Review Questions Flashcards
Ecology
Scientific investigation of the interactions among organisms and between organisms and their physical environment
AKA - “quantified natural history”
1866 - Ernst Haeckel: “oikos” - house + “logos” - study of
Ecology has also been called ____________?
“quantified natural history” -has origins in natural history
Biotic Components
Living things
Abiotic components
physical and chemical factors
Biome
environment defined by certain climate and geographic attributes
-historically defined by predominant plant types
Climate
the average atmospheric conditions and the extent of their variation over period of time -partially determined by solar input
Deciduous trees
predominant plants in temperate deciduous forests
Soil Profile
Top to Bottom
- organic
- topsoil
- subsoil
- weathered or decomposed rock
- bedrock
Topsoil
“Humus” - bacteria and fungi (decomposer organisms)
Bedrock
solid rock, bottom layer of soil profile -lots of granite
Coastal Zone
Shallow location max 200m depth
- highest dissolved O2 -fresh water input
- tidal action -fairly shallow
- high primary productivity
- lots of plant life
- divided into 2 zones: *littoral zone and *intertidal zone
Intertidal Zone
2nd part of coastal zone
- where waves crash btwn low and high tide water marks
- animals there adapt to change………..
Littoral Zone
- sand, sand dunes, “beach” by ocean
- by lakes, zone characterized by rooted plants
Pelagic Zone
-open ocean (dark blue water) -lots of floating things (plankton) -animals, plants
Photic Zone
-as far as light can reach (~200m deep) -90% of ocean life in this zone
Aphotic Zone
-too dark, no sunlight -no photosynthesis
Benthic Zone
ocean floor contains “bottom dwellers” -0.000 m deep to ~10,000 m deep (Abyssal zone) -critters able to live at deepest depths bc of thermal vents
Limnetic Zone
“lake”, no more rooted plants, deeper water
Anoxic
not enough dissolved oxygen to sustain normal life
Ecological Heirarchy
- Organismal: single organism
- Population: one species
- Community: multiple species interaction
- ecosystem: mult species + other abiotic components
- biosphere: global scale
Organismal Ecology
“what factors limit population size in habitat?”
Population Ecology
*one species only “what factors determine diversity of certain species in this habitat?”
Community Ecology
*multiple species interactions “what processes cycle nutrients in ecosystem?”
Ecosystem Ecology
*Multiple species and other non-living processes “how do ecological processes contribute to functioning of global ecosystem?”
Biosphere Ecology
*global scale
Which terrestrial biome is Greensboro found?
“Temperate Deciduous Forest” AKA temperate seasonal forest
Predominant Plants in Temp. Deciduous Forests and “layering” of plants
Deciduous trees are predominate plants -canopy trees: provide shade for organism -Understory trees: beneath canopy, aka ornamentals (ex dogwoods, holly), bloom earlier than canopy trees as to not be shaded out -Forest floor: ferns, lilies, cane, also flower early
Terrestrial Biomes
-rich diversity of animals here -migratory birds -mammals -amphibians -reptiles -insects (love NC!)
What is the highest geographic point in NC? What is the lowest?
Highest: Mt. Mitchell (6684’) Lowest: any beach (at sea level)
Identify the “zones” you would encounter at the NC coast if you started walking from a sand dune outward into the open ocean. What characteristics define each “zone” (in other words, how would you know that you’ve left one zone and entered the next one)?
- Coastal zone 2 sections:
1) littoral zone- beach,
2) intertidal zone where the waves crash between high and low water marks of tide - After the coastal zone is continental shelf- a steep drop
- Pelagic zone is the ocean floor once the shelf drops (open ocean)
Which of these zones of the marine habitat has the greater primary productivity: the coastal zone or the pelagic zone? Why?
coastal regions
Which of these zones of the marine habitat has the greater primary productivity: the photic zone or the aphotic zone? why?
-Photic zone- 90% of ocean life contained ~200 m from coast/water -^as deep as the light reaches
Identify the “zones” you would encounter at a Greensboro lake if you started walking from the shore line outward into the middle of the lake. What characteristics define each “zone” ?
