BIOL31134: Optimisation, Behaviour and Life Histories (Learn)

OBLH11: Identify and describe the research on the cost of reproduction in Atlantic Puffins, including the methods used, the findings, and what this supports...

Wernham & Bryant (1998): manipulation experiments as gave extra food to young of experimental group so parents have reduced effort, while no extra food to control group • Found no difference in proportion of parents returning (from the 2 groups) in the year after the experiment • However, found fledging success greater in experimental group(68% vs. 24%) & young of experimental group in better condition. • Conditions for these birds not very good in years of experiment, so in line with general idea that costs may only be revealed in bad years.

OBLH1: Define what sex is...?

"the recombination of genes from separate sources into a single organism"

OBHL12: Describe some of the potential reasons why females don't develop more oocytes to prevent menopause, and what are the medical implications in relation to this...

1. Adaptive: based on costs & benefits of reproduction after 45-50 yrs 2. Non-adaptive: side-effect of ageing • Indicates if adaptive = 'good' → don't interfere...? • But adaptive may be 'bad' for health I.e. maladaptive • So adaptive explanations are: (i) Benefit outweighs cost (ii) Lifespan long enough for selection to act.

OBHL12: Identify the two main theories as part of trade- offs and optimality (the evolutionary theories for decay)...

1. Antagonistic pleiotropy - by Williams (1957) 2. Disposable soma - by Kirkwood (1977)

OBLH11: Describe the two elements that individual variation in behaviour represents....

1. Noise around optimum (mean) 2. Consequence of underlying individual differences, with each animal at its own optimum

OBLH2: Who came up with the theory of sex allocation?

Charnov (1982)

OBLH11: Identify and describe the research on a certain bird of prey to understand the internal cost of reproduction, including the methods used and the findings

Daan et al., (1996): experimentally manipulated brood sizes of 39 kestrels, adding or removing eggs so that nests were either i) reduced, ii) control, or iii) enlarged • Used Doubly Labelled Water (DLW) technique to estimate energy expenditure of parents raising young • Studied time of death of parent, based on return of dead individuals by public (leg ring used to identify birds) • Found increased effort led to greater mortality over winter (low future reproductive success) → kestrel dropped dead from exhaustion

OBLH8: Describe the research evidence for Fisher's Theory by Blows et al. (1999)... (check - not fini)

Drosophila: Blows, M.W. et al. (1999). Rapid evolution towards equal sex ratios in a system with heterogamety, Evolutionary Ecology Research, 1, 277-283. (finish)

OBLH3: Identify and describe the female perspective in terms of the six different benefits of mating, including examples of these if possible...

Females can benefit from multiple mating Fertility insurance - i.e. have enough, fertile, sperm to fertilise eggs Extra care - trading paternity for male help (e.g in dunnocks, some females have more than 1 social mate, & each male feeds the young in proportion to how many times he has copulated with the female. Females with 2 mates have higher fledging success than monogamous females, due to extra help) Too costly to resist - only 'benefit' to the female is lower risk of injury Better genes - by mating with >1 male & getting their sperm to compete for her eggs, she may have a chance of getting fertilised by better genes Increased genetic diversity - e.g. in adders (that are inbred) females who mate multiply have offspring with higher viability than females who don't (Madsen et al (1992)

OBLH6: Describe the findings of Holland and Rice (1999), including what this indicates...

Found after 47 generations, the longevity of the monogamous females was higher, thus supporting sexual conflict theory • If mated to males from ancestral (unselected) stock, found survival of females from monogamous line was lower than females from polyandrous line • Suggests that monogamous females had lost some of their ability to resist negative effects of mating with males • Also found lower overall reproductive rate of polyandrous line & lower fitness, which demonstrates the cost of sexual conflict.

OBLH7: Identify and describe the research testing the theory of adaptive fat levels, including the researh methods and the findings...

Gosler et al. (1995): • Collected long-term data on great tit population • Sparrowhawk (main predator) abundance declined in '70s due to DDT (organophosphate pesticides) & then recovered • Looked at changes in great tit mass in relation to changes in predator abundance • Found great tits were heavier when sparrowhawks were rare • Wrens (control as rarely killed by sparrowhawks) had no change in mass

OBLH6: Describe Sex ratio distorter discovered in the mosquito Aedes (that spreads sleeping sickness), including how/why this has spread....

Has XX-XY sex determination like us, but some populations are male-biased Due to meiotic drive genes (two tightly linked genes) on the Y chromosome One gene produces a toxin that breaks down the X chromosome at meiosis Other gene confers resistance to toxin on its own Y chromosome, so biases meiosis in favour of Y chromosome • Genes on Y only passed on in males, so favours own spread at expense of X

OBLH 12: Patterns of reproduction and death Semelparity vs. iteroparity Give some examples of semelparity

Marsupial mouse, Antechinus Males shag themseves to death Sockeye, Pacific salmon Reproduce & die, use all resources & highly energetic

OBLH4: Identify and describe experimental research that provides evidence for the parasite theory, including any flaws with this study...

