In the marine environment, the main primary producers are:
Correct Answer:
(A) Phytoplanktons
Phytoplankton, also known as microalgae, are similar to terrestrial plants in that they contain chlorophyll and require sunlight to live and grow. Most phytoplankton are buoyant and float in the upper part of the ocean, where sunlight penetrates the water. Phytoplankton also requires inorganic nutrients such as nitrates, phosphates, and sulfur which they convert into proteins, fats, and carbohydrates.
Ques: 2
The example of “Lentic Habitat” in the freshwater community is:
Correct Answer:
(A) Ponds and swamps
Lentic Ecosystem refers to the static water habitats like ponds, lakes, swamps and marshes. Lotic Ecosystem refers to the dynamic water habitats like rivers.
Ques: 3
Which of the following is the most stable ecosystem?
Correct Answer:
(C) Ocean
Oceans are the cradle of life on Earth which harbour the highest level of biodiversity. No terrestrial ecosystem can match the biological richness of a coral reef, not only in some species but also in variety and originality of survival strategies.
Note: Freshwater, Grassland and Rainforest are examples of natural biome whereas cropland is an example of the anthropogenic biome.
Ques: 4
Consider the following statements:
Most of the world's coral reefs are in tropical waters.
More than one-third of the world's coral reefs are located in the territories of Australia, Indonesia and the Philippines.
Coral reefs host far more number of animal phyla than those hosted by tropical rainforests.
Which of the statements given above is/are correct?
Correct Answer:
(D)
1, 2 and 3
Corals are invertebrate animals. Reefs are created by hard corals which secrete a skeleton that can turn into giant structures like Australia's 'Great Barrier Reef'. Most of the world's coral reefs are located in tropical oceans near the equator. More than one-third of the world's coral reef is located in the territories of Australia. Indonesia and Philippines. Coral reefs are one of the most diverse ecosystems on the planet. These tropical marine communities occupy less than 1% of the ocean floor but are inhabited by more than 25% of all known marine fish species. 32 of the 34 recognized animal phyla are formed on coral reefs compared to 9 phyla in tropical rainforests.
Ques: 5
In the context of ecosystem productivity, marine upwelling zones are important as they increase the marine productivity by bringing the:
Decomposer micro-organisms to the surface.
Nutrients to the surface.
3. Bottom-dwelling organisms to the surface.
Which of the statements given above is/are correct?
Correct Answer:
(B) 2 only
Winds blowing across the ocean surface push water away. Water then rises up from beneath the surface to replace the water that was pushed away. This process is called "upwelling. Water that rises to the surface as a result of upwelling is typically colder & is rich in nutrients. These nutrients "fertilize" surface waters, meaning that these surface waters often have high biological productivity. Therefore, good fishing grounds are found where upwelling is common.