Distance from shoreline:
- Closest: littoral zone: Characteristic: rooted plants
- Next: limnetic zone “limne”
Lake Depth
- Photic zone- living. diatoms etc.
- Aphotic zone- no light
- Benthic zone- lake floor or substrate
Describe the process of nutrient turnover in a typical temperate lake. At what times of the year does this occur in lakes in North Carolina?
Nutrient turnovers 2/yr -Summer- more solar energy warms water photic temp increases whereas the deeper light is coolers between 20 and 6 C. -Thermocline- where the water gets colder (4 C at bottom where the water is deepest is the most dense and in fall) -the water cools and and the 4 C water will sink creating bottom top cycle displacing nutrients. Same thing occurs upon warming in the spring They are necessary for organisms to have nutrients like phosphates and oxygens and ex) algae soaking up oxygen in spring
What processes can result in anoxic conditions in lakes?
when too much oxygen dissolved o2 is soaked up to sustain normal life
Why is it less likely for streams and rivers to have anoxic conditions compared to lakes and ponds?
Chance of anoxic conditions low because moving water picks up oxygen
What does it mean to say that Greensboro is in the “Cape Fear River Basin”?
Buffalo creek -> haw river -> deep river -> cape fear –>We’re in cape fear river basin -Cape fear goes to southport, NC
What causes water in estuaries to have varying salinities? Why is it important to protect estuaries from overdevelopment?
Freshwater and saltwater meet = estuary -Salinity varies- “brackish water” concentration varies over time 0.5%-3.5% -Changes with the tide and distance from oceans -Increase of biodiversity -Many larval stages of marine animals here
Population
individuals of the same species simultaneously occupying the same general area, utilizing the same resources, and influenced by similar environmental factors
Populations have:
- a size
- a boundary
Population Density
Number of individuals per unit of area or volume (means you have to establish the population size, by direct counts - ex. census every 10 yrs, or estimation techniues - ex mark-recapture)
Direct Counts:
Census: -not everybody counted for various reasons
Techniques to Estimate Pop Size:
-count only in representative plots -count burrows, droppings, nests, tracks -mark-recapture Problems: animals figured out capturing technique
Mark-Recapture Equation:
N= [(# of captured 1st time)x(# captured 2nd time)] / # of marked recaptured
Population Dispersion
Spatial distribution of individuals –individuals exhibit a continuum of 3 general patterns of dispersion w/ respect to other individuals 1. clumped: -protection -due to resources, stay near 2. Regular -some space around each one -displayed by territorial organisms 3. Random -rare to see in nature with animals, common with plants (they don’t decide where seed grows)
Population Dispersion: Clumped
- clumped: -protection -due to resources, stay near
Population Dispersion: Regular
- Regular -some space around each one -displayed by territorial organisms
Population Dispersion: Random
- Random -rare to see in nature with animals, common with plants (they don’t decide where seed grows)
Equation Determining Changes in Population Size
N = N0 + (B-D) + (I-E) NO: initial pop. size B-D: births - deaths I-E: immigrants - emigrants
Demography
Can help us predict changes in population size
Age Structure
?
Sex Ratio
?
Age Structure and Sex Ratio:
- birth rates higher when you have a lot of reproductively active adults
- percent of reproductive-age females has a bearing on birth rates
- death rates higher when you have a lot of really old or really young
- all together - predictions for change in population size
Survivorship
the fraction of individuals that survive from birth to different life stages or ages
Survivorship Curves - Type 1
Physiological or “late loss”
*Survivorship: high through adulthood
*Parental Care: Considerable
*Fecundity: Low
*# Reproduced/Lifetime: iteroparity
*Examples: humans, large mammals
Survivorship Curves - Type 2
Ecological or constant loss
*Survivorship: constant decline through adulthood
*Parental Care: Some
*Fecundity: Low
*# Reproduced/Lifetime: iteroparity
*Examples: birds, smaller mammals
Survivorship Curves - Type 3
Maturational or Early Loss
- Survivorship: low for juveniles, high for adults
- Parental Care: little to none
- Fecundity: High
- # Reproduced/Lifetime: semelparity
Examples: insects, some fish, annual plants, inverts
Fecundity
Number of offspring per birth event
Iteroparity
multiple chances at reproduction (type 1 and 2)
Semelparity
reproduce once (type 3) ex: insects, some fish, invertebrates like clams, oysters, annual plants
Population Growth Models
pop ecologists can predict changes in pop size by various methods:
- quantifying birth and death rates
- lab analysis
- manipulating natural settings
- mathematical models
Exponential Growth
- J-Shaped curve
- only the physiological capacity of the organism limits growth
- under ideal conditions a population grows at the fastest rate possible
- many populations show exponential growth in the short term, but can’t sustain long term
dN/dt = rN
Logistic Growth
- s-shaped curve
- applies to most populations –> when population growth levels off as it approaches carrying capacity (K)
dN/dt = rN [(K-N)/K]
[(K-N)/K] is called what? What is relationship between N and K? From what equation?
