ecology - bio Flashcards
(43 cards)
population
community
ecosystem
habitat
biosphere
population: group of individuals of the SAME species in the same area
community: groups of populations living in the same area
ecosystem: all living organisms and the physical environment they interact with
habitat is just the physical surroundings not the animals
biosphere includes all of the planet’s ecosystems and landscapes (including atmosphere, hydrosphere, lithosphere)
niche? fundamental vs realized niche?
where an organism lives, what it uses (abiotic and biotic resources) to survive there, and its behaviours/roles in that environment
- two species CANT occupy the same niche indefinitely (eventually competition)
fundamental niche: range an organism can live in, theoretically
realized niche: where an organism actually lives (With factors like predators or food abundance)
biotic potential? what are some contributing factors?
maximum growth rate under ideal conditions (where resources are unlimited, predators and competition are absent, and all individuals are healthy)
several contributing factors:
- number of offspring per reproduction
- frequency of reproduction
- survivorship of offspring
- reproductive lifetime
- age of reproductive maturity
carrying capacity?
max number of individuals that a habitat can sustain
K vs R-selected species
K-selected:
- low number of offpsring
- higher parental care
- low population growth rate
- longer lifespan
- stable environments
- reach reproductive maturity slower
- stable population size
- larger offpsring
- lower mortality rates
- typically type 1 curve
R-selected:
- high number of offspring
- low parental care
- high population growth rate
- shorter lifespan
- unstable environments
- reach reproductive maturity quickly
- population fluctuates
- smaller offspring
- higher mortality rates
- typically type 3 curve
you arent just “kselected or r-selected”, theres a spectrum
What is the per capita birth rate, and how do you calculate it
- measures the number of births per individual in a population over a given time
- reflects how frequently reproduction is occuring
per capita birth rate (b) = B/N
per capita birth rate = total # births / total population size
Which two components contribute to species diversity?
Species richness:
- total # of diff species present in a biological community
- directly related to a community’s geographic area (the LARGER the geographic area, the GREATER the number of species)
- species-area curve (increased area = increased diversity of habitats = increase species)
Relative abundance:
- the proportion that each species represents out of all individuals in a community
What is the competitive exclusion principle?
Means that two species competing for the same limited resources cannot coexist indefinetely in the same time
- over time, one species will outcompete the other
- the other species either dies or is forced to adapt to different resources or a different niche
what is character displacement
competing species evolve distinct traits (physical, behavioural, etc) over time that further reduce competition
interference, exploitation vs apparent competition
interference competition:
- aggression directly between animals
- eg physically preventing from establishing a habitat
exploitation competition:
- occurs indirectly through depletion of a common resource
- one population is reduced
apparent competition:
- between two species preyed upon by the same predator
- indirectly compete for survival
What is symbiosis, and what is commensalism, mutualism and parasitism?
Symbiosis is an intimate association b/w two organisms that may or may not be beneficial
- some are obligatory
There are three types of DIRECT symbiosis:
1. Commensalism (+/O)
- one benefits and the one is unaffected
- eg remora & shark
- Mutualism (+/+)
- both organisms benefit
- eg lichen (fungus & algae) - Parasitism (+/-)
- organism benefits at the expense of the host
- eg tapeworm & host
INDIRECT symbiosis:
1. indirect commensalism
- one species benefits from an indirect relationship by an intermediate species, the other is unaffected
- eg there is no interaction between eagle and grass –> but by interacting with an intermediate species (Rabbit) and removing it as a source of harm, the grass benefits from the eagle
- facilitaiton (+/+ or -/-)
- species indirectly has positive effects on another without close contact by altering the environment
- common in plants
- eg balck rush making soil more hospitable for other plants
what is ecological succession, and what is primary and secondary ecological succession?
ecological succession is the change in composition of species over time
- one community is replaced by another gradually (over time diversity and biomass increase)
final stage = climax community
primary succession:
- occurs in areas that never previously supported living things (eg volcanic islands)
- essential process of soil building by the pioneer species (eg lichens)
secondary succession:
- begins in habitats where communities were entirely or partially destroyed by a catastrophic event (eg fires, floods, deforestation, etc)
- much faster than primary succession because the soil is already established
________ trophic levels are less stable & most sensitive to population fluctuations
higher or lower?
HIGHER
- eg, if fire kills primary producers, there’ll be less food for primary consumers, then even less food for secondary consumers, even less for tertiary, and barely any for quaternary
note: only 10% of energy is transferred when consuming (trophic efficiency)
The amount of energy/biomass/quantity of organisms is the ________ at primary producers, and the _________ at quaternary consumers
(highest/lowest?)
