front 1 life history strategies | back 1 sets of physiological and behavioral features that incorporate not only reproductive traits but also survivorship, length-of-life characteristics, preferred habitat type, and competitive ability |
front 2 life history strategies have important implications for | back 2 how populations grow and for the reproductive success of populations and species |
front 3 types of life history strategies | back 3 -iteroparity versus semelparity -continuous versus seasonal iteroparity -R and K selection -grime's triangle |
front 4 semelparity (common in insects and invertebrates) | back 4 a pattern when offspring are produced in a single reproductive event |
front 5 other organisms reproduced in | back 5 successive years or breeding seasons |
front 6 iteroparity (common in vertebrates and perennial plants such as tree) | back 6 a pattern of repeated reproduction at intervals throughout the life cycle |
front 7 seasonal iteroparity | back 7 species such as birds, mammals, or temperate forest trees have distinct breeding seasons that lead to distinct groups of individuals all born at the same time |
front 8 continuous iteroparity | back 8 for a few species, individuals reproduced repeatedly and at any time of the year (as well as some parasites, and some primates exhibit this strategy |
front 9 semelparous mode will favor if | back 9 the environments is stable, a single act of organism, will devote all energy in making offspring and not maintaining its own body |
front 10 iteroparos mode wil favor is | back 10 survival of juveniles is very poor and unpredictable, repeated/long reproductions will increase survival |
front 11 K-selected species | back 11 stable populations adapted to exist at or near the carrying capacity, K, of the environment |
front 12 r-selected species | back 12 high rate of per capita population growth, r, but poor competitive ability |
front 13 according to McArthur and Wilson such strategies can be considered a | back 13 continuum |
front 14 type I | back 14 most individuals die late inlife |
front 15 type II | back 15 individuals die at a uniform rate |
front 16 type III | back 16 most individuals die at a young age |
front 17 ruderals | back 17 are adapted to take advantage of habitat disturbance (annual plants adapted to colonizing disturbed areas) |
front 18 competitors | back 18 are adapted to live in highly competitive but benign [not harmful] environments (many tree species) |
front 19 stress tolerators | back 19 are adapted to cope with extreme environmental conditions such as high soil salt or temperatures that exist in salt marshes and deserts (mangroves and cacti) |
front 20 grime's triangle | back 20 plant life histories based on a model in which stress, disturbance, and competition are the important selective factors (based on data in grime 1979) |
front 21 life history strategies are subject to | back 21 evolution |
front 22 virginia opossums (Dipelphis virginiana) life only | back 22 20 months on average |
front 23 Austad (1993) found that possums living on Sapelo Island (GA) where no predators are found, lived | back 23 25% longer than average |
front 24 life history traits vary | back 24 widely among different species |
front 25 life histoy traits involve trade-offs | back 25 limited amount of energy to invest in survival, maintainance, and reproduction |
front 26 natural selection optimizes life history in light of trade-offs | back 26 -maximizes number of offspring surviving to maturity -depends on likelihood of survival to different age classes |
front 27 kirkwood (1979,2000) noted that | back 27 cells require repair and argued that narutal selection should favor levels of seld-repair that are good enough to keep an organism in sonund condition only for as long as it has a reasonable chance of reproducing |
front 28 data from opossums support predictions from | back 28 life history theory (island possums appeared to age slowly than the mainland possums) |
front 29 predation risk drives life history evolution in | back 29 guppies |
front 30 reznick et al. (2006) | back 30 compared guppies in streams with numerous predators to those in streams with few predators. fouund effect on number of offspring, offspring weight, and mean size at sexual maturity |
front 31 trnasplant experiments deomstrate | back 31 rapid evolution of life history traits |
front 32 transplanted fish exhibited rapid life history evolution in the | back 32 expected directions |
front 33 trade-offs arise when | back 33 allocation of resources to one life history trait reduces investment in another trait |
front 34 investment in reproduction often comes at the | back 34 expense of growth or body maintenance |
front 35 brown anolis (anolis sagrei) with their ovaries removed, | back 35 grew faster, bigger, and lived longer |
front 36 females are more likely than males to provide parental care | back 36 -males have less investment -males have uncertain paternity -these roles reversed in some species |
front 37 fishers principle | back 37 states that a 1:1 sex ration is an evolutionarily stable strategy, but not all individuals are able to mate at all times |
front 38 operational sex ratio (OSR) | back 38 is the ratio of male to female individuals who are available for reproducing at any given time (sexual selection becomes an important agent when members of one sex compete with each other to mate) |
front 39 degree of polyandry | back 39 mean number of mates per females |
front 40 male gulf pipefish cafry fertilized eggs in pouches. because males make bigger investment in rearing offspring, | back 40 males choose to mate with only a few high-quality females, eggs from larger females are more likely to develop into viable offspring |
front 41 organisms may regulate the number of offpring to maximize | back 41 -miscarriage -cannibalism |
front 42 organisms may also regulate the sex ration of offspring to | back 42 maximize fitness |
