-
spots on reef fish that looks like an eye and confuses predators
deflection spots
-
interspecific interaction that benefits both species
mutualism
-
2 examples of mutualism
- bird dentist cleaning alligator teeth
- plants give nectar to insects, insects pollenates
-
coevolution example
- Acacia trees & ants
- ants attack herbivores
- cleans to prevent fires
- get home and food(nectar)
- *trees w/no ants=no hallow thorns
-
one species benefits and the other is apparently unaffected
commensalism
-
why isn't cattle/birds & algae/turtle shells good examples of coevolution?
- birds eat ectoparasites and give warning call of predators=benefit to cattle
- turtle is camouflaged with algae, takes more energy to swim
-
reciprocal evolutionary adaptations of two interacting species
coevolution
-
2 caveats to coevolution
- loosely used to describe adaptations in community
- little evidence in most interspecific interactions
-
two types of species that exert strong controls on community structure
-
two fundamental features of community structure are
- diversity and feeding relationships
- tropic interactions
-
variety of organisms that make up the community
species diversity of a community
-
two components to species diversity of a community
- species richness
- relative abundance
-
total number of different species in the community
species richness
-
proportion each species represents of the total individuals in the community
relative abundance
-
feeding relationships between organisms in a community
*key factor in community dynamics
trophic structure
-
what links tropic levels from producers to top carnivores
*energy flow through system
food chains
-
equation to determine diversity and richness
Shannon weaver index
-
percent of lose for each step in a food chain
90%
-
what is at the bottom of the terrestrial & marine food chain
-
branching food chain with complex trophic interactions
food web
-
two hypothesis of why in each food chain in a food web is usually only a few links long
- 1. energetic hypothesis
- 2. dynamic stability hypothesis
-
food chain length is limited by inefficient energy transfer
energetic hypothesis
-
long food chains are less stable then short ones
dynamic stability
-
what hypothesis on limits on food chain length has the most data to support it?
energetic hypothesis
-
species that are most abundant or have the highest biomass
dominant species
-
what two things does the dominant species exert power over of other species?
occurrence and distribution
-
two hypothesis to explain dominant species
- 1. most competitive in exploiting resources
- 2. most successful at avoiding predators
-
species that are not necessarily abundant in community but exert strong control of community ecological roles, or niches
keystone species
-
actions that ripples through a system
eg. keystone species
tropic cascade
-
two examples of keystone species
-
organisms that exert influence by causing physical changes in environment that affects community structure
- ecosystem engineers
- foundation species
-
example of a foundation species having a negative affect on the community
- nutria-overgrown muskrat
- brought here for fur pelts, they escaped & population boom
- creating mud flats
-
model of community organization proposes a unidirectional influence from lower to higher tropic levels
bottom-up model
-
model proposes that control comes from the trophic level above
top-down model
-
example of bottom-up model
- phytoplankton
- base of food chain,
- none of these=no energy in system
-
what can help restore polluted communites
biomanipulation
-
a model that describes communities as constantly changing after being buffeted by disturbances
nonequilibrium model
-
an event that changes a community, removes organisms from it, and alters resource availability
disturbance
-
what 2 factors determine magnitude of impact on community response for a disturbance
intensity & frequency
-
disturbance hypothesis that suggest moderate levels of disturbance can foster higher diversity
intermediate disturbance hypothesis
-
most widespread agents of disturbance
humans
-
affects of human disturbance/nondisturbance
- -reduces species diversity
- -prevent naturally occurring disturbances
-
-
species that consumes dead materials
detritivore
-
sequence of community and ecosystem changes after a disturbance
ecological succession
-
occurs where no soil exists when succession begins
bare, starting point
- primary succession
- sand dunes, receded glacier
-
begins in an area where soil remains after disturbance
pushing to earlier time
- secondary succession
- cutting trees
-
plants(conifers need sun to grow)
shad intolerant
-
example of human disturbance preventing naturally occurring events
- hoover dam/Colorado river/lake mead
- have release of water to clean out debry & system
- -flushing effects
-
3 ways a species can change environment for future species
- facilitate appearance/make more favorable
- inhibit establishment
- tolerate later species/no impact
-
in what ways can early-arriving species inhibit establishment of later species?
secrete chemicals that prevent growth
-
rice farmers in CA were paid to flood land, why?
pop up wetlands good for migratory birds
-
what are pop up wetlands good for? 2 terms
- increase biodiversity
- reconciliation ecology
-
a valuable field-research opportunity for observing primary succession
retreating glaciers
-
two key factors correlated w/community's species diversity are:
-
Species richness declines probably due to history and climate
Equatorial-Polar gradients
-
where is species diversity the greatest?
tropics
-
what is the primary cause of latitudinal gradient in biodiversity?
climate
-
two main climatic factors correlated with biodiversity:
- solar energy
- water availability
-
term for measuring solar energy and water availability in a community
community's rate of evapotranspiration
-
evaporation of water from soil plus transpiration of water from plants
evapotranspiration
-
this curve quantifies that a larger geographic area has more species
species-area curve
-
what does species richness on islands depend on?
