| P75/Q1 |
|
DDT was an insecticide commonly used in
1930's and 40's. DDT is chemically very stable
("persistent"), which means it is not broken down
for many years. Leaching of DDT to streams/rivers
and its accumulation in the tissues (especially fat)
of fishes could result in penguins accumulating DDT
in their bodies, too (providing, they prey on the
fish which have DDT in their fat tissue).
|
| P76/Q2 |
|
B
|
| P78/Q3 |
|
17 + 41 = 58 58 - 17
(?) - 40
Size of the population (?) = (40 x 58) / 17 = 136
|
| P79/Q4 |
|
The released blue tits would not mix
thoroughly in the population. Instead, they would
return to their territories (from which they were
originally captured).
|
| P81/Q5 |
|
(1) The upper shore area needs to be
clearly defined. (2) Then, a plan of the upper
shore area with co- ordinates of the sampling areas
should be prepared.
(3) A group of sampling areas for the survey
should be randomly selected.
(4) Carry out a survey of the sampling areas
using quadrats; results in the table:
| |
No of individuals in the sampling area # |
| Species |
|
| A |
|
| B |
|
| C |
|
| etc. |
|
|
| P84/Q6 |
|
High speed of wind will normally pile up
sand on top of any plants growing there. In Marran
grass, leaves grow from the main stem, which is
growing vertically upwards. The more sand there is
deposited on top of the Marran grass, the more
vigorously it grows.
|
| P85/Q7 |
|
0 (zero).
|
| P87/Q8 |
|
Secondary succession. It takes place in
areas where there has already been a
community/population of living things (e.g. tussock
grass) which have been damaged as a result of
activities of another population (e.g. elephant
seals). Secondary succession in this case would mean
growth of some other plants in place of tussock
grass.
|
| P87/Q9 |
|
The diversity index calculated for shrubs
in an old hedge will be higher then the diversity
index for a young hedge.
|
| P88/Q1 |
|
The niche of the tiger may be
threatened because of:
- Reduced amount of food/prey
- Increased competition between tigers for hunting
territory
- Tigers may cross the boundary of the park and
migrate in search of prey.
|
| P88/Q2 |
|
Considering behaviour patterns of the
tiger it may be very difficult to use sampling
methods (such as mark - release - recapture)
because tigers are very vigilant and difficult to
capture.
|
| P89/Q3 |
|
In order to obtain photographs of
tigers at night (nocturnal patterns of behaviour -
they stay active at night). Photos can be used to
identify tigers because their unique arrangement of
stripes on their body.
|
| P89/Q4 |
|
6 Tigers, which were photographed at
least once since the previous date (curve B) may be
considered as resident in the area. Tigers are
territorial animals. They spent most of their time
in their "own" territory, and therefore can be seen
in their area more frequently than other tigers
without a territory of their "own". |
| P90/Q5 |
|
| Tiger |
(P) |
(L) |
(P/L) |
| A |
13 |
2 |
6.50 |
| B |
43 |
11 |
3.90 |
| C |
15 |
4 |
3.75 |
| D |
23 |
8 |
2.87 |
| E |
13 |
5 |
2.60 |
| F |
19 |
11 |
1.73 |
|
| P90/Q6 |
a) |
The smaller the ratio, the larger
the tiger's territory.
|
| |
b) |
1.73 and 2.60 →
tiger F and tiger E.
|
| P90/Q7 |
|
The use of the formula is based on the
assumption, that the size of a tiger's average
territory in the park area is the same as the size
of a tiger's average territory in the study area.
The formula does not take into account the presence
of migrating tigers (i.e. tigers without territory
of their "own").
|
| P90/Q1 |
a) |
A chosen species of a plant is
"artificially" propagated/maintained by the
application of various agricultural techniques
(sowing, fertilisation, watering, etc.). Other
species of plants and many species of animals are
systematically eradicated by the application of
herbicides and insecticides. As a result the
diversity of living things is reduced. 24 x 23
|
| |
b) |
(i) d = (24 x 23) / [(12x11)+(8x7)+(3x2)] = 2.84
|
| |
|
(ii) Index of diversity is a more accurate method of
describing a community than just number of species
alone. It is because the index takes into account
the number of individuals of each species, which are
present in the sample.
|
| |
c) |
| (i) |
- Draw a plan of the area
- Mark co-ordinates on the plan
- Use the co-ordinates to select randomly places for
survey to be carried out
- Use quadrats to survey the species present
- Use the table below to record the
result
|
| Species |
Total number of individual species |
A
B
C
Etc.
|
|
|
| |
|
(ii) Fig1: no clear relationship between Plant
species diversity and Bird sP diversity.
Fig2: the
higher Plant structural diversity, the higher Bird
species diversity.
|
| |
|
(iii) Structural diversity refers to different forms
of plants (herbs, shrubs, trees). Different forms of
plants will satisfy the demand for shelter, nesting
and feeding sites better than the areas where there
are not many different forms of plants (the
Structural diversity is low).
|
| |
d) |
(i) Graph:
|
| |
|
(ii) The bird species diversity will increase. The
overall trend shown in the table indicates an
increasing value of index of diversity for bird
species.
|
| P92/Q2 |
a) |
An ecological succession is a process
of progressively increasing diversity of plant and
animal communities. The process happens naturally
over a certain period of time.
|
| |
b) |
Feature 1: increasing numbers of species and
individuals within each species;
Feature 2: the
environment is gradually modified as a result of
activities of the organisms themselves.
|
| |
c) |
As a result of deforestation the number of the
trees will be reduced →
the amount of the leaf litter will be reduced
→ the amount of
the organic sediment carried by the river to the
lake will be reduced →
less nutrients →
slower process of succession in the lake.
|