- [(K-N)/K] = environmental resistance
- when N=K pop. growth stops, aka ZPG (zero population growth)
- from logistic growth equation: dN/dt = rN [(K-N)/K]
In growth equations, rN is called what?
biotic potential
In growth equations, what does dN/dt stand for?
Rate of change in size of population over time
In growth model curve graphs, what are x and y axis?
x: year y: # of people born
Equation using birth and death rates to predict population size? What is relationship between them?
population ecologists model prediction: r = b-d
b >d - positive r and population grows
b <d></d>
<p>b=d -ZPG (zero population growth)</p>
</d>
What are ideal conditions to allow for exponential growth?
- ample food
- ample habitat
- No predators
- Low wastes
Reasons exponential growth cannot be sustained long term?
When population size increases there is:
- less food
- less habitat
- more competition
- higher wastes
—> b gets smaller and d gets bigger
What does K stand for in dN/dt = rN [(K-N)/K]
K = carrying capacity
- used in the modified formula for predicting population growth
- when population is growing exponentially, environmental influences often change our predictions ab future population change, and growth levels off as it approaches carrying capacity
- modified formula takes into account K, and therefore:
- resource availability
- habitat space
- crowding
- energy availability
What factors limit population growth?
- density-dependent factors
- density-independent factors
- most natural populations are controlled by some combo of both ex: cold snaps kill lots of animals (density-indep), then those survivors must compete for limited food sources (density-dep)
Density-Dependent Factors
variables that exert greater influence on population size when population has high density -usually biotic factors:
- food supply/competition
- predators
- pathogens
Density-independent factors
variables that influence population size regardless of population density
- usually abiotic factors:
- weather events (hurricanes, tornados, etc)
- fires
- floods
Bust-Boom Cylce
sometimes population sizes change in “bust-boom cycles” that oscillate up and down ex - pred/prey relationships, a rhythmic cycle where if one goes up it affects other and vice-versa
r-stategists:
J-shaped or exponential curve -ex: bugs
k-stategists:
S-shaped or logistic curve -ex: big mammals *humans
What are the two big concerns of population ecologists in their research?
- What is the size?
- What factors cause the size to change?
How can an age structure pyramid be used to make predictions about the future change in a human population?
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What is meant by a species’ “life history strategy”?
?
Describe the trends in human population growth on this planet for the past 10,000 years. What has accounted for these trends?
?
Two measurements made with respect to populations:
- Population Density
- Population dispersion
What are the factors that determine Earth’s carrying capacity for humans? Have human population growth rates slowed in recent years? Why (or why not)?
Carrying capacity- Earth
- Improved crop yields, but still starvation and malnutrition
- Because transportation is limited
- Land use issues:
Ex) tropical rain forest for animals and plant growing (forms)??
-Accumulation of toxic wastes
Changing the future
- Contraception helps decrease birth rates
- ZPG programs by government decreases BR: Ex) china 1 child per home
- Change in cultural evolution
Community
individuals of different species simultaneiously occupying the same general area, utilizing the same resources, and influenced by similar environmental factors they have: -species interactions -boundaries
Coevolution
a change in one species that acts as a selective force on another species ex- passion flower vies and butterfies
Consumption
“predation”
Predator
the “eater”
Prey
the “eaten”
Cryptic Coloration
camouflage, coloring that conceals or disguises an animal’s shape
aposematic coloration
warning colors or poisons
Mimicry
made to look like smoothing else ex) banding patterns in non-poisonous king mtn. snake. Or sea dragon looking like sea weed.
