Chapter 52

Factors Determining Species Distribution

• Climate (temperature, precipitation) affects terrestrial organisms.

• Light and nutrient availability affect aquatic organisms.

• Dispersal and interactions among organisms play a role.

Ecology Defined

• Ecology studies interactions between organisms and their environment, determining their distribution and abundance.

• Research occurs at different biological hierarchy levels.

Scope of Ecological Research

Organismal Ecology

• Focuses on how structure, physiology, and behavior meet environmental challenges.

Population Ecology

• Analyzes factors affecting population size changes over time.

Community Ecology

• Examines interspecific interactions' effect on community structure.

Ecosystem Ecology

• Emphasizes energy flow and chemical cycling between organisms and the environment.

Landscape Ecology

• Focuses on energy, material, and organism exchanges across multiple ecosystems.

Global Ecology

• Examines how energy and material exchange influences organism distribution across the biosphere.

Climate's Influence

• Climate (long-term weather) significantly influences organism distribution.

Components of Climate

• Major components: temperature, precipitation, sunlight, and wind.

Global Climate Patterns

• Determined by solar energy and Earth's movement, creating temperature variations and circulation.

Latitudinal Variation in Sunlight Intensity

• Tropics receive direct sunlight; higher latitudes receive diffuse sunlight.

Global Air Circulation and Precipitation Patterns

• Tropics: rising air causes high precipitation.

• 30º N/S: descending air creates arid climates.

• 60º N/S: rising air causes abundant precipitation.

• Air flowing near Earth's surface creates global wind patterns.

Regional and Local Effects on Climate

Seasonality

• Middle to high latitudes experience seasonality due to Earth's axis tilt.

Bodies of Water

• Ocean currents and large water bodies moderate land climates.

Mountains

• Influence airflow, creating rain shadows and affecting sunlight.

Effects of Vegetation on Climate

• Forests absorb solar energy, cool via transpiration; deforestation leads to hotter, drier climates.

Microclimate

• Fine, localized climate patterns.

Abiotic and Biotic Factors

• Abiotic (nonliving) and biotic (living) factors influence life's distribution.

Global Climate Change

• Increased greenhouse gases cause warming, shifting patterns, and extreme events.

Species Response to Climate Change

• Species ranges shift; past responses help predict future effects.

Impacts of Climate Change on Organisms

• Shifts in geographic ranges, potential extinctions.

Terrestrial Biomes

• Major life zones characterized by vegetation type or physical environment.

Climate and Terrestrial Biomes

• Climate influences plant distribution, determining biome locations.

Climograph

• Plots temperature and precipitation in a region.

Features of Terrestrial Biomes

• Biomes grade into ecotones; vertical layering affects animal habitats; species composition varies.

Disturbance and Terrestrial Biomes

• Disturbance (storm, fire) changes communities; dominant plants depend on disturbance.

Specific Terrestrial Biomes

Tropical Forest

• Equatorial regions with high temperatures and rainfall; high animal diversity; deforestation is a major impact.

Desert

• Near 30º N/S with low, variable precipitation and extreme temperatures; plants adapted for water storage; urbanization reduces biodiversity.

Savanna

• Equatorial regions with seasonal precipitation and warm temperatures; fire-adapted plants; cattle ranching threatens mammals.

Chaparral

• Midlatitude coastal regions with seasonal precipitation; shrubs adapted to fire and drought; agriculture and urbanization reduce areas.

Temperate Grassland

• Seasonal precipitation and temperatures; plants adapted to drought and fire; agricultural land conversion.

Northern Coniferous Forest (Taiga)

• Northern regions with cold winters and variable precipitation; evergreen conifers; logging old-growth stands rapidly.

Temperate Broadleaf Forest

• Midlatitudes with significant precipitation; deciduous trees; mammal hibernation and bird migration in winter; heavily settled by humans.

Tundra

• Arctic areas with low temperatures and precipitation; herbaceous vegetation; permafrost restricts root growth; oil and mineral extraction.

Aquatic Biomes

• Characterized by physical and chemical environment; marine biomes average 3% salt; freshwater less than 0.1%.

Zonation in Aquatic Biomes

• Stratified into photic (light) and aphotic (no light) zones; thermocline separates warm and cold layers; turnovers mix oxygen and nutrients.

Specific Aquatic Biomes

Lakes

• Vary in size, salinity, O2, and nutrients; oligotrophic (nutrient-poor) and eutrophic (nutrient-rich) types; nutrient enrichment causes algal blooms.

Wetlands

• Water-saturated soil; high productivity; purify water and reduce flooding; draining and filling by humans has destroyed many.

Streams and Rivers

• Current is prominent; headwaters (cold, clear) to downstream (warm, turbid); pollution degrades water quality; damming impairs functioning.

Estuaries

• Transition between river and sea; salinity varies; saltmarsh grasses and algae are major producers; filling, dredging, and pollution disrupt.

Intertidal Zones

• Submerged/exposed by tides; oxygen and nutrients high; rocky or sandy substrates; oil pollution and construction disrupt.

Oceanic Pelagic Zone

• Open water; mixed by currents; oxygen high, nutrients lower; phytoplankton and zooplankton dominate; overfishing and pollution harm.

Coral Reefs

• Calcium carbonate skeletons of corals; warm, clear water; mutualistic algae; collection, overfishing, and pollution are threats.

Marine Benthic Zone

• Seafloor; cold, high pressure; hydrothermal vents; chemoautotrophic prokaryotes; overfishing and waste deplete fish.

Factors Limiting the Distribution of Species

• Ecological factors and evolutionary history influence distributions; biotic and abiotic factors.

Dispersal and Distribution

• Movement from origin contributes to global distribution.

Natural Range Expansions and Adaptive Radiation

• Dispersal influences distribution; long-distance dispersal leads to adaptive radiation.

Species Transplants

• Relocation indicates potential range; can disrupt communities.

Biotic Factors

• Interactions with other species reduce survival.

Abiotic Factors

• Temperature, water, oxygen, salinity, sunlight, and soil influence distribution.

Temperature

• Impacts biological processes; organisms function best within a specific range.

Water and Oxygen

• Water availability affects species distribution; low oxygen in deep/organic-rich waters.

Salinity

• Salt concentration affects water balance; aquatic organisms restricted to freshwater or saltwater.

Sunlight

• Limits photosynthetic species; high light increases temperature.

Rocks and Soil

• pH, mineral composition, and structure limit plant distribution; substrate affects water chemistry.