Biodiversity refers to the variety of genes, species, and communities in an area. Natural biodiversity changes with seasonal cycles and disturbances. Human-driven biodiversity loss is more severe and long-lasting
Ecological pyramids show biomass or bioproductivity at each trophic level. Pyramids can be energy, biomass, or number pyramids. Energy pyramids are typically upright, others can be inverted. Pyramids start with producers at bottom and progress through trophic levels
Detritus is organic matter from decomposing organisms and feces. Hosts communities of microorganisms that colonize and decompose it. Most important constituents are complex carbohydrates
80% of marine pollution comes from land-based activities. Rivers, sewage, and atmospheric pollution contribute significantly. Ships discharge ballast water and oil, spreading invasive species. Deep sea mining releases toxic metals into oceans
Invasive species are introduced organisms that harm their new environments. Human-facilitated introductions have greatly increased invasion rates since 20th century. Humans have been both accidental and deliberate dispersal agents for millennia
Ecosystems are communities of living things interacting with physical world. People depend on ecosystems for food, water, clean air, and recreation. Ecosystems can range from Yellowstone to single fallen tree