Ecology Chapter 10

Front 1

N(t+1) = (R0)(Nt)

Back 1

Nt = the number of individuals in generation

Nt+1 = the number of individuals in the next generation

R0= net reproductive rate

this equation gives an estimate of population in next generation

Front 2

if we wanted to estimate the change in population size, what equation would we use

Back 2

dN/dt = (b-d) N

b = birth rate

d = death rate

N = population size

Front 3

intrinsic rate of increase

Back 3

rate at which a population will change in size

dN/dt = rN

Front 4

greater values of (r) lead to...

Back 4

faster population growth

Front 5

(r)(N)

Back 5

exponential or geometric growth model

measures population size over time

Front 6

geometrically population growth

Back 6

when a population breeds seasonally

J shaped curves because no constraints on population growth

Front 7

exponentially population growth

Back 7

species reproduce almost continuously and generations overlap

J shaped curves because no constraints on population growth

Front 8

limitations to exponential growth

Back 8

resources will become limiting

the population will crash after numbers exceed sustainable levels of resources

the rate of population growth will slow as the population approaches resource limitations

Front 9

how to account for limitations of exponential growth model

Back 9

resource availability should reduce the rate of growth of a population

this limitation can be incorporated into a model to reflect changes in the pattern of population growth

Front 10

carrying capacity (K)

Back 10

the total number of individuals a habitat can support for a given population

K is incorporated into the logistic model of population growth to model changes in population size when growth is constrained

Front 11

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

Back 11

correction factor

how to build logistic growth model

if correction factor is large, population will increase

Front 12

population regulation

Back 12

processes that create bounds in fluctuations of population size

Front 13

density dependent regulation

Back 13

correlation between changes in population size and either birth rate or death rate

shaped by biotic interactions

Front 14

density independent regulation

Back 14

changes in population size are not related to changes in birth and death rate

driven by environmental factors

Front 15

equation for predicting thrip population

Back 15

Andrewartha and Birch (1954)

Front 16

life history

Back 16

any aspect of the developmental pattern and mode of reproduction of and organism

Front 17

life history strategies

Back 17

mechanisms by which organisms deal with or circumvent potentially harmful interactions and maximize reproductive success

adaptive strategies formed throughout natural selection

Front 18

semelparity

Back 18

when offspring are produces in a single reproductive event

common in insects

these organisms may live for many years before reproducing once, then dying

stable environment

Front 19

iteroparity

Back 19

the pattern of repeated reproduction at intervals throughout life cycles (seasonal)

common in vertebrates and perennial plant (trees)

variation occurs in the number of reproductive events and in the number of offspring per event

poor environment

Front 20

continuous iteroparity

Back 20

individuals reproduce repeatedly at any time of the year

parasites, primates

Front 21

bet hedging

Back 21

some species show characteristics of both r and K selection

Front 22

K selected species

Back 22

at risk of extinction

tend to be bigger

require more habitat to live

tend to have fewer offspring, so populations cannot recover as fast

breed at later age