Consumer-Resource
AKA Predation: +/- predator (the eater) and prey (the eaten) - host organism usually not killed, usually just weakened
parasite
“the eater”
host
“the eaten”
mutualism
+/+ -requires coevolution of both species -examples: pollinators and plants, frugivores and plants, nitrogen-fixing bacteria and plants, termites/ruminant animals and microbes
competition
- /-
- interspecific competition: two or more species in same community attempt to utilize the same limited resources
- one species will be more efficient at utilizing resources and will survive so other organism either moves, adapts, or dies off
- played a major role in shaping current ecological relationships:
- resource partitioning
- character displacement
- population density changes
niche
how an organism “fits” in the community (where, when, how….etc.)-
“competitive exclusion principle”
G.F. Gause (1934) says two species cannot compete for same limiting resources and still coexist in the community -experiment with paramecium -one species will be more efficient at utilizing resources and will survive -what are options for “other” species? -move/find diff habitat -adapt (change niche slightly) -die off/ go extinct *this is what most often happens
species richness
of different species present -species rich communities use resources more efficiently and are more productive (ex: study at U. of Michigan w/ diff species of grasses
species evenness
frequency of appearance of a species
species diversity
accounts for the frequency w/ which species appear in the community and the # of diff species species diversity = richness + evenness
monoculture
one species present, farmers eliminate weeds and herbivorous insects (pesticides) to grow only one crop =low species diversity -more susceptible to insect outbreaks
polyculture
-more crop diversity = increased productivity -becoming more common because: -more efficient users of nutrients and h20 -less vulnerable to pest attacks -decreased risk of catastrophic crop failure due to weird weather
ecological succession
pattern of change in community composition following a disturbance -primary succession -secondary succession -cyclical succession
commensalism
+/0 -symbiont (the moocher, one that is benefited) and the host (gets no apparent benefit) -through evolution, the symbiont continues to get a benefit -ex: cowbirds, army ants tropical birds
Amensalism
-/0 -one participant harmed, the other unaffected -accidental relationship to the biology of participants -identifiable evolutionary dynamic?? PROB NOT! ex: bison crushing/ killing grass/insects/etc
What are common adaptations of predators that make them more successful predators?
-acute senses -attack structures (claws, teeth, stingers…) -speed and agility to pursue food -camouflage (to “sneak up” on food) -camouflage ( to attract food)
What are common adaptations of prey that better enable them to avoid predation?
For plants:
- structures to make the plant difficult to eat (thorns, hooks, spines, crystals)
- distasteful chemicals (nicotine, poisons)
- insects hormone analogs
For animals:
- active: fleeing, self-defense, alarm calls, distraction, direct attack, mobbing
- passive: cryptic coloration, shape of body, deceptive markings, aposematic coloration
- mechanical, chemical (toxic chemicals, ink, spray, quills)
- mimicry
What are common adaptations of parasites that make them more successful parasites?
-able to locate and feed on host (passive or active) -specificity for the host species -could remain undetected by host (ex: ticks)
What are common adaptations of hosts that better enable them to mitigate harm from the parasite?
-toxins -immune system
“competitive exclusion principle” What does it say? Who came up with it, and how? Conclusions?
G.F. Gause (1934) -two species cannot compete for the same limiting resources and still coexist in the community -Gause did experiment with paramecium -one species will be efficient at utilizing resources and will survive -what are options for “other species”? 1. move/find diff habitat 2. adapt (change niche slightly) 3*. die off/ go extinct - most often happens
what are the three ways in which species can avoid “competitive exclusion”?
- Resource partitioning - ex move to diff part of tree to avoid other species
- character displacement: where phenotypes change overtime - ex. beak size in Galapagos islands
- population density changes
What two factors must be considered when determining species diversity in a community?
