Capture and mark group within population (C1). 

Capture another group within same population (C2). 

Count number of recaptured marked individuals (R).

N= (C1XC2)/R

Dispersion patterns: 

Clumped 

Uniform 

Random

Dispersion patterns are how organisms are spaced 

Clumped: clumped resources, social clustering behavior (starfish) 

Uniform: competition, territoriality, individual space (pengiuins) 

Random: resources are abundant, rare pattern 

(dandelions)

Survivorship Curves (n_x)

Type I 

Type II 

Type III

n_x: plots number of surviving individuals 

Type I: juveniles survive, adults die 

(predators, humans) 

Type II: uniform death rate 

(prey, birds, small mammals, reptiles)

Type III: juveniles die, adults survive 

(fish, invertebrates)

Life Tables: 

m_x

l_x

l_xm_x

m_x: cohort fertility rate (m=Mating)

l_x: cohort survivorship rate (l=Longevity)

l_xm_x: cohort population growth 

Life Tables: 

Net reproductive rate

R₀: Σl_xm_x 

R₀ negative: population decline 

R₀ positive: population increase 

R₀ =1: population equilibrium 

explosive growth due to unlimited resources 

ΔN/ΔT = births - deaths over time period = r 

r = per capita growth rate 

 r_max = intrinsive rate of increase, growth without limits

Logistical Growth 

Logistical equasion 

fastest rate equasion

Logistical Growth: resource limitations prevent exponential growth 

K: Carrying capacity 

(dN/dT) = rN(K-N/K)

Fastest rate: N = K/2

Density Dependent Factors: 

Density dependent 

Density independent 

Inverse density dependent 

Density Dependence: population size regulated by density

Density dependent: mortality increases with density 

(predation, competition) 

Density independent: mortality not affected by density

(hurricanes, floods) 

Inverse density dependent: mortality decreases with density 

(protection in numbers, flocks) 

Reproductive Strategies 

Semelparity 

Iteroparity (Seasonal/Continuous)

Semelparity: Single reproductive event, repro and die

(butterflies, annuals)

Iteroparity: many reproductive events 

Seasonal: breeding seasons 

(deer) 

Continuous: reproduce any time of year 

(humans)

Life History Strategies 

r-selected

k-selected 

(rates of cohort death, fertility, competition)

r-selected: (Type III) high per capita pop growth (r) 

high fertility, high juvenile death 

poor competition

k-selected: (Type I) pop close or at carrying capacity (k)

low fertility, low juvenile death 

good competition

Innate behavior 

Fixed action pattern FAP

sign stimulus 

innate behavior: genetically programmed 

FAP: behavior continues until completed 

sign stimulus: proximate cause: stimuli for behavior

ultimate cause: reason why behavior happens 

(egg rolling, attacking red belly) 

Learned Behavior: 

Habituation 

Habituation: non-associative learning, ignore if no consequence 

(environment)

Learned Behavior: 

Classical Conditioning 

Operant Conditioning 

Imprinting

classical conditioning: associative learning: conditioned response of conditioned stimulus 

(pavlov's dog)

operant conditioning: trial-and-error

reward vs consequences 

(bird eating monarch)

Imprinting: phase sensitive learning 

(goslings) 

Learned behavior: 

Cognition

congnition: solve problems with observation and analysis 

tool use and modification 

(chimps stacking boxes) 

Local Movement: 

Kinesis 

Taxis

Kinesis: movement in response to stimulus 

Taxis: movement towards/away from stimulus 

(chemo-, photo-)

Migration

Piloting 

Orientation 

Navigation 

Piloting: following landmarks 

(coastlines, mountain ridges) 

Orientation: follow compass bearings 

(juvenile birds)

Navigation: adjust compass bearings 

(experienced birds)

Foraging 

Optimal foraging

Territory size 

optimal foraging: maximum energy intake to minimum energy expenditure 

intake - expenditure = positive number net gain 

Territory: fixed area which excludes other individuales 

size dependent on optimal foraging 

Living in Groups 

Hunting 

Reduced predation 

Hunting: Hunt cooperatively to maximize optimality 

(dolphins) 

Many eyes hypothesis: scanning time vs foraging time vulnerable to cheaters 

Safety in numbers: "selfish herd" 

