Biomes and the Phosphorus Cycle

Today's Agenda

  • Phosphorus Cycle
  • Start Biomes
  • Quiz 5 opens after class ends today and closes before class starts on Wednesday

Phosphorus Cycle (Chapter 12.2)

  • Abundance
  • 0.13% in Earth's crust
  • 11th most abundant element in the lithosphere
  • Comprises 0.5–1.0% of living tissues
  • Chemical Behavior
  • Phosphorus dissolves in soil and water
  • Sources: minerals and decomposing organic matter
  • Biological Pathways
  • Plants absorb phosphorus from soil and water
  • Animals obtain phosphorus through food consumption
  • Geological Cycle
  • Phosphorus eventually carried to oceans, sinks to the bottom, and becomes sedimentary rock

Human Impact on Phosphorus Cycle

  • Activities Affecting Cycle
  • Mining phosphorus from the ground
  • Harvesting guano (bird excrement)
  • Spreading manure on agricultural lands

Scales of Environmental Biology

  • Levels of Organization
  • Cells
  • Individuals
  • Populations
  • Communities
  • Ecosystems
  • Biomes
  • Biosphere

Definitions of Key Terms

  • Biome: A large, naturally occurring biological community of flora and fauna occupying a major habitat (e.g., forest or tundra). It can encompass various ecosystems responding to their physical environment and regional climate.

Biomes and Evolution

  • Similar organisms in distant locations may evolve similar adaptations due to:
  • Convergent Evolution: Unrelated species evolving similar traits or features due to adapting to similar environments or ecological niches.

Categories of Biomes

  • Types
  • Terrestrial Biomes
  • Marine Biomes
  • Freshwater Biomes
  • Focus for this unit is on terrestrial biomes.

Terrestrial Biomes Overview

  • Communities of similar organisms characterized by a specific climate, determined primarily by atmosphere and climate.
  • Key Variables: Temperature and precipitation.
  • May be grouped into three climatic zones:
  • Tropical Zone: Equator to 25° N/S
  • Temperate Zone: 25° to 60° N/S
  • Polar Zone: Above 60° N/S

Climate Influences on Biomes

  • Proximity to Water
  • Continental Climate: Significant temperature variance (interior areas)
  • Maritime Climate: Less temperature variation (near oceans/lakes)

Tropical Biomes

  • Tropical Zone
  • Average monthly temperatures normally above 20° C (68° F) with minimal seasonal change
  • Tropical Rain Forest:
  • Annual rainfall > 2,000 mm (80 in)
  • Plentiful rainfall and warm climate
  • High biodiversity: Significant plant and animal diversity
  • Highest Net Primary Production (NPP) among terrestrial biomes
  • Rapid cycling of nutrients; contains many unique niches and endemic species
  • Endemic Species: Species found only in specific environments/geographic areas; do not occur elsewhere.