50 Flashcards
what # of species are undescribed
5-30 million
organismal ecology is subdivided into the disciplines of
physiological, evolutionary, behavioral ecology
organismal ecology concerns hw
an organism’s structure, physiology, and (for animals) behavior meet the challenges posed by the environment
population ecology concentrates mainly on
factors that affect how many individuals of a particular species live in an area
community ecology focuses on how
interactions affect community structure and organization
in ecosystem ecology, the emphasis is on
energy flow and chemical cycling among the various biotic and abiotic components
landscape ecology focuses on
the factors controlling excahnges of energy, materials, and organisms among the ecosystem patches making up a landscape/seascape
patchiness
environmentl characteristic; every landscape/seascape consists of a mosaic of diff types of “patches”
precautionary principle
the introduction of a new product or process whose ultimate effects are disputed or unknown should be resisted
dispersal
movement of individuals away from centers of high population density or from their area of origin
one direct way to determine if dispersal is a key factor limiting distribution is to
observe the results of intentional/accidental transplants of a species to areas where it was previously absent
for a transplant to be considered successful,
some of the organisms must not only survive in the new area but also reproduce there
a transplant’s success may not be determined until
at least 1 life cycle is complete
if a transplant is successful, then we can conclude that
the potential range of the species > actual range; the species could live in certain areas wher eit currently doesn’t
when individuals seem to avoid certain habitats, even when the habitats are suitable, their distribution may be limited by
habitat selection behavior
photoperiod
relative lenghts of daytime and nighttime
wind amplifies the effects of environmental temperature on organisms by
increasing heat loss due to evaporation and convection; increasing the rate of evaporative cooling and transpiration
wind can have a substantial effect on the morphology of plants by
inhibitng the growth of limbs on the windward side of trees, resulting in a “flagged” appearance
4 abiotic factors __ are the major components of climate
temp, water, sunlight, wind
climatic factors, particularly __ and __, have a major influence on the distribution of organisms
temp and water
macroclimate
patterns on the global, regional, local level
microclimate
very fine patterns – ex, those underneath fallen log
earths global climate patterns are determined largely by
input of solar energy, planet’s movement in space
__ contribute to the patchiness of the biosphere
regional and local climate variations
earths curved shape causes
latitudinal variation in sunlight intensity
tropics
regions that lie btwn 23.5degnorth and 23.5degsouth latitude
at higher latitudes, sunlight strikes earth at an __, and thus __
oblique angle; light energy is more diffuse
earths tilt causes
seasonal variation in solar radiation intensity
bc the planet is tilted on its axis by 23.5deg relative to its plane of orbit around the sun, the tropics experience
greatest annual solar radiation input and the least seasonal variation
seasonal variations of _ and _ ______
light, temp, ; increase steadily toward the poles
march,september equinox:
equator? pole? hours of sunlight/darkness
equator faces sun directly; neither pole tilts toward sun; all regions experience 12h daylight, 12h darkness
december solstice: northerm hemipshere __, winter begins in __, summer begins in __
tilts away from sun; NH; SH
june solstice: northerm hemipshere __, winter begins in __, summer begins in __
tilts toward sun; SH,NH
as earth rotates on its axis, land __ moves __ than __, ___________ and creating __ and __
land near equator moves faster than land at poles, deflecting the winds from the vertical paths shown above; more easterly and westerly flows
cooling trade winds
blow easter to west in tropics
prevailing westerlies
west to east in temperate zones
temperate zones
regions btwn tropics and arctic/antarctic circle
high temps in tropics evaporate water from earths surface and cause warm, west air masses to rise and __
flow toward poles
high-altitude air masses (after releasing water content in tropics), now dry, descend toward earth, _____(2)
absorb moisture from land and creating an arid climate that make deserts common at 30degN and S latitudes
the air masses again rise and release abundant precipitation @
latitudes around 60deg N and S
why are the polar regions rainless and bitterly cold
air masses from 60deg latitudes flow toward the poles, where they absorb moisture and descend and flow back to the equator
when land is hotter than a large lake/ocean?
air over the land heats up and rises, drawing a cool breeze across the land
when large lake/ocean warmer than land?