HIGHEST at primary producers
LOWEST at quaternary consumers (decreases going up)
What are some adaptations in herbivores?
flat teeth for grinding plants, long tongues, hooves for stability, and LONG DIGESTIVE TRACTS
What are decomposers, and the different types?
Decomposers are organisms that decompose or break down and absorb nutrients from dead & decaying organic material
Different types:
1. Saprophytes
- a type of decomposer that lives on the decaying organic material
- releases digestive enzymes to digest it EXTERNALLY
- eg many molds
- Detritivores
- organisms that consume detritus (ie fragments of things)
- physically breaks down nonliving organic materials & digests it INTERNALLY
- typically animals (worms or beetles) - Scavengers
- animals that feed off large dead animal corpses
- eg vultures and hyenas
- technically not decomposers, but nonetheless break apart dead animals to help start the process of decomposition (just not breaking them down from organic –> inorganic material like decomposers)
Dominant species
Keystone species
Foundation species
Apex predators
Dominant species
- most abundant or largest biomass in the community
Keystone species
- not usually abundant but have a major impact on the balance of the ecosystem
- pivotal ecological role in community
- eg sharks (regulate levels of their prey, if we remove them from the ecosystem the entire thing collapses, stingray population increases (overpopulaion) and other crab, shrimp, clam, etc populations collapse)
Foundation species
- dramatically alter their physical environment
- build & maintain habitats
Apex predators
- on the top of the food chain
- no other creatures predate it
biogeochemical cycles? what is a reservoir, assimilation and release?
follow the flow of essential elements/compounds
- there are three kinds: the hydrologic cycle, the carbon cycle, and nitrogen cycle
a reservoir is the major storage location
assimilation is when elements are incorporated from the environment into living organisms
- usually inorganic –> organic form
- eg drinking water from a river (putting it into you)
release is when elements are returned BACK into the environment
- usually organic –> inorganic form
- eg urinating into the soil
The hydrologic cycle? What are the reservoirs? How is it assimilated? Released?
- explains how water moves b/w environment and living organisms
reservoirs:
- oceans, air (water vapor), ground water & glaciers
assimiliation:
- plants absorb water from soil
- animals drink water
release:
- plants transpire
- animals & plants decompose
- animals respirate and excrete
The carbon cycle? What are the reservoirs? How is it assimilated? Released?
reservoirs:
- atmosphere (CO2), fossil fuels (coal & oil), peat & organic matter
assimilation:
- plants fix CO2 in photosynthesis
- this is ‘carbon fixing’ (inorganic CO2 to organic compounds)
- animals consume plants
release:
- release CO2 through cellular respiration and decomposition (decomposers release carbon via respiration back into the atmosphere, making it available to plants for photosynthesis)
some carbon gets trapped in the soil, and over a very long time gets transformed into fossil fuels, which humen burn back into the atmosphere
The nitrogen cycle? What are the reservoirs? How is it assimilated? Released?
- required to manufacture amino acids and nucleic acids
Reservoirs:
- atmospheric N2 (g)
- ammonium (NH4+) and nitrate (NO3-) in the soil
Some organisms can use NH4+ (ammonium), others need it to be converted into NO3- (nitrate). Done through two processes:
1. Nitrogen fixation
- atmospheric N2 is converted to NH4+ or NO3-, (nitrification can further convert NH4+ –> NO3)
- done by bacteria in soil (specifically located in the root nodules of legumes**) making NH4+
- can also be done by lightning and UV making NO3-
2. Nitrification
- done by nitrifying bacteria
- NH4+ is sequentially oxidized to NO3- (which plants and animals can uptake)
Assimilation:
- plants, other autotrophs and microorganisms uptake inorganic nitrogen from the soil in the form of NH4+ & NO3-
- the inorganic nitrogen taken up by plants and bacteria is converted to organic forms via the synthesis of proteins, nucleic acids, and other organic molecules
Release:
- denitrification (done by denitrifying bacteria that convert NO3- in soil back to the atmospheric reservoir as N2)
- ammonification (decomposition) where dead organisms and waste return nitrogen back into the soil. animals excrete ammonium, urea, or uric acid through decay
nitrogen fixation is done by what?
- Done by bacteria in soil (specifically located in the root nodules of legumes**) making NH4+
- the legumes are infected with bacteria that are nitrogen fixing, the relationship between the bacteria and the plant is symbiotic - can also be done by lightning and UV making NO3-
Nitrogen and carbon fixation in vertebrates
vertebrates DO NOT fix carbon OR nitrogen!!!
- instead, they directly consume organic forms
- carbon is ONLY fixed through the process of photosynthesis by plants and autotrophs
- nitrogen is only fixed by lightning or nitrogen fixing bacteria
In the root nodules of legumes, symbiotic bacteria convert atmospheric nitrogen (N2) into __________.
NH4+ (ammonium)
