FINAL EXAM Flashcards
what is geomorphology?
the study of landforms and the processes that create them
what are examples of landforms?
dune, delta, mountain, valley, hill, wash, canyon, beach, volcano, ridge, bluff
geomorphology has significant affects on the characteristics of what?
soils, vegetation, and on plant growth
how many tectonic plates exist on Earth’s surface currently?
9 tectonic plates exist and are the centers of volcanic activity
what occurs along tectonic plate boundaries?
earthquakes, volcanic activity, mountains, and ocean trench formation
what are examples of two mountain ranges that are created by convergent plate boundaries?
the Andes and the Himalayan mountains
what are examples of two volcanoes that are currently active?
Mt. Saint Helens, WA and Kilauea, HI
what is erosion?
the displacement or weathering of solids by water, gravity, ice, wind, or animals.
_______ and _______ are reduced by erosion and mass wasting
elevation and relief
what is mass wasting?
the movement of entire slopes under the influence of gravity.
Erosion and mass wasting result in _______
denudation
what does denudation produce?
produces sediment that is deposited elsewhere and will form particular landforms as a result
what are alluvial fans produced from?
alluvial fans are produced by the movement of water eroding the landform and leading to deposition of eroded materials downslope in a valley floor.
the disruption of a water course affects what?
the disruption of a water course affects what plants can and cannot grow nearby.
In relatively arid environments, what do water courses represent?
water courses represent areas that are very active for plant growth since water accumulates here (washes).
what is the main difference between large and small particle size?
large particles size has an increased infiltration rate but less total water retention. small particle size has a decreased infiltration rate but an increased long-term water retention rate.
small particles in soil experience ______ _______ during precipitation than larger particles
more runoff
large particles in soil experience _______ _______ during intense precipitation
less runoff
______ particle sizes are associated with alluvial/delta areas.
large
why are large soil particles important for plants?
large particles have a higher infiltration rate and allow more water to be available in the soil for plant growth
what is the desert paradox?
plants dependent on summer precipitation grow “better” in soils with larger pore size because there’s less runoff and more infiltration in high intensity storm events.
what are the four crucial words to sum the desert paradox?
higher rate of infiltration
who created the desert paradox?
Homer Shantz; one of the first people to use repeat photography
what is deposition?
movement of the underlying soil and rock
landslides, avalanches, glaciers, and wind can have profound affects on ___________ and _________
vegetation and deposition
what do sand dunes result from?
wind, erosion and deposition.
Sand avalanches occur on the _____ side of dunes
leward
wind speed, average direction, and topography _______ to produce a variety of different types of ______ _______
interact
sand dunes
human activity like construction, vegetation management, water diversion, agriculture, and energy use/climate change can cause what types of changes?
changes in landforms and can affect
the type of vegetation that grows there
what is weather?
all phenomena in a given atmosphere at a given time. Includes interactions with the hydrosphere.
activity of weather phenomena are over periods of _____ to _____
hours to days
weather is ultimately caused by what?
weather is caused from complicated transfers of energy; temperature differences among locations = differences in solar energy
true or false: solar energy differences can be large scale or small scale
true
what is the difference between large scale and small scale solar energy differences?
large scale: equatorial regions receive more solar energy than polar regions do.
small scale: different surfaces absorb/reflect solar energy differently.
the amount of solar radiation received is affected by the orientation of the _______ ______
Earth’s axis. summer months receive the most solar energy
differences in temperatures can cause differences in _________ _______
atmospheric pressure
with low atmospheric pressure, there is ____ weight above its location.
less
with high atmospheric pressure, there is ______ weight above its location.
more
warm air rises –>
cold air falls –>
low atmospheric pressure
high atmospheric pressure
differences in atmospheric pressure (pressure gradients) result in what?
movement from areas with high atmospheric pressure to low atmospheric pressure. results in distinctive weather phenomena.
prevailing winds are associated with global ______ of high and low _______ ________
belts
atmospheric pressure
what is the Hadley cell circulation?
the temperature near the equator is hot and heat rises until around 30-35 degrees N and S from the equator where temperatures begin to fall and cool air sinks and is drier.
what is it called when there is equal amounts liquid and vapor in the air?
equilibrium
what is it called when vapor turns into liquid?
condensation
what is it called when liquid turns into vapor?
evaporation
as air cools, the ________ rate drops more rapidly than the _________ rate.
evaporation
condensation
what is the dew point?
the temperature where there is net condensation and a cloud forms.
precipitation requires the development of some _____ _______ form of water
non vapor
describe how a rain drops form
1) ice nucleates on bacteria/dust particles
2) drops will grow thru coalescence
3) drop will fall when it reaches its critical mass
what are the different types of precipitation?
