Sem 2, Unit 6: Ecology

ecology

the study of interactions among organisms and their environment

1) also known as the study of ecosystems

population chain (order)

organism → population → community → ecosystem → biome

ecosystem

the collection of abiotic and biotic factors in an environment

abiotic factors

non-living factors in an environment

1) ex: pH, weather, etc.

biotic factors

living factors in an environment

1) ex: animals in an community

matter cycles (explanation)

matter cycles through an ecosystems (matter doesn’t just disappear)

1) ex: water cycle

2) decomposers = important for nutrient cycling

energy flow (explanation)

energy flows through an ecosystem (eventually exits the ecosystem)

1) ecosystems need a constant fresh supply of energy from the sun

2) sunlight → chemical energy → heat that escapes out into space; ecosystems reset by taking up sunlight again

autotrophs

primary producers of ecosystem

1) synthesize food from sunlight (or chemicals)

aquatic autotrophs (examples)

diatoms, algae, and phytoplankton

land autotrophs

terrestrial land plants

consumers

organisms that receive energy from eating producers and/or other consumers

primary consumers

consumers that eat producers

secondary consumers

consumers that eat primary consumers

tertiary consumers

consumers that eat secondary consumers

1) (and so forth and so forth; system depends on what you eat)

omnivores

primary and secondary consumers

organisms that eat dead organisms

decomposers, detritivores, and scavengers

1) recycle nutrients

scavengers

break down/eat large dead things things

1) ex: vulture

detritivores

eat smaller dead things

decomposers

eat microscopic dead things

food chains

show the flow of energy within an ecosystem

levels of a food chain (high → low)

4) tertiary consumers

3) secondary consumers

2) primary consumers

1) producers

number of organisms per tier (explanation

as you go up the chain, number of organisms decreases as amount of available energy decreases it

1) Rule of 10%

energy amount in food chain (explained)

energy decreases as you move up the food chain because every organism that takes energy uses some of the gained energy for daily activities (converts into thermal energy)

1) so when you climb up the food chain, consumers are eating things with less and less energy to pass on, leading to an energy decrease as you move up

Rule of 10%

10% = the average percentage of energy transferred from one layer to another

1) less energy to pass on as you move up the chain because spend it as thermal energy for daily activities

community

all the different living species in a given area

1) shows biotic ←→ biotic interactions

coevolution

when closely associated species influence each other’s evolution

1) ex: flower flower adopting the smell of female bees to attract male bees (could have only evolved this way because of interaction) or flowers/hummingbirds evolving together with shape

symbiosis

extremely close longterm relationships

1) three types = mutualism, commensalism, and parasitism

mutualism

+,+ symbiotic relationships

1) ex: humans and gut bacteria

parasitism

+,- symbiotic relationships

1) ex: parasites in pig intestine that starve the host by using its food

2) # of parasites >= # of free living organisms b/c every parasite needs a host

3) parasites typically don’t kill hosts because rely on them for life

commensalism

+,0 symbiotic relationships

1) barnacles using whales as transport or trees and birds with nests

endoparasites

parasites within an organism

1) ex: tapeworm

ectoparasities

parasites living outside of an organism

1) ex: ticks

non-symbiotic relations

when species are less close than symbiosis but still close enough for coevolution to commonly occur

1) competition (-,-)

2) facilitation (+,-/0)

3) predations (+,-)

competition

a non-symbiotic relationship dependent on organisms fighting for the same resource

1) negative for both sides

interspecific competition

competition between two separate species; = fighting

1) bad for both species (lion might beat hyena in one fight, but it’s now injured and wasted energy; ultimately negative)

Interspecific Competition Theory

theory that true competition doesn’t exist in nature unless under extreme circumstances [ASK IF JUST INTERSPECIFIC]

1) because competition is negative for both sides, nature would never promote it

2) extreme circumstances ex: not having enough food to go around

facilitation

when organisms help each other out

1) ex: moss + lichens break down rocks to help form soil for larger plants

predation

when one organism eats the other (+,-) (animal on animal)

1) coevolution response typically = camouflage or mimicry

mimicry

prey mimicking another species

1) types = Batesian Mimicry and Mullerian Mimicry

Batesian Mimicry

when a harmless species mimics a poisonous or unpalatable species

1) ex: viceroy butterflies (mimic poorly tasting monarch butterflies to avoid being eaten by bird who previously ate those butterflies)