air over water rises, drawing cooler air from the land to the water, replacing land’s cool air with warmer air
what causes upwelling
seasonal changges in wind patterns
what causes development of tropical deciduous forests
belts of wet and dry air on both sides of equator move slightly northward and southward w/ the changing angle of sun, producing marked wet and dry seasons around 20deg latitudes
turnover defnition
lakes, semiannual mixing of waters as a result of changing temperature profiles
turnover brings
oxygenated water from lakes surface to bottom and nutrient-rich water from bottom to surface
when do turnovers occur
spring and autumn
why do cleared areas experience greater temperature extremes than forested areas
greater solar radiation and wind currents that are established by the rapid heating and cooling of open land
2 master factors limiting geographic ranges of organisms
temp and moisture
until __ yrs ago, continental glaciers covered north armerica and eurasia
16,000
what happened to tree distribution when climate warmed
tree distribution expanded northward
biomes
major types of ecological associations that occupy broad geographic regions of land/water
__ account for the largest part of the biosphere in terms of area
aquatic biomes
marine biomes salt concentrations
average 3%
freshwater biomes salt concentrations
<1%
the largest marine biomes, the __, cover __% of earths surface
oceans; 75
photic zone
upper layer; sufficient light for photosynthesis
aphotic zone
lower layer; little light penetrates
benthic zone
at the bottom of all aquatic biomes
benthic zone made of __ and __
sand, organic and inorganic sediments “ooze”
benthic zone occupied by
communities of organisms collectively called benthos
detritus
major food source for benthos; dead organic matter; rains down from photic zone
in aquatic environments, communities are distributed according to (4)
water depth, degree of light penetration, distance from shore, open water vs bottom
(3) found in photic zone
phyto, zooplankton, many fish species
most of the ocean volume is
virtually devoid of light (aphotic zone) and harbors relatively little life
(3) found in aphotic zone
microorganisms, sparse populations of luminescent fishes and invertebrates
temperate vs tropical lowland lakes
temperate: seasonal thermocline
trop lowland: year-round thermocline
__ is low in oligotrophic lakes and high in eutrophic lakes
amount of decomposable organic matter in bottom sediments
oligotrophic lakes
nutrient-poor, oxygen-rich
eutrophic lakes
nutrient-rich, oxygen-poor if ice-covered in winter and in deepest zone during summer
oligotophic vs eutrophic lakes in terms of geologic features
oligotrophics tend to have less surface area relative to their depth
littoral zone
shallow, well-lighted waters close to shore
littoral zone inhabitants
rooted and floating aquatic plants
limnetic zone
water is too deep to support rooted aquatic plants
limnetic zone inhabitats
phyto, zooplankton and cyanobacteria
profundal zone
deep, open water, aphotic
top to bottom, lake layers
littoral, limnetic, profundal, benthic
benthic zone inhabitants
variety of invertebrate animals; species composition depends on oxygen levels
wetland
area covered w/ water for a long enough period to support aquatic plants
basin wetlands
develop in shallow basins, ranging from upland depressions to filled-in lakes and ponds
riverine wetlands
develop along shallow and periodically flooded banks of rivers and streams
fringe wetlands
occur along the coasts of large lakes and seas, where water flows back and forth b/c of rising lake levels or tidal actions; include both freshwater and marine biomes
swamps and bogs vegetation
swamps: woody plants
bogs: sphagnum mosses
wetlands are among the most
productive biomes on earth
chemical environment of wetlands
high organic production and decomposition; low in dissolved oxygens
wetlands have a high capacity to
filter dissolved nutrients and chemical pollutants
most prominent physical characteristic of streams and rivers
current
headwater streams are
cold, clear, turbulent, swift
farther downstream,
tributaries may have joined and formed a river; warmer and more turbid due to sediment
streams and rivers stratification
vertical zones, extending from surface water thru groundwater
headwaters are rich in
oxygen
chemical environment: streams and rivers; change?
