A1 - How Energy Enters The Biosphere

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Questions and Answers

What is the biosphere?

The zone around Earth that supports life (correct)

The highest point in the atmosphere

The system of landforms and elevations on Earth

The total amount of water on Earth

What does the first law of thermodynamics state?

Energy cannot be converted at all

Energy can be created and destroyed

Energy is always lost in conversions

Energy can only be converted or transferred (correct)

Which statement best describes energy flow through trophic levels?

Energy is stored in the soil.

Energy is equally divided among all trophic levels.

Energy moves in a one-way direction from producers to top predators. (correct)

Energy can only flow from consumers to producers.

What percentage of the Sun's energy actually reaches the Earth's surface?

51% Signup and view all the answers

Which of the following best defines albedo?

The measure of energy reﬂected by surfaces Signup and view all the answers

What role do producers play in the energy flow of the biosphere?

They convert solar energy into chemical energy. Signup and view all the answers

How does the second law of thermodynamics apply to energy conversions?

Some energy is always lost as heat in conversions. Signup and view all the answers

Which of the following is true about cellular respiration?

It converts chemical energy into usable energy. Signup and view all the answers

What process do producers use to convert radiant energy into chemical energy?

Photosynthesis Signup and view all the answers

What is the main fuel source generated during cellular respiration?

ATP Signup and view all the answers

What term describes organisms that produce their own food using sunlight?

Autotrophs Signup and view all the answers

What happens to glucose during cellular respiration?

It is broken down into pyruvate. Signup and view all the answers

In what type of environment does fermentation occur?

Anaerobic Signup and view all the answers

Which of the following is a product of photosynthesis?

Oxygen Signup and view all the answers

What is produced in large amounts during regular aerobic respiration?

ATP Signup and view all the answers

What do consumers derive their energy from?

Other organisms Signup and view all the answers

What characterizes the first trophic level in an ecosystem?

It consists of autotrophs that produce energy. Signup and view all the answers

What is the main role of decomposers in an ecosystem?

To release trapped nutrients from dead organisms. Signup and view all the answers

What happens to energy as it is transferred from producers to higher trophic levels?

Some energy is lost as unusable heat. Signup and view all the answers

Which statement is true about the relationship between autotrophs and heterotrophs?

Heterotrophs depend directly on producers for energy. Signup and view all the answers

What does the second law of thermodynamics imply about energy use in ecosystems?

Energy conversion leads to a loss of usable energy. Signup and view all the answers

What is the primary by-product of chemosynthesis by some bacteria?

Sulfuric acid Signup and view all the answers

What defines primary consumers in an ecosystem?

Organisms that eat plants and autotrophs Signup and view all the answers

In what environments are specialized bacteria that perform chemosynthesis typically found?

Deep-sea vents Signup and view all the answers

Which of the following best describes heterotrophs?

Organisms that cannot synthesize their own food and consume others Signup and view all the answers

What is a characteristic of secondary consumers?

They mainly eat herbivores or primary consumers. Signup and view all the answers

What process allows organisms in the absence of light to create energy?

Chemosynthesis Signup and view all the answers

Which of the following organisms would be classified as a tertiary consumer?

Eagles Signup and view all the answers

What is the function of decomposers in an ecosystem?

To recycle nutrients by breaking down waste matter Signup and view all the answers

What limits the number of trophic levels in an ecosystem?

The Rule of 10 Signup and view all the answers

What is a primary characteristic of food webs compared to food chains?

They reflect multiple feeding relationships Signup and view all the answers

What is the approximate percentage of energy lost at each trophic level?

90% Signup and view all the answers

If a grass plant receives 10,000 kJ of energy from the sun, how much energy is available to the eagle at the end of the food chain?

10 kJ Signup and view all the answers

How do arrows in a food web represent energy transfer?

