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What is the main source of energy of all life?

Write your answer to the above question on your piece of paper independently. When I instruct you, please compare your answer to those of your partners. Be ready to share.

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The main source of energy for all life is...

The SUN!

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Now...

Let’s use this strategy again to answer the following question:

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How does energy from the sun get to you and me as humans?

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Today’s Objectives

  • Distinguish between the terms “autotroph” and “heterotroph”
  • Provide examples of both autotrophs and heterotrophs.
  • Analyze the reactants and products of photosynthesis.

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Autotrophs

Auto= self

troph= feeding

Autotrophs- organisms that can convert carbon dioxide and water (or other simple inorganic substances) into organic molecules. Autotrophs are also called producers because they produce their own food.

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Types of Autotrophs

Photoautotroph

Chemoautotroph

Autotrophs (such as plants, some bacteria, and algae) that use the energy of light to convert inorganic substances, such as carbon dioxide and water into organic glucose (chemical energy)

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These autotrophs use photosynthesis.

Autotrophs (such as extreme bacteria) that use the chemical energy from inorganic substances such as iron to make chemical energy.

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Chemoautotrophs are often found in harsh conditions and are called extremophiles.

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Photoautotrophs

Photoautotrophs use photosynthesis.

In photosynthesis, light energy from the sun is used to convert inorganic carbon dioxide and water into organic glucose.

Light energy→chemical energy

Inorganic molecules→organic molecules

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Heterotrophs

hetero= other

troph= feeding

heterotroph= organisms that must get energy from food instead of directly from sunlight or inorganic substances. Heterotrophs are also called consumers.

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Types of Heterotrophs

Carnivores: kill and eat other animals to get energy

Herbivores: obtain energy by eating plants

Omnivores: obtain energy by eating a variety of foods, such as meats and plants

Scavengers: obtain energy by eating the carcasses of organisms that have been killed.

Decomposers: obtain energy by breaking down organic matter

Detritivores: obtain energy by feeding on decomposing matter

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Question

Which group of organisms are more important to sustaining life on earth: autotrophs or heterotrophs? Explain why.

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Food Pyramids

What types of organisms are always at the base of a food pyramid?

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What does this say about the importance of these organisms?

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