community ecology Flashcards
community
interactions between populations of multiple species
ecological niche
a specie’s lifestyle
fundamental niche
full range of environmental conditions where a species can potentially survive and thrive.
-based on biotic factors
realized niche
where an organism actually lives
-based on abiotic and biotic factors
-smaller niche due to interactions with other species
competition is a ___/___ interaction
lose/lose (reduces population of both parties)
what are species in competition over?
limited resources
interspecific competition
competition between different species
infraspecific competition
competition with members of own species
which is worse and why: interspecific competition or infraspecific competition?
infraspecific because you are competing with individuals that share the same niche as you and 100% of your needs overlap
competitive exclusion
two species cannot fill the same niche
-one species is a netter competitor and the other is extirpated
resource partitioning
dividing up a resource between users to avoid competitive exclusion
how does resource partitioning work?
-use different parts or aspects of the resource
-natural selection favors avoiding competition as much as possible
example of resource partitioning
Anole (lizard) in the Caribbean all eat insects which puts them in competition. But they eat insects in different places (trunk anoles, shrub anoles, log anoles, leaf anoles, etc.)
-They don’t cross over as much, reducing competition
resource partitioning can only occur…
between DIFFERENT species
exploitation is a __/___ scenario
win/lose
types of exploitation
herbivory, predation, parasitism
herbivory
animal benefits while plant/algae is harmed
predation
predator benefits while prey os harmed
predator and prey often…
evolve characteristics to counter each other
parasitism
parasitic species benefits while host is harmed
natural selection favors defenses in exploited organisms such as:
physical harm (spines/spikes)
foul taste (chemicals)
toxins (harmful chemicals)
exploiting organisms may develop..
resistance
how can coloration help against exploitation?
-camouflage
-warning colors: warns that they contain toxic chemicals
-mimicry: copies a foul tasting/toxic organism
how can safety in numbers help against exploitation?
-confuse predator (make it confusing and hard to pick an individual to chase)
-protect each other
predator prey cycle is said to be
boom and bust
predator prey cycle:
- High prey population
- High predator population
- Predators destroy prey population
- Many predators starve
- Fewer predators and prey population regrows
types of positive interactions:
commensalism, mutualism, facilitation
commensalism
o Win- neutral interaction
o One species benefits while the other is unaffected
mutualism
o Win-win interaction
o Both species benefits
o Species may become dependent on each other
facilitation
o Improves physical environment for another species
o Example: coral creates reefs
species diversity is higher in..
more complex environments (only 1 species per niche, but greater variety of niches for species)
measures of diversity include
species richness
species evens
diversity buffers community against..
disturbance: communities with low diversity are easier to damage, and they recover more slowly
species richness:
of different species
species evenness or relative abundance:
how many of each species compared to total
ecotones occur where..
physical environment changes (border between 2 ecosystems)
why do ecotones often have higher biodiversity?
Because greater number of niches = more diversity, and between two ecosystems there are more niches available.
producers
create energy from the sun
-Most important source of energy in most ecosystems
consumers
obtain energy from other organisms
primary consumers
eat producers
secondary consumers
eat primary consumers
detritivores
eat dead things
trophic structure
feeding relationship between species
food chains
linear path that shows what eat what
*Transfer of food through trophic levels
order of food chain (bottom to top)
primary producers, primary consumers, secondary consumers, tertiary consumers, quaternary consumers
food webs
combination of multiple food chains
*Feeding relationships between many species
bottom up control
-regulation of ecosystem dynamics by the availability of energy or nutrients
-reduces the overall energy supply, narrowing the base of the ecological pyramid
- it influences every trophic level above it
In this scenario, changes at the bottom of the pyramid have widespread effects throughout the entire ecosystem, highlighting the interconnectedness of species and their reliance on resource availability.
bottom up control
Top-down control
-Predation pattern of top predators
-Changes consumer abundance in lower trophic levels
keystone species:
maintain diversity and hold up many species in the environment
example of keystone species (otters)
- They eat urchins
- Urchins are bad since they eat kelp and destroy forests
- Otters facilitate kelp forest habitats, which are one of the most diverse marine systems
communities are dynamic:
change as environment changes
ecological succession
- Occurs when all vegetation is removed
- Predictable progression of plant and animal species
- One species prepares environment for next species
primary succession
-area that has no established soil
-Usually new volcanic island or after glacial retreat
-Occurs in stages
stages of primary succession
pioneer stage, dryas stage, alder stage (puts nitrogen into soil), spruce stage
secondary succession
land that has been destroyed by disaster
* Bare soil
* Often after fire