They show the direction of energy flow Signup and view all the answers

Study Notes

How Energy Enters the Biosphere

The biosphere is the narrow zone around Earth that supports life. It has three main structural zones: lithosphere (land), hydrosphere (water), and atmosphere (air).
The laws of thermodynamics govern energy flow.
The first law states that energy cannot be created or destroyed, only converted from one form to another. Radiant energy is converted to chemical energy in carbohydrate molecules.
The second law states that energy conversion isn't 100% efficient - there's an energy loss with each conversion and less usable energy with each step in the chain.
All organisms need energy to survive. This energy comes from the sun and is captured and converted through photosynthesis and chemosynthesis.
Living things obtain energy through photosynthetic/chemosynthetic and cellular respiration processes.

Energy Flow

All organisms need energy.
Energy cannot be created or destroyed (First Law of Thermodynamics)
Plants and some bacteria capture energy from the sun through photosynthesis.
Chemical energy (glucose) is stored then used in cellular respiration which releases energy in the form of ATP (adenosine triphosphate) to fuel organismal function.

Albedo

100% of Earth's energy comes from the Sun.
Not all of the Sun's energy reaches Earth's surface - some is reflected (Albedo).
~30% of the incoming solar radiation is reflected.
51% is absorbed at Earth's surface.

Photosynthesis

Photosynthesis is how producers (plants, algae, bacteria) convert light energy to chemical energy stored in the bonds of glucose (sugar).
The equation for photosynthesis is: 6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2

Cellular Respiration

Cellular respiration is how consumers (and some producers) convert chemical energy from glucose into the usable energy molecule ATP.
The equation for cellular respiration is: C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy.
ATP is used to power organismal activities like movement and metabolic processes.

Fermentation

Fermentation is an anaerobic process that occurs in the absence of oxygen.
It converts glucose into other byproducts like ethanol (alcohol) and lactic acid, and releases energy in the form of ATP, but is less efficient than aerobic respiration.
Different organisms and situations (e.g. muscle cells) result in different fermentation outcomes.

Chemosynthesis

Chemosynthesis is a process used by some organisms that don't use sunlight.
Instead, they use chemical energy from inorganic substances like hydrogen sulfide to build organic molecules.
It's a crucial process in environments like deep-sea vents where sunlight is absent.

Producers and Consumers

Producers: (autotrophs) create their own food through photosynthesis/chemosynthesis.
Consumers: (heterotrophs) obtain energy from consuming other organisms (producers or other consumers).

Trophic Levels

Trophic levels categorize living things by how they obtain energy.
The first trophic level consists of producers which create energy using sunlight or inorganic compounds.
Subsequent trophic levels consist of consumers that obtain their energy from other organisms.
Decomposers break down dead organisms for nutrient recycling.

Decomposers

Decomposers are organisms that break down dead organisms and wastes, returning essential nutrients to the ecosystem.
They play a vital role in nutrient cycling.

Energy Transfer

Energy transfer along the trophic levels is less than 100% efficient.
There are losses as heat, unusable energy.
Organisms in higher trophic levels require more consumed energy to equal energy gains.

Food Webs

Food webs represent energy transfer and feeding relationships within an ecosystem.
They depict organisms feeding at multiple trophic levels.
Arrows demonstrate the direction of energy flow.

Rule of 10

Approximately 90% of energy is lost at each trophic level.
Less than 10% of energy is transferred to the next trophic level.
This limits the number of trophic levels in food chains/webs.

Pre-Assessment Questions

What is the biosphere? (The narrow zone on Earth that supports life.)
How does matter/energy cycle through the biosphere? (Through processes like photosynthesis, cellular respiration, and decomposition.)
What impacts might humans have on the biosphere? (Many.)

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Description

Explore how energy enters the biosphere and the laws of thermodynamics that govern its flow. This quiz covers the conversion of radiant energy into chemical energy, the role of photosynthesis, and the efficiency of energy transfer among organisms. Test your knowledge on these fundamental concepts of ecology.