Community Ecology (PP23) Flashcards
define metacommunities
group of communities between which movement & interactions may take place
what does community ecology consider
Considers the interactions between all species in a defined geography
Species inhabit specific niches within their environment, which affects how they interact with the larger community
what is phenolgy and If a certain prey / predator changes its behaviour due to seasonal changes, will it have consequences on the dynamic of the community?
Study of plant & animal life cycles & how these are influenced by seasonal changes in climate
yes it will have significant consequences
explain niche
specific ecological role a particular species plays, as well as the biotic & abiotic influences the environment has on that organism
what is a fundemental niche?
full range of resources or habitat a species could exploit if there was no competition with other species (i.e. theoretical niche)
what is a realized niche
resources or habitat a species actually uses (i.e. actual niche)
what are the two ecological niches and explain them.
give an example of a species that is each of them
Generalist: very broad niche (consumes many types of resources) (ie. Racoon/ seagull)
Specialist: very narrow niche (consumes only a small range of resources) (ie. Koala, panda)
define range
geographical area over which an organism lives
What is a species range determined by?
Each species has its own range determined by physiological & resource constraints
When is considering range important?
Important when considering the specific habitat of an organism & what this means for the population and community ecology
What are populations linked by and what do they affect
Populations are linked by interspecific interactions that affect the survival & reproduction of the species engaged in the interaction
what are the community interactions`
Competition Predation Herbivory Parasitism (e.g. disease) Symbiosis (mutualism / commensalism)
What does intraspecific mean?
competition among members of the same species
Often intense due to same space and nutritional requirements
what does interspecific mean?
competition between members of different species
define terrioriality
organisms defend specific areas
Primarily against members of own species.
Resource allocation & spacing
what is the Principle of Competitive Exclusion
2 species cannot occupy the exact same niche for a prolonged period:
One will eventually out-compete the other & claim that resource
what will happen to the losing species according to the principle of competitive exclusion
Losing species will either migrate, become extinct, or partition the resource (utilize a sub-set of the same resource)
give an example of the principle of competitive exclusion
you will generally not find foxes & coyotes living in the same area due to competitive exclusion
what are predator adaptations
Claws, teeth, fangs, stingers, venom
what are prey adaptations?
Colouration, mimicry, detachment / vomiting, spines, bioluminescence, toxins
exaplain cryptic coloration give an example
Cryptic colouring: colouration blends in with its environment, so not be easily detected by predators (camouflage)
lizard camouflaging on brach
explain disruptive colouring and give an example
Disruptive colouring: colouration hides the physical “edges” (ends) - strong contrasts in light & dark across the patterns of the animal
(ex. zebra)
explain counter shading and give an example
Counter shading: helps cancel the effects of shading / shadows, of an animal - have a lighter underside & darker upper part cancel out natural shadow
(deer)
explain aposematic colouring
Aposematic colouring: poisonous organisms tend to be brightly coloured to warn predators that they are, in fact, poisonous
are all animals that display aposematic colouration actually poisonous?
Not all animals that display aposematic colouration are actually poisonous – some only mimic animals that are poisonous.
True or false? Predators never learn to avoid types of animals with bright colouration>
false, the bright colouration serves as a warning in the future
explain batesian mimicry
Batesian mimicry: animal that lacks poison / venom appears similar to another animal that is
explain mullerian mimicry
Müllerian mimicry: animal that mimics a poisonous / venomous one still has some poison, though not necessarily to the same degree
explain aggressive mimicry
Aggressive mimicry: predator attracts its prey towards itself with a lure or mimicked cry
what is symbiosis
Relationship in which 2 or more organisms are closely associated in a way that benefits at least 1 of the participants
explain mutualism and give an explanation
Both organisms in an interaction benefit from one another: Win / Win (+/+)
e.g. Humans & intestinal flora: while there may be a slight disadvantage in this relationship (have to carry the bacteria around), this disadvantage is outweighed by the benefit (help digest our food)
explain facultative mutualism and give an example
Facultative: organisms are able to live without each-other
e.g. Clownfish & sea anemones
explain obligate mutualism and give an example
Obligate: one organism cannot survive without the other
e.g. Yucca & yucca moth
explain commensalism and give an example
One organism in an interaction benefits & one is unaffected: Win / Meh (+/0)
Remora fish (suckerfish) & sharks/whales: remora gets a snack while it hitches a ride on the fish/whale, while the latter isn’t much bothered but doesn’t gain anything
Cattle egret & buffalo: egret benefits from all the insects kicked up by the buffalo, which gets nothing in return
explain parasitism and give an example
One organism in an interaction benefits at the expense of the other: Win / Lose (+/-)
Tapeworms & host: tapeworm enters intestinal tract, grows, & reproduces, causing the host abdominal pain, diarrhoea, weight loss
Disease & host: disease completes its life cycle at the expense of the host, causing physical symptoms & possibly death
what are the two ways to measure species diversity and explain them
Species richness: total number of different species in the community
Does not take into account concentrations of different organisms
Relative abundance: compares the relative quantities (proportions) of different species in the same community & looks at density
true or false: there is a latitudinal gradient of species diversity for most taxa
true or false: Species diversity increases as latitude increases?
