Introduction to Ecology and the Biosphere

Introduction to Ecology and the Biosphere

• Ecology: Study of interactions between organisms and their environment.

• Biosphere: Global ecosystem encompassing all living beings and their relationships with the environment.

Terrestrial Biomes

Climate Influence on Biomes

• Climate strongly influences the distribution of terrestrial biomes.

• Key factors for biome characterization: distribution, precipitation, temperature, plants, and animals.

Forest Biomes

• Tropical Rain Forests:

  • Constant high rainfall

  • High temperatures year-round

  • High animal diversity (examples: Sloth, Jaguar, Anaconda, Capuchin).

Desert Biomes

• Characteristics:

  • Found near 30° N/S and continental interiors.

  • Low precipitation; temperature fluctuates greatly.

• Adaptations:

  • Plants: Heat and desiccation tolerant, water storage, reduced leaf area.

  • Animals: Mostly nocturnal, adapted for water conservation.

Savanna Biomes

• Distribution: Equatorial and subequatorial regions.

• Characteristics:

  • Seasonal precipitation and temperature.

  • Dominant plants: fire-adapted species.

• Ecological Importance:

  • Grasslands support large herbivores and insects.

  • Threats from human activities (overhunting, ranching).

Chaparral Biomes

• Distribution: Mid-latitude coastal regions.

• Environmental Conditions:

  • Highly seasonal precipitation and temperature (rainy winters, dry summers).

• Flora and Fauna:

  • Dominated by shrubs, small trees; many species adapted to fire/drought.

  • Wildlife includes birds, reptiles, small mammals.

Temperate Grasslands

• Location: Occur across continents.

• Characteristics:

  • Highly seasonal precipitation; cold dry winters, hot wet summers.

• Dominant Vegetation:

  • Grasses and forbs adapted to drought and fire.

• Human Impact:

  • Most grasslands converted to farmland.

Northern Coniferous Forest

• Distribution: Primarily mid-latitudes.

• Characteristics:

  • Precipitation varies; cold winters, mild summers.

• Vegetation:

  • Dominated by conifers (pines, spruces).

• Wildlife:

  • Large mammals (moose, bears) and diverse bird species.

Broadleaf Forest Biomes

• Distribution: Widespread at mid-latitudes.

• Precipitation: Rain and snow throughout seasons.

• Tree Species:

  • Dominated by deciduous trees; adapted to freezing conditions.

• Ecological Notes:

  • Recovery from human settlement is seen in various areas.

Tundra Biomes

• Location: Arctic regions, alpine areas at various latitudes.

• Climate: Cold winters and cool summers; low annual precipitation.

• Soil Characteristics:

  • Permafrost inhibits root growth; topsoil remains soggy.

• Vegetation and Wildlife:

  • Dominated by herbaceous plants; wildlife includes muskox, arctic hares, various carnivores.

Aquatic Biomes

Wetlands

• Description: Among the most productive ecosystems.

• Flora: Includes lilies, cattails, and others.

• Fauna: Diverse invertebrates, birds, amphibians, otters.

• Human Threats: Up to 90% of wetlands have been destroyed.

Estuaries

• Definition: Transition zones between rivers and seas.

• Salinity: Varies with tides; nutrient-rich and productive environments.

Coral Reefs

• Composition: Formed by calcium carbonate skeletons of corals.

• Requirements: Need high oxygen concentrations; mutualistic relationships with algae.

• Threats: Overfishing, global warming, pollution.

Intertidal Zones

• Description: Areas periodically submerged by tides.

• Conditions: High oxygen and nutrient levels.

• Flora and Fauna: Diverse, adapted to extreme tidal conditions.

Freshwater Biomes

• Composition: Includes lakes, rivers, and wetlands.

• Key Species: Zooplankton, fish, invertebrates.

• Human Impact: Nutrient enrichment induces algal blooms and fish kills.

Seasonal Turnover in Lakes

• Process: Temperature boundaries separate warm upper layers from cold deep waters.

• Function: Turnover mixes oxygenated surface water with nutrient-rich bottom water, crucial for lake health.