Lesson 45 + 46: Energy and Energy Flow in Ecosystems


Lesson 45 + 46: Energy and Energy Flow in Ecosystems

I. Energy Flow in Ecosystems:

1. Common Energy Pathway:

  • Sunlight → Autotrophs → Heterotrophs → Energy returns to the environment

Note:

  • Sunlight is the primary source of energy for all ecosystems.
  • Autotrophs (plants, algae) absorb sunlight to synthesize organic matter, providing food for heterotrophs.
  • Heterotrophs (animals, fungi, bacteria) consume autotrophs or other heterotrophs to obtain energy.
  • Energy is transferred from lower trophic levels to higher trophic levels, but the amount of energy transferred decreases due to losses during metabolism, growth, and reproduction.
  • Ultimately, energy is returned to the environment as heat.

2. Ecological Efficiency:

  • The percentage of energy transferred from one trophic level to the next.
  • Formula: Ecological efficiency = (Energy accumulated at higher trophic level / Energy accumulated at lower trophic level) x 100%
  • Average ecological efficiency is about 10%, meaning only about 10% of energy is transferred from one trophic level to the next.

3. Reasons for Energy Loss in Ecosystems:

  • Organisms cannot utilize all energy: Some energy is excreted as waste (feces, urine).
  • Energy lost through respiration: Organisms expend energy to maintain life functions such as respiration, movement, and foraging.
  • Energy loss through death: Some energy is lost when organisms die and are decomposed by microorganisms.

II. Energy Sources:

1. Clean Energy Sources:

  • Solar energy: Renewable, non-polluting energy source.
  • Wind energy: Renewable, non-polluting energy source.
  • Wave energy: Renewable, non-polluting energy source.
  • Tidal energy: Renewable, non-polluting energy source.

2. The Biosphere Exists and Thrives due to Energy:

  • The Sun: The sun provides light energy for plants to perform photosynthesis, ultimately fueling all other life.

III. Producers:

1. Producers utilize:

  • Visible light: Producers use sunlight, specifically visible light, for photosynthesis.

2. Primary Productivity:

  • The rate at which organic matter is created by producers in a given time.
  • Produced by: Producers (plants, algae).

3. Organisms in Food Chains Receive Energy from the Abiotic Environment:

  • Producers: Producers act as a bridge between the abiotic and biotic environments, providing energy for heterotrophs.

IV. Resources:

1. Non-renewable Resources:

  • Coal: Formed from the remains of ancient plants buried underground over millions of years, a non-renewable resource.
  • Oil: Formed from the remains of marine organisms buried underground over millions of years, a non-renewable resource.

V. Biodiversity:

  • The richness of gene pools, species, and natural ecosystems.
  • Important Roles:
  • Provides food, medicines, and building materials.
  • Maintains ecological balance.
  • Preserves genetic diversity.

Note:

  • Protecting biodiversity is protecting life on Earth.
  • Conserving clean energy sources and using energy efficiently is protecting our environment.
  • Understanding energy flow in ecosystems helps us utilize resources effectively and protect the environment.



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