B2.1 human problems, sampling strategies

Question 1

For most of human history our global carrying capacity was around…

Answer 1

600 million people

Question 2

what meant we were able to overcome limiting factors

Answer 2

our mental capacity

Question 3

what stopped food being a limiting factor

Answer 3

Agriculture was invented in around 8500 BC in Syria. Basic herdsmanship and cultivation was improved by the invention of the plough in Egypt.

Question 4

what key moment stopped disease being a limiting factor

Answer 4

Germ theory started scientists looking at causes and cures for disease particularly spurred by the
Bubonic Plague.

Question 5

the industrial revolution helped humans…

Answer 5

overcome all limiting factors technocentrically

Question 6

in the industrial revolution, what inventions stopped disease (2), food and space, predators

Answer 6

• Sewer systems to eradicate disease
• Transports systems to use all space and attain food
• Weapons systems to eradicate predators
• Medicine to cure even more disease.

Question 7

what percentage of land surface remains unaffected by humans?

Answer 7

3%

Question 8

what is the carrying capacity or niche for humans?

Answer 8

there isn’t one! we have no definable niche as we have been able to overcome every limiting factor. our cc estimate can only be ‘now’

Question 9

what are the 3 approaches to sampling?

Answer 9

random sampling, transects, systematic sampling

Question 10

what are random quadrats used to do

Answer 10

determine the species in an area

Question 11

method for random quadrats

Answer 11

• place random quadrats in an area (generated mathematically to remove bias)
• estimate population using either % cover or % frequency
• multiply up

Question 12

whats the minimum amount of intervals you can have in a transect

Answer 12

7

Question 13

an alternative to transects could be…

Answer 13

splitting an area into arbitrary zones, eg: low tide, high tide, foredunes, white dunes, grey dunes etc. and then take a quadrat from each of these areas.

Question 14

what is an example of opportunistic sampling

Answer 14

looking at organisms in a rock pool

Question 15

how to do percentage cover

Answer 15

place quadrats in an area and make broad estimates about the percentage cover of each plant in each square. so for example, 20% dandy lions, 70% grass and 10% daisies.

Question 16

disadvantage of percentage cover

Answer 16

it is affected by the size of the plant/leaves and so larger species will be over represented.

Question 17

how to calculate percentage frequency

Answer 17

• note how many squares in the quadrat each species appeared in
• divide it by the total number of squares.
• Average this out across your quadrats and multiply up.

Question 18

what is the ACFOR scale?

Answer 18

Abundant (30%+)
Common (20 to 20%)
Frequent (10 to 19%)
Occasional (5 to 9%)
Rare (1 to 4%)

Question 19

methods for sampling animals:

Answer 19

• visual counting
• aerial photographs
• non lethal traps

Question 20

main method of sampling for capture recapture:

Answer 20

• pooters
• nets
• pitfall traps

Question 21

lincoln index use

Answer 21

used to estimate population size. aka capture recapture. not a sampling technique

Question 22

what is the lincoln index method?

Answer 22

• safely capture organisms using pooters, nets or pitfall traps
• mark them in a way that does not cause harm or predation bias
• release them
• repeat the sample the following day/week
• calculate population size

Question 23

how to calculate population size with lincoln index?

Answer 23

(n1 x n2) / n3
n1 = number collected in first capture
n2 = number collected in second capture
n3 = number of marked in second capture

Question 24

limitations of lincoln index

Answer 24

• can only be used on mobile organisms
• based on assumptions that there was no immigration, emigration, hibernation, births or deaths