Ecology

abiotic

the non-living features of the environment

controlled experiment

an experiment where the experimental group (which has the factor being tested) is compared against a control group (which lacks the factor being tested)

ecology

the scientific study of interactions btwn organisms and their enviornment

population

a group of individuals of a single species that live in a particular area and interact with one another

community

an association of interacting populations of different species that live in the same area at the same time

biotic

the living components of a natural system

ecosystem

a collection of communities of organisms plus the physical environment in which they live

landscapes

areas that vary substantially from one place to another, typically including multiple ecosystems

biosphere

all living organisms on Earth plus the environments in which they live

adaptation

a feature of an organism that improves its ability to survive/reproduce in its enviornment

natural selection

evolutionary process in which individuals that possess particular characteristics survive/reproduce at a higher rate than other individuals b/c of those characteristics

producer

an organism that uses energy from an external source, like the sun, to produce its own food without having to eat other organisms or their remains

consumer

an organism that obtains its energy by eating other organisms or their remains

NPP

Net primary production, the amount of energy that producers fix by photosynthesis, minus the amount of energy they use in cellular respiration

nutrient cycle

the cyclic movement of a nutrient between organisms and the physical enviornment

natural selection

individuals with particular characteristics tend to survive and reproduce at a higher rate than other individuals b/c of those characteristics

nutrient cycle

the cyclic movement of a nutrient btwn organisms and the physical environment

climate change

a directional change in climate (such as warming/precipitation) that occurs over three decades or longer

weather

the current temperature, humidity, precipitation, wind, and cloud cover

climate

the long-term description of weather at a given location, based on averages and variation measured over decades

greenhouse effect

when gases like CO2, methane, and nitrous oxide that are emitted into the atmosphere as a result of human activities absorb energy and then radiate it back to the surface

latent heat flux

heat loss due to evaporation

conduction

the transfer of energy that is transferred through the exchange of kinetic energy by molecules in direct contact with one another

convection

energy that is transferred through the movement of currents of air and water

sensible heat flux

energy transfer from the warm air immediately above Earth’s surface to the cooler atmosphere by convection and conduction

uplift

since warm air is less dense than cool air, so long as a pocket of air remains warmer than the surrounding air, it will rise

atmospheric pressure

the force exerted by air’s molecules on the air and surface below it

subsidence

the process of air reaching a temp similar to that of the surrounding atmosphere, and then descending toward Earth’s surface

Hadley cell

the tropical uplift of air that creates a large-scale pattern of atmospheric circulation in each hemisphere

polar cells

atmospheric circulation cells that occur at the north and south poles. cold, dense air subsides at the poles and moves toward the equator when it reaches earth’s surface. the descending air at the poles is replaced by air moving through the upper atmosphere from lower latitudes. subsidence at the poles creates an area of high pressure, so there is little precipitation.

ferrell cell

atomspheric circulation cell that exists at midlatitudes between the hadley and polar cells that is driven by the movement of the hadley and cells and by the exchange of energy between tropical and polar air masses in a region known as the polar front

tropical zone

btwn 30N and 30S

temperate zones

btwn 30N and 60N and 30S and 60S

polar zones

btwn 60N and 90N and 60S and 90S

Coriolis effect

the apparent deflection of winds due to the rotation of the earth. deflected to the right (clockwise) in the northern hemisphere and to the left (counterclockwise) in the southern hemisphere

heat capacity

the amount of heat energy required to change the temperature of an entire object or system by one degree Celsius (or one Kelvin). water has a higher heat capacity than land, so it absorbs and stores more energy with less temperature change than land

upwelling

ocean process where deep, cold, and nutrient-rich water rises toward the surface to replace surface water pushed away by winds

maritime climate

coastal terrestrial regions that are influence by an adjacent ocean, characterized by little variation in daily and seasonal temps, and often w higher humidity than regions more distant from the coast

continental climate

much greater variation in daily and seasonal temperatures, areas centered by large continental land masses

rain shadow effect

lower precipitation and soil moisture on the slopes facing away from the prevailing wind (the leeward slopes) and higher precipitation and soil moisture on the windward sides. lush plants on the windward side and sparser on the leeward side.

albedo

the amount of solar radiation that a surface reflects

evapotranspiration

the sum of water loss by transpiration and by evaporation

intertropical convergence zone (ITCZ)

the seasonal changes are associated with the movement of zone of max air uplight and precipitation in the hadley cells. the zone of max uplight corresponds with the part of the tropics where the sun strikes earth most directly, thus the ITCZ moves from 23.5N in June 23.5S in December, bringing the wet season with it

lake turnover

A lake "turns over" when the water at the surface mixes completely with the water at the bottom. This natural process usually happens twice a year in deeper lakes—once in the fall and once in the spring.

ENSO (el nino southern oscillation)

climate episodes associated with a switch/oscilliation in the positions of high and low pressure cells over the pacific, which leads to a weakening of the easterly trade winds that normally push warm water toward southeast asia. during normal conditions: cold in south america, warm in asia. la nina is stronger version of this. during el nino: warm in south america, cold in asia.

Pacific Decadal Oscilliation (PDO)

long-term oscillation in sea surface temp and atmospheric pressure. described for the north pacific after its influence on salmon numbers was discovered.

salinity

the concentration of dissolved salts in water. salts are ionic compounds made of cations (+) and anions (-) that disassociate when placed in water

salinization

when soils become more saline in arid regions as water from deeper soil layers is brought to the surface by plant roots or through pumping of groundwater for irrigation. as the transported water evaporates, it leaves its salt behind.

acidity

level of acid which are compounds that give up protons to the water they are dissolved in

allkanity

level of bases, which take up protons or give up hydroxide ions

hypoxia

low oxygen conditions

Why are regional and local physical environments important?

