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Flashcards in Ecology Deck (485)
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241

nestling

eggs that hatch

242

fledglings

birds that can fly from nest

243

in order to construct age specific life table

follow cohort from eggs to adults for 1 generation

244

blue tit cohort

50 eggs followed, x eggs lost, y nestlings, x nestlings die, y fledglings, x fledglings die, y new adults, x new adults die, y adults left

245

survivorship calculated

relative to original cohort
3 new adults left, out of 50 eggs = 6% survivorship

246

mortality calculated

relative to each stage
3 new adults, 30 fledglings = 1 - (3/30) = 90%

247

time-specific life table

age structure at single point in time
long lived, large animals
snapshot in time
'static life table'
requires age distribution of a population

248

determining age for time specific life table

growth rings- mussels/clams/trees/fish scales
cross section of tooth- large animals
horn growth- mt sheep

249

survivorship in time specific life table

I_x = N_tx / N_t
number entering age class / total count

250

mortality

1000q_x = ( N_tx - N_tx+1 ) / N_tx
number entering age class x, minus number in age class x+1 divided by number entering age class x

251

life expectancy

e_x - expected number of additional years of life remaining at any specific age

252

lowest mortality rates

intermediate age- healthiest, predators attack old and young

253

more information in

mortality rate curve than survivorship curve

254

Idealized survivorship curves

Type I
Type II
Type III

255

survivorship curve type I

k-strategists, many mammals, number of survivors relatively constant till later age

256

survivorship curve type II

many birds, small mammals, lizards, turtles, linear with negative slope, probability of survivorship is same each successive year

257

survivorship curve type III

many invertebrates, fish, amphibians, plants, r-stratigists, why they lay so many eggs, largely decreasing survivorship at early age

258

dominant cause of survivorship curve shape

predation

259

atual survivorship curves

are ~same shape, lower (in survivors) than idealized curves

260

population growth

occurs when births (natality) and immigration exceed mortality and emigration

261

ASFR

age specific fecundity rate

262

ASFR =

average number of male and female offspring produced per female for each class

263

TFR

total fertility rate
average number of male and female offspring produced per female over her lifetime

264

TFR =

ASFR x number of years in age class (range)

265

critical information for population growth

sex ratio- life tables often calculated only for females

266

importance of sex ratio

A=10 reproductive adults, B=100
A produces 9X more offspring than B?
A= 1 male, 9 females
B= 99males, 1 female

267

NRR

net reproductive rate

268

NRR =

Ro = ∑ Ixmx

269

Ixmx

survivorship of reproductive females in any age group * number of daughters produced for each age class of female

270

Ro

number of breeding daughters that will be produced by each breeding female in the population per generation