Ecology- conditions

• latitude: causes incident radiation and seasonality
• timing and strength
• uneven heating causes wind

• movement of air (and rain) due to earths rotation
• affects climate in different areas

• characteristic types of vegetation found across earths surface
• dictated by climate- temperature and precipitation
• latitude, weather patterns, ocean currents, topography all affect biome location

• direction surface faces
• slope (amount of rain that soaks in, water storage)

• refelection of a surface
• high: reflective (water, snow, ice, light colors)
• low: dark colored, forests

• bigger: causes lots of pores which allow water to move thru
• smaller: holds water in

• gravel road (base components affect acidic environment)
• impermeable surfaces (roads)
• irrigation
• CO2 concentrations

• summary of all the resources requirements and condition tolerances of a organism
• bounds on where an organism cal live, grow, and reporduce

studies what determines the distribution and abundance of populations

• determine sustainable harvest levels
• minimum populations sizes for threatened and endangered species
• control of pests

birth, death, immigration, emigration

constantly accelerating or decelerating

each individual is predicted to add same number of new individuals (or lose)

per capital growth rate is constant

• used to predict the change in size of a population growing exponentially, when individuals only reproduce only at a specific time each year (discrete breeding)
• generations do not overlap

generates periodic estimates of population size

N_(t) = N₍₀₎ Y^t

Its the RATIO thats constant, not the number added or lost from population

used to predict the change in population size growing exponentially when individuals reproduce continuously and the generations overlap

N_t = N₀ x e^rt

generates instananeous estimates of populations size

r = instantaneous per capita rate of population increase

N_(t) = N₍₀₎ert

• dN/dt = rN
• dN/dt = net rate of population change, rate at which the size of the population as a whole is changing at a given instant in time, slope of line tangent to anywhere on the curve

Nt = N0 x ert

r = lnY

• curves predicted by both models are unchanging thru time
• due to per capita rate of increase or decrease is unchanging
• biological processes contributing to population growth are unchanging too (birth, death, immigration, emigration)

• another method to predict population growth, based on geometric
• more detailed: focuses on survival and reproduction of different stages of an individual (age, size, dev. level)
• transition probabilities: likelihood of each possible transition between 2 categories

• 2 field seasons
• year 1: assign stages and count number in each
• year 2: determine probability of transition by comparing 1st year to 2nd year

• stages based on biomass (plant size)
• models run until population is stabilized and lambda is calculated

• native: evolved within a given geographic area
• exotic: evolved outside a given geographic area
• invasive: rapidly spreading, dominates areas into which is spead
• non-invasive: not rapidly spreading

ease with which a new species enters a community

Edge vs intermediate vs center plots represent invasion, growth and today,

introduction of natural enemies from an invasive exotic species native range to control the invaders population in a new area

controversial- expense, lack of effectiveness, bad outcomes

Y = N_(t+1)/N(t)

• Y >1 : population increasing
• Y < 1 : population decreasing
• Y = 1 : constant

when Y stabilizes Y = N_(t+1)/N_(t) is the same from timepoint to timepoint

model uses same transition likelihoods. biology driving population to increase or decrease is not changing

• things that take a bigger percentage cut out of larger populations
• must decrease reproduction/immigration, or increase death/emigration
• intraspecific competition is big factor

• use or defense of a resource by one individual that reduces the availability of that resource to other individuals
• same species (have same needs)

food, nutrients, water, oxygen, space, structures

• might be unable to get limiting resources
• must look harder and further, energy expense
• increase stress (defending territory, aggression to individuals)

• predators (as prey increase, predators eat them)
• parasites
• disease (higher density, increase disease)

• density dependence: negative (population increases, growth rate decreases)
• postiive (small populations, panda)

• density independent: effects population regardless of size, based on proportion, no logistic growth