They determine the distribution and abundance of organisms, which creates biomes and communities

What controls regional and local physical environments

• topography

• chemistry

• geology

• organisms (including animals)

Major factors that affect regional and local terrestrial environment

• global climate

• geological topography

• soils

• organisms

• human engineering

Global climate

its a foundation for regional and local conditions

• air temperatures

• precipitation

geological topography (mountains and valleys)

• with elevation, temperature decreases

  • precipitation and windspeed increase

rain shadow effect of mountains

the windward mountain slope facing the prevailing winds has high precipitation and lush vegetation; the leeward slope gets little precipitation.

• moving air mass picks up moisture

• on windward slope, air rises & cools (releases moisture as precipitation)

• on leeward slope, dry air descends and warms (little precipitation)

the effect of valleys

they creates temperature inversions that produce extremes in temperature and air moisture

• results in morning fog and afternoon heat

temperature inversions

a weather condition where a layer of warm air sits on top of a layer of cooler air near the ground

• warm air traps the cooler and heavier air close to the ground

• cool air flows down into valleys after solar radiation ceases

• by dawn, there is cooler air in valleys and warmer air on mountaintops

soil

mix of mineral particles and organic matter

roots in soil function to anchor plants, allow uptake of nutrient and water, and habitat for small and microbial organisms

soil layers

layers are a combination of rock, minerals, and organic matter

• O horizon: Organic horizon: upper layer contains loose, somewhat fragmented plant litter. litter in lower layer is highly fragmented. Humus.

• A horizon: mineral soil mixed with some organic matter. clay, iron, and soluble organic matter are gradually leached from A horizon. Minerals w/ humus.

• B horizon: Depositional horizon. Materials leached from A horizon are deposited in B horizon. Deposits minerals and metal salts.

  • C horizon: Parent rock. Partly weathered rock.

how is soil formed?

• parental rock - igneous (magma), sedimentary (deposited sediments exposed to great pressure), and metamorphic (both igneous and sedimentary)

• climate - influences the rate of weather (temperature, rainfall, wind)

• biotic influence - break up rocks, add organic matter from decomposition

• topography - influences how much weather can occur

• time - how long weathering and decomposition have occurred

sensible heat loss

the outward transfer of thermal energy that causes a drop in temperature

evapotranspiration

the energy a body/system loses when moisture evaporates, changing liquid water into a gas w/o changing the temperature

latent heat loss

the actual amount of thermal energy consumed when liquid water changes into water vapor

deforestation and its effect on conditions

• removing trees- increases albedo, lowers absorption of solar radiation

• increases sensible heat loss

• reduces latent heat loss by evapotranspiration

• therefore, reduces cooling effects of evapotranspiration

  • net increase in temp

Human engineering’s effect on local climate

structures like cities, buildings, roads can create regional and local climate. cities can create country breezes

country breezes

urban centers trap massive amounts of heat, and at night, the hot air over the city core rises. at the same time, a surface inversion develops in the country. As a result cool air flows toward the city, producing a country breeze.

where is all the water stored?

• ocean water

• snow and ice

• fresh surface water

• ground water

• water vapor in air

• water in organisms

  • 97% of earths water is ocean, the remaining 3% is freshwater

  • of that, 75% is locked up in the polar glaciers

  • less than 1% total water on earth is available as fresh liquid for organisms to use

how are glaciers formed?

snow piles up year after year in cold places like high mountains or polar regions, more snow falls in the winter than melts in the summer over many years

factors affecting regional and local aquatic enviornment:

1. global climate

2. ocean topography

3. tides

4. chemical composition of seawater

5. organisms

6. human engineering

ways that global climate affects regional/local climates

Global climate change drives rising ocean temperatures, which directly alter regional and local climates through heat distribution, moisture cycles, and extreme weather intensification.

ways that ocean topography affects regional/local climates

Determines how much light, temperature, oxygen, and nutrients an ocean region or locale receives

• Topography exposes organisms to widely varying conditions

• Drives diverse forms and functions

ways that tides affects regional/local climates

• Moon’s gravitational pull creates a bulge of water = High Tide

• Earth rotates on an axis once every 24h

• Coasts experience 2 High Tides/24h cycle

• earth-moon-sun alignment differences result in gravitational differences that “pull” watter away from earth’s surface more or less

  • when they are all aligned- extreme high/low tides

  • not all aligned - moderate high/low tides

• also creates intertidal zones

ways that seawater affects regional/local climates

• chemical composition of seawater is constant

• but, lower salinity occurs nearshore due to terrestrial freshwater runoff, eg. estuaries where rivers meet the ocean

• ocean currents cause temperature differences in the ocean-creates a “thermal conveyer belt” of heat transfer

  • when gulfstream reaches arctic, water loses heat, becomes denser and saltier, and then sinks

ways that organisms affect regional/local climates

coral reefs and kelp forests create habitats

ways that human engineering affects regional/local climates

structures such as dams, bridges, and nuclear power plants can influence regional and local climate

• for example, dams change sediment, currents, oxygen, temperature as well as block passage for migratory fish

dune grass case study

1. dune grass was planted on the pacific coast in the early 1900s

2. it helps to stabilize the sands

   1. foredune creation: tan hills of sand

   2. stabilization of sand

   3. forest formation behind the foredune

3. effects of the hills, created by non-native dune grass:

   1. the invasions change topography, vegetation, albedo

   2. dune grasses cause a decline of native plant species richness through competition

   3. cause the decline of the western snow plover, currently listed as threatened by changing the nesting habitat

   4. BUT grasses create green infrastructure or hills of sand that can protect people and property along the coast

thus, in most cases, there are tradeoffs. the grasses are bad for some native species and can decrease the biodiversity of dine, but they are good for stabilizing sand and creating barriers to large waves that can protect people and property