Exam One: Learning Objectives Flashcards
What are the two experimental approaches in ecology?
comparative and manipulative
Describe an example of a comparative approach.
Surveying on algae abundance among lakes that differ in phosphorus concentrations
Describe the comparative approach
nothing in manipulated, only natural and societal process manipulate
purported cause and hypothesized effect varies
Describe an experimental approach
a hypothesized casual factor is manipulated to see if the expected effect occurs
Give an example of an experimental approach
C and N were added to the water on one side and C, N, and P were added to the other side, then was observed
What are the two key features of any good test?
large contrast in hypothesized casual factor
other factors standardized or controlled for
How does phosphorus related to algal bloom?
lakes with higher P concentration tend to have higher algae biomass
How do C and N have impact on algae?
no impact, only changes with phosphorus
The presences of zooplanktivorous fish __ __ algae abundance
strongly boosts
If you remove zooplankton and fish, algae is still __, suggesting algae does not need __ recycled by fish
high; nutrients
T/F: adding nutrients (fish pee) give the algae a __ __ but not much
a little boost
Why are models useful?
ecological properties are influenced by many factors, models decomplexify
Define an ecosystem
an area that includes all the organisms, plus all components of the abiotic environment within its boundaries
Level of organization determines the type of __ an ecologist __
question; asks
What are the levels of organization from lowest to bottom
organisms
populations
communities
ecosystems
biomes
biosphere
Old People Creep Everyone By Being Bald
Define climate
average weather conditions over time for a given place
What are four reasons climate varies across the Earth?
- spherical shape
- earth’s rotation
- distribution of continents and oceans
- topography
How does spherical shape vary climate across the earth
uneven solar heating of Earth’s surface, more solar radiation per unit area in the tropics than at the poles
How does earth’s rotation impact climate across earth?
rotation causes Coriolis effect, which redirects winds
How does the distribution of continents and oceans affect climate across the Earth?
creates high and low atmospheric pressure centers
influences direction of air and water currents that redistribute heat and water around planet
How does topography affect Earth’s climate?
influenced by elevation and aspect (direction)
heating of Earth surface and __ drives atmospheric __ and __
atmosphere
circulation; precipitation
DESCRIBE FIGURE 02.08
As Earth spins around its axis, points __ the equator travel __ than do points further north or south
nearer; faster
The difference in velocity causes a __ in air currents ( __ __ )
deflection; Coriolis effect
Describe how regional geography influences climate and thus biome
moist, warm air rises, cooling air loses moisture as rain on windward side
Dry, cool air descends and pulls water from the soils on leeward side
Why is there deserts around 30° N and S and rain at equator/ tropical rainforests?
sun heats at equator and causes moisture in the air, forming clouds causing rain
warm air rises and ascending air flows N/S and cools, as it cools it falls and sucks moisture around 30°
What are the six soil forming factors?
climate
organisms
parent material
topography
people
time
Soils have ___ and ___
composition; structure
What are the four (sometimes five) vertical layers of horizons?
Organic
Eluviated
A
B
C
Describe the organic layer of soil
almost purely organic matter; decomposing remains of once-living biomass
Describe the A layer of soil
mixture of well-decomposed organic matter and mineral sediments (sand, silt, clay)
Describe the B layer of soil
mineral material tends to be lost of clay; any organic matter is old and extremely decomposed
Describe the C layer of soil
almost entirely mineral material that is mostly broken-up bedrock
Where would you find E horizons?
acidic soils
Describe the E horizon of soil.
light colored zone of leaching
Composition and structure of soil affect how soil __
functions
Describe the climate of tropical rainforests
warm and wet year-round
little month-to-moth variation in rain and temperature
Describe the soils in a tropical rainforest
nutrient-poor, acidic, thin, and low in organic matter
Where do tropical dry forests exist?