Milinski (1990): • Used sticklebacks as males are red in breeding season (red is from carotenoids via diet) • Females allowed to choose between parasitised & healthy males • Choice trials under white or green light • Found in white light, choose healthy males, but in green light, choose randomly • Issue: may be less motivated to choice under weird lighting. So maybe not because shades of RED can't be discriminated, but because females are scared under the odd lighting etc.

OBLH13: Identify and describe the research on how temperature can cause of 'stress' to result in Fluctuating Asymmetry (as part of environmental causes), including the research methods used and the findings...

Mpho et al. (2002): used different experimental treatments as mosquitoes (Culex pipiens) were reared at different temperatures (25°C, 30°C, or 37°C) & the lengths of the wings etc were measured on right & left side • Found as the temperature increases there is increasing amounts of asymmetry in wings for both males & females • So there was a relationship between FA values for a number of wing morphological traits & developmental temperature

OBLH11: Identify and describe the research on the importance of breeding timing for blue tits, including the methods used and the findings

Nilsson & Svensson (1996): these birds moult once a year immediately after breeding, so carried out experimental manipulation as delayed breeding by removing 1st clutch of some breeding pairs (2nd clutch laid a week later) • Caused costs of female having to lay a second clutch & have to feed young later than the best time • Found experimental females delayed moult, while compared to controls, experimental birds had higher energy expenditure & higher mass loss in winter as well as a lower survival likelihood to next year • Also found experimental females laid later in following year • Indicates trade off between reproductive effort & moulting effort as poor feathers → poor insulation.

OBLH8: Describe the Conflict over the sex ratio as studied by Trivers & Hare (1976), including what forms the basis of this model...

Reproduction in social hymentoptera is haplodiploidy • Males = haploid, unfertilised egg, females = diploid, fertilised egg • Isn't just the mother who controls allocation of resources, as relatedness between interested parties differs • E.g. worker to sister relatedness = 75%, vs worker to brother relatedness = 25% • Based on Fisher's sex ratio theory & Hamilton's kin selection

OBLH4: Identify and describe experimental research in birds that provides evidence for the parasite theory, including any issues...

Thornhill & Zuk (1990) • Male Red Jungle Fowl have combs, wattles, long tails, colourful feathers • When infected by blood diseases, comb is particularly affected • Found in choice between parasitised versus healthy males, comb is best predictor of choice • Issue: correlation doesn't equal causation

OBHL 12: Identify and describe the research on semelparity vs. iteroparity for two different plant forms of lobelias, including the methods used, the findings, and what this indicates...

Young (1990): analysed long-term data on two species of Mount Kenya lobelias which were the Lobelia telekii & Lobelia keniensis • Found despite growing in dry habitat & being semelparous L. telekii greater reproductive output per flowering episode than that of the iteroparous L. keniensis in wetter habitat • Mutual species of bird that pollinates both, greater reproductive output for L telekii, suggests environment determines strategy • But different species ― not ideal comparison.

OBLH8: What does the equation below represent (NfCf) / (NmCm) = rf / rm

rf / rm is called the relatedness asymmetry Investment in females/Investment in males = relatedness asymmetry If relatedness asymmetry = 1, Equal investment (Fisher).

OBLH8: What did Bob Trivers define parental investment as, and what could this mean in terms of cost...

• "the reduction in future expected reproductive success due to investment in the current offspring" • So may be sex differences in parental investment after weaning • In some species, (some of) the investment is repaid e.g. Helpers at the nest or den.

OBLH6: Describe Sex ratio distorters in a certain species of wasp as an example of conflicts between genes in the same body.....

• 'msr' (maternal sex ratio) produces female-based sex ratios in the parasitoid Nasonia (haplodiploid) • msr is a degenerate bacterium living in the cytoplasm A zygote's cytoplasm comes from the egg, not the sperm • msr, being cytoplasmic, is only inherited down the female line • By converting an unfertilised egg to diploid (by causing the chromosome numbers to double) it ensures all-female offspring

OBLH8: Describe the conflict over the sex ratio in social insects as demonstrated by ants when monogamous mating...

• 1 queen mates with 1 male, so queen isequally related to sons & daughters (1:1 investment in reproduction) • Workers 3x more related to sisters than to brothers, so investment in females:males = 3:1 • Trivers & Hare (1978) agued workers would have control • Recent analysis suggests proportion invested in females 0.63 rather than 0.75

OBLH10: Describe the mating strategies of Dunnocks AKA Hedge Sparrows (Prunella modularis)...

• 4 different Mating strategies: - Monogamy ♂ ♀ - Polygyny ♂ ♀ ♀ - Polyandry ♂ ♂ ♀ - Polygynandry ♂ ♂ ♀ ♀ • Different mating/care systems are seen in dunnocks, even within the same population - unusual

OBLH4: Describe the relationship between Fisher's and Zahavi's theories... (not fini)

• A Fisherian ornament is still likely to be bigger & better in a (genetically) high quality male • So a Fisher trait starts to signal viability which females may choose • If females prefer a Handicap trait (ornament), then their preference is passed onto their sons, who spread it • So a viability signal starts to signal attractiveness benefits • The theories are inter-linked

OBLH7: Describe Life-history theory including its main features and potential examples of these...

