Question

Some of the stages in the hydrach are labeled as
A) Marsh meadow stage
B) Reed swamp stage
C) Submerged plant stage
D) Phytoplankton stage and
E) Submerged free-floating plant stage
Identify the choice that represents the correct sequence of these stages
A) D,C,E,B and A
B) C,E,A,B and D
C) B,D,C,A and E
D) D,E,C,B and A
E) E,C,B,A and D

Answer 1

Hint: It is a succession that occurs in the aquatic environment. A succession mainly takes place in small and shallow ponds because in large or deep water bodies, strong waves and other powerful physical forces are active which results in a stable aquatic community and any changes occurring in the succession will not be recognizable.

Complete step by step answer:
Hydrosere is a succession that takes place in an aquatic environment.
There are seven stages of aquatic succession-
1) Phytoplankton stage: Algal spores are brought into the water body. Pioneer colonizers are bacteria, algae, phytoplankton, and zooplankton which are floating in the water. They together add a huge quantity of organic matter and nutrients in the water because of their various life activities and they settle at the bottom of a pond and form a layer of muck after their death.
2) Submerged stage: in this stage formation of a loose layer of mud at the bottom of the pond started to take place. Submerged hydrophytes begin to grow. Submerged aquatic vegetation started to develop where the water depth is about 10 feet or more.
The pioneers of this stage are Utricularia, Chara, Ranunculus, etc. Wendy's plants die there and remain deposited at the bottom of the pond. The eroded soil particles and other materials all deposit. All this led to a decrease in the depth of water. Now, this habitat is less suited for the Submerged vegetation but favorable for other plants.

3) Floating stage: the submerged vegetation gradually starts disappearing when the water depth reaches up to 4 to 8 feet. The occurrence of Floating plants in that area and the continuous interaction between the plant and aquatic environment takes place. The changing of habitat takes place both physically and chemically. A large number of dead bodies of plants, airborne soil deposited at the bottom, and the substratum rise in a vertical direction. Important floating plants of this stage are Traps, Pistils, Nymphaea, etc.
4) Reed Swamp stage: in this stage amphibians plants will come in place of floating plants as the water depth Decreases (up to 2 to 3 feet) . The amphibian plant can live easily in an aquatic and aerial environment. Many secondary species start to grow when the bottom starts to reach close to the water surface like a polygonum, Sagittaria, etc.
5) Sedge Marsh or Meadow stage: this stage results in marshy soil which is unsuitable for pre-existing plants as the soil is too dry for them to grow. No new plants started to grow that are well adapted to marshy habitat like Circuits, Mentha, Gallium, etc. All these plants absorb water and transpire a lot and also collect plant debris, air, and water-borne soil particles, which result in a dry habitat, and gradually hydrophytes disappear and mesophytes start appearing. At last, replaced by sedge vegetation.
So, the correct answer is, " D, C, E, B and A".

Note:
-The sixth stage is the woodland stage, some shrubs, and medium-size trees grow to form the woodland vegetation.
-The last stage is the climax forest, It is a stable stage and consists mostly of Woody trees making a mesophytic forest. At this stage complete harmony develops between plant community and habitat.