10 - 25 °
Describe the climate of tropical dry forest
invariant temperature and highly variable rainfall
Describe the soils of tropical dry forest
old, more nutrient-rich than in tropical rain forest
Where do tropical savannas usually occur?
10 - 20° of equator
Describe the climate of a savanna
distinct wet and dry seasons with impermeable soils
Describe the climate of the mediterranean woodland and shrubland
seasonal - drought in summer, rain in winter
Discuss the climate in deserts
varies among deserts; high temperature and little rain fall
How are deserts characterized?
water loss from evaporation + transpiration exceeding precipitation for most of the year
Describe the soils in temperate grasslands
deep, fertile and rich in organic material
Discuss the climate of temperate grasslands
peaks in rain coincide with height of growing season; rain and temperature increase over summer
Temperate grasslands share similar latitudes as?
temperate forests
Discuss the climate of temperate forests
mild winters, moist growing seasons at least four months - deciduous trees dominate
drier summers and colder winters - favor coniferous forests
Where are temperate forests found?
30 - 55°
Where is a boreal forest located?
50-60°
Discuss the boreal forest climate
long and harsh winters
extreme variable, wide temperature swings
Describe where the tundra is found
encircles the globe north of boreal forests
What is the photic zone
mixed layer where light reaches the bottom
What are the layers of stratification in the photic zone?
thermal - water is less dense and floats on top of colder water
Describe the thermocline
separation of well-lit, warm, and lower density waters that separate the dark, cold, higher-density waters which is a region of rapid temperature change
Describe kelp forests
macroalgae
can gro 30-50 m
complex habitat, home to many species
high bio diversity
established on firm substrates
Describe coral reefs
clonal animals that can reproduce sexually and asexually
live symbiotically with algae
What is the result of coral bleaching?
loss of zooxanthellae
Intertidal zones and organisms are affected by extreme variation in (5)
light
temperature
wave energy
salinity
exposure to air
Intertidal zonation results in __ zonation
biological
What are the two types of intertidal zones
rocky wave exposed N. Amer W coast
soft-substrate, wave-protected E and Gulf coasts
Describe salt marshes
shoreline habitats with herbaceous vegetation
Where are salt marshes found?
temperate to high-latitude areas
Describe the biology of salt marshes
exhibit zonation of species owing to gradients in tidal inundation time and salinity
Describe the climate of mangrove forests
shoreline habitat with woody, salt-tolerant plants; intolerant to frost
Where are mangrove forests found?
tropics and sub tropics
What is an estuary?
where river meets the sea
What is a stratification of an estuary?
salinity gradient that often results in stratification as low density, low salinity water flows above high-salinity water
Define a river drainage network
branching system of streams and rivers that converge and deliver water downhill
What is the river continuum concept?
the source and fate of organic matter changes from high to low in the drainage network
Describe the river continuum concept in terms of organic matter, energy, and drainage networks
(1) energy from land sources, leaves, shredders and collectors
(2,3) some internal energy; periphyton and vascular plants; fine organic matter from upstream, grazers and collectors
(4,5) energy mostly from upstream; fine organic matter; collectors and some phytoplankton
Define the hyporheic zone
water flowing down stream through the sediments beneath the surface channel
Water can move _ or _ between surface water and hyporehic zone as it flows __
up; down
downstream
Stream/ river ecosystems extend laterally onto __ to include the __ zone
land; riparian
Define the riparian zone
transitional habitat between uplands and river or stream
Water movement through the __ zone soils helps filter it before it reaches the __ channel
riparian; surface
Define lakes
landscapes that collect water
What creates basins?
plate tectonics, volcanism, glacial activity, sinkholes
What lakes are saline?
lakes with no outflow
What is the shallow margin of lakes called?
littoral zones
What plants are found lakes
macrophytes
The open deep water of a lake is the __ zone and this zone is __ stratified
pelagic; thermally
benthic habitat =
bottom sediments
Define lake turnover
when the whole water column mixes
Define evolution
change in frequency of heritable traits; descent and modification from an ancestral form
Define phenotypic variation
variation in traits among individuals in a population
what do phenotypic variation arise from
individuals differ genetically
individuals experience different environments
What is an example of phenotypic variation?
