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26 Cards in this Set

  • Front
  • Back
The science of ecology is defined as the study of
the interaction of organisms with their environment. In this context, environment is meant to include
both the abiotic (non-living or physical) and biotic
The response (performance) of an
organism to environmental conditions
is a function of various factors:
to its physiological, morphological and
behavioral characteristics. Enviro: surrounding conditions,
influences, or forces, by which living forms are influenced and
modified in their growth and development.
The air, water and land in or on which people, animals and plants
Examples of physical characteristics; Org. respond and Influence environ. condit. [see US w/ pollutants and acidity]
Bird beaks: seeds, insects, probing, flesh-eating, nectar-feeding.
Plants both respond to the prevailing light conditions and
influence the light environment for other plants
Human Influence
Population Growth
1) Activity 2) Population (6.5 billion) = Impact. Growth graph: in 4 generations, indiv x16.
As the population approaches the carrying capacity,
the rate of population
growth approaches zero and the population reaches an equilibrium with the
limiting resource(s). This simple model assumes that the resources are
renewable. Logistic Growth. But, often eratic beh, sudden drops.
Malthus's main contribution to economics was his theory of population,
Essay on the Principle of Population (1798). According to Malthus, population tends to
increase faster than the supply of food available for its needs. Whenever a relative gain
occurs in food production over population growth, a higher rate of population increase is
stimulated; on the other hand, if population grows too much faster than food production, the
growth is checked by famine, disease, and war.
World Population
- Change graph to orders of magnitude/log 10; Transitions. The history of human population growth encompasses three great
technological-cultural phases. During each of these phases the population
increased, with growth rates eventually slowing as the limits of human growth
are approached, limits imposed by climate, disease, food, space, and energy. Two transitions: Hunter-gath to agricult to industrial.
Photosynthesis: the process by which plants use light energy to make
food molecules (simple sugars - C6H12O6) from carbon
dioxide and water. Oxygen (O2) is produced as a by-product. Expanding
territory could increase the energy supply, but it could not raise the total that could
be applied to a single task. It is impossible to concentrate more than a few thousand
bodies on a given project, be it construction or battle.
During the first phase of human history,
dependence on plants and animals for
energy was the major constraint on
human population growth. Huntergatherer
society consisted of small,
autonomous bands of a few hundred
individuals that were dependent on the
productivity and abundance of plants and
animals that make up natural ecosystems,
and their ability to extract and utilize those
natural resources.
The Development of Agriculture
The Neolithic period (8,000-5,000 BC)
saw the development of agriculture –
the cultivation of plants and the
domestication of animals.But most importantly, it increased the quantity
and predictability of food resources –
effectively increasing the human carrying
The Industrial Revolution
The mechanical energy of animals and human labor
upon which the human population relied was to be
replaced by a much more concentrated form of energy:
COAL. Nutritional variety decreased. Farm labor 2-3% vs half of popul.
Energy Demand
By 1990’s the average global citizen deploys
about 20 “human equivalents” working 24 hrs
a day, 365 days a year – making economic
and population growth possible.
Tropical Rain Forests
**Highest NPP, High rate of Decomp;** equatorial zone (high precip); warm and wet despite some seasonality.
Tropical Seasonal Forest
A short dry season, transition zone to drought decid. Slightly less precip than TRF but still hot.
Distinct dry season but still hot. Dominated by DD (Drought Decid trees); seasonality precip; dec mean annual; Decrease in tree density & height. More grasses. 2) Absolute precip very low; defined by lack of productivity/vegetation.
Decreased Precip and Cold (hold less moisture)
TD (Temperate Decid), C (Conifer/Boreal Forest/Taiga), Tundra.
Temperate Decid
Seasonal; distinctive winter and summer. Winter decid trees. Slower rate of decomp than Trop, but more than Conifers; less coming in but more on floor.
Higher lat, 40-50 degrees above equator, temp low, short growing season. Needle leaf evergreen. Some mountain regions. **MOST CARBON IN SOIL VS TREES; LITTLE Prim Produc. Low rate of decomp.
Further north, lower temp, lose trees. Alpine tundras (Narrow extending southward on map -> distinct tree lines) Permafrost: soil permen frozen **Distinctive char of tundra. Limits zone of plant growth, physically and by cooling surface soil.
Temperate Grasslands
No trees, insuff moisture; high range after tree loss but dec precip; productive grasslands but drier (short grass per) Tall grass prairies - short - mixed grass (Gradient)
Primary Productivity
High near equator. Good for growth all yr (Trop RF); dec in grass prairies, along lat gradient and gradient of precip. Lowest in poles; deserts. NEP: considers decomp: loss in carbon by het. Difference betwn carbon in and out.
Gap in graph btwn NPP and decomp; gap greatest in conder environ; Cold = slowed decomp w/ colder soil. Diff slopes: decomp steeper/inc diff w/ NPP.
Seasonality of temp vs at equator. Lower rel hum. Low precip above/below equator. Wet and hot: Tundras, Savanna/Dry Decid, Deserts (Dry and hot)
Littoral zone
Distance btwn high and low tide; exposed w/out water. Innertidal zone shows gradients of life w/ diff phy environ.
Shallow coastal waters:
Coral Reefs (Warmer, trop waters; East coast of S. Am) vs Kelp forests (W. conast, Colder currents even at same lat). Direc of surface currents and water temp, tide.
Productivity in oceans
High in regions that are coastal and shallow, thermocline turnover, land's nutrients. Also Trop waters less produc (thermocline) Inc PP in colder regions. **See Atlantic - zone of upwelling - fisheries; horizontal finger stretching. Highest regions of productivity - opp of land (Trop Waters)**