4.1

Question 1

Ecosystem

Answer 1

A biological community of interacting organisms and their physical environment

Question 2

Photosynthesis

Answer 2

The process by which green plants and some other organisms use sunlight to synthesize foods with carbon dioxide and water, producing oxygen as a by-product.

Question 3

Cellular Respiration

Answer 3

The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

Question 4

Biomass

Answer 4

The total mass of all living organisms in a specific area or ecosystem.

Question 5

What stays in an ecosystem? What leaves?

Answer 5

Matter (e.g., nutrients) stays in the ecosystem, cycling between organisms and the environment, while energy flows through and eventually leaves the ecosystem as heat.

Question 6

What is the net equation for photosynthesis?

Answer 6

carbon dioxide + water + sunlight → glucose + oxygen

Question 7

During photosynthesis, what kind of energy is converted to another kind?

Answer 7

Light energy is converted into chemical energy stored in glucose.

Question 8

What does GPP stand for?

Answer 8

Gross Primary Productivity is the total amount of energy producers capture in an ecosystem through photosynthesis.

Question 9

What does NPP stand for?

Answer 9

Net Primary Productivity is the energy that remains after plants use some energy for respiration, available for the next trophic levels.

Question 10

What is the net equation for cellular respiration?

Answer 10

glucose + oxygen → carbon dioxide + water + energy

Question 11

On average, what percent of energy in the previous level is available for the next?

Answer 11

Approximately 10% of energy is transferred to the next trophic level.

Question 12

What is the main difference between the movement of matter and the movement of energy in an ecosystem?

Answer 12

Matter cycles within ecosystems (e.g., water, carbon, nitrogen), whereas energy flows in one direction and eventually leaves the system as heat.

Question 13

What products are produced as cells undergo cellular respiration, and how are they released from the body?

Answer 13

Cellular respiration produces carbon dioxide, water, and ATP. Carbon dioxide is exhaled, water is released through urine or sweat, and ATP is used by cells for energy.

Question 14

Explain how energy enters the ecosystem, how it passes from one trophic level to the next, and how it leaves the ecosystem.

Answer 14

Energy enters the ecosystem through sunlight captured by producers (plants) during photosynthesis. It passes from one trophic level to the next through consumption. Most of the energy is lost as heat during each transfer, and eventually, all energy leaves the system as heat.

Question 15

Describe how the potential energy in the biomass that an organism eats gets used and released by an organism.

Answer 15

The energy is used for cellular respiration (to produce ATP), and growth (building new biomass), and is partially lost as waste (undigested material). Due to these processes, only about 10% of energy is transferred to the next trophic level, making energy transfer inefficient.

Question 16

Explain the shape of an ecological pyramid using the rule of 10%.

Answer 16

An ecological pyramid is shaped with a broad base and a narrow top because only about 10% of energy from one trophic level is passed to the next. Most energy is lost as heat, resulting in fewer organisms and less biomass as you move up the pyramid.