This set of Class 12 Biology Chapter 14 Multiple Choice Questions & Answers (MCQs) focuses on “Ecosystem – Hydrarch Succession”.
1. What is the sequence of successional stages occurring in water called?
a) Xerarch succession
b) Hydrarch succession
c) Ecological succession
d) Biological succession
View Answer
Explanation: The sequence of successional stages occurring in water is known as hydrarch succession. It is also known as hydrosere and starts in a newly formed pond or lake.
2. Which of the following succession starts with the colonization of phytoplankton in the water?
a) Hydrarch succession
b) Xerarch succession
c) Biological succession
d) Ecological succession
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Explanation: The sequence of successional stages occurring in water is known as hydrarch succession or hydrosere. It usually starts with the colonization of small phytoplanktons. These organisms act as the pioneering species in hydrosere.
3. Who replaces the phytoplanktons in a hydrarch succession?
a) Zooplankton
b) Rooted-submerged plants
c) Angiosperms
d) Fishes
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Explanation: A hydrarch succession starts with the colonization of small phytoplanktons. These phytoplanktons, later with time are replaced by rooted-submerged plants in a hydrarch succession. Some examples of the rooted-submerged plants are Ceratophyllum, Chara, Elodia, Potamogeton, etc.
4. Who replaces the rooted-submerged plants in a hydrarch succession?
a) Free-floating plants
b) Phytoplankton
c) Zooplankton
d) Rooted-floating angiosperms
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Explanation: The sequence of successional stages occurring in water is known as hydrarch succession or hydrosere. The rooted-submerged plants with time are replaced by rooted-floating angiosperms. An example of a rooted-floating angiosperm is water lily.
5. Who replaces the rooted-floating angiosperms in a hydrarch succession?
a) Phytoplankton
b) Zooplankton
c) Free-floating plants
d) Rooted-submerged plants
View Answer
Explanation: The sequence of successional stages occurring in water is known as hydrarch succession or hydrosere. The rooted-floating angiosperms with time are replaced by free-floating plants in a hydrarch succession. Some examples of the floating plants are Pistia, Nymphaea, Pistia, Nymphaea, etc.
6. Who replaces the free-floating plants in a hydrarch succession?
a) Rooted-submerged plants
b) The reed-swamp
c) Free-floating angiosperms
d) Phytoplankton
View Answer
Explanation: The sequence of successional stages occurring in water is known as hydrarch succession or hydrosere. The free-floating plants with time are replaced by the reed-swamp in a hydrarch succession. Some examples of the reed-swamp plants are Bothrioclova, Phragmites (Reed), Typha, etc.
7. Who replaces the reed-swamp in a hydrarch succession?
a) Rooted-submerged plants
b) Phytoplankton
c) Free-floating angiosperms
d) Marsh-meadow
View Answer
Explanation: The sequence of successional stages occurring in water is known as hydrarch succession or hydrosere. The reed-swamp with time is replaced by the marsh-meadow in a hydrarch succession. Some examples of the marsh-meadow plants are Caltha, Gallium, Mentha, Cicuta, etc.
8. What is the marsh-meadow replaced by in a hydrarch succession?
a) Free-floating angiosperms
b) Rooted-submerged plants
c) Scrub
d) Free-floating plants
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Explanation: The marsh-meadow with time is replaced by the scrub in a hydrarch succession. The scrub stage is also known as the woodland stage. Some examples of the plants of the woodland community are Acacia, Cassia, Cephalanthus, Salix, etc.
9. What is the woodland stage replaced by in a hydrarch succession?
a) Free-floating angiosperms
b) Scrub
c) Rooted-submerged plants
d) Trees
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Explanation: The sequence of successional stages occurring in water is known as hydrarch succession or hydrosere. The woodland stage in a hydrarch succession is replaced by the trees. This results in the formation of a forest.
10. What is the climax community in a hydrarch succession?
a) Rooted-submerged plants
b) Free-floating angiosperms
c) Forest
d) Scrub
View Answer
Explanation: The sequence of successional stages occurring in water is known as hydrarch succession or hydrosere. The climax community in a hydrosere is a forest. It consists of various trees such as Acer, Quercus, etc.
11. To which climax community does succession in water lead to?
a) Mesozoic
b) Mesic
c) Cenozoic
d) Pteridophytes
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Explanation: The hydrarch succession finally leads to the formation of a mesic community. It consists of a moderate or well-balanced supply of moisture. Few examples of mesic habitat are streamsides, wet meadows, springs, irrigated fields, etc.
12. In primary succession in water, what does the water body converts to?
a) Sea
b) Pond
c) Land
d) Ocean
View Answer
Explanation: The sequence of successional stages occurring in water is known as hydrarch succession or hydrosere. The hydrarch succession finally leads to the formation of a mesic community while the water body with time is converted into the land.
13. Which of the following is the correct sequence of hydrarch succession?
a) Rooted-submerged plants → Rooted-floating angiosperms → Phytoplanktons → Marsh-meadow Scrub → Forest
b) Phytoplanktons → Rooted-submerged plants → Rooted-floating angiosperms → Free-floating plants → Reed-swamp → Marsh-meadow → Scrub → Forest
c) Reed-swamp → Marsh-meadow → Scrub → Forest → Phytoplanktons → Rooted-submerged plants
d) Phytoplanktons → Rooted-submerged plants → Rooted-floating angiosperms → Forest Marsh-meadow → Scrub
View Answer
Explanation: The sequence of successional stages occurring in water is known as hydrarch succession or hydrosere. It mostly starts from phytoplanktons and ends with the formation of a forest. The pioneering species grow with time leading to a formation of a climax community called a forest.
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