Lecture Notes: Heterotrophs and Autotrophs

Introduction

• Discussion on favorite animals and their diets.
• Emphasis on the importance of understanding what different animals eat.

Key Concepts

Heterotrophs

• Animals are generally heterotrophs, consuming organic matter.
• Heterotrophs are also known as consumers.
• Includes animals, fungi, some protists, bacteria, and archaea.

Autotrophs

• Plants are generally autotrophs, making their own food.
• Autotrophs are known as producers.
• They make organic substances like glucose from inorganic substances like carbon dioxide through photosynthesis.
• Carnivorous plants also perform photosynthesis but digest insects for nitrogen.
• Includes some protists, bacteria, and archaea.

Mixed Nutrition

• Some organisms can be both autotrophs and heterotrophs:
  • Example: Euglena can perform photosynthesis and also consume organic matter.

Detailed Classifications

Sources of Carbon and Energy

• Autotrophs: Use inorganic carbon sources to make food.
• Heterotrophs: Obtain carbon from organic sources.
• Photo: Energy source is light.
• Chemo: Energy source is chemical.

Examples

• Photoautotrophs: Use light as an energy source, e.g., plants.
• Chemoautotrophs: Use chemical energy, e.g., bacteria at deep sea vents.
  • Oxidize inorganic substances like hydrogen sulfide.
• Chemoheterotrophs: Consume organic matter and use organic compounds as an energy source, e.g., humans.
• Photoheterotrophs: Consume organic matter but use light as an energy source.
  • Found in some prokaryotes.

Cellular Respiration

• Organisms perform cellular respiration to generate ATP from food.
• Processes can vary:
  • May involve oxygen or not.
  • Use different electron acceptors.

Conclusion

• Fascination with how organisms obtain nutrients to survive.
• Encouragement to stay curious about biological processes.