Living Organisms & Their Surroundings

Identify the correct answer from the hints provided: I am a major abiotic factor. I influence climate, water cycles, and the ability of organisms to survive. My fluctuations can lead to migration and hibernation in animals. Who am I?

1. Soil
2. Water
3. Temperature
4. Minerals

Answer: (c) Temperature

Identify the incorrect statements: 1. Desert plants have broad, flat leaves to absorb more sunlight. 2. Creosote bushes use tiny hairs to trap moisture. 3. Succulent plants rely on frequent rainfall for water storage. 4. Cactus stems store water, which helps them survive in dry conditions.

1. 1 and 3
2. 2 and 4
3. 1, 2 and 3
4. Only 4

Answer: (a) 1 and 3

Fill in the blanks: Unlike most environments, deserts force animals to conserve water through (i)_______. This is achieved by producing (ii)________ instead of liquid urine, allowing them to excrete waste without losing excessive moisture.

1. (i) Increased perspiration, (ii) Urea
2. (i) Water storage in bladders, (ii) Ammonia
3. (i) Reduced water loss, (ii) Uric acid
4. (i) Drinking more water, (ii) Diluted urine

Answer: (c) (i) Reduced water loss, (ii) Uric acid

Which of the following statements about ecosystems is incorrect? 1. Energy in an ecosystem flows in a cyclic manner, continuously being reused. 2. Matter cycles through an ecosystem, while energy flows in one direction. 3. In a food chain, only 10% of energy is transferred from one trophic level to the next. 4. Producers are the only organisms that can convert sunlight into usable energy.

1. Only 1
2. 2 and 3
3. 3 and 4
4. Only 4

Answer: (a) Only 1

Marine scientists design artificial seaweed for coastal protection. Which characteristic should it have for maximum stability?

1. Strong holdfasts to anchor firmly
2. Gas-filled bladders to float freely
3. Flexible stems to move easily with waves
4. Broad leaves to capture more sunlight

Answer: (a) Strong holdfasts to anchor firmly

A scientist introduces a new species of plant into a tropical rainforest. Within a few years, this plant spreads rapidly, replacing many native plant species. What is the most likely ecological consequence of this event?

1. Increased biodiversity due to the presence of a new species
2. A decrease in herbivore populations due to fewer native food sources
3. An increase in oxygen levels due to more plants performing photosynthesis
4. No impact, as all plants provide the same function in an ecosystem

Answer: (b) A decrease in herbivore populations due to fewer native food sources

If grassland plants have extremely large leaves instead of small ones, what could be the most significant consequence?

1. Increased photosynthesis leading to better growth.
2. Better absorption of carbon dioxide for survival.
3. More attraction of herbivores due to increased foliage.
4. Higher transpiration causing water loss and wilting.

Answer: (d) Higher transpiration causing water loss and wilting.

A team of ecologists recorded the food preferences of rainforest birds based on beak shape. A sudden decline in flowering plants is observed in the rainforest. Which bird species will be most affected? Bird Species Beak Shape X Short, strong Y Long, curved Z Sharp, hooked

1. X
2. Y
3. Z
4. All are equally affected

Answer: (b) Y

A marine scientist simulates climate-induced salinity changes by gradually increasing the salt concentration in a coastal marine ecosystem. Over several weeks, some marine animals begin to show signs of stress, while others survive. Which of the following adaptations would MOST LIKELY enable an animal to survive prolonged exposure to increased salinity?

1. Highly permeable skin
2. Inactive feeding behaviour
3. Thin-walled cells
4. Salt-excreting glands

Answer: (d) Salt-excreting glands

In a large freshwater lake, scientists observe that some plants float freely, some are rooted but have floating leaves, and some are completely submerged. During a severe drought, water levels drop significantly. Which group of organisms is most likely to experience the least impact, and why?

1. Fishes like catfish and loaches
2. Plants like lotus and water lily
3. Plants like hydrilla and vallisneria
4. Plants like duckweed and water lettuce

Answer: (d) Plants like duckweed and water lettuce