Unit 2.3 Flows of energy and matter

Question 1

Flows of energy and matter

Answer 1

Movements (flows) of energy and matter link ecosystems together.

Question 2

BIOMASS

Answer 2

ENERGY

Question 3

Earth’s energy budget

Answer 3

Total absorption: 70%

Total reflection: 30%

Question 4

The amount of light captured by plants and converted to glucose

Answer 4

Less than 1% of light energy falling on the Earth is captured by plants and converted to glucose thanks to photosynthesis.

Question 5

PRODUCTIVITY

Answer 5

The conversion of energy into biomass for a given period.

measures rate at which living organisms convert energy from sunlight pr other into organic matter through processes like photosynthesis.

Question 6

Primary productivity

Answer 6

The production of chemical energy or biomass by
autotrophs (producers).

It is measured as biomass
or energy per unit area per unit time.

Question 7

Secondary productivity

Answer 7

The biomass gained by heterotrophs through
feeding and absorption.

It is also measured in units
of mass or energy per unit area per unit time.

Question 8

GROSS PRIMARY PRODUCTIVITY (GPP)

Answer 8

GPP is the total energy converted by photosynthesis

Question 9

NET PRIMARY PRODUCTIVITY (NPP)

Answer 9

NPP = GPP - Respiratory loss

Question 10

GROSS SECONDARY PRODUCTIVITY (GSP)

Answer 10

GSP = food eaten - fecal loss

Question 11

NET SECONDARY PRODUCTIVITY (NSP)

Answer 11

NSP = GSP- Respiratory loss

Question 12

MAXIMUM SUSTAINABLE YIELD

Answer 12

the largest crop or catch that can be taken from
the stock of a species (a forest, fish, etc.) without depleting the stock.

equivalent to the net primary or secondary productivity of a system

Question 13

Human impact on energy flows

Answer 13

1. Ancient Energy Source: Sunlight was humanity’s sole energy source for thousands of years, with plants capturing solar energy through photosynthesis for food.
2. Population Limit: Limited food availability from natural sources constrained population growth.
3. Industrial Revolution Shift: The use of fossil fuels (coal, oil) during the Industrial Revolution allowed humans to unlock solar energy stored in these materials for millions of years.
4. Increased Energy Availability: This newfound energy source fueled industrial expansion and enhanced agricultural productivity through machinery, significantly boosting food production.
5. Population Growth: The increase in food output led to rapid population growth.
6. Environmental Impact: The shift in energy usage has caused numerous environmental issues, including habitat destruction, climate change, depletion of non-renewable resources, and acid deposition.
7. Fossil Fuel Combustion Effects: Burning fossil fuels changes how solar energy interacts with Earth’s atmosphere and surface, increasing CO2 levels and temperatures, and leading to Arctic ice melt.
8. Reduced Sunlight Reflection: The decrease in Arctic ice reduces the Earth’s ability to reflect sunlight, contributing to global warming.
9. Atmospheric Changes: Pollution has altered atmospheric interactions with solar radiation, including increased reflection and absorption by atmospheric particles and molecules, affecting Earth’s energy flows.

Question 14

FLOWS OF MATTER

Answer 14

nutrients (matter) cycle between the
biotic and abiotic environment. Nutrient cycles can be shown in simple diagrams which show stores and transfers of nutrients ( biochemical cycles )

1. The carbon cycle
2. The nitrogen cycle

Question 15

Carbon

Answer 15

the basic building block of life and the fundamental
element found in carbohydrates, fats, proteins and nucleic acids (DNA and RNA).

Question 16

Carbon cycle

Answer 16

process that moves carbon between plants, animals, and microbes; minerals in the earth; and the atmosphere.

Question 17

BLUE CARBON

Answer 17

carbon captured by the world’s ocean and coastal
ecosystems.

Question 18

Carbon flows (processes)

Answer 18

• Photosynthesis
• Respiration
• Death and decomposition
• Fossilization
• Combustion
• Feeding/consumption
• Dissolving

Question 19

Carbon sinks/storage

Answer 19

Inorganic storages
- Atmosphere
- Soil, rocks
- Fossil fuels
- Ocean

Organic storages
- Animals
- Plants

Question 20

Nitrogen

Answer 20

a vital element for all organisms, as it is a component of proteins and DNA. It is the most abundant gas in the atmosphere but it is not directly accessible by animals or plants.

Question 21

Nitrogen storages

Answer 21

Inorganic storages
- Atmosphere
- Soil
- Fossil fuels
- Water bodies

Organic storages
- Animals
- Plants

Question 22

Nitrogen flows (processes)

Answer 22

• nitrogen fixation by bacteria and lightning
• Absorption
• Assimilation
• consumption (feeding)
• Excretion
• death and decomposition
• denitrification by bacteria in water-logged soils.

Question 23

Human impacts on matter cycles

Answer 23

• Tropical rainforests play a crucial role in trapping CO2 through photosynthesis, helping maintain low atmospheric CO2 levels.
• Human activities like agriculture and timber production lead to deforestation, disrupting the natural carbon cycle by eliminating forests’ ability to absorb CO2 and create new biomass.
• The removal of trees destroys the canopy, which normally intercepts rainfall, leading to soil and nutrient erosion, particularly of nitrogen, from the leaf litter and soil.
• Harvesting crops and transporting them moves nitrogen out of its local cycle