for M.R.R

Answer 24

No change in population size (death rate birth rate constant, no migration)

Shouldn’t make more susceptible to predators

Shouldn’t be lost or rub off

Sufficient time to redistribute byt not long that births or deaths occur

Question 25

Wind speed device

Answer 25

Anemometer

Question 26

Soil pH device

Answer 26

pH probe

Question 27

Light intensity device

Answer 27

Lux meter

Question 28

Sere

Answer 28

Complete succession from pioneer community to climax community

Question 29

Seral stage

Answer 29

Particular stage in succession with its own distinctive community of organisms

Question 30

Climax community

Answer 30

Final stage in ecological succession

Stable and changes very little

Question 31

Hostility

Answer 31

Abiotic factors unfavourable

Few species adapted to survive in these conditions

Question 32

Primary succession

Answer 32

Pioneer colonises
Changes environment
Less harsh
Others can survive and colonise
Changes biodiversity (more)
Increased stability/less hostile
Climax community

Question 33

Secondary succession

Answer 33

After forest fire
Spores, seeds remain viable in so
Influx of animals and plants through dispersal and migration from surrounding area

Begins with intermediate species

Question 34

Deflected succession

Answer 34

Climax community prevented from establishing
E.g human practices
Community maintained is called a plagioclimax