Altruism 

group selection vs individual selection 

criticism 

altruism: favoring others survival over individuals

group selection: individual sacrifices for betterment of group 

criticized: altristic individuals do not pass on genes 

assumes individuals can predict food resources 

Altruism 

Inclusive behavior 

Kin selection 

Hamilton's Rule

inclusive behavior: favors own genes and relatives genes (coeffient of relatedness: r) 

kin selection: favor relatives genes over own 

Hamiltons rule: rB › C 

Altruism 

eusocial haplodiploidy

Haplodiploidy: r_father: .5 + r_mother: .25 = .75 

high inclusive fitness

(colonial bees, ants, naked mole rats) 

Mating systems: 

Monogamy

Mate guarding 

Male assistance 

Female-enforced 

Monogamy: one mate, monomorphic 

mate guarding: male guards female from being fertilized to prevent cuckoldry 

male assistance: male assists in parenting to increase offspring survival 

female enforced: females guard males from wandering 

Mating systems: 

Polygamy 

Polyandry 

Resource based 

harem mating 

communal courting 

Polygamy: multiple partners, dimorphic 

polyandry: one male, many females 

resource based: male guards resources, female visits 

(deer)

harem mating: male guards herd of females 

(horses)

communal courting: males display in lek, intersexual competition and female's choice 

(peacocks)

Mating systems: 

Polygamy: Polygyny

 one female, many males

reverse sexual dimorphism 

breeding is short, lots of resources 

(widow spiders, seahorses)

groups containing altruists more likely to survive than groups containing selfish individuals – altruist sacrifices so  group survives (communism)

CONTROVERSY
selfish individuals have more young < fitness 

natural selection works faster on individuals who die                              off more quickly than groups
how can individual predict future resources and need                                   to sacrifice today for the future

altruistic behavior tied to coefficient of relatedness (r), will protect own and relatives genes 
Hamilton's Rule
Haplodiploidy 

Monogamy 

Mate guarding 
Male assistance
Female enforced  

Mate-guarding hypothesis:
males prevent females from being fertilized by other males, prevent cuckoldry
happens when females are scarce
Male assistance hypothesis:
better offspring survival with a “daddy”
ensure survival of offspring (birds share incubating duties)
Female-enforced monogamy:
females prevent males from mating with other females
minimize parental care for other female’s offspring

Polygyny

resource based

harem mating 

communal courting

resource based: males monopolize territory, females visit and get breeded (deer) 

harem mating: males dominate a herd of females (horses) 

communal courting: males display in lek and females choose their mates (peacocks)

intraspecific competition 

interspecific competition 

interference competition 

resource competition

intra/specific: individuals within a species compete 

inter/specific: individuals of different species compete 

interference: individuals interact directly aggressively (defending territory)

resource: individuals interact indirectly by consuming all the resources (caterpillar eats entire leaf) 

fundamental niche

realized niche

Fundamental niche: range that a species COULD occupy when no other species around 

Realized niche: range that species DOES occupy with other species around 

competitive exclusion principle

resource partitioning 

character displacement 

competitive exclusion principle: two species with same niche cannot coexist, one will outcompete the other (paramecium experiment)

resource partitioning: similiar species coexist with different niches (warblers)

character displacement: physical changes due to competing w other species (galapagos finches beaks)

1. defense 

2. cryptic camoflage coloration 

3. aposematic coloration 

4. mimicry 

5. predator satiation 

mullerian mimicry: two toxic species look similar, reinforce signal (viceroy, monarch)

batesian mimicry: one palatable species looks similar to toxic species, weakens signal (hover fly looks like bees) 

Latitudinal gradient 

hypotheses: (3)

Latitudinal gradient: more species in tropical than polar 

1. Time: glaciers retreated polar more recently, haven't had time to reintroduce multiple species 

(doesn't account for marine life) 

2. Area: larger areas can support more species than smaller areas, true in local communities

(doesn't work with large tundra or open oceans) 

3. Productivity: more energy supports more diversity

evapotranspiration rates

(doesn't work with fertilizer polluted lakes, some deserts)

Hs = -Σp_i(lnp_i)

p_i: proportion of all individuals in a species

diversity stability hypothesis 

high diversity = high stability 

more resistant to changing conditions, take advantage of different conditions