1) rain
2) drizzle (<0.5mm)
3) sleet (small ice pellets)
4) freezing rain (snow–>rain as it falls)
5) hail (ice pellets repeatedly lifted in thunderstorms)
6) snow (crystalline water ice; water condenses directly into ice crystal)
what factors impact what type of precipitation will occur?
depends on the temperature conditions and the amount of water that a drop contains
what are the three atmospheric conditions that lead to precipitation?
convectional, orographic, and frontal
what is the convectional atmospheric condition?
thunderstorms; rapid upwards movement of warm, moist air
what is the orographic atmospheric condition?
mountains; warm, moist air moves upward as wind hits a mountain (only large mountains)
what is the frontal atmospheric condition?
cyclonic; warm, moist air goes up as it hits a cold front and forms clouds.
the boundary between air masses is called a ______
front
what is a rain shadow?
A rain shadow is an area of significantly reduced rainfall behind a mountainous region, on the side facing away from prevailing winds, known as its leeward side
where is a good example of a rain shadow?
the Sierra Nevadas
describe the air flow of the North American monsoon season
-winds coming from W/NW
-midsummer: tropical moisture brought in
-daytime heating and orographic lift causes storms over high mountains
-rain-cooled air (outflow) moves to lower elevations and acts like a small scale cold front to produce storms in late afternoon and evening
what is the definition of climate?
averages and variation in weather over year long periods of time (~30+ years)
where does climate data come from?
-instruments
-written records
-tree rings*
-ice cores*
-coral*
-sediments*
- = used to reconstruct paleoclimates
what is phytogeography?
the study of the geographic distribution of plant species.
plant species present at a given site are largely reflective of ________
climate
describe the Tucson vegetation
desert shrub landscape; scattered succulents, shrubs, subshrubs, C3 and C4 grasses, saguaros. monthly precipitation is low.
what is the coupled ocean-atmosphere phenomena?
global el niño and la niña events associated with sea surface temperature anomalies >0.5 degrees celsius in central tropical E Pacific ocean. irregular intervals of ~2-7 years with a duration of ~2 years. Has widespread biological affects
what is climate change?
mean/average temperature increase associated with CO2 concentration increase. Since 1980s, we have been above the mean global temperature consistently.
how could you describe the climate of a specific region?
by describing the types of plants present
what is a community?
a group of populations that coexist in time and space and interact with one another directly or indirectly. includes plants, animals, fungi, bacteria, and all other organisms.
what are boundaries (in space) usually defined by?
boundaries are usually defined based on changes in the abundance of the most common/dominant species and are often fuzzy.
when describing a plant community, what factor is very important and may have significant affects on how you may describe the vegetation and surrounding community present?
the scale (dimensions) that you’re observing in very important
species are distributed individually based on their environmental requirements and what other 5 things?
-competition
-herbivory
-historical contingency (events that may or may not occur ex: fire or flood)
-random factors influencing colonization
-human activity
community composition (pattern) changes ________ along environmental gradients.
gradually
_____ changes in species composition are most likely where there are abrupt changes in the environment
abrupt
who was R.H. Whittaker (1950s)?
Whittaker was a plant ecologist who characterized the vegetation communities of the Santa Catalina Mountains.
What did Whittaker demonstrate?
He demonstrated that plant species do not appear and disappear at the same point along an environmental gradient.
what are 3 different ways to describe communities?
-with the dominant species “profile”
-species richness: number of species present
-species density: number of species present in a specific region/area
describe how you could you go collect species richness data
-walk through and make a list of the number of species present (must be done at different times of the year).
the experiment must be set up using a plot-based method:
-sample quadrats are laid out over a large plot of land and species lists are generated for each.
-or transects (long, narrow sampling areas) are laid out and species lists are generated for each based on the transect.
in what case would species richness not be a useful measure of biological diversity?
species richness wouldn’t be a useful measure of biological diversity if there was a community with a large majority of its composition being the same species and a small number of other single species
the number of species observed is related to the area sampled by generating a ______-_____ _______.
species-area curve
what are the two common patterns in species-area curves?
-concave: always increasing but at a decreasing rate
-sigmoid: increases but only to a certain limit then plateaus.
the more “even” a community, the more __________
diversity
what is one way to quantify the diversity in a community?
with Simpson’s index (D) which measures the probability that 2 randomly selected individuals from the same community belong to the same species.
what do high “D” values mean?
high D values = low diversity
what is physiognomy?
the 3-dimensional structure, form or appearance of a plant community; often focuses on the vertical structure. description may include life forms and function.
what is used to describe the changes or differences in a community’s physiognomy?