- species richness 2. species evenness
What is equation to measure species diversity?
species diversity = richness + evenness
What experimental evidence suggests that polycultures are better agricultural practices than monocultures?
11-year study from U. of Minnesota: -plots have btwn 1-35 species of grasses -even if individual species weren’t efficient users of resources, the overall community was stable -species richness = more productivity = better use of resources = more biomass ***More diversity = more productivity, more efficient users of nutrients and water, less vulnerable to pest attacks or crop failure due to weather -
List some natural disturbances to communities.
-storms -fires -floods -freezes -draughts
List some animal-caused disturbances.
-overgrazing -damaging communities -removal of organisms -altering resource availability (e - draining pond or lake) -intro of exotic species
Primary Succession
-all existing life stripped away, exposing bare substrate -ex: volcanoes, fires -1st moraine leads to lots of bacteria, fungi, microbes, then come lichens, moses, shallow rooted herms (1st plants), then shruby willows, alders, more nitrates/minderals in soil to grow bigger, then after ~120yrs, spruce trees emerge and turns to spruce forest (climax) -pioneer plants > alders > transition stage > climax
Secondary succession
-AKA “old field succession” -some life still left behind, usually soil organisms year after disturbance - organisms present: 1 - grasses, weeds 2 - taller grasses, broomsedge 3 - blackberries, shrubs 4-6 - pine trees, seedlings 6-20 - pine forest w/ hardwood seedlings up to 40yrs - pines, hardwoods 60-80yrs - hardwoods (pines die off, shaded out) ~150yrs - mature deciduous forests (climax community)
r-selected species vs k-selected species in secondary succession
r-selected: early stages (up to ~4yrs), want to reproduce as much and as fast as possible (grasses, weeds, broomsedge, blackberries, shrubs) k-selected species: replace r-selected over time b/c of competition
Cyclical succession
periodic disturbances, such as forest fires in pine forests -can wipe out plant life, but succession follows and can be rejuvenating for community -can also happen in grasslands
Ecosystem
all the organisms living w/in a given area and the abiotic factors w/ which they interact -boundaries of an ecosystem are investigator-defined
Trophic levels
levels distinguish way in which energy is obtained -producer -consumer -decomposer
Food Chain vs Food web
food web is more appropriate/ correct version of food chain -describes relationship b/c organisms at diff trophic levels
Producer vs Consumer vs Decomposer
….
Biomass
=weight of dry organic matter per unit of area
Productivity
…
What is the ultimate source of energy for all ecosystems on this planet? And what organisms can directly access it?
the sun, producers
Charles Elton and his “claim to fame”
-his research in the Arctic in 1920s -trophic levels -pyramids of numbers, biomass, and energy
The 3 Eltonian Pyramids
-Pyramid of numbers -Pyramid of biomass -Pyramid of energy
Why do plants utilize so little of the electromagnetic energy that is sent out from the sun?
…..
Gross Primary Productivity vs Net Primary Productivity
GPP: the amount of solar energy that plants can convert to chemical energy by photosynthesis -generally accepted to be 2% of total solar energy NPP: the amount of chemical energy that plants store away in the tissues after photosynthesis -energy is accessible to animals -generally accepted to be 10% of GPP -Plants use most of GPP for respiration, reproduction (R) NPP = GPP - R
Raymond Lindeman
studies energy flow dynamics in Minnesotan Bogs 1942
- discovered animals store only about 10% of chemical energy as biomass
- animals use 90% for respiration, undigested materials, not eating all available food
Moral: food chains can’t be too big
If humans wanted to access the most energy from the sun, at what trophic level should they be in a food chain?
…
Describe water (hydrologic) cycle
….
Describe carbon cycle
….
Describe the nitrogen cycle
…
Describe the phosphorous cycle
…
Discuss the negative impact of human disturbances in the carbon, nitrogen cycles, and phosphorus cycles
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What are the two processes that happen at ecosystem level that aren’t defined in lower levels of ecological hierarchy?
-energy flows -nutrients cycle
Herbert Bormann and Gene Likens
studied in hubbard brook experimental forest 1963
- 60% of h20 added exits w/ streams
- 40% exits via EVAPOTRANSPIRATION
