Class 8 General Science Notes: - Unit-1: Ecology: Solved Exercise Part- D (Structured Questions and Answers)

(National Book Foundation - New Book/New Syllabus Based on National Curriculum Pakistan 2023-2024 and Onwards)

(Class 8 General Science Notes for 8th Centralized Exam 2023-2024 and onward, FDE, Islamabad)

Click Here for Solved MCQs Unit-1

D. Structured questions

1. Blind Indus dolphin is endemic to the river Indus. It is an endangered species of water animal in Pakistan.

a. Enlist the factors which lead to the threat of extinction of the Indus dolphin.

Ans:

The factors which lead to the threat of extinction of the Indus dolphin are the following:

1. The main reason for the declining Indus Delphine population is the construction of numerous dams, barrages, and water diversions on the river Indus. This construction split their population into small groups and disturbs their migration, breeding cycles, and habitat of Indus dolphin.

2. Heavy water pollution due to industrial waste and agrochemicals.

3. Poaching and fishing in the river.

4. Vessel traffic.

OR (Very short answer)

The factors that lead to the threat of extinction of the Indus dolphin are Entanglement, Habitat degradation, noise, chemical contaminants, and Unsustainable fishing practices.

b. What is the present status of this mammal?

Ans:
The Indus River dolphin is listed as an endangered mammal. They can only be found now in the lower parts of the Indus River in Pakistan. This unique animal is now being threatened with extinction, with less than 1,000 dolphins left.

c. Suggest the steps to help the conservation of the Indus dolphin.

Ans:

1. Government, NGOs, local communities, and individuals should work together to contribute towards growing the population of endangered species. The awareness campaign aimed at getting more people involved in conservation work is a very effective way for species conservation.

2. The Government should ban and impose penalties on catching or killing dolphins, or trading in their meat.

2. Most of the islands of Maldives are less than one meter above sea level.

a. What could be the effect of global warming on such islands across the globe?

Ans:

Global warming is a severe threat to the existence of the low-lying islands country of the Maldives. As according to the World Bank report "future sea levels projected to increase in the range of 10 to 100 centimeters by the year 2100, hence the entire country of Maldives could be submerged".

b. Suggest ways to save coastal cities from flooding or being submerged.

1. Making flood barriers to protect infrastructure. Flood barriers to protect critical infrastructure include levees, dikes, and seawalls.

2. Relocate facilities to higher elevations.

3. Restrict construction in at-risk areas.

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