Ecosystem Energy Flow, Biomes, and Nutrient Cycles

Why aren't there many top predators in every ecosystem?

Energy is lost at each trophic level, limiting the energy available to support large populations of top predators.

What percentage of energy is transferred from one trophic level to the next?

Only about 10% of energy is transferred.

What are producers or autotrophs?

Organisms that capture sunlight through photosynthesis, such as plants, algae, and some bacteria.

What is the photosynthesis equation?

6CO₂ + 6H₂O + sunlight → C₆H₁₂O₆ + 6O₂

What do chemosynthetic bacteria use for energy?

They use energy from hydrogen sulfide (H₂S) at hydrothermal vents.

What is the equation for chemosynthesis?

6CO₂ + 6H₂O + 3H₂S → C₆H₁₂O₆ + 3H₂SO₄

What are the types of consumers?

Herbivores, carnivores, omnivores, detritivores, and decomposers.

What is the role of decomposers?

They break down nonliving matter and recycle nutrients in ecosystems.

What is the cellular respiration equation?

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy

What is the Pyramid of Energy?

A representation of energy flow in an ecosystem, showing primary producers at the bottom and top predators at the top.

What is a food chain?

A simple, linear feeding relationship in an ecosystem.

What is a food web?

A complex network of interconnected feeding relationships in an ecosystem.

What is a keystone species?

A species that has a strong or wide-reaching impact on its community.

What is the carbon cycle?

The movement of carbon through biotic (living) and abiotic (non-living) parts of Earth.

What are the key processes in the carbon cycle?

Photosynthesis, cellular respiration, and burning fossil fuels.

What is nitrogen fixation?

The process by which nitrogen-fixing bacteria convert atmospheric nitrogen (N₂) into ammonia.

What is the nitrogen cycle summary?

Fixation → N₂ → ammonia; Nitrification → ammonia → nitrite → nitrate; Assimilation → plants absorb nitrates; Consumption → animals eat plants; Decomposition → returns nitrogen to soil; Denitrification → nitrates → N₂ gas.

What is the phosphorus cycle?

The movement of phosphorus through the environment, essential for DNA, ATP, and cell membranes.

How do human activities impact the nitrogen and phosphorus cycles?

Fertilizers cause eutrophication, leading to algal blooms, low oxygen levels, and dead zones in aquatic ecosystems.

What is the largest carbon reservoir?

Limestone on the ocean floor.

What happens to carbon in sediments and fossil fuels?

Dead organisms become soil carbon, which can turn into coal, oil, and natural gas over millions of years.

How does ocean circulation relate to carbon?

Oceans are a major carbon reservoir; CO₂ dissolves in water and can become rock over millions of years.

What is the impact of deforestation on the carbon cycle?

It reduces CO₂ absorption, contributing to increased atmospheric CO₂ levels.

What role do decomposers play in the nitrogen cycle?

They break down nitrogen in dead organisms, returning it to the soil for reuse by plants.

What is ecological succession?

Gradual change in an ecosystem over time where new species replace earlier ones.

What is primary succession?

Succession that begins on bare rock with no soil, such as on new volcanic islands or after glacial retreat.

What are pioneer species in primary succession?

Species like lichen and moss that are the first to colonize bare rock.

What is secondary succession?

Succession that occurs in areas where soil already exists, typically after disturbances like fire or floods.

What is a climax community?

The final, stable stage of ecological succession that is in equilibrium with the environment.

How do natural fires contribute to succession?

They remove dead brush, create space for new plants, and prevent larger destructive fires.

What is old field succession?

Succession that occurs when farmland is abandoned, leading to a progression from grasses to a mature forest.

Define a biome.

A large group of ecosystems with similar climate, vegetation, and animal communities.

How does climate influence biomes?

It determines which plants can grow, affecting the types of ecosystems present.

What is the relationship between latitude and temperature?

Latitude affects sunlight exposure; areas near the equator are warmer, while areas near the poles are colder.

What adaptations do organisms have in deserts?

Succulents store water, and many animals exhibit nocturnal behavior or burrowing to conserve moisture.

What characterizes tropical rainforests?

Hot, humid conditions with heavy rainfall year-round and extremely high biodiversity.

What are the layers of a rainforest?

Emergent layer, canopy, understory, and epiphytes.

What is the taiga biome?

A biome characterized by long, cold winters and dominated by coniferous trees.

What are savannas?

Grass-dominated ecosystems with scattered trees, characterized by distinct wet and dry seasons.

What is eutrophication in freshwater ecosystems?

Nutrient runoff leading to algal blooms, oxygen depletion, and fish death.

What are the main types of marine ecosystems?

Coastal and open-ocean systems, including estuaries, salt marshes, mangroves, and coral reefs.

What is the significance of coral reefs?

They are limestone ecosystems that support high biodiversity and are sensitive to environmental changes.

How does human activity impact ecosystems?

Through pollution, habitat loss, overfishing, and climate change, leading to biodiversity loss.

What adaptations do tundra organisms have?

Shallow roots, thick fur for insulation, and migratory behaviors to cope with cold temperatures.

What is the role of decomposers in ecosystems?

They recycle nutrients by breaking down dead organic matter.

What are the characteristics of temperate forests?

Moderate rainfall, distinct seasons, and fertile soil, often with deciduous trees.

What is the impact of urban development on chaparral ecosystems?

It leads to habitat loss and increased frequency of wildfires.

What is the function of wetlands?

They filter pollutants, reduce flooding, and provide habitat for diverse species.

How do organisms adapt to the open ocean?

They adapt to varying salinity, tides, and light availability, with phytoplankton as main producers.