BioManiaa!!
Lesson Plan for Grade 10, Science Biology
Chapter 18 : Organisms and their environment
Theory Quests!
1. The source of all energy in a food chain is the sun True or False
Ans: True (Produces absorbs light energy from the sun).
2. How is chemical energy transferred up the food chain?
Ans: Chemical energy is transferred up food chains when organisms consume the
chemical energy stored in the tissues of other organisms
3. How can energy in the food chain be transferred to the environment?
Ans:
● Heat loss from living organisms
● Excretion of waste from living organisms
4. What do food chains show?
Ans: Food chains shows the energy from one organism to the next
5. What do food webs show?
Ans: Food Web shows networks of interconnected food chains.
6. Define the term producer
Ans: A producer is an organism that that can produce its own carbon compounds
(Photosynthesis)
7. Define the term primary consumer ?
Ans: A primary consumer is an organism that eats producer . ( Its also called
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Herbivore)
8. Define the term Secondary consumer?
Ans: Secondary consumer is an organism that eats Primary consumers. (carnivores
or omnivores)
9. Herbivores are secondary consumers. True or False
Ans: False Herbivores are primary consumers.
10.Define the term carnivore.
Ans: Carnivores are animals that gain their energy by eating other animals.
11. Define the term tertiary Consumer
Ans: Tertiary consumers are organisms that feed on secondary consumers. (They
are carnivores and are present at the 4th trophic level of the food chain).
12.Define the term decomposer
Ans: Decomposers are organisms that gain energy from dead or waste organic
material
13.How might overfishing by hoomans affect a marine food web?
Ans: There might be increase in population size of the organisms normally
consumed by the fish
14.What do pyramids of numbers show?
Ans: A pyramid of numbers show how many organisms are present at each level of
food chain
15.True or False Pyramids of numbers are always pyramid shaped.
Ans: False ( Pyramids of numbers are not always pyramid shaped )
16.What do Pyramids of Biomass show?
Ans: Pyramids of biomass show the mass of living materials present at each stage of
the food chain.
17.What rules should be followed when drawing a pyramid of numbers or biomass
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Ans: The producers should always be at the base, Each box should be labeled with
its trophic level
18.What is the advantage of using a pyramid of biomass rather than a pyramid of
numbers
Ans: The advantage of using it is it gives cleared representation of the mass of living
material present at each trophic level.
19. Define the term trophic level
Ans: A trophic level is the position of an organism in a food chain or food web.
20.What type of organisms is present at the first trophic level in food chain
Ans: The first trophic level contains Producers.
21.The second trophic level of the food chain contains secondary consumers . True or
False?
Ans: False. The second level of the food chain contains Primary consumers.
22.What type of organism is present at the third trophic level of a food chain
Ans: Secondary consumers
23.What does a pyramid of energy illustrate ?
Ans: It illustrates the chemical energy contained within the biomass of organisms at
each trophic level of the food chain.
24.Pyramids of Biomass and energy are always pyramid shaped due to energy losses
between trophic levels.
Ans: True . Energy losses at each trophic level mean that each trophic level will
contain stored energy.
25.What are some reasons for energy loss at each trophic level of a food chain?
Ans: Because organism rarely eat every part of the consumed organs
26.Why are food chains rarely made up of more than five trophic levels?
Ans: Because of the energy losses at each trophic level. The total energy becomes
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too small to support another trophic level.
27.Why is it more energy efficient for hoomans to eat plants than meat?
Ans: Because the resulting food chains has fewer trophic levels
28.How is carbon taken out of atmosphere.?
Ans: Carbon is taken out of the atmosphere in the form of carbon dioxide by the
plants during photosynthesis
29.How is Carbon Transferred from one organism to another in carbon cycle?
Ans: It's transferred from one organism to another by the process of feeding
30.How is carbon returned to the atmosphere in the carbon cycle
Ans: Carbon is returned to the atmosphere when it is released as carbon dioxide by
:respiration in plants and animals, respiration of decomposites (bacteria)
31.What is the role of combustion in the carbon cycle?
Ans: Combustion releases carbon dioxide into the atmosphere (occurs at fossil
fuels)
32.The action of decomposites converts plant and animal protein into ammonium
ions True or false?
Ans: true Decomposers break down protein in dead and waste material
33.What is the role of nitrifying bacteria in nitrogen cycle
Ans: Nitrifying bacteria convert ammonium compounds to nitrites and then to
nitrate
34.Plants and animals can absorb nitrogen directly n from air true or false
Ans: Neither plants nor animals can absorb nitrogen directly from the air.
35.In what form do plants absorb nitrogen from the soil
Ans : In the form of nitrates
36.Why is nitrogen needed by living organisms
Ans: Nitrogen is required by living organisms to make amino acids and protein.
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37.How do animals obtain nitrogen they need?
Ans; By eating other organisms and digesting the proteins in their tissues.
38.Define the term Population
Ans: A population is a group of organisms of the same species living in the same
place at the same time.
39.Define the term Community
Ans: A community include all of the population of different species living in an
organisms
40.Define the term Ecosystem
Ans: A natural area where living and non-living things interact.
41.What are factors that affect the rate of population growth?
Ans: Food supply, Competition, Disease, Predation
42.Why do some population enter death phase
Ans: When death rates exceed birth rates due to limited resource or production of
harmful waste product
Some Key Points!
● Predation: if the predator population falls, the prey population will rise.
● Immigration and Emigration: People moving in and out of the population
● Lag phase: The number of mature, reproducing individuals is low and they may be widely
dispersed
● Exponential (Log) phase: exponential growth occurs, the conditions are ideal, and the
maximum growth rate is reached. Limiting factors do not limit growth much.
● Stationary phase: limiting factors slow growth as the population has reached the
“carrying capacity” of its environment; when mortality rate = birth rate, the curve levels
off and fluctuates around this maximum population size.
● 10% Rule : Only 10% of energy is passed to the next level.
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