6.3 Everything is reused - part 2

• biologie
• Middelbare school
• vwo
• Leerjaar 3

Which of the following best describes the importance of biogeochemical cycles?

1. They chart how biotic changes destroy unstable ecosystems.
2. They describe how the adaptations of organisms change based on environmental pressures.
3. They show how certain elements and compounds move through the environment and are continually used and recycled.
4. They explain how energy moves through trophic levels of an ecosystem.

Which of the following steps of the carbon cycle is occurring at point A?

1. combustion
2. respiration
3. decomposition
4. photosynthesis

Respiration: the cow takes in organic carbon as glucose and returns it to the environment as carbon dioxide 

keypoints water cycle (copy in your notebook) 

1. The vast majority of Earth's water is saltwater found in oceans. Only a tiny fraction is readily accessible freshwater, which is what humans need.
   
2. Water found at the Earth's surface can cycle rapidly, but much of Earth's water lies in ice, oceans, and underground reservoirs; this water cycles slowly.
3. The water cycle is complex and involves state changes in water as well as the physical movement of water through and between ecosystems.
4. Groundwater is found underground between soil particles and in cracks of rocks. Aquifers are groundwater reservoirs often tapped by wells:

Many living things depend on this small supply of surface fresh water,

The water cycle drives other cycles: In particular, surface runoff helps move elements from terrestrial, land-based, to aquatic ecosystems.

importance of water

These cycles don't happen in isolation, and the water cycle is a particularly important driver of other biogeochemical cycles. For example, the movement of water is critical for the leaching of nitrogen and phosphate into rivers, lakes, and oceans. The ocean is also a major reservoir—holding tank—for carbon.

importance of water 

Many living things depend on this small supply of surface fresh water,

The water cycle drives other cycles: In particular, surface runoff helps move elements from terrestrial, land-based, to aquatic ecosystems.

Which of the statements regarding the nitrogen cycle is true?

1. Animals obtain nitrogen through the process of cellular respiration.
2. Denitrification occurs when a nitrogen containing compound is produced from nitrogen in the soil.
3. Atmospheric nitrogen is absorbed through the leaves of plants.
4. Nitrogen fixation is the process atmospheric nitrogen is converted into biologically usable forms.

The nitrogen cycle: key points

• Nitrogen is a key component of the bodies of living organisms. Nitrogen atoms are found in all proteins and DNA.
• Bacteria play a key role in the nitrogen cycle. Nitrogen exists in the atmosphere as N2-gas. In nitrogen fixation, bacteria convert N2 into ammonia (NH3), a form of nitrogen usable by plants. When animals eat the plants, they acquire usable nitrogen compounds.
• Nitrogen is a common limiting nutrient in nature and agriculture. A limiting nutrient is the nutrient that's in shortest supply and limits growth.
• When fertilizers containing nitrogen and phosphorus are carried in runoff to lakes and rivers, they can result in blooms of algae—this is called eutrophication.

How much water is there available in lakes and rivers?

1. 0,3% of the total amount of water
2. 1,3% of the total amount of water
3. 13% of the total amount of water
4. 30% of the total amount of water