Ch 50: An Introduction to Ecology and the Biosphere: Lecture notes

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Coarse grained environment: patches are so large in relation to size and activity of the organism that an individual organism can choose among patches

  • Fine grained environment: Patches are small relative to size and activities of an organism. Example an herbivore in a field of grass, all species are eaten.

  • Environments can also be temporally grained depending on daily and seasonal shifts

    The variety of adaptations in response to spatial and temporal variations are as follows

    0.0 Behavioral Responses:

    0. Modification of the environmental change be movement or social behavior

    0. fish move to a cooler part of the lake during the summer

    0. desert animals burrow into the shade during daylight

    0. migration

    0.00 Physiological responses

    0. slower then behavioral responses, but is a metabolic change to cope and maintain homeostasis in

    an animals environment

    0. acclimation is a gradual process and is related to the range of environmental conditions

    experienced under natural conditions

    3. Example: Humans adapting to lower partial oxygen pressure at elevated altitudes

    0.0 Morphological Responses

    0. Responses that alter body form or internal anatomy

    0. increased coat of fur during the winter

    0. a change in color

    0.00 Adaptations over evolutionary time

    0. organisms are evolutionarily adapted to their environment

    0. they may not be transported different locations with an altered microclimate

    0. they may even die out in their present location if conditions change enough
    0.00 Geographical distribution of terrestrial biomes is based on regional variations in climate

    1. Biomes: communities and ecosystems typical of a broad geographic region

    2. Latitude has an effect on the biome distribution because of the latitudinal patterns in climate

    3. Biomes are often named for the predominant vegetation, but each is also characterized by microorganisms, fungi and animals adapted to that particular environment

    0. exotones are transitional areas between two communities
    0.00 Tropical forest

    1. within 23.5' latitude, typical temp is 23'C and daylight is usually 12 hours

    2. vary according to rain

    0. prolonged dry seasons tropical dry forest

    0. wet and dry seasons tropical deciduous forests

    0. wet season is prolonged tropical rain forest

    (*) great plant diversity that supports great animal diversity

    (*) competition for light is the strong selective force

    (*) soil is poor due to rapid nutrient recycling

    many layers due to amount of light that penetrates

    0.000 Savanna: grassland with scattered individual trees

    0. 3 season cool-dry, hot dry, warm wet

    0. frequently have fires, soil is poor and dry

    0. have large herbivores

    0. is often in association with forests

    0. humans have impacted these areas and cause increasing loss of vegetation and desertification

    0.0 Desert: low and unpredictable precipitation ,less than 30 cm) exist in both cold and hot regions

    0. occur in two distinct belts between 15'C and 35 ' latitude in both hemispheres

    0. density of vegetation cycles with growth and reproduction is keyed to precipitation

    0. animals have adaptive and physiological adaptations, their reproduction is also tied to rainfall.

    0.0 Chaparral: regions of dense, spiny shrubs with tough evergreen leaves. Along coasts where cool

    ocean current circulate offshore resulting in mild, rainy winters and long hot dry summers

    0. found between 30' and 40' latitude

    0. frequently has fires, plants are adapted to fire

    0. browsers such as deer, fruit eating birds and seed eating ants and rodents, snakes and lizards are


    0.0 Temperate Grasslands: some characteristics of tropical savannas but occur in regions with relatively

    cold winters

    1. Typically plains regions

    2. Fires and drought prevent trees from growing

    3. Has a very deep rich soil, that holds moisture

    4. many are converted to farm and pasture lands

    0.0 Temperate Deciduous Forest: grow throughout midlatitude regions with sufficient moisture to support

    growth of large, broad leafed deciduous trees

    0. eastern U.S. middle Europe and E. Asia

    0. temp range is large -30'C to 30'C

    0. 5 to 6 month growing season

    0. lots of precipitation and throughout the season

    0. rich soil with slow nutrient cycling

    0. many have been logged and converted to farmland

    0.0 Taiga: boreal forest characterized by harsh winters and short, wet summers

    0. largest terrestrial biome in north America Europe and Asia and in high attitudes

    0. lots of precipitation in the form of snow

    0. lots of conifer, little undergrowth

    0. soil is poor due to waxy needles and short season

    0. coastal coniferous forests are similar to taiga but are typically dominated by few species

    0. have a longer season and more water

    0.00 Tundra: northern most limits of plant growth and shrubby or matlike vegetation (2 types)

    0. Arctic tundra: encircles north pole and extends to taiga

    0. lots of water, due to low evaporation

    0. plant growth is in short warm and high photoperiod

    0.0 Alpine tundra: occurs at high elevations at all latitudes

    0. both typically have many insect and birds that feed on them

    0. as well as some large and small herbivores
    0.00 Aquatic ecosystems occupy the largest part of the biosphere

    1. life evolved in water and it still has the greatest amount and diversity

    2. Freshwater biomes have salt concentrations less than 1% and marine concentrations are typically above 3%

    3. Marine biomes cover 65% of the Earth's surface

    0. is responsible for production of the majority of the worlds oxygen

    0. greatly affects word climate and wind patterns

    0.00 Ponds and Lakes

    0. standing bodies of water on terrestrial environments

    0. Ponds exhibit a vertical stratification based on

    0. light

    (*) photic zone light enough for photosynthesis

    (*) aphotic zone no light

    0.0 Temperature

    (*) heat is retained in the upper layers of water moving from warmer upper water to colder

    water is called the Thermocline

    0.00 Distribution of plants and animals

    0. littoral zone: shallow well lighted close to shore

    0. limnetic zone: open well lighted far form shore

    0. profundal zone deep aphotic zone laying beneath the limnetic zone

    (*) usually bacteria and recycling organisms

    (*) mixing of these zones occurs twice a year due to density differences related to


    0.00 Classification of lakes

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