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Ecological techniques > ecological techniques > Flashcards

ecological techniques Flashcards

1
Q

deine the term ecology

A

the scientific sttudy of the factors which determine the distribution and abundance of organisms

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2
Q

define the term population

A

all the individuals of one species in a habittat

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3
Q

define the term community

A

all the organisms/ populations present in a habitat/ ecosystem

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4
Q

define the term ecosystem

A

the community and the non living/ abiotic factors components of the environment

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5
Q

give examples of abiotic factors

A
  • co2
  • o2
  • water
  • ph
  • light intensity
  • temperature
  • shelter
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6
Q

give examples of biotic factors

A
  • competition
  • predation
  • symobioisi
  • parasites
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7
Q

define the term ecological niche

A

an organisms role in its ecosystem

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8
Q

give the two ways in which the distribution of organisms can be measured

A
  • randomly placed quadrats, or quadrats along a belt transect, for slow-moving or non-motile organisms
  • the mark-release-recapture method for motile organisms.
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9
Q

what can quadrats be used to measure?

A
  • density
  • frequency
  • percentage cover
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10
Q

when using a quadrat what two factors should be considered?

A
  • the positioning

- the number of quadrats used

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11
Q

why is random sampling used?

A
  • avoid bias
  • be representative
  • produce statistically significant results
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12
Q

how do we select the areas we sample in when using random sampling?

A
  • random number generator

- random number table

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13
Q

how doe the NE rule or equivalent help when using quadrats?

A
  • avoids dealing with only parts of an organism
  • avoids counting the same organism twice
  • ensures consistency
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14
Q

why does the sample size need to be large?

A
  • so it is representative of the population

- so a statistical test can be carried out

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15
Q

what is the minimum number of quadrats that should be taken?

A

20

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16
Q

give a technique used to decide if the sample size is large enough

A
  • running mean
  • adding the new data collected from the quadrat to the previous quadrat
  • when the mean no longer changes you will have collected a big enough sample
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17
Q

describe measuring the frequency of a species

A

this is when you just record the presence or absence of a species in each quadrat

18
Q

describe measuring percentage cover

A

this is a measure of the proportion of the ground occupied by the species in the quadrat, as a percentage of the total area

19
Q

describe measuring the species density

A

counting the number of individuals of a species in a quadrat

20
Q

give the advantages of measuring the frequency of a species

A

quick and easy in large ecosystems

21
Q

give the advantages of measuring percentage cover

A
  • quicker than counting

- useful when difficult to distinguish individual plants, and when one finishes an one starts

22
Q

give the advantages of measuring species density

A

-allows you to calculate an estimate of the population size can calculate species diversity

23
Q

give the disadvantages of measuring species density

A
  • time consuming
  • miss counts possible if in large numbers
  • difficult to distinguish different plants
24
Q

give the disadvantages of measuring percentage cover

A
  • it is subjective so estimates by different people will differ
  • doesnt give an actual population size
25
Q

give the disadvantages of measuring the frequency of a species

A
  • no estimate of population size
  • can give an inaccurate indication of relative abundance
  • results not detailed as one organism of a species counts the same as a 100 in a different sample
26
Q

what is a transect ?

A

taking a sample along a line

27
Q

wat is a transect used for ?

A

investigating how species distribution changes across and area

28
Q

which is more detailed a line transect or belt transect ?

A

belt transect

29
Q

Describe how you would collect data on the population of daisies in a field using random sampling

A

 tape measures to mark out a grid
 random numbers, from tables or a calculator to generate coordinates
 place quadrat and count all daisies in area – decide on rules for overlapping edges
 repeat until you have a large sample/ do a running mean until it settles out
 work out the mean number per quadrat and multiply by the number of quadrats in the area, or calculate the mean per m2 and multiply by the area in m2
.

30
Q

Describe how you would investigate how the
distribution of plants changes from the middle
to the edge of a woodland.

A

interrupted belt transect
 could do more than one quadrat at each point to increase sample size and gain a more representative sample / reduce impact of anomalies / increase reliability
 need regular measurements to be able to establish pattern/detect trends
 estimate % cover / species frequency / species density
 can convert to kite diagram

31
Q

what is the advantage of doing more than one quadrat at each point?

A

increase sample size and gain a more representative sample / reduce impact of anomalies / increase reliability

32
Q

describe the process of a line transect

A

A measuring tape is stretched across the habitat and plants are sampled at regular intervals, for example every 10cm. Each plant touching the line is identified and recorded.

33
Q

describe the process of a belt transect

A

Quadrats can be placed next to each other along a transect and estimates of the percentage cover or frequency of each species is recorded.

34
Q

what is a pitfall trap used for ?

A

crawling animals

35
Q

what trap catches crawling animals?

A

pitfall trap

36
Q

what trap catches water or sediment living organisms?

A

a kick sample net

37
Q

what is a kick sample net used for catching?

A

water or sediment living organisms

38
Q

what catches flying insects?

A

butterfly net

39
Q

what assumptions do we make when using the mark recapture release method?

A
  • no immigration or emigration
  • no births or deaths
  • marking does not increase the likely hood of been recaptured or preyed upon
  • marked individuals have had a chance to mix fully back in with the population
40
Q

give the equation used when using the mark recapture release method

A

population number estimate= ( the number captured first x the number captured on second occasion) / the number recatured that were marked

41
Q

describe the method of mark release recapture

A
  • using random sampling a large sample of organisms are caught
  • then the organisms are marked, counted and released back into the ecosystem
  • after release animals are given time to move around and thoroughly mix with the rest of the population
  • then again capture a large sample using the same technique as before
  • count the total number captured and the total number marked and then apply the equation
42
Q

when marking organisms what should you ensure?

A

the mark does not harm the animal or in any way affect their chance of survival

Ecological techniques (1 decks)

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