Unit 4, Week 3: Population Ecology
Unit 4, Week 3: Population Ecology BIOL 1108
Popular in Biology 1108
Popular in Department
verified elite notetaker
This 6 page Class Notes was uploaded by Skyler Tuholski on Wednesday November 25, 2015. The Class Notes belongs to BIOL 1108 at University of Georgia taught by Dr. Farmer in Fall 2015. Since its upload, it has received 73 views.
Reviews for Unit 4, Week 3: Population Ecology
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 11/25/15
1111 13 162015 Population Ecology Wednesday November 11 2015 1252 PM Learning Objectives Describe how lifetables and survivorship curves represent populations over time Describe tradeoffs between survival and reproduction life history traits Relate population growth to organisms environments abiotic and biotic Population Ecology study of populations in relation to their environment 0 Births 0 Deaths 0 Immigration 0 Emigration Population density number of individuals per unit of area Population dispersion Spacing of individuals in a population 0 Clumped fungi and plants insects salamanders schools of fish flocks of birds 0 Uniform much less common Penguins 0 Random Windblown dandelion seeds Population Monitoring 0 Mark and Recapture xn sN I 5 number of animals caught during first sampling I n number of animals caught during second sampling I X number of animals caught in second sampling that were already marked I N estimated total size of population 0 Demography study of vital statistics of populations and how they change over time Usually deals with birth and death rates 0 Lifetables agespecific summaries of survival table 53 Life Table for Belding s Ground Squirrels Spermophllus beldingi at Tioga Pass in the Sierra Nevada of Californiaquot FEMALES MALES Number Average Number Average Number Proportion of Additional Number Proportion of Additional Alive at Alive at Deaths Life Alive at Alive Deaths Life Age Start of Start of During Death Expectancy Start of at Start During Death Expectancy years Year Year Year Ratet years Year of Year Year Rate39 years 0 1 337 1000 207 061 133 349 1000 227 065 107 12 2521 0386 125 050 156 248t 0350 140 056 112 2 3 127 0197 60 047 160 108 0152 74 069 093 3 4 67 0106 32 048 159 34 0048 23 068 089 4 5 35 0054 16 046 159 11 0015 9 082 068 5 6 19 0029 10 053 150 2 0003 2 100 050 67 9 0014 4 044 161 0 Biology Page 1 O Survivorship curves graphical representations of life tables that show how long various age groups live 1000 lt 100 10 Number of survivors log scale I Type 1 large mammals with few offspring and provide extensive child care I Type 2 moderate number of offspring some care Many lizards some rodents and invertebrates I Type 3 very large number of offspring no care Fish most invertebrates and insects Number of survivors log scale Percentage of maximum life span 0 Clicker Question Why do humans have a longer survivorship curve than squirrels and oysters Humans have fewer offspring than squirrels or oysters 0 Formula for growthyr of kids 22 x avg birth age x 100 0 Reproductive tables fertility schedules measure reproduction of a cohort for the life span of the cohort Records of female offspring produced by each age group cohort Biology Page 2 table 522 Reproductive table for Belding s Ground Squirrels at 1093 Pass Moan Mean Proportion Size of Number Avomgc of females Liners 0 humor Age Wrnmng Mules Female of FMquot Ne years a uttcv lemoch 391 a Line U sptznq39 l l 0 l quotn n 39 I I 3 ll U gt3 1 l l gt3 Val 4 3 gt 7 y M sly Table 522 0 Growth curves 0 Exponential each generation doubles in size Often results in environmental degradation 0 Logistic Population expands more slowly as it reaches its carrying capacity Realistic model dNdt rN1 lquotpnmnlial growth r r39 logistic grmx lh r39 l r A A 2 ll Time it gt 418 0 Reproductive TradeOffs O Semelparity reproduction only occurs once in an organism39s lifetime and then typically dies after reproducing Ex salmon agave I Occurs when survival rate of offspring is typically low and where the likelihood that the adult will survive to reproduce again is low 0 lteroparity Repeated reproduction Ex loggerhead turtle brazil nut I Favored in dependable environments where adult is expected to long enough to breed again and where competition for resources may be intense Biology Page 3 I Fewer but wellpositioned offspring 0 Rselection natural selection for traits that maximize reproductive success in environments that are not crowded Occurs in populations well below carrying capacity or where individuals face little competition Ex dandeHons 0 Kselection selection for traits that are sensitive to population density and are favored at high densities Densitydependent selection Kselection acts on pops near carrying capacity Ex humans if Selection m 0 Population Regulation Births and deaths Dispersal BDEpopulation growth OOO Selection i L 39lh up 7 paquot 4quot 3 9 J i a J I F iquot I 39 3 Tquot is i39 a if I fair In I39ll if Silurile ful llslimiting F iiifliuzepi ine Ii llquoti39t39 litt39 limmil El 151 til ii heftle mam rri Short life Super cial Il39 lilil innsh i 329 filmsill mature l Lilling lift Loin lltitlit39ltltii ilit 39 High jll39lll i39lfllllillit 39 Cfiaiiilllilll iililiEH quot mm 15 I Birth Immigration Deaths Emigration 0 Density dependent Limiting Factors determine carrying capacity of an environment for a species Population Size an be lumtwd by Natural disaster Competition Unusual weather Predation Parasmsm and disease 0 Factors that lessen population growth when density increases Places to live Pathogens transmission rate increases w high pop Predators easier to detect and capture prey Parasites easier to find host Biology Page 4 I E H llgll i 11wle film i Riellll relatllitiii lilips Density independent El Densitydependent regulation is a negative feedback loop higher the density the more some other factor reduces pop density 0 Densityindependent factors regulate populations I Ex prairie dogs were hunted by ranchers so the ferret population declined and is endangered because that was their main food source Prairie dogs are a keystone species therefore altering the density of many other dependent species I Predators can also limit the distribution of their pray Mussels are only found on exposed coastlines because their predators only live on sheltered coastlines O Bacteria are useful for studying population curves I Lag phase when you first inoculate plate I Log growth rapid increase I Stationary phase resources become scarce I Log Death phase population has used all resources and is rapidly declining Logor exponen al a gnounh 395 phase 8 a n 6 2 g Lag 2 phase 398 U o l 0 Time hr 0 Factors that allow populations to increase I Reduced infant mortality rate I Reduced overall mortality rates I Greater longevity I Females bearing progeny at a younger age 0 Clicker Question Why is the birth rate expected to decrease but world population growth is expected to increase 0 There is a lot of inertia built into population growth You can39t just reverse the expected growth rate quickly It is a very slow process 0 Clicker Question After being relatively stable for thousands of years why did human pop begin to dramatically increase beginning in 18005 0 Increased ease of transportation 0 Decrease in infant mortality rates 0 Clicker Question What exactly has allowed the human population to increase so dramatically and steadily since the 180039s Biology Page 5 0 Ancient sunshine fueled photosynthesis which led to current deposits of fossil fuels Biology Page 6
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'