Ecology and Ecosystem Dynamics Flashcards

Grade 12 · Science · Flashcards

Essential ecology vocabulary for Grade 12 Science.

Flashcards

Autotroph (producer): Organism that makes its own food via photosynthesis or chemosynthesis; base of food chains.
Heterotroph (consumer): Organism that obtains energy by consuming other organisms.
Trophic level: Position in a food chain; producers = level 1; each successive consumer level = next level.
10% rule: Only ~10% of energy passes to the next trophic level; explains the pyramid of energy.
Carbon cycle: Photosynthesis captures CO₂; respiration/decomposition releases it; fossil fuel burning adds extra CO₂.
Nitrogen cycle: N₂ → NH₃ (fixation) → NO₃⁻ (nitrification) → plant protein (assimilation) → N₂ (denitrification).
Carrying capacity (K): Maximum sustainable population size in an environment given limited resources.
Logistic growth: Population growth that slows as it approaches carrying capacity; produces S-shaped curve.
Keystone species: Species with outsized ecological impact; ecosystem structure depends on their presence.
Primary succession: Succession starting on bare, lifeless substrate (no soil); begins with pioneer species like lichens.
Ecological niche: Full range of conditions and resources a species uses; includes food, habitat, time of activity.
Competitive exclusion: Two species cannot occupy the exact same ecological niche indefinitely; one will outcompete the other.