- island size
- distance from mainland
- immigration
- extinction
-
model showing the balancing number of species on an island
island equilibrium model
-
2 hypothesis on community structure emerged:
- integrated hypothesis-Clements
- individualistic hypothesis-Gleason
-
hypothesis that describes a community as an assemblage of closely linked species/locked into association by MANDATORY biotic interactions
who's is it?
- Integrated hypothesis
- Clements
-
hypothesis that proposes that communities are loosely organized associations of independently distributed species with the same abiotic requirements
who's is it?
- individualistic hypothesis
- Gleason
-
what does the individualistic hypothesis predicts on how each species is distributed
according to its tolerance ranges for abiotic factors
-
this model suggests that all species in a community are linked in a tight web of interactions
rivet and redundancy models
-
model that proposes that if a species is lost, other species will fill the gap
-AND that loss of even a single species has strong repercussions for the community
rivet and redundancy models
-
consists of all organisms living in a community, as well as the abiotic factors with which they interact
ecosystem
-
range of ecosystems
microcosm(aquarium)->large area(lake or forest)
-
two main processes involved with dynamics o ecosystem
- energy flow-through system
- chemical cycling-inside system
-
how do ecologists view ecosystems?
as transformers of energy and processors of matter
-
laws of physics and chemistry apply to ecosystems, so energy is conserved but....
degraded to heat during ecosystem processes
-
flow of energy and nutrients in trophic relationships
- primary producers(autotrophs)->
- primary consumers(herbivores)->
- secondary consumers(carnivores)
-
Flow of energy in an ecosystem
light->chemical->heat
-
what connects all trophic levels and how?
- decomposition
- bc we die, rot and provide nutrients
-
what recycles essential chemical elements by decomposing organic material and returning elements to inorganic reservoirs
name 2
- detritivores
- bacteria & fungi
-
what are we determining when frogs are blended, drained and dried in oven?
- ecological energies
- calories required to live
-
term for the fraction of energy stored in food that is not used for respiration by organism
production efficiency
-
funny story about Standora researching production efficiency of turtles
poop condom filled with farts
-
percentage of production transferred from one tropic level to the next
Trophic efficiency
-
-
typical percent of energy used for growth of animal from food
5% to 20%
-
things that settle to the bottom
-nutrients to the bottom of the ocean
sedimentary
-
what is happening to pigs right now in America -what is it relevant too
-how many deaths
-percentage
- PEDv
- density dependent via disease
- 7 million deaths since June
- 10% of US hogs
-
PEDv
porcine epidemic diarrhea virus in pigs
-
what follows a succession on the moraines in Glacier Bay, AK
predictable pattern of change in vegetation and soil characteristics
-
2 plants and ways they are modifying habitat for the next generation(primary succession)
- spruce needles lower the pH of the soil 7->4
- Alder releases N2 into soil
-
number of times more tropical growing season is compared to poles
5X
-
who made the idea of the super organism?
Clements
-
when sedimentary settles to the bottom of the ocean and much much later gets turned up
hydrologic cycle
-
example of nutrient cycling organic & inorganic
- organic: ditritavores eating the dead
- inorganic: sea turtle egg shells Ca2+
-
4 factors of biogeochemical cycles
- 1. each chemicals biological importance
- 2. forms of chemical available or used
- 3. major reservoirs for each chemical
- 4. processes driving movement of chemical through cycle
-
This represents the loss of energy with each transfer in a food chain
pyramid of net production
-
How much energy(J) is passed up a pyramid of net production(food chain)
- 10%
- cut off a 0 at the end of J's
-
what 2 processes move nutrient between organic and inorganic parts of the ecosystem
-
nutrient circuits in ecosystems involving biotic and abiotic components are often called:
biogeochemical cycling
-
4 ecological energetics (abiotic)/ cycles contributing to biogeochemical cycling
- solar cycle
- hydrologic cycle
- gaseous cycle-carbon
- sedimentary cycle-phosphorous
-
what drives the hydrologic cycle
sun & gravity
-
when is H2O in abundance but unavailable for the ecological system
frost drought
-
what is the efficiency of energy transfer between trophic levels?
less then 20%
-
the amount of chemical energy in food converted to new biomass during a given period of time
secondary production of an ecosystem
-
when conducting bomb calorimetry experiment what 2 things can the calories used be contributed to?
- growth
- cellular respiration
-
what do farmers do to put nutrients back into their soil?
- nitrogen fixing bacteria
- plants legumes, Rhizobium, or root nodules
- grow for a year and till into soil
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