Life Histories PDF

Life Histories 10.1, 10.4–10.13 © Scott 2024  Eggs Sperm...

Life Histories 10.1, 10.4–10.13 © Scott 2024  Eggs Sperm · small · yolk - ⑭ Short · · large lived Mating Systems Social constructs surrounding mate selection - mentypicallyare ew raising Promiscuous species develop no pair-bonds offspring ↳ no different individuals long term bonds will reproduce with , · bio-i nurture, no territory defence https://howlingpixel.com/wiki/Western_gull In species that develop pair-bonds, individuals can form: – One bond = Monogamy life long pair-bonds Both parents nurture and defend male + female look alike – Multiple bonds = Polygamy females many Y ↳ I male has Polygyny – bio-♀ nurture, bio-♂ defend https://www.kimballstock.com/results.asp?db=a&txtkeys1=harem for Polyandry – bio-♂ nurture, bio-♀ defend 7 I female has males one sex many http://www.uniprot.org/taxonomy/227175 © Scott 2024  can produce differences Sexual Selection between male a female Intrasexual selection occurs from competition within one sex (either ♂–♂ or ♀–♀) antlers -bigger – Traits evolve that intimidate others Body size Threat organs lantlers) Intersexual selection occurs when one sex has preferences of the other – Mate selection based on physical/physiological/behavioural characteristics – Traits evolve that attract based on the preferences Physical appearance Courtship songs Courtship dances 10.8 & 10.9 © Scott 2024  is a fixed income energy Life Histories Limited resources = limited energy intake Life histories describe how organisms spend (allocate) their energy – Survival & maintenance – Growth energy spent on one can't – Reproduction the be spent on other These choices must be made throughout an organism's lifespan – Choices have consequences © Scott 2024 Life History Traits 1. Body size (growth) 2. Age at maturity 3. Frequency of reproductive events 4. Number of offspring 5. Size of offspring (now much yolk is packed into eggs) 6. Parental investment 7. Senescence There are trade-offs for every energy allocation choice to maximize Lifetime reproductive success © Scott 2024 Life History Strategies Two major strategies include: Divert E to reproduction 1. Invest heavily in the current reproductive event ) little ↳ growth – Drain parent energy reserves ↳ survival can be compromised they only reproduce once lif Growth – ______________ they don't need to Survival – ______________ survive after) Fecundity – ______________ ↳ Fecundity reproduction egg production · 2. Invest in growth over reproduction – Delay reproduction to a future event Growth – ______________ Invest E into growth Survival – ______________ survive get large + ↳ Fecundity – ______________ later ↳ reproduce ↳ lower fecundity © Scott 2024 Cost of Reproduction care of taking In Scottish red deer (Cervus elaphus scoticus) younga mortality rate – Milk hinds have babies, yeld hinds do not – Energy spent on calving and nurturing young increases mortality of milk hinds because they reproduce greater risk of dying – The cost of reproducing in one year reduces the chance the following year Lower fecundity · less likely to have an offspring the following year babies last · if a yeld hind had no year one this they are likely to have year 10.5 © Scott 2024 then they will become milk kinds Cost of Reproduction When reproduction is prioritized, growth slows Douglas fir (Pseudotsuga menziesii) Round sardinella (Sardinella aurita) of the tree · investing in growth the reproduction 10.7 (ring size) rather © Scott 2024 (cones) The Trade-Off Female fecundity correlates with body size 18 month old bigger Producing eggs earlier, means fewer are produced females = more offspring the the bigger you start · more successful 10.8 · bigger crabs produce more eggs © Scott 2024 · if you wait to get bigger... then you can produce more offspring  reproducing reproducing later early 1 The Trade-Off It’s about the overall reproductive success don't grow grow larger – x = age in years anymore = so can have – bx = births at age x (birth rate) offspring more Start earlier = ________ more years to reproduce less – But size is smaller = ____________ offspring/year low – Cumulative offspring = __________ ones that less Start later = ________ years to reproduce the waited have caught up – Size is larger = ____________ more offspring/year ↑ – Cumulative offspring = __________ more 10.9 © Scott 2024 When to Begin Reproduction? Body size correlates with fecundity Age at maturity impacts final body size No reproduction max growth rate early reproduction Body Size Fecundity (growth is hindered) Body Size Age © Scott 2024 Life History Trade-offs Predict the relationship between seed size and seed number decreases – As seed size increases, the number