Biology Photosynthesis Flashcards

Study Notes

Energy in Ecosystems

Ecosystems generally depend on sunlight as the primary energy source.
Producers (plants, algae, cyanobacteria) utilize photosynthesis, while consumers, detritivores, and saprotrophs are heterotrophs that derive energy from food.

Photosynthesis

Light energy> chemical energy transformation occurs during photosynthesis:
CO2 + H2O + light energy → C6H12O6 + O2.
Producers convert sunlight into chemical energy, which helps synthesize carbohydrates, lipids, and other carbon compounds.

Roles in Energy Supply

Producers absorb light and convert it to chemical energy; they form the foundation of the food chain.
Consumers, detritivores, and saprotrophs obtain energy via the consumption of producers or other organisms.
Food chains start with producers that convert sunlight into carbon compounds through photosynthesis.

Energy Flow in Food Chains

Food chains illustrate the linear transfer of energy where each organism feeds on the preceding one.
Arrow notation indicates energy direction, with two to five organisms typically represented in a chain.
Energy and biomass transfer is generally limited to about 10% from one trophic level to the next.

Trophic Levels

Organisms are classified into trophic levels: producers (1st level), primary consumers (2nd level), secondary consumers (3rd level), and tertiary consumers (4th level).
Food chains commonly contain three or four levels, rarely exceeding five.
Energy loss at each level explains the restricted length of food chains and the biomass of higher levels.

Energy Utilization and Loss

Chemical energy in carbon compounds is released via respiration, which is vital for ATP production.
Cellular activities such as synthesizing macromolecules, active transport, and internal movement require ATP.
Approximately 80%-90% of the energy in carbon compounds is lost as heat during these transformations.

Inefficiency of Energy Transfer

Living organisms cannot convert heat energy back into usable forms; they can only convert light and chemical energy into other forms.
Energy flow in ecosystems does not allow complete transfer; heat is consistently lost to the environment.

Heat Loss and Ecosystem Balance

Heat generated by living organisms dissipates into the abiotic environment, ultimately affecting the ecosystem's energy balance.
Ecosystems rely on an external energy source (primarily sunlight) to compensate for ongoing energy losses.

Energy in Food Chain Transfers

Energy transfer to detritivores or saprotrophs occurs when:
- Organisms die before being consumed.
- Portions of organisms remain uneaten (bones, fur).
- Indigestible parts (cellulose) are excreted as waste.

Energy Pyramid Overview

Energy pyramids represent energy distribution among trophic levels, highlighting the inefficiency and loss of energy as it moves through the food chain.

Description

This quiz provides flashcards focused on the process of photosynthesis and its role in ecosystems. Learn how sunlight serves as the initial energy source for producers and how energy is transferred through different biological communities.