C4.1 populations and communities Flashcards
populations
interconnecting groups of organisms of same species living in an area, interact with eachother within a community able to interbreed with each other
order ofindividual to biosphere
individual, population, community, ecosystem, biome, biosphere
what happens when 2 popuations live in differenet areas
unlikeley to interbreed with each other, if 2 populations of same species geographically isolated for longer time many develop differences in characters, eventually becoming different species
what are 2 common sampling methods for sessile organism
quadrant sampling, belt transect
quadrant sampling
take measurment of an area without systematically deciding where to take it, eliminates bias may infleunce measurments, used with quadrants when working out population size of a species of stationary animal/plant
procedure of random sampling
baseline along edge of habitats using measuring tape, generate random numb, first number determinates distance along tape and 2nd distance quadrant placed at that distance
belt transect
takes samples from area along straight line
random dispersion
individuals are dispersed randomly no predictable pattern
uniform dispersion
individuals are spread out in regular pattern often occurs when individuals compete for limited resource eg water or light
clumped dispersion
individuals clustered in groups
lincoln index
estimate populations size for mobile organisms that can be captured and marked eg. ring, tag, dab of coloured paint
what are methods used to collect organisms
pitfall traps, pouters, mammal traps, nets
formula for population size
1st capture * 2nd capture (marked and unmarked) and divide by 2nd capture marked only
carrying capactiy
the bigger the population grows the more resources are taken from enviornment, sme point limit is reached if a population grows too large
carrying capacity= max size a population which enviornment can support
what are examples of density dependent factors
fod and water avilability
space territories
availability of mates
diseases
predation
what are examples of density independent factors
enviornmental change
build up toxic by products metabolism
injury
senescence (death from age related to illnesses)
what are population size limited by
density dependent factors and density independent factors
density dependent factor
factors which depend on population size
density independent factors
factors affect all population in similiar way more dependent of population size for example; drought, deforistation
negative feedback in terms of population size
when population becomes too large for an ecosystem, population declines and no longer enough resources
what are the 3 main groups of the density dependent factors
competition
predation
disease, parasites, infestation
competition
what do animals and plants compete for, higher number of individuals reduce amount of available resources so competition is higher
predation
higher density of a population more intense predation becomes
disease, parasites, infestation
higher density, more likelyspread/ transmission of diseases
dependent factors cause….
population size to fluctuate due to negative feedback control, resulting in it stabilising over time, fluctuation in population size continues to occur as population oscillates around carrying capacity
negative feedback loop
type self regulating system, any deviation from steady state is counteracted to promoted stability
exponential stage
births and immigration is bigger than mortality and emmigration
plenty supply of resources
limiting factors not restricting growth and rate of population growth
transition stage
growth rate and population growoth is slower than start some limiting factores more resulting in bigger competition but births still have higher than deaths
plateau stage
limiting factors more restrictive effect, population growth reached carrying capactiy births= deahts
immigration
increase in population size from external populations
natality/ births
increase in population size via reproduction
emmigration
decrease to population size as a result os loss to external population
mortality
decrease in population size, result of death
population size equation
(natality + immigration) - ( mortality + emmigration)
what do density dependent factors lead to
negative feedback prevents exponential growth , when absent population grows exponentially
community
all interacting organisms in an ecosystem all species depend on relationship with other species for long term survival
group of population living together in area, interacting with eachother
interactions
effects organisms have in one another
intraspecific interactions
effects individuals of same species have on one another eg. plants competing for light
interspecific interactions
effects individuals of different species have on one another eg.leopards and lions fighting for same prey
mutualism
both species benefit from interaction
whydoes competition between members of same species occur
because individuals share same ecological niche with similiar recquirments for resources
what do plants compete for
light, space, water nutrients in soil or polen to be distributed by pollinatores competition for pollinators
cooperative relationships, give examples
all individuals benefit
eg. communal roosting in birds, provides warmth, protection to each member
eg. group hunting, social predation increases chance succes
eg. fish form tight pack harder for predators to catch
eg. shared parental care, allows other parents to see other tasks
what do animals compete for
compete for space or nesting sites, water as a resource
