Biotic and abiotic factors
Kavungya answered the question on June 15, 2019 at 07:16
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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...
(Solved)
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
(i) Calculate the population size of the crabs in the lagoon
(ii) What is the name given to this method of estimating the population size
Date posted:
June 15, 2019
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Answers (1)
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What do you understand by the term trophic level?
(Solved)
What do you understand by the term trophic level?
Date posted:
June 15, 2019
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Answers (1)
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A fish farmer wanted to know the number of fish in a pond. He collected 10 fish from the pond
and labeled each, by a tag...
(Solved)
A fish farmer wanted to know the number of fish in a pond. He collected 10 fish from the pond
and labeled 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
a) Estimate the total number of fish in the pond (show your workings)
b) What two assumptions are being made in this methods of estimating population
Date posted:
June 15, 2019
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Answers (1)
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An investigation was carried out on a terrestrial ecosystem. The population sizes and species biomass were determined and recorded as shown in the table...
(Solved)
An investigation was carried out on a terrestrial ecosystem. The population sizes and species
biomass were determined and recorded as shown in the table
a) If these organisms had a feeding relationship, construct a simple food chain involving all the organisms
b) Construct pyramid of numbers using the data provided above
c) State one disadvantage of using pyramid of number in expressing feeding relationships in ecological ecosystem
Date posted:
June 15, 2019
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Answers (1)
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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...
(Solved)
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.
a) State the method used in this exercise
b) Calculate the tilapia population.
c) State two assumptions made by the students during the investigation
Date posted:
June 15, 2019
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Answers (1)
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Use the food web below to answer the questions that follow:-
(a) Construct a food chain ending with crocodile as a quartenary consumer
(b) Name the organisms...
(Solved)
Use the food web below to answer the questions that follow:-
(a) Construct a food chain ending with crocodile as a quartenary consumer
(b) Name the organisms in the food web hat has only one predator
Date posted:
June 15, 2019
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Answers (1)
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Explain how oil as a pollutant may affect aquatic plants and animals.
(Solved)
Explain how oil as a pollutant may affect aquatic plants and animals.
Date posted:
June 15, 2019
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Answers (1)
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State the advantage of a biological control method over the chemical control method of pests and parasites
(Solved)
State the advantage of a biological control method over the chemical control method of pests and parasites
Date posted:
June 15, 2019
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Answers (1)
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Explain why Biomass of producers is greater than that of primary consumers in a balanced ecosystem.
(Solved)
Explain why Biomass of producers is greater than that of primary consumers in a balanced ecosystem.
Date posted:
June 15, 2019
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Answers (1)
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Explain why the biomass of organisms decreases at each preceding trophic level.
(Solved)
Explain why the biomass of organisms decreases at each preceding trophic level.
Date posted:
June 15, 2019
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Answers (1)
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Birds feed on grasshoppers that feed on grass.
Draw a possible food chain from the above information
(Solved)
Birds feed on grasshoppers that feed on grass.
Draw a possible food chain from the above information
Date posted:
June 15, 2019
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Answers (1)
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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...
(Solved)
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
b) Calculate the population of grasshoppers using the above data
Date posted:
June 15, 2019
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Answers (1)
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Explain one demerit of transpiration in plants
(Solved)
Explain one demerit of transpiration in plants
Date posted:
June 14, 2019
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Answers (1)
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Describe and explain the relationship between the stomatal aperture and transpiration rate.
(Solved)
Describe and explain the relationship between the stomatal aperture and transpiration rate.
Date posted:
June 14, 2019
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Answers (1)
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The graph below shows the changes in transpiration rate and the width of the stomatal aperture in Zea mays (maize) over a 24-hour period.
a) What...
(Solved)
The graph below shows the changes in transpiration rate and the width of the stomatal aperture in Zea mays (maize) over a 24-hour period.
a) What is meant by the term transpiration?
b) Account for the rate of transpiration between
i)3am and 5am
ii)6am -12 noon
iii)1.00 pm -9.00 pm
Date posted:
June 14, 2019
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Answers (1)
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State the reasons why glucose level should be maintained constant.
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State the reasons why glucose level should be maintained constant.
Date posted:
June 14, 2019
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Answers (1)
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Name one example of a characteristic in man that is transmitted by multiple alleles.
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Name one example of a characteristic in man that is transmitted by multiple alleles.
Date posted:
June 14, 2019
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Answers (1)
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State the importance of crossing over in the study of genetics
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State the importance of crossing over in the study of genetics
Date posted:
June 14, 2019
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Answers (1)
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Give 2 advantages of cross-pollination over self-pollination.
(Solved)
Give 2 advantages of cross-pollination over self-pollination.
Date posted:
June 14, 2019
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Answers (1)
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Suggest the biological significance of each of the following
i) Development of the pollen tube in fertilization in plants.
ii) Fusion of petals to form funnel-shaped corolla...
(Solved)
Suggest the biological significance of each of the following
i) Development of the pollen tube in fertilization in plants.
ii) Fusion of petals to form funnel-shaped corolla tube in certain
flowers.
Date posted:
June 14, 2019
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Answers (1)