The Scope of Ecology

• Study of interactions between organisms 

  and their environment (biotic and abiotic)

  Hierarchy:

      Ecosystem ecology

      Community ecology

      Population ecology

Abiotic Factors of the Biosphere

• Biosphere: the global ecosystem including temperature, water, sunlight, wind, rocks and soil, periodic disturbances

• Climate (prevailing weather conditions of a locality), usually most concerned with rainfall and temperature

Aquatic and Terrestrial Biomes

• Aquatic Biomes

  • Largest part of biosphere (75+%)

  • Freshwater < 1% salt

  • Marine > 3% salt

• Terrestrial biomes

  • Determined by climate

  • Grade into each other, lack sharp boundaries

  • Dynamic, disturbances rather than stability is the rule

Aquatic Ecosystems-Freshwater

• Often exhibit vertical stratification

• Lakes (oligotrophic, mesotrophic, and eutrophic)

• Streams and rivers - move continuously in one direction

• Wetlands - one of the richest and most valuable biome

• Estuaries - freshwater merges with the ocean, very productive

Estuary

• Coastal body of water with access to both and ocean and fresh water from rivers

• Transition from land to sea; freshwater to salt water

• Called bays, lagoons, inlets or sounds

• Shore birds, fish, crabs and lobsters, marine mammals, clams and other shellfish, marine worms, and sea birds

Marine Ecosystems

• Intertidal zone

  • Shoreline between low and high tides

• Coral Reefs

• Benthic Environment

  • Ocean Floor

• Neritic Province

  • open ocean from shoreline to depth of 200 meters

• Oceanic Province

  • Ocean deeper than 200 meters

Aquatic Life

• Aquatic life divided into

  Plankton

  • Free-floating organisms

  Nekton

  • Strongly swimming organisms

  Benthos

  • Bottom-dwelling organisms

Terrestrial Biomes

• Often named for major physical or climatic features,

  and for the predominant vegetation

• Ex: Deserts, grasslands, savannahs, deciduous forest, rainforest, taiga, chaparral, and tundra

Arctic Tundra

•  Northernmost biome

  • Frozen layer of subsoil (permafrost)

  • Low-growing vegetation adapted to extreme cold/short growing season

  • Plants include sedges, mosses, lichens, grasses and 400 varieties of flowers

  • Animals include caribou, musk ox, arctic hare, voles and lemmings are the principal herbivores, which enable a few carnivores like the arctic fox, snow owl, polar bear, and wolf to survive.

Taiga

•   Coniferous trees dominate the taiga, or boreal forest

  • Cold winters, short growing season, and acidic, mineral-poor soil

  • Belted Across North America and Eurasia

  • Animals include fur-bearing predators like the lynx and members of the weasel family (e.g., wolverine). Herbivores include the snowshoe hare, red squirrel, and lemmings

Temperate Coniferous Forests

• Large conifers

• High precipitation 

    200 – 350 cm as rain and snow

• Average temperatures 0^oC to 20^oC

• Main stretch of this habitat is along the northwestern coast of North America from northern California though southern Alaska

• Plants include Douglas fir and Western red cedar, Mountain hemlock, Western hemlock, spruce and Lodgepole pine

• Animals include deer, bears, coyotes, slugs, grouse, etc.

Temperate Deciduous Forests

• Precipitation relatively high 

(30 to 60 inches a year)

• Soils rich in organic matter

• Broad-leaf trees that lose their leaves seasonally dominate

• Average annual temperature in a deciduous forest is 50° F.

• Four distinct seasons - spring, summer, autumn, and winter

• Oaks, maples, hickory, elms

• Eagles, black bear, deer, squirrels, coyotes

Grasslands

• Deep, mineral-rich soil

• Moderate but uncertain precipitation

• Well suited to growing grain crops

• Chaparral

  • Thickets of small-leaf evergreens

  • Climate of wet, mild winters and dry summers

Dry Biomes - Deserts

• Cold deserts in temperate climates

• Warm deserts in subtropical or tropical regions

• Low levels of precipitation

• Organisms with specialized water-conserving adaptations

• Cactus, roadrunners, peccary, yuccas, Gila monster, kangaroo rat, bobcat, etc

Tropical Biomes

• Savanna

  • Tropical grassland

  • Widely scattered trees interspersed with grassy areas

  • Occurs in topical areas with low or seasonal rainfall

  • Giraffes, elephants, lions, hyenas, springbok

  • Acacia trees, elephant grass, baobab trees, Bermuda grass

Tropical Biomes

• Tropical rain forest

  • Mineral-poor soil

  • High rainfall evenly distributed throughout the year (50 to 260 inches )

  • High species richness and high productivity

  • Average temperature between 20^oC to 34^oC

Biogeography

• -geographic distribution of plants and animals

  
  

  Each species originated from its center of origin

  
  Alfred Wallace divided the Earth’s land areas into six major biogeographic realms

Human Effect On Biomes

• Tundra

  • Oil exploration and military exercises result in long-lasting damage

  Taiga And Temperate Rain Forests

  • Clear-cut logging destructive

  Temperate and Deciduous Forests and Tropical Rain Forests

  • Removed by logging and development