4 Life Histories with Notes PDF

4 Life histories 23 Friday, 20 October 2023 4 Life histories 23 14:56 Very different methods of reproduction and lots of variation The life history of a species is the pattern of survival an typical for a member of the species nd reproduction events Two bird species, relative similar s...

4 Life histories 23 Friday, 20 October 2023 4 Life histories 23 14:56 Very different methods of reproduction and lots of variation The life history of a species is the pattern of survival an typical for a member of the species nd reproduction events Two bird species, relative similar size, but blue tit lives 2 years Hummingbird much longer lived, produce far fewer eggs Very different ways of existing Kiwi's lay huge eggs, due to the fact they were never preda investing a lot into an egg. Lots of variation in life history, s and lay 10 eggs roughly. ated on and hence worth Life historyies fall upon axis of variation R = growth rate K = carrying capacity Don’t rally talk about r and k selection anymore Some animals are made for rapid growth but others for surviv Elephants slow - grow slow etc Rats live quick die young Other axis is how quick offspring production is done etc etc. ving c how long they spend together Life history trait is how individuals live Life history trait is how individuals live Life history trait is a component of fitness, but still part of phe enotype Reproductive value - number of offspring Individual expects (e.g. not going to have many at age 80) In stable population each individual expects to have otherwise population increasing or decreasing Reproductive value increases as they age initially they reproduce - expectation for reproduction rise ( only true in same size, stable population ) Age of maturity, reproductive value peaks at age of ma to reproduce, so expectation of future reproduction be to have over rest of life e reproductive value of 1 - - other individuals die before es, to keep same size population aturity - as some individuals start egins to fall to reproduce, so expectation of future reproduction be Reproductive schedules Different individuals and species may time their reprodu Is there a difference in fitness between these two genot First genotype the first is getting grandchildren in seco If this is modelled reproduction much quicker for first g egins to fall uction type ond year, second genotype won't. genotype. The Darwinian demon doesn't exist because of constraints These are examples of trade offs These are examples of trade offs Principle of allocation - got a certain pool of resources and ca You can put resources into maintenance of cells or reprod an use in different ways duction Pie of how you allocate your resources There are only certain ways you can divide up your resources There are only certain ways you can divide up your resources E.g if you have 10 energies to use you can do between points 8 re maintenance However you actually see posotive correlations between life E.g. here Birds that died in winter actually were the ones who did less thought have more energy for itself eproduction and 2 on history traits s egg laying which is backwards as Birds that died in winter actually were the ones who did less thought have more energy for itself House and car problem People have resources to spend, buy a house or car and someho Nice house bad car Bad house, nice car But this doesn't work, noramlly nice car and nice house or s egg laying which is backwards as ow split them r bad car and bad house But this doesn't work, noramlly nice car and nice house or Some individuals have more to allocate up Consequences to trade offs differences Yellow has more and can allocate more If there is more variation in condition of organisms In a pop correlation in life history traits pulation you get this positive Experimental evidence Some invidual of lizards, were; Females had ovaries removed some kept females ovaries. Ablate possibility of reproducing. In these you see these ones who got ovaries removed generally off y are bigger etc, showing a trade Selecting for life history traits and the effect it has on other life Evidence of negative correlation between larval negative e history traits e How should organisms allocate resources then? Evolution balances these across lifetime of organisms In blue they die earlier, hence reproductive success is overall lo earlier, as compared to green. ower and also does reproduction These fish eat small guppies but upstream in waterfall These eat large guppies and exist downstream Fish mature later and at larger size where there is less predation n More recently apparent that Body size gets smaller when predated Iteroparous - Semelparity and iteroparity differences His idea is that changing to semelpariry give of dying e you one more offspring at cost Hidden assumption that ruins this is - survival of offs Adult is already fully grown and alive/ survived so its Resolution of the paradox - P is adult survival and y is offspring survival Semelparous has to add p/y to litter size spring and adult are the same. s not the same Resolution of the paradox - P is adult survival and y is offspring survival Semelparous has to add p/y to litter size P is much higher than y so parent has to add lots of offsprin survives. Importance of relative survival of offspring compared to ad High reproductive investment in semelparous spe Expect semelparity if p/y is small and parent surv ng to make sure 1 of those dult ecies to offset their own death vival is low Itroparous When finished flowering it dies - seemelparoius These are related species ( same genu us ) These are related species ( same genu As conditions get better the plant invests more in Makes more flowers Reproductive success is less in dry sites, effort per episode constant with change in Semelparity is favoured in dry sites, becau of reproduction us ) n reproduction but relatively greater in telekii. Keniensis keep n moisture, but flower more frequently. use plants unlikely to survive to a second bout Salmon die in large numbers Huge difference in time spent alive Longest lived organism is this Atlantic clam - live to 500 yea Hydras seemingly immortal ars old Most organisms age and die Senescence is a cellular response characterized by other phenotypic alterations that include a pro The contribution of organism to next generation declines past age a stable growth arrest and oinflammatory secretome. of maturity meaning Selection becomes ineffective at removing mutations in old Traits/ mutations later on in life no longer come under se Over generations can get mutation accumulation due t Accumulation of mutations that have bad effect in late Accumulation of mutations in evolutionary time - not i der aged organisms election to this. That come on in later life er life. in ones lifetime Accumulation of mutations in evolutionary time - not i Comparing heteroyzgote and homoezygote populat Heterozygote have higher reproductive success for much Also these bad mutation accumulate idea is that these bad mut in ones lifetime tions in flies longer as the don’t get mutation accumulation as tations have a positive effect earlier in life Also these bad mutation accumulate idea is that these bad mut Called antagonistic pleiotropy Positive effect when young - negative effect when old tations have a positive effect earlier in life There are evidence for both of these ideas Unsure what actually shapes senescence Expect senesce to be greater when external factors causing E.g if likely to die in a year if you are that organism should j Invest in the here and now. g mortality are great just reproduce now. E.g if likely to die in a year if you are that organism should j Invest in the here and now. Rate of senencve is high when rate of mortality is high as y just reproduce now. you'd expect from previous slide Negative correlation with initial mortality rate This doesn’t really make sense ( not to me in biology ) Y axis just means senesce Need to think about role of Disease is important