Ecology intro

Study of interactions between species and speciess and species and their environemnt everything in ecology is scale dependent, scale changes the data you collect

Structural -what is there , who is there , Dynamical-how does that strucutre…, how does things change through time, mainly about time

individuals of the same species interacting at the same spatial and temporal scale

exponentia - not realistic, population grows exponentially logistic - includes carrying capacity, curve flattens out at some point The chang in population density over time

dN/dt = rN(K-N)/K N is population density K is carrying capacity r per capita population growth rate (the amount of growth in the population per individual)

the interaction of a population through time and space meta pop - group of small isolated populations

Source poulations - birth exceeds death Sink pop - death exceeds birth

any parameter that prevent pop from growing exponentially can be inter specific or intra specific

has to do with interaction, it is not a physical presence of organisms or population ex you can interact with something without being there by having lasting effect on area

competition consumption -predation, parasitism, herbivory mutualism commensalism

any interaction between two species where and increase in density of tierh species causes a decrease in the per capita population growth rate of the other mutually neg interaction

consumption - they eat the same resource preemption - mere presence reduces shared resouce, common in sessile orgs, ex trees and space, sunlight allelophathy - one org changes chem composition of resource, make env more hostile for others terrioriality - inhibits resources for others via behavior aggression

two species cannot use same resource in the same way and coexist Even if they feed on the same tree it has to be different parts for two species to coexist intra comp>inter comp

if the interspecies competion> intraspecies competition then one species will be competitively excluded and eventually die out

interaction between species where increase increase in species i(prey) causes increase in per capita pop growth rate of sp. j(predator) and increase in density of sp. j causes decrease in per capita pop growth of i

The giraffe eating leaves is not hurting the leaves method of reproduction. This is consumption but not predation But if a bird eats seeds then its stopping the flower from reproducing. This is predation. depends on if dead after interaction

per capita consumption rate of a predator given prey density based on time Total time = time searching for prey+ time killing prey

equation used for interactions between 2 species, interaction via consumption Logistic model only looks at 1 species growth over time dN/dt = rN(K-N-aN’)/K N - pop density of prey N’ - pop density of predator r - per capity pop growth rate t- time K-carrying capacity a - competition coefficient

the sp. i proportional effect that sp j has on sp. i effect of i on j is not the same as j on i ex if aij = 0.25 every j in the community affect i 0.25 times as much as an i affecting an i if aij>1 then you have more interspecies comp than intra and there is competitive exclusion

prey - dN/dt = rN-aNP Predator - dP/dt = c(aNP) - dp P -predator pop c - conversion efficiency factor d - per capita death rate aN - Predator funcitoning response (how fast a single predator consumes things) r - pre capita population growth rate of prey

type 1 - linear, increasing - higher pop density the higher the rate of consumption - ex spider in web with flies, more flies = more consumption Type 2 - saturating curve, like root x graph - as pop increases, fewer get consumed proportionally - wolf and rabbit, more prey consumed but wolf can only eat so much so fast Type 3 - starts off exponential but plateaus - aN, funct resp, increase expo in beginning but then saturation curve - ladybeetles, When they find colony they makes their area of predation smaller so it takes less time to find prey and they get more but at some point they can only eat so quickly.

like 2 sinusoidal graphs, slightly off phase, delay in predator increase when prey increases

any factor that causes a decrease in number of indivs in a population It could be a severe winter Or a predator It could be covid 19 It could be a change in the severeity in the tidal forces A rise in sea level Stock market crash Forest fire Could be a random new predator Any population regulating factor

Type -abiotic, biotic Freq - is happening regularly, randomly, regular but on a big scale Severity- is it normal or is going to kill a lot of things.