what are the different categories of interspecific relationships
herbivory, predation, competition, mutualism, parasitism, pathogenicity
explain herbivory
primary consumers feeding on producers, producer may or not be killed, eg. bison grazing on grasses
aphids feeding on plant sap, limpets feeding on algae on rockyshore
predation
one consumer species, killing and eating another consumer species eg. anteater feeding on ants, starfish eating oysters, cheetah hunting gazelle
competition
2 or more species using same resource with amount taken by one species reducing amount available to other species
eg. lios + hyenas feeding on same prey, ivy growing on trees cowbird laying eggs in nest
mutualism
2 species living close association, both species benefit
eg. mycorrizob in roots, birds picking teeth crocadiles, clownfish living with sea ane,one
parasitism
one species living inside or outer surface of another species, obtaining food from them, host is harmmed, parasite benefits eg.roundworm living inside guts racoons, tick feeding blood of host, mosquito drawing blood
pathogenicity
1 species (pathogen), living inside another species (host), causing diseases in host
eg. potato blight fungus, tubercolosis in badgers
mutualism
an interspecific relationship that benefits both species
explain root nodules in fabacea
fabacea are large plant family including species like clover, peas, beans. Many have devloped mutualistic relationship with rhizobium bacteria, live in root nodules grown by plant, assissting with uptake of nitrogen az, used for buildup of proteins, nitrogen in air cannot be absorbed
what are the benefits received from bacteria and by the plant in root nodules in fabacea
benefits received by bacteria- receives protection, sugars made by plant (photosynthesis)
benefits received by plant- oxygen concentration inside nodule low, rhizobium absorbs nitrogen converts into NH4, plant uses for production of proteins, prevents nitrogen deficiency
mycorrhizae in orchidaceae
roots most plants form association with fungi called mycorrhizae in soil, orchid seeds dont contain food supplies, particularly dependent mycorrhizae during early growth and germination. The fungal hyphae grow into root cells without penetrating plasma membrane supplying nutrients
what are the benefits of fungi amd plant in mycorrhizae in orchidaceae
benefits to fungi- orchid supplies carbon compounds from photosynthesis
benefits to plant- fungus absorbs nitrogen, phosphorus, fixed carbon and water from soil, supplies to plant, orchid seeds do not contain food reserve, needs nutrients
zooxanthellae in hard corals
hard coral secrete CaCO3 from skeleton where indiviual animals can live coral reefs formed. Coral live close relationship with photosynthetic (chlorophyll containing) alge= zooxanthellae, close to surface of sea (sunlight)
benefits to coral and alge in zooxanthellae in hard corals
benefits to coral- algae supply glucose, amino acidsm oxygen for photosynthesis
benefits to algae- coral provides co2 from cellular respiration for photosynthesis
describe the predator prey relationship
this is an example of a density dependent control of animal population
when predator kills prey, prey population becomes smaller but doesnt change much because births= deaths rate
as prey population increass, predator increases as more food for predator to eat and same if they decrease , when there is less food resources cyclic oscillations can become out of synch
within the food chain interaction between differnet species can operate in 2 directions them being;
top down and bottom up
explain top down direction interaction
control acts from hgiher trophic level to lower oneincrease in predator number decreases population size of prey
explain bottom up direction interaction
control acts from lower trophic level to higher one population of producer may be limited by number of nutrients in soil or water for example, amount of seaweed avialable determine number turtles are feeding on the,, have impact on consumers which are higher up food chain
what are secondary metabolites used for
some organisms have devloped special ways as a part of their metabolic pathways to deter potential competitors from their ecological niche, pathways producing secondary metabolits, not essential for cell growth or function
production of antibiotics
many fungi produce antibiotic substance prevent growth of other species by interfering with cell wall components of them, eventually cause bursting and death
allelopathy
is realese of chemicals as secondary metabolites or toxins by plants, given off into soil to prevent nearby competitive plants to grow in sam area
give an exmaple of a plant which uses allelopathy
sunflower, realse chemicals which inhibit growth of other plants, relaese toxin through roots, stem, leaves fruits, flowers and seads, chemical affect germination of seeds, roots, shoot development, photosynthesis and respiration
endemic species
species occur naturally in ecological niche in an area. Density dependent factors usually naturally control and regulate population size
invasive or alien species
specieis introduced by humans, delibertly or accidentally they are often not effectively controlled due to absense of naturaly predators that would control them in their antive habitat
eg. asian lady beetle, invasive in switzerland very strong immunity against pathogens so thries
what is a test for interspecific ompetition
chi squared test
positive association
species found same habitat eg. predator and prey
negative assocaition
species occur seperatelyin different habitats
no association
species occur as freuqnetly togehter as far apart
