ECOLOGY AND A FEW OF OTHER TOPICS
Ecology and a few of others
- A
student wanted to estimate the number of grasshoppers in 5km2
grass field near the school compound. Using a sweep net he captured 36
grasshoppers. He used a red felt pen to mark the thorax of each insect
before releasing back into the field. Three days later he made another
catch of grasshoppers. He collected 45 grasshoppers of which only 4 had
been marked with red mark.
a. Name the above method used in the population estimation.[1m]
b. Calculate the population of grasshoppers using the above data.[2m]
- What is
the significance of the following in the ecosystem?
a.Decomposers[1m]
b.Predators. [1m]
- Birds
feed on grasshoppers that feed on grass.
a. Draw a possible food chain from the above information. [1m]
b. Explain why the biomass of organisms decreases at each preceding
trophic level. [1m]
- Define
the following terms:-
- Autecology.
[1m]
- Biomass.
[1m]
- State two most important factors that
favour exponential growth of a population of gazelle in a park. [2m]
- (a)
Distinguish between habitat and niche. [1m]
(b)
Explain why Biomass of
producers is greater than that of primary consumers in a balanced ecosystem.[1m]
(c)
State two advantages of a biological control method over the chemical
control method of pests and parasites. [1m]
(d)
Explain how oil as a pollutant
may affect aquatic plants and animals? [1m]
- The
diagram below shows part of a food relationship in an ecosystem:-
i.
Name the food relationship
above. [1m]
ii.
How many trophic levels are
shown in the diagram above?[1m]
iii.
State main source of energy in
the ecosystem. [1m].
- Use the food web below to answer the questions that follow:-
(a)
Construct a food chain ending
with crocodile as a quartenary consumer. [1m]
(b)
Name the organisms in
the food web hat has only one predator. [2m]
- 50 black
mice and 50 white mice were released in an area inhabited by a pair of
owls. After four months, the mice in the area were recaptured and only 38
black mice and only a white mice remained.
- How
would you explain these results? [1m]
- Name
the theory of evolution that support the results in (a) above. [1m]
- In a
certain school Form three class did an experiment to estimate the number
of Tilapia in their fish pond. 725 tilapia were netted marked and
released. After two days 974 tilapia were netted among which 139 were
marked.
- State
the method used in this exercise. [1m]
- Calculate
the tilapia population. [1m]
- State two assumptions made by the
students during the investigation. [1m]
- An investigation was
carried out on a terrestrial ecosystem. The population sizes and species biomass
were determined and recorded as shown in the table
SPECIES
|
POPULATION SIZE
|
SPECIES BIOMASS
|
A
|
1x103
|
1x103
|
B
|
1x103
|
1x10-1
|
C
|
1x105
|
1x10
|
D
|
1x10
|
1x104
|
a.
If these organisms had a
feeding relationship, construct a simple food chain involving all the organisms.
[1m
b.
Construct pyramid of numbers
using the data provided above.[1m]
c.
State one disadvantage of using pyramid of number in expressing feeding
relationships in ecological ecosystem. [1m]
- The
figure represents a feeding relationship in an ecosystem.
a.
Write down the food chain in
which the Guinea Fowls are secondary consumers. [1m]
b.
What would be the short term
effects on the ecosystem if lions invaded the area? [1m]
c.
Name the organism through which
energy from the sun enters the food web. [1m]
- Outline three roles of active transport in
human body. [3m]
- Distinguish
between community and population. [1m]
- Describe
how the belt transect can be used in estimating the population of a shrub
in a grass land. [1m]
- A fish farmer wanted to know the number
of fish in a pond. He collected 10 fish from the pond and labelled each,
by a tag label on its fin and returned the ten fish to the pond to mix
with other fish. When he later
collected 50 fish from the pond, he found only four of them had labels
- Estimate
the total number of fish in the pond (show your workings) [1m]
- What two assumptions are being made in
this methods of estimating population? [1m]
- What is
the importance of saprophytic fungi and bacteria in an ecosystem? [1m]
- i) Name one
main cause of global warming. [1m]
ii) What are the effects of global warming?
[1m]
- Explain
how saliva is important in digestion. [1m]
- Give a
reason why two species in an ecosystem cannot occupy the same niche. [1m]
- Below is
a pyramid of numbers indicating trophic levels:-
a.
What do you understand by the
term trophic level? [1m]
b.
Name the trophic level numbered
5 on the pyramid [1m]
c.
What is the significance of the
arrow R. [1m]
- {EVOLUTION}Two
populations of the same species of birds were separated over a long period
of time by an ocean. Both populations initially fed on insects only.
Later, it was observed that one population fed entirely on fruits and
seeds, although insects were available. Name this type of evolutionary change.
[1m]
- To
estimate the population size of crabs in a certain lagoon, traps were laid
at random. 400 crabs were caught, marked and released back into the
lagoon. Four days later, traps were laid again and 360 crabs were caught.
Out of the 360crabs, 90 were found to have been marked
- Calculate
the population size of the crabs in the lagoon. [1m]
- What is
the name given to this method of estimating the population size? [1m]
- State
the function of each of the following apparatus: [2m]
- Pooter
- Sweep
net
- State
the role of the following apparatus in the study of living things. [3m]
- Sweep
nets.
