Intro to Ecology

The equatorial parts of the earth moving faster then the poles.

Causes the winds to be deflected to the right of their direction of travel in the Northern Hemisphere and left of their direction in the Southern Hemisphere

little if any permanent vegetation

vast regions in the northern hemisphere where there are hardy plants

• northern coniferous or Russian word for boreal
• forest)- dominated by evergreens

• warm summers and cold winters, a lot of
• rainfall, support a wide variety of deciduous trees.

• low precipitation, decomposition is slow and
• soils tend to be rich and fertile.
• Bread baskets
• Peak moisture meets peak temperature

relatively mild, with winter rains and summer droughts, dominated by woody shrubs with hardy evergreen leaves, humans have been around for a long time and they have greatly reduced the faunal diversity

 very little rain (typically <25 cm per year), fluctuate between hot and cold

• warm and receive a good bit of precipitation
• (90-150 cm, annually), prolonged periods of drought (5 cm per month), fire and grazing are important maintaining factors
• Human made fires may have played an important ecological role for the past few thousand years

• found between the Tropics of Cancer and Capricorn, receive abundant rainfall and sunlight and are relatively warm, high biodiversity, rapid nutrient cycling but soils tend to be nutrient-poor
• Tropical Rainforests
• Tropical Dry Forests (longer dry seasons)
• Tropical Savanna (even sharper dry and wet
• seasons)

• 1. Organic horizon (O)- leaves decomposing organisms.
• 2. A horizon (rooting zone)- decomposed material, leaching of minerals.
• 3. B horizon (depositional)- ex: caliche, hard pan.
• 4. C horizon- above the parent material (bedrock)- weathers the parent material.

long term average temperature, precipitation, and atmospheric circulation.

the boundary between warm and cold water (not much mixing between)

the limits on environmental conditions that an organism can tolerate

• the sum of transpiration and evaporation. The
• total amount of water leaving the ground (or other surface) and going back into
• the atmosphere.

• Total amount of evapotranspiration that would take place if there were enough water available.
• The rate at which an area would evapotranspirate at a determined temperature

• the constellation of environmental conditions
• under which a species can survive.

lose water and dry out

• 1. Idea that limiting or controlling resource that influenced or determined the distribution of different species
• 2. Originally proposed by Justus von Leibig (German Chemist in the 1800s)
• Theory was that growth and reproduction are limited by the most scarce resource

a substance that lowers the activation energy of a chemical reaction, but is not itself consumed in the reaction

• are catalysts. Most are made of proteins and
• nearly all chemical reactions that occur in living cells require enzymes. 
• Enzyme activity is affected by temperature,
• chemical environmental factors such as pH, and the concentrations of the substrates whose reactions enzymes catalyze.

• a family of proteins that help other proteins to fold into their proper shape. These are known as heat-shock proteins because if
• an organism is heated up beyond its normal temperature range (a “heat shock”), the organism will produce extra copies of the proteins to help stabilize all its other proteins.

• different versions of a gene. May differ in
• nucleotide sequence, amino acid sequence, or both

• Acclimation that is not changed easily, or at
• all when the environment changes.
• Ex: oak leaves developing to sunny or shady
• forms stay that way even if the surrounding conditions change.

approximated by calculating the surface-to-volume ratio of a sphere.

• is a measure of energy used over time. One watt is equal to one joule per second. A joule is a unit of energy (like calories –
• a joule = 4.18 calories)

• is the transmission of energy. Light is a form
• of radiation, as is heat, as are X-rays. Radiation can be thought as traveling
• in a wave, and the different forms of radiation have different wavelengths. The
• longer the wavelength, the lower the energy level of that radiation.

• the heat gain, in watts, for an organism exposed to solar radiation, is given by the following formula: Absorbed Radiation = (exposed area) x (solar radiation) x (absorption)
• Here, solar radiation is expressed as a flux, in watts per area. Absorption is the fraction of incident radiation that is absorbed by the body (the remainder is reflected back).

• the rate at which an organism produces energy when resting.
• For birds and mammals, this is : Basal Metabolic Rate (BMR) = 0.03 x Mass^0.7

• describes the energy radiated by a black body object as a function of its temperature. A black body is an idealized physical body that absorbs all incident electromagnetic radiation, reflecting none back (thus appearing black). Radiation from this body is expressed as the power (energy per time) emitted per area of the body’s surface, and is given by the formula: j* = eoT^4
• a. j* = radiation (per unit)
• b. e = the emissivity (the power to radiate) of the object
• c. o (Stefan-Boltzmann constant) = 5.67 x (10)^-12 W (cm)^-2 (K)^-2
• d. T = absolute temperature (Kelvin scale)
• Resulting re-radiation is expressed in watts per area.