Ecology Principles Overview

Overview

This lecture introduces the main principles of ecology, covering levels of ecological organization, biotic and abiotic factors, biomes, population dynamics, ecological succession, symbiotic relationships, and feeding roles within ecosystems.

Principles of Ecology

• Ecology is the study of interactions between organisms and between organisms and their environment.
• Biotic factors are living components (plants, animals, bacteria, fungi, protists); abiotic factors are non-living elements (water, sunlight, temperature, rocks, soil).

Levels of Ecological Organization

• From smallest to largest: organism, population, community, ecosystem, biome, biosphere.
• Organism: one individual living thing (e.g., a rattlesnake).
• Population: group of the same species in an area (e.g., rattlesnakes).
• Community: all interacting populations (e.g., rattlesnakes, lizards, cacti).
• Ecosystem: community plus abiotic factors (e.g., sunlight, sand, rocks).
• Biome: large group of similar ecosystems (e.g., deserts).
• Biosphere: all biomes on Earth, anywhere life exists.

Biomes and Classification

• Biomes are classified by climate (precipitation, temperature), typical plants, and animals.
• 98% of Earth's water is saltwater; only 2% is freshwater, mostly in glaciers or underground.
• Major terrestrial (land) and aquatic (water) biomes vary by climate and life present.
• Shallow aquatic zones have the most biodiversity due to more sunlight and producers.

Graph Interpretation & Biome Examples

• Use precipitation and temperature graphs to identify biomes (e.g., temperate deciduous forest at 150 cm rain, 10°C).
• Temperate deciduous forests are found closer to the equator than coniferous forests.
• Climatograms show rainfall and temperature to help identify biome types (e.g., tropical rainforest: warm, wet year-round).

Habitats, Niches, and Limiting Factors

• Habitat: where an organism lives; niche: its role in the ecosystem.
• Limiting factors restrict population size (e.g., water, food, predators).
• Carrying capacity is the maximum population an environment can support.
• Limiting factors can be density-dependent (disease, competition) or density-independent (weather, pollution).

Ecological Succession

• Ecological succession is the process of one community replacing another due to changing biotic and abiotic factors.
• Primary succession occurs on new rock without soil (e.g., after a volcanic eruption); starts with pioneer species.
• Secondary succession occurs where soil remains after a disturbance (e.g., fire, flood).

Species Interactions

• Competition: organisms try to use the same resource, not necessarily fighting.
• Predation: one organism hunts/kills another (predator vs. prey).
• Symbiosis: long-term close relationship between different species.

Types of Symbiosis

• Mutualism: both benefit (e.g., oxpecker and zebra).
• Commensalism: one benefits, other unaffected (e.g., bird nesting in tree).
• Parasitism: one benefits, other is harmed (e.g., tick on a dog).

Feeding Roles in Ecosystems

• Autotrophs (producers): make their own food (e.g., plants via photosynthesis).
• Heterotrophs (consumers): obtain energy by eating others; types include herbivores, carnivores, omnivores, detritivores, scavengers, and decomposers.

Key Terms & Definitions

• Ecology — study of interactions among organisms and environment.
• Biotic factor — living part of an ecosystem.
• Abiotic factor — non-living part of an ecosystem.
• Population — group of same species in an area.
• Community — all living populations in an area.
• Ecosystem — community plus abiotic factors.
• Biome — large area with similar climate, plants, and animals.
• Biosphere — all life-supporting areas on Earth.
• Habitat — place where an organism lives.
• Niche — role an organism plays in its environment.
• Limiting factor — factor that restricts population growth.
• Carrying capacity — maximum population an environment can sustain.
• Primary succession — development where no soil exists.
• Secondary succession — development where soil remains.
• Mutualism — both species benefit.
• Commensalism — one benefits, other unaffected.
• Parasitism — one benefits, other harmed.
• Autotroph (producer) — makes its own food.
• Heterotroph (consumer) — eats other organisms.

Action Items / Next Steps

• Complete your notes organizer using this lecture and associated PowerPoints.
• Review graphs and charts on biomes and water distribution.
• Study key terms and definitions for upcoming class discussions.
• Preview biome classification PowerPoints and tutorial links as needed.