community ecology Flashcards
what is a biological community?
is an assembly of populations that live close enough together for possible interactions
can ecologically similar species live together?
yes, as long as they have niches with 1+ differences
what is a habitat?
- a place where an organism lives
- has physical and chemical components
- shared with other species
what is a niche?
- specific role that a species takes in its community
- total use of biotic and abiotic elements of a particular population
what is an interspecific interaction, what does it have an effect on?
relationships/interactions between members of a community. it has an effect on the survival and reproduction (evolution) of species
interspecific interaction: competition
what is it, who does it harm/help?
give example
- /-
- species compete for limited resources
- usually detrimental to both
eg. 2 species of eat same prey -> change eating times, or one gets eliminated
interspecific interaction: predation
what is it, who does it harm/help?
give example
+/-
- predator eats prey
- predator benefits, prey dies
eg. wolves eat deers
interspecific interaction: herbivory
what is it, who does it harm/help?
give example
+/-
- herbivore eats plant/algae
- herb benefits, plants dies
- subset of predation/parasitism
eg. deers eat grass
interspecific interaction: parasitism
what is it, who does it harm/help?
give example
+/-
-One organism, the parasite, derives its nourishment from another organism, its host, which is harmed in the
process
-eg. tick on an animal
interspecific interaction: mutualism
what is it, who does it harm/help?
give example
+/+
- both species live closely together and benefit
eg. lichen, mycorrhizae, digestive bacteria
interspecific interaction: commensalism
what is it, who does it harm/help?
give example
+/0
- species that live closely together where one benefits at no harm/gain to another
eg. tree frogs hide in plants
what is resource partitioning, give example?
when competing species share a resource, but alter how they use it
eg. hunting at different time, shade vs sun
what is competitive exclusion, give example?
when species are competing for the same niche, but one is better and the other dies out
what is cryptic colouration, give example?
when species develops a morphological adaptation to look like something else, ie. camouflage
eg. a moth that has same colour pattern as bark of a tree
what is aposematic colouration, give example?
typically found in those with a chemical defense -> bright warning colours
eg. brightly coloured poisonous frogs
what is batesian mimicry, what is an example?
- when a harmless species mimicks a harmful species
eg. moth eggs that look like a snake
what is mullerian mimicry, what is an example?
a form of mimicry in which two or more noxious animals develop similar appearances as a shared protective device, the theory being that if a predator learns to avoid one of the noxious species, it will avoid the mimic species as well
-eg. many butterflies share similar orange/red/black coloration
what is an ectoparasite, give an example
ectoparasite is one that lives on external surface of host
eg. lice, fleas
what is an endoparasite, give an example
endoparasite lives on the inside of host
eg. hookworm
what is obligate mutualism, give an example
is a mutualism in which both need the other to survive
eg. microbes that live in the reticulum chamber of a cows stomach -> digests cellulose for cow, microbe gets food
what is a facultative mutualism, give an example
is a mutualism where together both species benefit, but they could both survive on their own
eg
what is a trophic structure?
The feeding relationships between organisms in a community
what is the producer’s role in the trophic structure? how do they do this?
to support the rest of the community
-synthesize sugars and other organic compounds for
their own growth
-using inorganic compounds (e.g. CO2 and H2O)and
an external energy source (e.g. sunlight)
what are consumers? What kind of consumers are there in a trophic structure, what do they eat?
-consumers obtain their organic compounds from other organisms in the trophic structure 1. Primary consumers -consume producers 2. secondary producers -consume primary consumers
what are food chains?
food chains are pathways in energy is transferred from producers to consumers
what are food webs?
food webs are interconnected food chains, with complex trophic interactions
-shows species can play more than one role in a community
what is trophic efficiency?
efficiency with which food energy is converted to biomass in each link of the trophic structure
how much energy is not transferred between trophic levels? what is the rule for trophic efficiency, what does it mean?
- about 80-95% of energy is NOT transferred
- there is a 10% rule for trophic efficiency.
- this means only 10% of energy is transferred between levels, and that at each level, consumers need to consumer more
give an example food chain, with 10% rule
- Producer -> grass -> 20,000J
- Primary consumer -> grasshopper -> 2000J
- Secondary consumer -> frog -> 200J
- Tertiary consumer -> snake -> 20J
what is an ecosystem?
the community of organisms in an area and the physical factors with which they interact
what affects primary productivity?
Abiotic factors -> eg. sunlight, water, nutrients
what is symbiosis?
Two or more species living in direct and intimate
contact with one another
what do omnivores feed on?
feed on both producers and consumers
what do decomposers consume?
are consumers of non-living organic matter
what two factors effect distribution of organisms?
biotic (predators, competition, symbiosis)
abiotic (water availability, temperature, wind, rocks)
what is climate?
- water and temperature
- Long-term prevailing weather conditions in an area
what is a microclimate?
- consists of very fine local patterns
- E.g. underneath a fallen log
what effect does the sun have on climate?
The sun affects:
- temperature variations
- cycles of air movement
- evaporation and precipitation of water
the dynamics of an ecosystem are determined by what 2 factors?
ENERGY FLOW AND
CHEMICAL CYCLING