2) ex: scarlet kingsnake imitating the dangerous/poisonous corn snake

Mullerian Mimicry

2 or more unpalatable species resembling each other

1) gives the appearance that all of those species are on the same team, so don’t try to mess with one when you just failed to fight the other

2) is an analogous development; we don’t know how they got to be this way

1) ex: similar colored bees/wasps that all have the same defense mechanism

herbivory

predation but when animal eats a plant

1) one benefits; other suffers

2) plants coevolved to develop strategies to fight off predators (ex: poison) but are at a disadvantage because they can’t move

succession

how a community re-establishes itself after a disturbance

1) occurs pretty much all the time because disturbances are constantly happening

2) ex: ecosystem rebuilding after eruption of Mt. St. Helens

primary succession

succession that starts with barren rock (no soil)

1) begins with no life because most plants need fertile soil and moist environments (except pioneer community that comes in here)

2) takes a long time

3) occurs on the community level

secondary succession

succession that starts with soil present

1) would happen for ex: after a forest fire

2) takes less time than primary succession

3) occurs on the community level

pioneer community

the first colonizers of a land after a disturbance

1) = low growing plants (mosses, ferns, and lichens)

2) have low nutrient requirements, are small, and are photosynthetic

3) break weathered rock surface, creating the first layer of soil

climax community

the last organisms to colonize an area

1) are the most stable

2) include large trees

3) typically end up killing the pioneer community because are 1. taller than those low-growing plants to shade them out and 2. have seeds that can erminate in the shade of other plants unlike pioneer community

seral communities

communities formed between the pioneer and climax communities

1) typically, newer community kills off the earlier generation

2) include animals that begin to appear to feed on growing plant diversity; pioneer plants die and animals poop leading to more nutrients in the soil; grazing animals also control population

soil

provides water, nutrients, and a place for plants to grow

ecology niche

all of a species’ requirements and roles in an ecosystem

1) animal niches: temperature, species it eats, places to breed, etc.

2) plant niches: soil, water, light, and pollinator requirements

range of tolerance

an organism’s optimal range for a specific niche

specialists

animals with narrow niches

1) less adaptable; more likely to become extinct; easily effected by changing conditions

2) have an advantage in constant conditions because nobody else wants what they want (ex: koalas with eucalyptus leaves or pandas with bamboo)

generalists

animals with broad niches

1) very adaptive; less likely to become extinct; large range of tolerance

2) have advantage when conditions change but are at a disadvantage in constant conditions (competition0

3) ex: rats and raccoons

competitive exclusion

theory that two species cannot occupy the same niche

1) 2 species with the same niche can survive separately, but in the same environment, one species always dies out/declines

2) competition in general doesn’t exist naturally because is bad for both

resource partitioning

species coevolving to try to make niches as different as possible among one resource (to avoid competition)

1) is the result of coevolution (evolved to avoid competition)

2) ex: roots of close species have roots at different lengths to take nutrients from different depths of the soil

keystone species

a species (or set of species) whose impact on its community or ecosystem is much larger and more influential than would be expected from mere abundance

1) basically, a high-impact connecting piece of a species within an ecosystem (Derrick White)

2) can be a predator or prey

3) ex: salmon, otters, white oak trees, pollinators, beavers, and wolves

indicator species

can be used to measure an environmental factor or change because are influenced by/linked heavily to a factor

1) ex: mayfly nymphs indicating low pollution and high dissolved oxygen or certain amphibians signaling climate change or pollution or fecal coliforms

fecal coliforms

indicator species found in intestines and waste of warm-blooded animal

1) ex: E.Coli (don’t necessarily cause diseases though)

2) indicate animal waste contamination with the potential for the presence of pathogens

exotic species

a species that entered an ecosystem from their foreign ecosystem

invasive species

a harmful exotic species

1) don’t play by the rules of non-competition in other communities because didn’t coevolve with those organisms; out-compete natives

2) ex: zebra mussels, brown tree snakes, bush honeysuckle (shades understory plants), and starlings (push out native birds out of nesting cavities)

pyramid types

1) pyramid of numbers

2) pyramid of biomass

pyramid of numbers

show the population at each level of a community

1) not always great because makes it seem like one oak tree has less energy than a ton of caterpillars (not true)

pyramid of biomass

shows the total mass of a population

1) better because makes it seem like the oak tree has more energy (which is true)

limiting factors

something that restricts

aquatic limiting factors

sunlight, DO, nitrogen, and phosphorus

terrestrial limiting factors

water, nitrogen, phosphorus, and potassium [ADD MORE NOTE CARDS]