salt and nutrient content of streams and rivers increases from headwaters to the mouth
headwater streams that flow thru grasslands/deserts may be rich in what vegetation
algae or rooted aquatic plants
streams that flow through temperate/tropical forests: __ is source of food for aquatic consumers
leaves and other organic matter produced by terrestrial vegetation are the primary source of food for aquatic consumers
in rivers, a large fraction of the organic matter consists of
dissolved and highly fragmented material carried by the current from forested headwater streams
estuary
transition area btwn river and sea
describe estuary flow patterns
rising tide: seawater flows up the estuary channel
falling tide: seawater flows back down again
salinity varies w/
rise and fall of tides
__ make estuaries, like wetlands, __
nutrients from the river; among the most productive biomes
__ and ___ create a complex network of tidal channels, islands, natural levees, and mudflats
estuarine flow patterns, sediments carried by river and tidal water
major producers in estuaries
saltmarsh grasses, algae (inc. phytoplankton)
b/c of the abundant food in estuaries, many marine invertebrates and fishes use them as a
breeding ground
intertidal zone
periodically submerged and exposed by the tides, 2x daily on most marine shores
intertidal zone: __ and __ levels are __high/low;
renewed w/
oxygen and nutrient levels are generally high;
renewed w/ each turn of the tides
__ zone of rocky intertidal zones has more biodiversity
lower
substrates of intertidal zones are either __ or __
rocky, sandy
oceanic pelagic biome is
vast realm of open blue water, constantly mixed by wind-driven oceanic currents
__ turn over during __
surface waters of temperate ocean areas; fall thru spring
b/c of __, the __ zone of the __ biome extends to greater depths than in __
higher water clarity, photic, oceanic pelagic, coastal marine waters
oxygen levels in oceanic pelagic biome
high
oceanic pelagic biome – __ lower than in coastal waters
nutrient concentrations
b/c they’re __, some __ areas of oceanic pelagic biome have lower nutrient concentrations than __ regions
thermally stratified; tropical, temperate
oceanic pelagic biome covers __% of earths surface
70
oceanic pelagic biome has average depth of nearly
4000 m
deepest pt in the ocean is ___ beneath the surface
> 10,000 m
__ and __ produces a surge of phytoplankton growth
spring turnover, renewal of nutrients in temperate oceans
photosynthetic plankton account ofr __ of the phtosynthetic activity on earth
less than half
reef building corals are limited to the ____
photic zone of relatively stable tropical marine environments w/ high water clarity
corals are sensitive to temps below __ and above __
18 to 20 C, 30C
corals require __
high oxygen levels
corals are excluded by
high inputs of freshwater and nutrients
corals require __ for attachment
solid substrate
coral reef
formed largely from calcium carbonate skeletons of corals, develops over a long time on oceanic islands
describe formation of coral reef
begins as a fringing reef on a young, high island
forms offshore barrier reef later in the history of the island
becomes a coral atoll as older island submerges
mutualistic relationship within corals?
unicellular algae live within tissues of corals, provides corals w/ organic molecules
__ and __ contribute substantial amounts of photosynthesis on coral reefs
red, green algae
corals are a diverse group of
cnidarians
marine benthic zone
consists of seafloor below the surface waters of the coastal zone and offshore pelagic zone
neritic
coastal
most of the oceans benthic zone
receives no sunlight
abyssal zone
very deep benthic zone; deepest regions of ocean floor
temps in abyssal zone
around 3degC
chemical environment of benthic zone
oxygen is present at sufficient concentrations to support a diversity of animals
__ cover most of the benthic zone
soft sediments
photosynthetic organisms, mainly __ and __, ae limited to __
seaweeds, filamentous algae;
shallow benthic areas w/ sufficient light to support them
deep-sea hydrothermal vents are of __ origin; located on __
volcanic; mid-ocean ridges
deep-sea hydrothermal vents: describe environment
dark, hot, oxygen-deficient environments
deep-sea hydrothermal vents: food producers are
chemoautotrophic prokaryotes that obtain energy by oxiding H2S formed by hot water reacting w/ dissolved sulfate
more animals associated w/ deep-sea hydrothermal vents
giant tube dwelling worms
giant tube dwelling worms are nourished by
chemosynthetic prokaryotes that live as symbionts within the worms
invertebrates such as __ and __ are abundant around hydrothermal vents
arthropods and echinoderms
beyond the photic zone, most consumers depend entirely on
organic matter raining down from above
neritic benthic communities include __ and __
numerous invertebrates and fishes
most impt abiotic factor in determining why a particular terrestrial biome is found in a certain area
