Ecosystems, Ecology, and Biomes Notes

Ecosystems, Ecology, and Biomes

• Chaparral vs. Coastal Sage Scrub (Southern California):

  • Chaparral:

    • Tall shrubs (5–9 feet).

    • Evergreen.

    • Thick, leathery, shiny, rigid leaves.

    • Dense, woody clusters.

    • Deep root systems (~25–30 feet) which help prevent erosion, hold thin soil together, and recharge aquifers.

  • Coastal Sage Scrub:

    • Shorter shrubs (1.5–4 feet).

    • Drought-deciduous (lose leaves in dry periods).

    • Soft, flexible, feathery leaves.

    • Less densely spaced.

    • Softer stems.

    • Shallow, wide lateral root systems.

• Climate Factors Influencing Biome Type:

  • Annual precipitation.

  • Annual mean temperature.

• Ecotone Definition:

  • Transition area between two biomes.

  • Characteristics of both biomes blend.

• Major Terrestrial Ecosystems in San Diego County (West to East):

  • Coastal Sage Scrub.

  • Chaparral.

  • Coniferous Forest.

  • Desert.

• Desert Biome:

  • General latitude: ~30°.

  • U.S. states: California, Arizona, New Mexico, Western Texas.

• Rain Shadow:

  • Occurs on the leeward side of mountains.

  • Dry air descends, leading to desert formation.

• Coniferous Forest Biome Types:

  • Taiga.

  • Temperate Rainforest.

  • Montane Coniferous Forest.

• Coniferous Forests in California Mountains:

  • Elevation range: ~5,500 to 10,500 feet.

  • Mean annual precipitation: ~30–35 inches.

• Mediterranean Biome:

  • General latitude: 30°–40°, west or southwest coasts of continents.

  • Other global locations: Mediterranean Basin, Southwest Australia, Central Chile, Cape Region of South Africa.

• Biome Identification:

  • Defined by precipitation patterns, temperature, and dominant plant types.

• Chaparral Ecosystem:

  • Average annual rainfall: ~20–25 inches.

  • Rainy season: Mild and cool, December–March.

  • Dry season: Hot and dry, May–November.

• Chaparral Topography:

  • North-facing slopes of coastal canyons.

  • North-facing slopes of foothills.

  • Mid-elevations of Peninsular and Transverse Ranges.

• Chaparral Elevation in Southern California:

  • ~2,000–5,000 feet.

• Ocean Current:

  • California Current; cold; flows southward.

• Grasslands:

  • U.S. locations: Great Plains.

  • California locations: Central Valley and coastal valleys.

• Temperate Broadleaf Forests:

  • U.S. locations: East Coast and Southeast, east of the Mississippi.

• Tundra Biome:

  • Global locations: Arctic and high mountains.

  • Alpine tundra in CA: ~11,000–14,000 feet in the Sierra Nevada.

Trophic Levels, Food Webs, Keystone Species

• Definitions:

  • Herbivore: Eats only plants.

  • Carnivore: Eats only animals.

  • Omnivore: Eats plants and animals.

  • Detritivore: Eats detritus/dead material.

• Trophic Levels in a Food Web:

  • Producer → Primary Consumer → Secondary Consumer → Tertiary Consumer → Quaternary Consumer → Decomposer

• Primary Production:

  • The conversion of solar energy into chemical energy by photoautotrophs through photosynthesis.

• Producers:

  • Marine: Phytoplankton, cyanobacteria, kelp.

  • Terrestrial: Plants.

• Energy Loss at Trophic Levels:

  • 90% energy loss at each level.

• Energy Loss from Food:

  • ~50% as waste.

  • ~35% in respiration.

• Species Richness vs. Abundance:

  • Richness: Number of unique species.

  • Abundance: Proportion of individuals per species.

• Biodiversity Hotspot:

  • San Diego is in the California Floristic Province (CFP).

• Endemic Species:

  • A species with a restricted range, found nowhere else.

• Starfish Removal Experiment:

  • Mussels overpopulated, other species declined.

  • Biodiversity decreased.

• Starfish Example:

  • Keystone species.

• Keystone Species in Aleutian Kelp Forests:

  • Sea otter; preys on sea urchins.

• Ecosystem Upgrading:

  • Restoring ecological balance through the reintroduction of a keystone species.

• Yellowstone Reintroduction:

  • Wolves were introduced and they maintained the deer population.

Geography and Topography of California

• Cities to Label:

  • San Diego, Los Angeles, San Francisco

• Topographic Features to Label:

  • Peninsular Range, Transverse Range, Central Valley, Salton Sea, Colorado River, Point Conception, Mojave Desert, Colorado Desert, Big Sur, Catalina Island, San Clemente Island, Santa Cruz Island, Santa Rosa Island, San Nicolas Island, Santa Barbara Island, San Miguel Island

• Mountain Range:

  • Cuyamaca and Laguna Mountains are located in the Peninsular Range.