front 43 blank and nolan (1983) | back 43 found youn female red-winged blackbirds produced more females, while order females produced more male |
front 44 sand gobies cannibalize eggs | back 44 these adjustments increase the proportion of offspring surviving |
front 45 frequency-dependent selection | back 45 -production of each sex favored when rare -rare sex has more mating opportunities |
front 46 fewer feamles | back 46 sex ratio stabilizes (natural selection will favor mutant females that produce more males) |
front 47 any population that deviates from the 50:50 sex ratio will be | back 47 shifted back to it by natural selection |
front 48 females may alter sex ratios of | back 48 offspring |
front 49 hymenopterans | back 49 often exhibit haplodiploidy (haploid males, diploid females) so females can alter sex ratio of offspring by choosing whether or not to fertilize eggs with sperm (fig wasps produce fewer mles with larger clutches) |
front 50 trivers-willard hypothesis | back 50 states that parents in good condition tend to bias their offspring sex ration toward the sex with a higher variation in reproductive values, whereas parents in bad condition favor the opposite sex |
front 51 mothers alter sex ratio depending on conditions | back 51 -produce females when in poor condition; daughters will likely have some offspring even if in poor condition -produce males when in good condition; males likely to benefit more from being large and will more readily attract mates |
front 52 some species switch sex in | back 52 trivers-willard-predicted manner (start as females and breed as such when young and small, but switch to male when they are large) |
front 53 sex ratio adjustment in seychelles warblers | back 53 -with high resources females favored -up to three helping daughters beneficial -with low resources males favored -disperse away from poor habitat |
front 54 strategies to maximize offspring produced over a lifetime can | back 54 differ for the sexes |
front 55 among penduline tits (remiz pendulinus), mothers and fathers has interest conflict over who should provide care the longest | back 55 consequently, male-only care, female-only care and biparental desertion all occur |
front 56 parental-offspring conflict | back 56 occurs when parents benefit from withholding parental care from some offspring and invest in other offspring |
front 57 skylark chicks within a nest compete for | back 57 attention with loud begging calls and bright red mouths |
front 58 triming the feather of this chicks makes them | back 58 appear black, influencing parental feeding rates (sibling competition in American coots) |
front 59 offspring-offspring conflict (sibling rivalry) | back 59 occurs when sibling compete for parental care for parental care or limited resources (in some cases it can lead to siblicide/the killing of another sibling) |
front 60 parent-of-origin effect | back 60 effect on the phenotype of an offspring caused by an allele inherited from a particular parent (ex. hinny: result of horse stallion + female donkey) |
front 61 genomic imprinting | back 61 occurs when genes inherited from one or the other parent are silenced due to methylation (offspring express either maternal or paternal copy of gene, but not both) |
front 62 methylation | back 62 the process by which methyl groups are added to certain nucleotides (associated with altered gene expression) |
front 63 wilkins and haig (2003) suggest that | back 63 imprinting genes evolved through conlfict between parents which is resolved in their offspring |
front 64 intralocus seuxal conlfict | back 64 is a conflict between the fitness effects of alleles of a given locus on mals and females |
front 65 senescence | back 65 deterioration in the biological functions of an organisms as it ages (cells accumulate malformed protein, immune less effective, etc) |
front 66 calorie restriction can | back 66 slow the aging process (genes involved in repair switched on under stress |
front 67 may involve trade-offs (increase fitness of an allele while decrease fitness of another allele) | back 67 worm mutants that age more slowly have lower fitness |
front 68 transcription factor DAF-16 controls the expression of a battery of genes, many of which have small effects on | back 68 lifespan (promoting either aging ot longetivity) in Caenorhabditis elegans |
front 69 genes that promote ageing include | back 69 some that encode yolk proteins and insulin-like INS-7 |
front 70 actuarial and reproductive senescence | back 70 age-related declines in survival and reproduction respectively (the rule in free-ranging populations of vertebrates |
front 71 hamilton (1966) proposed that | back 71 the decrease in the force of natural selection inevitably leads to actuarial senescence in any age-structured population, but does not adress reproductive senescence |
front 72 the force or strength of natural selection, a measure of how strongly selection acts on survival and/or reproduction, | back 72 declines as a function of age |
front 73 aging exists because | back 73 selection is weak and ineffective at maintaining survival, reproduction, and somatic repair at old age |
front 74 mutation accumulation (MA) | back 74 aging evolves because selection cannot efficiently eliminate deleterious mutations that manifest themselves only late in life |
front 75 antagonistic pleiotropy (AP) | back 75 aging evolves as a maladaptive byproduct of selection for increased fitness early inlife, with beneficial early-life effects being genetically coupled to deleterious late-life effects that cause aging |
front 76 aging clearly shortens lifdespan, but lifespan is also shaped by | back 76 selection fo an increased number of lifetime reproductive events (balance with pros and cons) |
front 77 mother hypothesis | back 77 risk of reproduction at older age selects for reduced fertility (investment in current offspring) |
front 78 grnadmother hypothesis | back 78 loss of fertility associated with shift in investment to grandchildren |
front 79 human females live | back 79 long-reproductive lives |