PIC IN SLIDES
true
FALSE Species diversity declines as latitude increases
increase in biodiversity is associated with what
increase in community productive
increase in community stability and
increase in ecosystem services
explain increase of community productivity
↑ Community productivity:
- Production of biomass (biological organisms) / reproduction
- More diverse community has greater quantities of life forms
- Enables different species to rely on those species from which they best obtain nutrients (greater selection)
explain increase in community stability
↑ Community stability:
Resilience of community against extinction of 1 or more species
At low diversity, loss of 1 species triggers a domino effect leading to more extinctions
explain increase in ecosystem services
↑ Ecosystem services:
Benefits to humans from an ecosystem (e.g. clean water)
Greater diversity means a broader range of organisms that can offer benefits
define stability
Stability: constant composition or abundance
Consistent pattern in fluctuations
what are the elements of stability
Resistance:
Resilience:
(Elasticity):
(Amplitude):
what is elasticity
how quickly the system returns to its previous state
what is amplitude
to what degree the system can be moved but still return to its previous state
what is resilience
how much of the system’s function & structure is retained, & how easily/quickly can it recover
what is resistance
how little / how much the system changes
what is a climax/mature community
Climax / mature community: when a community reaches a relatively unchanging state
Will still cycle through small population changes, but will not undergo large changes (succession) until it faces a disturbance
what is a disturbance
Any major event that has an impact on the community: can be abiotic or biotic
what can a disturbance result in
SEE DIAGRAM IN SLIDES
Results in succession
Process whereby the community in a given habitat changes
(primary and secondary)
explain primary succession
Primary succession: when community forms for very first time & new species arrive in a geographic region
only ever happens once
explain secondary succession
Secondary succession: when growth and changes take place in the environment in response to the disturbance
what are the 3 basic categories of organisms
producers (autotrophs)
consumers (heterotrophs)
decomposers
explain decomposers
Decomposers
Break down / regenerate remains & waste products of plants & animals into simple inorganic nutrients
Major role in biogeochemical cycle
explain producers
Producers (Autotrophs)
Produce own food through photosynthesis. Only way carbon & energy get into the system.
Autotrophic algae, bacteria, plants
explain consumers
Consumers (Heterotrophs) Depend on autotrophs or the organic compounds they produce for their food supply Herbivores: eat plants or algae Carnivores: eat other animals Omnivores: eat both plants and animals Bacteriovores: eat bacteria
define herbivores
Herbivores: eat plants or algae
define carnivores
Carnivores: eat other animals
define omnivores
Omnivores: eat both plants and animals
define bacteriovores
Bacteriovores: eat bacteria
define trophic level
each of the different feeding levels of organisms
what are the 3 basic trophic levels
1st: primary producers (autotrophic phytoplankton & plants)
2nd: herbivores (zooplankton & animals feeding on plants)
3rd: carnivores (animals feeding on other animals)
True of false: Total biomass decreases with increasing trophic level
true
what is the 10% law of ecological efficiency
: only about 10% of the resources from one trophic level are passed on to the next level
define transfer efficiency
energy provided to the next higher trophic level divided by the energy received from the next lower trophic level
What are losses of mass and energy due to ?
Losses of mass & energy within each trophic level due to respiration, feces, etc.
who invented the 10% rule
lindemen
what do food webs do?
Food webs link the trophic levels from producers to top carnivores
who is the primary consumer
Primary consumer: herbivore (plant eater)
who is the secondary consumer
Secondary consumer: carnivore (meat eater): tertiary consumer
what does an omnivore do?
Omnivore: eats both plants & animals
what does the top carnivore do?
Top Carnivore: eats other carnivores
who are the decomposers
Decomposers: detritivores (detritus eater): bacteria
who are the phototrophs
Phototrophs: plants, algae (phytoplankton), bacteria
who are the primary producers
autotrophs
FOOD WEB DIAGRAM
LOOK IN SLIDES
what is a food chain
simple, linear sequence of organisms through which energy is transferred
true or false Usually only 1 species at the consumer levels
TRUE
food chain show…
Highest transfer efficiency and maximum harvest
what is a food web?
complex food chain with many links between producers and consumers
what is the problem but also upside of a food web?
Less efficient but more resilient
what is a keystone species
: particularly important part in a trophic web
what will the disruption of a keystone species cause?
Its disruption will cause a major trophic cascade
what is the argument of keystone species
Argument that, in one way or another, all animals are keystone species, since it is impossible to remove one species entirely without having major impacts on a trophic web
KEYSTONE OTTER SLIDE
NOTE SLIDE
what is a Bottom-up trophic cascade
Bottom-up trophic cascade: If an animal that is lower on a trophic pyramid is removed
what is the consequence of bottom up trophic cascade and give an example
Subsequent layers of the pyramid will be impacted & will diminish
e.g. if a primary producer is reduced, this will decrease the presence of primary consumers, which will decrease the presence of secondary consumers, etc.
what is the consequence of top-down trophic cascade
Population of the next highest trophic level will increase → this increase will result in a decrease in the next trophic level, which causes an increase in the level below it, etc.
What is a Top-down trophic cascade
: elimination of a higher predator
what will trophic cascade shifts cause?
These shifts emphasize the important interspecific interactions within an ecosystem
what is bioaccumulation
organism cannot eliminate the toxin → toxin accumulates over its lifetime
what is the result of bioaccumulation?
Results in increased concentration of toxin in the organism’s body
true or false: When an organism affected by bioaccumulation is eaten by a higher trophic level-animal, the toxins pass to this animal
true
give examples of toxins
DDT, PCBs, Mg
what is bio-magnification
Bio-magnification: toxins become more concentrated with each successive trophic level
what does bio-magnification result from>
Results from biomass at each trophic level being produced from a much larger biomass ingested from level below
biomagnification occurs under what conditions
- Pollutant/toxin must be long-lived.
- Pollutant/toxin must be concentrated by producers
- Pollutant/toxin must be fat-soluble & transferred to higher trophic levels
what is the schema of the concentration of toxin
Concentration of toxin:
3rd trophic > 2nd trophic > 1st trophic