climate
climograph
plot of temp and precipitation in a particular region
northern coniferous vs temperate forests; precipitation and temp
precipitation ranges are similar. temp ranges diff
temperate grasslands found where
in middle latitudes
forest layers top to bottom
canopy, low-tree stratum, shrub understory, ground layer of herbaceous plants, forest floor (litter layer), root layer
ecotone
area of intergradation btwn biomes
taiga
nothern coniferous forest
in many biomes, the doinant plants depend on
periodic disturbance
tropical rain forests precip
rainfall constant; 200-400 cm per year
tropical dry forests precip
highly seasonal; 150-200 cm; 6-7 month dry season
tropical forest temp
25-29C; little seasonal variation
__ genrally cover forest trees
epiphytes such as bromeliads and orhcids
__ dominant in tropical rain forests (vegtation)
broadleaf evergreen trees
2 types of plants common in tropical dry forests
thorny shrubs, succulents
deserts distribution
occur in a band near 30deg latitudes OR other latitudes in the interior of continents
deserts precip
low and highly variable; <30 cm per year
desert temp
variable seasonally and daily;
hot deserts: >50degC
cold: < -30
savanna distribution
equatorial and subequatorial regions
savanna precip: rainfall and dry season
rainfall: seasonal; 30-50 cm per year
dry season: up to 8 or 9 mo
savanna temp
warm year-round, averaging 24-29 C
temp in savanna vs tropical forests
savanna has more seasonal variation
dominant vegetation in savanna
scattered trees; thorny w/ reduced leaf surface area
chaparral distribution
midlatitude coastal regions; far-flung distribution
what’s chaparral called in north america
chaparral
what’s chaparral called in france
garigue, maquis
what’s chaparral called in south africa
fynbos
what’s chaparral called in spain and chile
matorral
chaparral precip
highly seasonal. rainy winters, long and dry summers. 30-50 cm per year
temp: each season and daytime
fall, winter, spring: 10-12C
summer: 30C
daytime max: >40C
adaptations to drought in chaparral
tough evergreen leaves of woody plants, which reduce water loss
chaparral dominated by (4)
shrubs, small trees, high diversity of grasses and herbs
describe plant diversity in chaparral
high; many species confined to a specific, relatively small geogrphic area
temperate grassland latitudes
north and south of 23.5deg lat
temp (winter and summer) for temperate grassland
winter: cold. avg temps < -10C
summer: hot. approaching 30C
precipitation in temperate grassland
precipitation is highly seasonal; dry winters, wet summers. 30 - 100cm annual prrecip; periodic drought common
temperate grassland dominant plants (2)
grasses and forbs
(2) animals temperate grasslands
large grazers; ex: bison, wild horses
burrowing mammals; ex prairie dog
coniferous forest distribution
broad band across northern North America and Eurasia to the edge of the arctic tundra; btwn 50degN and arctic circle
coniferous forest precipitation
30-70cm. periodic droughts are common.
seasons coniferous forest
cold and long winters; hot summers
temp coniferous forest
-70C; over 30C
wat vegetation dominates fonierous forests
cone-bearing trees
conical shape of conifers does what
prevents too much snow from accumulating and breaking their branches
temperate braodleaf forest distribution
midlatitudes in Northern Hemisphere; smaller areas in New Zealand and AUS
temperate braodleaf forest precipitation
70 to >200 cm annually. significant amounts of precip fall during all seasons
temperate braodleaf forest temperature and seasons
winter temps: around 0C summers: max near 30C, hot and humid
a mature temperate broadleaf forest has
distinct, highly diverse, vertical layers
layers of temperate broadleaf forest
closed canopy, 1 or 2 strata of understory trees, shrub layer, herbaceous stratum
dominant plants in Northern Hem temperate braodleaf forest
deciduous trees
deciduous trees
drop leaves before winter, when low temps would reduce photosynthesis and make it difficult to take up water from frozen soil
dominant plants in AUS temperate braodleaf forest
evergreen eucalyptus
animals in NorthernHem temperate braodleaf forest
winter: mammals hibernate; birds migrate
tundra distribution
covers expansive areas of the Arctic. 20% of earths land surface
alpine tundra
plant communities similar to those of the tundra biome; created by high winds and cold temps; occur on very high mountainstops at all latitudes, even tropics
tundra and alpine tundra precip
T: 20-60cm annually
AT: >100cm
tundra temps and seaosns
winters: long and cold; averages < -30C
summers: short, avg < 10C
vegetation of tundra mostly
herbaceous
permafrost
permenantly frozen layer of soil; generally prevents water infiltration
tundra animals
- resident
- migratory
- use as breeding grounds during summer
musk ox; caribou and reindeer; birds
human impact on tundra
focus of signifciant mineral and oil extraction in recent years /