-vertical profile diagrams
-repeat photography
large scale (regional) patterns in vegetation are placed within units called ______ that differ in what four main things?
biomes
1) structure of the vegetation
2) dominant plant species
3) plant adaptations
4) ecological roles played by the plants
what are biomes defined by?
biomes are defined by the physiognomy of the dominant or most obvious plants
biomes are strongly determined by ______, especially what 3 factors?
climate
1) temperature
2) precipitation
3) seasonality
regions with similar ______ will contain similar ________
climates
biomes
biomes are broad, regional entities with significant _________ ________.
intrabiome variation
climate is only one factor affecting vegetation composition, what other three factors also affect this?
-soil
-human activity
-topography (the arrangement of the natural and artificial physical features of an area)
generally, what are the 5 main biomes?
1) forests
2) shrublands
3) grasslands
4) deserts
5) tundra
what is an ecosystem?
all of the living organisms in an area and all of the abiotic (non-living) materials and energy with which they interact.
ecosystems can exist over a variety of _______ and they typically _______ with other ecosystems
scales
overlap
in an ecosystem, what role do plants have?
-plants are conduits of energy and materials into different forms
-plants are factors affecting the supplies and flows of energy and materials
what are biogeochemical cycles?
pathways through which a chemical element or molecule moves through the biotic and abiotic components of an ecosystem
______ and _______ within a cycle are related through turn over time and retention time
pools and fluxes
what is turn over time?
a measure of how rapidly materials will move through that ecosystem
what is retention time?
the average length of time that something will reside in a particular ecosystem component
what is a closed system?
occurs when all chemical components are recycled
what is an open system?
occurs when something is always being added (solar energy)
what is productivity?
rate of carbon transformation from one trophic level to the next. pyramids of energy are one way to describe this
what is net primary production (NPP)?
gross primary production - respiration (uptake of CO2, H20 and energy).
what is NPP measured in?
g carbon/m^2/year
if plant growth is present, the NPP is ______
positive
NPP is broadly limited by ______
climate
inadequate temperatures –> insufficient moisture for growth –> length of growing season shorter
NPP varies greatly on a ______ scale. in ___ ecosystems, NPP tends to be directly _______ to total leaf biomass/m^2/year
continental
proportional
what are four ways you could measure NPP?
-measure standing biomass
-measure evapotranspiration
-remote censoring methods/satellites
-measuring CO2 concentrations
what are the downsides of measuring standing biomass?
-it can be destructive
-you can often only measure shoots, not roots
-hard to do over a larger area
what is evapotranspiration?
occurs when water evaporates from photosynthesizing leaf surfaces. (can’t measure NPP when both precipitation and temperatures are high)
how have remote sensing methods been useful in indirectly measuring NPP?
satellites/drones measure the amounts of “greenness” bc green plants reflect near infrared radiation. NDVI = normalized difference vegetation index
how useful is satellite imagery for measuring NPP?
not super useful
how does measuring CO2 concentrations relate to NPP?
net ecosystem CO2 exchange = CO2 in and out of an ecosystem. NPP = CO2 captured - CO2 released by plants
what is frequently used to measure CO2 uptake and release amounts by plants?
flux towers that measure different CO2 levels at different points in the atmosphere.
during daytime flux towers measure the amount of CO2 being _______ by plants and during nighttime flux towers measure the amount of CO2 being ________ by plants
uptaken
released
what factor can be problematic for flux towers to work properly?
wind because it may change CO2 concentrations
what major nutrient commonly limits individual plant growth and ecosystem productivity?
nitrogen, which also makes up plant protein components, chlorophylls, and nucleic acids.
NPP and nitrogen input are ________ and nitrogen inputs may ______ NPP
proportional
limit
there is a huge global pool of nitrogen in the atmosphere (78.08%) with a _____ overall turnover but a ______ flux through living organisms
slow
rapid
how have humans impacted nitrogen in our atmosphere?
human deposition of nitrogen has increased with fossil fuel burning, industrial fixation and livestock production
describe the process of how nitrogen enters our biosphere
nitrogen enters biosphere through nitrogen fixation which converts N2 gas into a molecular form of nitrogen that can be used by living organisms.
what preforms nitrogen fixation?
bacteria either free living in the soil or in symbiosis with certain plants. Rhizobium, Ceanothus, and Frankia Alnus are all plants that are symbiotic with bacteria
nitrogen fixation yields ________ either free in the soil where it can be taken up by roots or directly from a symbiotic organism/plant
ammonium
