BIO 201 - Botany

ECOLOGY

Ecology definition = Study of the relationship between organisms and the environment in which they live

Two important components to the study of ecology:

Biotic = living organisms
    Can study at several levels:
      1) Population = involves only one species
           Ex.: all dogs in Newberry
      2) Community = all species in a particular defined area
          Ex: a pond, river flood plain
      3) Biome = series of communities with the potential for   a particular type of vegetation
          Ex: savannah, temperate deciduous forest

Abiotic = nonliving material and weather
      1) Weather/climate = precipitation, temperature, light, fire
      2) Soil = loose material roots can anchor into
          sources: weathering of bedrock (eg. Sandstone) à sand, silt, clay
          organism interactions (tree roots growing; moles digging) à organic matter
          water and air important also

ECOSYSTEMS

Definition: Ecosystem = A visibly definable area system involving both the biotic and abiotic components

Biotic components fit into one of several categories (pp.783-786):
    1) Producers - photosynthetic organisms
        obtain energy from the sun
    2) Consumers - organisms which eat other living organisms
        a) herbivores - eat plants & fungi
        b) carnivores - eat animals
        c) omnivores - eat all types organisms
    3) Decomposers - organisms which live on dead organisms
        important for returning material to simple chemicals

Can study how energy moves through the ecosystem:
      thought of as an Energy Cycle

Sun light to producers to consumers to decomposers to soil and back to producers
      this is a cyclic process resulting in the recycling of the elements and molecules as well as some energy

Don't have a complete energy transfer from one level to another:
    due to incomplete energy transfer from one to next:
        1) food not eaten or consumed
        2) food not digested (feces)
        3) loss of energy as heat
    general input from Sun Light, general loss as Heat

ECOSYSTEM COMPLEXITY

The complexity of an ecosystem can be measured two ways:
    1) diversity - number of species present
         numerous statistical measures of diversity
    2) stability - resistance of the ecosystem to change
         if stable loss of 1-several species has little effect
    Naturally the most diverse & stable ecosystem is a Tropical Rainforest
         the closer to the equator, greater the diversity & stability

Humans have greatly altered the complexity of many ecosystems
        most commonly they have wishes for systems of one species, a monoculture
        eg. corn field
A monoculture requires great energy input to maintain:
       1) fertilizer
       2) pesticides & herbicides
       3) water
       4) seeds/plants

BIOMES

Biomes defined by the type of vegetation present

How are they classified:
      a) precipitation (total amount, and seasonality)
      b) temperatures (average and seasonality)
      c) dominant vegetation growth form (herb, shrub, tree, vine)

TROPICAL EVERGREEN FOREST – with broad leaves; highest diversity of plants
      warm and humid with year round growing season
      commonly greater than 150 cm rain per year
      areas of equatorial South America, Africa, Asia & Australia

SAVANNA - scattered trees in an otherwise open area
      may have abundant rainfall, but growth limited by long dry season
      many trees loose leaves during dry season
      most well known in eastern Africa (tropical)
      also historically in eastern South Carolina Savanna controlled by fire

SHRUB-SCRUB - no trees, just shrubs, commonly with bare soil
      also known as Mediterranean scrub
      rainfall very limiting
      common in western USA, southern Africa & western Australia

TEMPERATE DECIDUOUS FOREST - wide variety of trees
      warm dry summers, cool moist winters
      includes much of eastern USA and southern Europe
      some places with a mixture of conifers & broad-leaved

CONIFEROUS OR BOREAL FOREST (Taiga) – mostly conifers
      also knows as taiga
      short cool & moist summers; long winters
      much of southern Canada and northern Europe

TUNDRA - low growing vegetation
      grasses, sedges, dwarf shrubs, lichens, mosses
      frost possible most days of year, short summer
      two types:
         a) arctic (circumpolar) - near poles
         b) alpine - high elevation

GRASSLAND - only herbaceous plants dominant
      sparse shrubby, thorny, xerophytic vegetation
      precipitation main limiting consideration
      common to have fires during dry season
      distinct warm and cold seasons

DESERT - sparse vegetation, only rarely is there just open sand
      rainfall < 25 cm per year
      thorny, xerophytic vegetation
      Two types:
         hot - Sahara, Chihuahua
         cold - Antarctica, all water locked up as ice

Map of North America with details of many biomes types and subtypes:

Tropical Evergreen Forest - 15

Savanna – found within 8

Shrub-Scrub – 11, 12, 13, 14

Temperate Deciduous Forest – 8

Boreal Forest – 3, 4, 5, 6, 7

Tundra – 2

Grassland – 9

Desert – 10