5 short answer

Explain how global warming is affecting the coral reefs and some ocean mollusks. (2) Why is this significant? (3)

Global warming affects: 

1. Coral bleaching and habitat loss: Rising sea temperatures causes corals to expel the symbiotic algae that provide them with food and colour, leaving corals vulnerable to starvation and disease (ex: in the Great Barrier Reef) 

2. Shell formation: Organisms like oysters, clams, and mussels will struggle to build and maintain their calcium carbonate shells, leaving them more vulnerable to predators

Significance: 

1. Coral reefs support around 25% of all marine species. Their destruction leads to loss in biodiversity and risk of extinction for many species. 

2. Provides food and income for millions worldwide through fishing and tourism. 

3. Mollusks fill the ecological niche of filter feeders and as prey for larger marine animals. Their decline disrupts marine food webs. 

Describe the significance of ocean acidification. What is its cause? Which organisms are being affected and how? Why is this important? (5)

• Significance: Threat to marine ecosystems, global food security, loss of biodiversity, collapse of important marine habitats. Calcium carbonate structures are important for the survival of many species, affecting entire food chain. 

• Cause: Increase in atmospheric carbon dioxide, due to human activities like burning fossil fuels, and deforestation. As carbon dioxide dissolves in seawater, it reacts with water to form carbonic acid. Lowering the pH of the ocean and making it more acidic

• Organisms being affected: coral reefs relying on calcium carbonate to build their skeletons. Acidification reduces availability of carbonate ions. 

  • Shellfish, relying on calcium carbonate to form their shells. Lower pH makes it more difficult for them to produce and maintain their shells. 

• Loss of income for millions of people in coastal areas.

What are coral reefs? How are they formed? Why are they important? (5)

1. Are large, underwater structures made up of colonial polyps. These polyps secrete calcium carbonate.

2. Coral reefs are formed when coral polyps attach to hard surfaces such as rocks or the ocean floor, usually in shallow, warm waters. As the polyp grows, they create a skeleton that builds up layer by layer.

3. Supports a vast array of marine life, fish mollusks, crustaceans, and others. Often called the rainforests of the sea, due to their rich biodiversity and complex food webs. 

4. Provide essential ecosystem services, coastal protection, acting as natural barriers against storms and erosion. Supports local economies through tourism and fishing industries. 

5. Highly vulnerable to climate change, pollution, and overfishing. 

The octopus is a super cool animal. Describe some of the unique features of this organism. (5)

1. High Intelligence: the ability to open jars to access food

2. Flexible and shapeshifting body: no internal skeleton, allowing them to squeeze through incredibly small spaces

3. Eight arms with suction cups: each arm operates semi-independently, with its own neural control

4. Colour and Texture changing ability: Can rapidly change their skin colour and texture to camouflage with their surroundings using chromatophores (specialized cells) 

5. Ink Defense: when threatened, octopuses can eject a cloud of ink to confuse predators and make a quick escape. Ink contains melanin to disorient attackers, allowing octopus to flee

We are currently undergoing one of the largest extinctions in the earth’s history. What are the major causes of this? Describe what are some of the most effective solutions to stopping or at least slowing this serious problem. (8)

• Habitat destruction: Deforestation, urbanization, and agriculture are destroying natural habitats, forcing species to face extinction due to loss of shelter and resources.

  • Solution: restore natural habitats, enforce anti-deforestations laws

• Climate change: Rising temperatures, changing weather patterns, and ocean acidification caused by human activities are disrupting ecosystems and pushing species beyond their tolerance limits

  • Solution: Reducing greenhouse gas emissions, transitioning to renewable energy. Using less electricity each day can contribute to a lot long term

• Pollutants: Pollution from plastics, chemicals, and waste products is poisoning ecosystems and harming wildlife, affecting species survival.

  • Solution: Banning harmful chemicals, reducing plastic use

• Overexploiting: Overfishing, hunting, and logging are depleting species at unsustainable rates, causing population crashes and threatening biodiversity

  • Solution: Promoting sustainable fishing, ban factory farms, eating less meat