of seeds produced _____________ Predict the relationship between seed size and survivorship increases – As seed size increases, the seed survivorship _____________ - – Is this the same in all conditions? does it germinate ? bigger seeds will have 4 survival rates & ⑧ feeds play a role embryo on but dry vs wet environments endosperm and a Overall reproductive success bigger seed would have more = seed number x seed size – Under environmental influence · same species may choose different strategies QE 10.1 © Scott 2024 How Often to Breed? Semelparous species breed only once in their life – Common among species with short life spans Potential for multiple generations in a season – Many insects – Rarer among species with long life spans When suitable seasons occur infrequently – Agave (Agave tequilana) – Cicada (Magicicada cassinii) – Not all individuals survive the reproduction event Salmon back to freshwater won't during migration some survive Iteroparous species breed multiple times in their lives © Scott 2024 How Many Offspring at a Time? Considered more with iteroparous organisms due to the reproductive costs Great tits (Parus major) – Survivorship changes with the number of babies increased Increasing brood size _____________ mortality Resources per offspring few eggs ↑ survival Masked booby (Sula dactylatra) – Siblicide increases available resources Wolves vs dogs wolves are wild (search + if mother has of litter size too somemart large kill food) food handed to them · dogs get chick litter size one kill the · large -will other © Scott 2024 Life History Classifications Strategy 1 Strategy 2 Body size small large Age at maturity Creproduction) early 1 a + e # reproductive events semelparous iteroparous Size of offspring small large Number of offspring few many Parental care low high Strategy 1 – put all of your eggs in one basket – Mortality of offspring = high needateles mortalityisnighyou if in next generation – Competition = low – Population growth = Increasing fast Strategy 2 – save effort for subsequent events – Mortality of offspring = low fewer offspring keeps competition – Competition = high under control – Population growth = Slow © Scott 2024 Variable Life Histories Not all populations of a species employ the same strategy from eachother Brook trout at two locations in Newfoundland close but separated · different environments fish are # #2 * bigger older – Freshwater River – Cripple Cove River Mean size at maturity 93 mm 163 mm same size in both Minimum size at maturity 70 mm 110 mm ↓ populations Fish @ 150 mm Body weight composed of eggs Fecundity ( = 5 eggs) 103 78 Egg Size (diameter; volume) 5 mm; 65 mm3 4 mm; 33 mm3 ↑ © Scott 2024 bigger egas with doesn't align #  * logically you should spread out germination period Bet Hedging SEED GERMINATION · water · temp High variation in reproduction duration is selected for – Seed germination over a range of days in spring - Frost – Cod spawning during periods of high productivity (algal blooms) bigger fish can pp * spread out spring spawning only plants kilseedlings that germinate after the frost will survive Spawning Large cod 1 Large cod 2 Time Large cod 3 Small cod 1 Small cod 2 http://www.theveryworstmissionary.com/2013/09/seedlings.html Small cod 3 High ↑ Productivity algeal © Scott 2024 blooms Copyright © All images copyright of Pearson Canada Inc. © 2015 unless otherwise noted. – Used with permission or under Fair Dealing as per Canada’s Copyright Act. This PDF file, any associated video recording, and PowerPoint is copyright Kevin Scott © 2024 This copyrighted work is made available for private study only and must not be distributed in any format. Do not upload copyrighted works to a learning management system (such as UMLearn), or any note-sharing website, unless an exception to the Copyright Act applies or written permission has been confirmed. For more information, see the University’s Copyright Office website at http://umanitoba.ca/copyright/ or contact [email protected]. © Scott 2024 Copyright © All images copyright of Pearson Canada Inc. © 2015 unless otherwise noted. – Used with permission or under Fair Dealing as per Canada’s Copyright Act. This PDF file, any associated video recording, and PowerPoint is copyright Kevin Scott © 2024 This copyrighted work is made available for private study only and must not be distributed in any format. Do not upload copyrighted works to a learning management system (such as UMLearn), or any note-sharing website, unless an exception to the Copyright Act applies or written permission has been confirmed. For more information, see the University’s Copyright Office website at http://umanitoba.ca/copyright/ or contact [email protected]. © Scott 2024