swallowtail butterflies
Define phenotypic plasticity
capacity of a genotype to express more than one phenotype, in response to the environment
What does a reciprocal transplant experiment test for?
whether phenotypic differences between populations result
What are the three tests for reciprocal transplant experiment
i. from genetic differences between populations
ii. from environmental differences between the locations where the populations live
iii. from a combination of genetic and environmental influences
What are the necessary conditions for Hardy-Weinberg equilibrium
random mating
no mutations
large population size
no immigration
equal fitness between all genotypes
What are mechanisms that change trait and allele frequencies in a population?
mutation
selection
gene flow
genetic drift
What are two forms of genetic drift?
population bottlenecks
founder effects
What can mutations result from?
DNA copying errors
transposable elements
mutagens
What is a mutagen?
environmental agents that cause mutation
__ is the only mechanism for change in allele frequency that results in adaptive evolution
mutation
__ is the only mechanism that adapts populations to their environment
selection
Directional selection favors an __ value of a trait
extreme; beak size
Disruptive selection favors __ extremes of a trait
both; plumage
Stabilizing selection favors __ values of a trait
intermediate; egg size
What is artificial selection?
variation among individuals in ancestral populations; desirable traits are more prevalent in subsequent generations
Interbreeding can increase the frequency of?
deleterious alleles
In small populations, many alleles can become __ which means
fixed
be the only allele left for a given gene, so the gene can no longer evolve
Define the microclimate
local temperature, wind and moisture conditions that an organism actually experiences
Temperature __ differs among habitats
variation
Aspect affects __
microclimate
Peak performance occurs over a narrow __ range
temperature
Enzymes function best over a narrow __ range
temperature
Outside __ temperature range, an organism would have to invest __ energy to accomplish any biological task, which leaves __ energy for other tasks (reproduction)
optimal; more
less
Energy used for __ function is…
one; not available for others
What is the principle of allocation
given limited energy, if an organism allocates energy to one function, it reduces the amount of energy available to other functions
Discuss the concept of an evolutionary tradeoff
suggests being adapted to one set of conditions makes an organism poorly suited to other conditions
What is an example of an evolutionary trade off?
ancestral populations at one temperature reduces fitness at other temperatures
Acclimatization is generally __
reversible
What is acclimatization?
individual organisms during their own lifetime can make physiological (not genetic) adjustments to changes in their environment
Poikilotherms and body temperature
cannot regulate body temperature
Describe body temperature regulation of ectotherms
can regulate body temperature; cant use metabolic energy
Describe body temperature regulation of endotherms?
regulate body temperature and use metabolic energy
Describe the body temperature regulation of homeotherms
organisms that maintain fairly constant temperatures, using metabolic energy while regulating body temperature
What are the six H terms in heat budgets?
S - system
M - gain by metabolism
T - loss by radiation
E - loss by evaporation
Cd - loss or gain by conduction
Ev - loss or gain by convection
Adaptations that affect H help an organism?
maintain a regulated body temperature, despite variation in environmental temperature
What do ectotherms use to regulate body temperature?
behavior
Describe the inverse relationship of an endothermic plant between metabolic rate and environmental temperature
increased metabolic rate is required to maintain constant body temperature as surrounding air temperature drops
What is a method of heat conservation?
countercurrent exchange
How does breathing and countercurrent exchange help aquatic birds and mammals maintain constant body temps?
as air breathes, blood flows from warm to cold, redirects to keep appendages warm
cool blood returns and warm is sent out
By taking air into internal lungs, marine mammals avoid exposure of large __ rich surface area to __ water, thereby preventing __ loss
blood; cold
heat
What is torpor?
a state of low body temperature and low metabolic rate
Torpor is __ term
short