- Pooter.
- Pit
fall trap.
- Name three density dependent factors in
an ecosystem. [3m]
- (a) What
are the two main components of
an ecosystem? [2m]
- (b) Apart
from mere observation of actual feeding suggest two methods that can be used to determine the type of food
eaten by animals. [2m]
- The
chart below represents a simplified nitrogen cycle.
What is
represented by X, Y and Z? [3m]
- In an
ecological study, a locust population and that of crows was estimated in a
grassland area over a period of one year. The results were tabulated as
shown below.
Months
|
J
|
F
|
M
|
A
|
M
|
J
|
A
|
S
|
O
|
N
|
D
|
No. of Adult
locusts x 102
|
90
|
20
|
11
|
25
|
200
|
652
|
15
|
10
|
35
|
192
|
456
|
Number of
crows
|
4
|
2
|
0
|
1
|
8
|
22
|
2
|
1
|
1
|
5
|
15
|
Amount of
rainfall
|
20
|
0
|
55
|
350
|
520
|
350
|
10
|
25
|
190
|
256
|
350
|
- Draw a
graph of population of locusts and crows against time. [6m]
- i)
State the relationship between rainfall and locust population. [1m]
ii) Account for
the relationship you have stated in b
(i) above. [1m]
- What
happens on the populations of locusts and crows in the months of January
to March?
Give a reason. [2m]
- If the
area of study was one square kilometre, state one method used to estimate the population of :-
i) Locusts. [1m]
ii) Crows. [1m]
- (i)
State the trophic levels of the (i) Locusts and (ii) crows. [2m]
(ii)Construct a
simple complete food chain involving these organisms. [1m]
- If the
locust were removed from the food chain, what would be its effect? [1m]
- Define biomass. [1m]
- Two species of antelopes were introduced into an ecosystem at the same time in equal numbers. The graphs below show their relative numbers during the first eight years of their co-existence. Study the graphs carefully and answer the questions that follow.
- i) Which
species of antelope has better survival adaptations? [1m]
ii) Give a reason
for your answer above. [1m]
- i) Name the type of curves shown. [1m]
ii) Name the
phases labelled PQ, QR, RS, ST. [4m]
- Explain the shape of the curve for the
species of Antelope A between
a)
Q and R. [1m]
b)
S and T. [1m]
- i)
State the type of competition shown by the two species of antelopes.[1m]
i) State any two symptoms of intraspecific
competition in plants.
- Suggest
how the species B avoids competitive exclusion. [1m]
- State
any three adaptations that
enable the antelopes to overcome predation. [1m]
- State
any two possible methods by
which populations of the two antelopes’ species were
determined. [2m]
- Explain five abiotic factors that affect
the ecosystem. [20m]
- The data
shown below was taken from Savannah grassland habitat. Examine it
carefully and then answer the questions that follow.
Organism
|
Population
|
Grasses
|
1000
|
Caterpillars
|
500
|
Squirrels
|
300
|
Frogs
|
200
|
Gazelles
|
300
|
Elephants
|
100
|
Snakes
|
50
|
Hunting dogs
|
40
|
Vultures
|
40
|
Lions
|
40
|
Hawks
|
10
|
- Draw three food chains. [1m]
- Draw a
pyramid of numbers for a food chain with four trophic levels and indicate
the trophic levels at which each member feeds. [2m]
- State
the immediate effect of removing the hunting dogs. [1m]
- Why is
it advisable to feed 100kg of grain to man instead of using it to fatten
steers then supply beef to human population? [1m]
- Study
the following food web and answer questions that follow
- (i)
Name the organisms that occupy the second trophic level. [1m]
(ii) What is the
other name for the second trophic level? [1m]
- Write
down two food chains in each
case from the food web that:
(i) End with
hawks as tertiary consumer. [1m]
(ii) End with
hawks as quaternary consumer. [1m]
- Giving
reasons state;
(i) the organism
with largest biomass. [1m]
(ii) the organism
with least biomass. [1m]
- (a)
Explain how food as a factor regulates the population of animals in an
ecosystem. [5m]
(b) Describe the
flow of energy from the sun through the different trophic levels in an ecosystem.
[15]
- (a)
Describe how a population of grasshoppers in a given area can be estimated.
[10m]
(b) Describe how
the belt transect can be used in estimating the population of a shrub in a
grassland. [10m]
- The flow chart below represents a feeding relationship in an ecosystem.
- Name;
(i)
The producers in the ecosystem.
[1m]
(ii) Two
organisms which are both secondary and tertiary consumers. [1m]
- State two short term effects of
immigration of insects in the ecosystem. [1m]
- Which
organism has the least Biomass in the food web? Explain. [2m]
- State three disadvantages of using
synthetic pesticides over Biological control. [3m]
- State
the role of each of the following in an ecosystem;
(i)Saprophytes.
[1m]
(ii) Leguminous
plants. [1m]
- Explain
the role of producers in an ecosystem. [1m]
- Name one method that would be used to
estimate the population of small fish in the ecosystem. [1m]
38. How are leaves of mesophytes adapted to their functions? [20m]
These are good questions but would be helpful if one had answers for revision purposes
ReplyDeletewhere can i get the answers?
ReplyDelete