Transcript Measuring biotic/abiotic components in a sys. notes

Measuring Biotic and Abiotic
Components of a System
2.1.1, 2.3.1-2.3.5, 2.7.1-2.7.3
 Biotic

=
Examples:
 Abiotic

=
Examples
 Terrestrial
• Marine
• Freshwater
 Precipitation:
rain gauge
 Temperature: thermometer
 pH: pH strip; pH probe
 wind speed: aerovanes
 Dissolved Oxygen: DO Probe or chemical test
 Salinity: Hydrometer
 Quadrat
- A quadrat is a frame of any shape that can
be placed over vegetation so that species can be
listed or counted, and population density, percent
frequency and percent cover can be estimated. = For
non-mobile organisms
 Capture-Mark-Release-Recapture (Lincoln Index) = For
mobile organisms
 N=
the estimated population (what you are looking
for)
 T1: total organisms you caught and marked in 1st
sample
 T2: total organisms you captured in 2nd sample
 M: the number that were marked in the 2nd
sample. (meaning they have been So,
recaptured)
do you have a larger
population if you have a
 N = T1 x T2
large or small “M”?
M
Why?
Example…
 Cap/Mark/Recap:



Only works with a static population…..does this
occur in nature?
Marked individuals are more noticeable to
predators
Losing their marks by molting, rain, etc
 Quadrats:
Limit accuracy by amount of money you have
to spend on counters.
 Less counters or smaller quadrats mean less
accuracy.
 Placement of quadrats can cause results to be
skewed.

 Biomass
- estimate of dryweight in g/m2 of an
organism.
 Method?
 Three
types: Habitat, species, genetic
 2 components:


A
1. Richness = # of different species in an area
2. Evenness = a measure of relative abundance
of each species in an area. (number of
organisms of each type of specie)
community that is dominated by one or
two species is less diverse than one that
has several different species with a
similar abundance, even if they have the
same richness amount.
 Ex?
A
measure of species richness of an area.
 A high value suggests a stable, climax
community.
 A low value could suggest pollution, early
stages of succession or agricultural
management………Why?
 D=
Simpson’s Diversity Index
 N = TOTAL # of organisms of all species
found.
 n = number of individuals of a particular
species.
 D = N(N-1)
Σ[n(n-1)]
Species
N

A
3

B
4

C
2

D
2

E
4
 Total = N = 15
 N(N-1) =
15(15-1)
= 210
(210 is your top
number!)

n(n-1)
6
 12
2
2
 12
 Σ[n(n-1)] = 34

(34 is your bottom
number!)
 Simpson’s
Index:
D = N(N-1)
Σ[n(n-1)]
D = 15(14) = 210
34
34
D = 6.17
 Is
this area diverse?
 Here is the problem:




You CAN’T tell from this
equation.
All you can do is tell relative
diversity when compared to
another area/Diversity
number
ie: This area would be less
diverse than an area whose
Simpson’s Index number is 10.
Only used for comparative
purposes
 Rainfall
= rain gauge
 Temp = thermometer
 Species diversity = quadrats or mark and
recapture and then Simpson’s Diversity Index
 Species abundance = quadrats or mark and
recapture
 All of these stats would be taken over a set
amount of time………..mutiple data sets (at
least 2....when?)
 What
is a gradient?
 Therefore
an environmental gradient is a
change in abiotic or biotic factors over an
area.
 Examples of where you can see this?
 How should you measure this?
 YOUR
LABS DO THIS!!
 Examples of human effects and how to
measure them?
 Could also include satellite images and maps.

An EIA is a government report prepared before a
development project that will change the use of land (in
the planning process).

Ex: major new road networks, airports, building power stations,
dams, quarrying, planting a forest, converting fields to a golf
course, large-scale housing projects, etc.
The EIA weighs up the relative advantages and
disadvantages of the development.
 It will try to quantify how the abiotic and biotic factors
would change if the development occurs.
 Therefore, a baseline study is necessary first....what the
environment is like now.
 The EIA will forecast both negative and positive impacts
on the natural environment and human populations (if the
development might have an effect on human health or a
community’s economy).

 EIA’s
measure the social and environmental costs
of the development and tries to translate these
into monetary values.

Ex: number of jobs provided, net profit of the
development, land degradation, habitat loss,
pollution, human health, etc.
 What
issues can there be with many of these
assessments?
 Homework:



Find pictures of or draw 8 organisms and
print them out.
Make a dichotomous tree and then a key
On a third sheet of paper, print the pictures
out again and make an answer key.