Ecosystems Study Guide

Ecosystem Basics

• Individual Organism: A single organism, e.g., an elk.
• Population: A group of individuals of the same species, e.g., an elk herd.
• Community: All living organisms in a particular area.
• Ecosystem: Comprises all living and non-living things in an area, including plants, animals, rocks, soil, water, and air.
• Biome: A large area with similar climate conditions that influence the species of plants and animals found there. Example: Tropical rainforest.

Organism Interactions

• Mutualism: A relationship that benefits both organisms. Example: Coral reefs.
• Competition: Interaction where organisms compete for resources like food or shelter, which limits population size.
• Predation: One organism uses another as an energy source (includes hunters, parasites, and herbivores).
• Commensalism: A relationship that benefits one organism without impacting the other. Example: Birds nesting in trees.

Types of Competition

• Resource Partitioning: Different species use the same resource differently, reducing competition and limiting population sizes.
• Temporal Partitioning: Species use the same resource at different times (e.g., wolves and coyotes hunting at night vs. day).
• Spatial Partitioning: Species using different areas of the same habitat (e.g., plants with different root lengths).
• Morphological Partitioning: Resources are utilized based on evolved body features differences among species.

Terrestrial Biomes

• Biome Characteristics: Biomes are characterized by average yearly temperature and precipitation.
• Adaptation: The community of organisms in a biome is uniquely adapted to live in that environment. Example: Camels and cacti in the desert.

Biomes and Climate

• Biomes are defined by annual temperature and precipitation averages.
• A biome chart can predict the locations of biomes on Earth:
  • Tundra & Boreal: Higher latitudes (60° and above).
  • Temperate: Mid-latitudes (30° to 60°).
  • Tropical: Closer to the equator.
• Latitude affects temperature and precipitation, resulting in a predictable pattern of biomes.

Climograph/Climatogram

• A graphical representation that shows average climate conditions by month.
• Hybrid line-bar graph format (temperature usually shown as a line, precipitation as bars).

Shifting Biomes

• Biomes can shift in location due to climate change (e.g., warming climates pushing boreal forests north as permafrost thaws).

Aquatic Biomes

Characteristics of Aquatic Biomes

• Depth: Influences sunlight penetration and photosynthesis potential.
• Temperature: Warmer water holds less dissolved oxygen, limiting aquatic organisms.
• Salinity: Levels of salt in water determine species survivability and water usability (freshwater vs. estuary vs. ocean).
• Flow: Affects the types of plants and organisms that survive and the amount of oxygen in water.

Freshwater Biomes

Rivers

• High oxygen levels due to water flow and mixing with air. Carry nutrient-rich sediments leading to fertile soils.

Lakes

• Standing bodies of freshwater, key drinking water sources.
  • Littoral Zone: Shallow water with emergent plants.
  • Limnetic Zone: Area where light penetrates for photosynthesis; no rooted plants, only phytoplankton.
  • Profundal Zone: Too deep for sunlight, thus no photosynthesis.
  • Benthic Zone: Murky bottom where invertebrates live; nutrient-rich sediments.

Wetlands

• Areas with soil submerged/saturated for at least part of the year and suitable for emergent plants (e.g., cattails, lily pads).
• Benefits of Wetlands:
  • Store excess water during storms, reducing floods.
  • Recharge groundwater through rainfall absorption.
  • Roots filter pollutants from drainage water.
  • High plant growth due to nutrient-rich sediments.

Coral Reefs

• Found in warm, shallow waters beyond shorelines; they are the most diverse marine biome on Earth.
• Features a mutualistic relationship between coral and algae:
  • Coral utilizes CO₂ from the ocean to create calcium carbonate for its exoskeleton and provides CO₂ to algae.
  • Algae, in turn, provide sugars (energy) to coral via photosynthesis.

Open Ocean

• Characterized by low productivity per area, as primarily algae and phytoplankton survive.
• Photic Zone: Area where sunlight reaches and photosynthesis occurs.
• Aphotic Zone (Abyssal): Too deep for sunlight; crucial as algae and phytoplankton produce a significant amount of Earth's oxygen and absorb CO₂.