Ecosystem Unit Lecture Notes

Introduction

• Food Web: A tool for understanding how organisms relate and interact within environments.
• Core focus of the ecosystem unit, heavily emphasized in 7th and 8th grade in Florida.
• Interdependence: All life forms depend on other organisms for survival.

Levels of Organization

• Organism: The individual entity.
• Population: Group of individuals of the same species in a location.
• Community: All living organisms in a particular area.
• Ecosystem: Living and non-living things in an area (e.g., houses, roads included).
• Biome: Large area with similar climate and weather conditions.
• Biosphere: All life on Earth.

Biodiversity

• Definition: Variety of life in a particular habitat or ecosystem.
• Importance: Greater biodiversity leads to more stable ecosystems.

Factors Affecting Ecosystems

• Abiotic Factors: Non-living elements like soil, pollution, climate.
• Biotic Factors: Living organisms like predators and competitors.

Habitats and Niches

• Habitat: Specific environment where a population resides.
• Niche: The specific role or function of an organism within an ecosystem.

Energy Flow and Nutrient Cycling

• Energy: Limited resource vital for life processes.
• Producers: Organisms (autotrophs) that create energy, usually through photosynthesis.
• Consumers: Heterotrophs that obtain energy by consuming other organisms.
• Decomposers: Break down dead organisms, recycling nutrients back into the ecosystem.

Models of Energy Flow

• Food Pyramid: Illustrates energy flow and 10% energy transfer between trophic levels.
• Food Chain: Direct path of energy movement from one organism to another.
• Food Web: Complex network showing all possible energy paths within an ecosystem.

Nutrient Cycles

• Water Cycle: Movement of water via evaporation, condensation, precipitation.
• Carbon Cycle: Movement of carbon through photosynthesis, respiration, and decomposition.
• Nitrogen Cycle: Transformation of nitrogen into usable forms for plants and animals.

Limiting Factors

• Definition: Factors that restrict population growth.
• Abiotic Limiting Factors: Include temperature, water availability, pH, etc.
• Biotic Limiting Factors: Include predation, competition, and disease.
• Carrying Capacity: Maximum population size an environment can sustain.

Ecological Relationships

• Mutualism: Both species benefit (e.g., bees and flowers).
• Predation: One organism benefits, the other is harmed.
• Parasitism: One benefits, the other is harmed but not usually killed.
• Commensalism: One benefits, the other is neither helped nor harmed.

Examples of Relationships

• Commensalism: Scorpions gaining dispersal via beetles.
• Mutualism: Ants protecting aphids.
• Parasitism: Cowbirds using nests of other birds for raising chicks.

Conclusion

• Importance of understanding these concepts for tests and quizzes.