• About how an animal should organise it's life via key descisions e.g. When to reproduce, Where to live, Breed once or repeatedly, How many offspring etc. • Based on the idea that evolution is constrained by trade-offs among some of the traits that contribute to fitness e.g. energy vs. risk of being killed, maintenance & repair vs. reproduction, number vs. quality of offspring, current vs. future reproduction etc.

OBLH7: Describe the different scenarios in which birds may or may not survive the night...

• Above energy threshold = bird will survive the night, but below threshold = bird dies • Bird that survived night could of rested as still enough reserves to survive • If energy reserve lower then survive possibly by foraging

OBHL12: Describe the main explanations for the possibility that the benefit of menopause outweighs the cost... Hint:

• Advantage of stopping outweighs cost as large brain → long period of dependence, while there is high risk mother dies in childbirth • Switch to other activities as look after dependent children or help grown daughters by lookimg after grandchildren → enhances reproductive success • AKA "Mother hypothesis" as mothers age, the costs of reproducing become greater, & energy devoted to those activities would be better spent helping her offspring in their reproductive efforts

OBLH6: Describe Sexually antagonistic coevolution in terms of Inter-locus conflict (as part of sexual conflict theory) from the gene's perspective, including examples....

• Alleles at different loci, one has beneficial effects when in one sex, but not the other (or costly in other) • E.g. genes on Y & X chromosomes: - Genes on Y only occur in males, so selection for traits that benefit males even if costly for females - Genes on X spend 2/3 of their lives in females, so selection for traits that benefit females even if costly for males

OBLH8: Briefly describe another example of helpers causing a sex-bias...

• Alpine marmot • Males help mum raise young • Male-biased sex ratio when helpers absent.

OBLH1: Identify & describe the processes that occur in sex for most eukaryotes...

• Alternation between diploid and haploid life stages (diploid isn't always dominant eg in mosses, can look identical eg seaweed) • Reduction division via meiosis (allows transition) • Crossing over during meiosis • Fusion of haploid gametes with those of another individual (AKA syngamy) of the opposite sex

OBLH2: Describe how the egg and the sperm could have arisen via the classic theory by Parker et al. (1972) as an example... (not fini) Hint: O + O = v.high O + o = high o + o = low

• Ancestral population of single-celled protists in which all gametes are the same. • Selection for larger gametes to produce larger resulting zygotes (higher offspring fitness) • But once zygotes are fairly large, there are diminishing returns as further size increases won't increase benefit much. • Allows a mutant strategy of SMALL gametes to arise (in one sex) as it's not disastrous if a large gamete fuses with a small gamete. • Not viable for two small gametes to fuse together as very small zygote wouldn't be viable. • Selection on SMALL to find LARGE is greater than selection on LARGE to avoid SMALL. • This asymmetry allows a mutation for small gametes in the population • This, in turn, increases selection on large gametes to get bigger. • selection for egg & sperm

OBHL 13: Identify an example of potentially dodgy science, and what this indicates...

• Anders Møller accused of data fabrication in 2007 so the Oikos paper retracted • CNRS investigated - not guilty of fraud but guilty of poor scientific practice • Suggests other research by Møller should be taken with a pinch of salt

OBHL 12: Describe the theory by Williams (1957)...

• Antagonistic pleiotropy, as antagonistic means both negative & positive effects, while pleiotropy means the gene has multiple effects • small positive effect early in life can counter big negative effect late in life • If die then small chance of paying this cost.

OBLH3: Describe how Darwin thought sexual selection worked...

• Darwin proposed sexual selection acts in 2 main ways: 1. Intra-sexual selection: - Competition between members of one sex for access to other sex - Usually male vs male competition 2. Inter-sexual selection: - Choice of individuals of one sex by members of the opposite sex - Usually female choice

OBLH9: Describe the Seychelles warbler as an example of how both Local Resource Enhancement (LRE) and Local Rescource Competition (LRC) can occur in the same species...

• Are cooperative breeders & these small birds are extremely territorial, when few new territories available, some young will remain at their natal nest & help raise siblings. • Majority of helpers are daughters, whether a helper is advantageous or disadvantageous for her parent depends upon the quality of the territory, which depends upon the availbility of insects for food. • On high quality territories, helpers are beneficial from the point of view of their parent, & increase the number of young produced (LRE). • On low quality territories, the increased competition for food with helpers means that their presence is disadvantageous form the point of view of their parent (LRC).

OBLH8: Describe the research by McNutt and Silk (2008), including the research methods used, the findings, and what these findings indicate...

• Assessed African wild dog pack composition at the beginning of the denning season, & the size & composition of litters included in the analysis were recorded within 8 weeks of pup emergence. • Analysis focused on 84 litters born to 40 females in 33 packs for which complete information about pack composition (number of adult males, adult females, yearlings, age of the breeding female, litter size, and litter sex ratio) was recorded, as able to identify individuals based on their unique color markings. • Used parametric pairwise correlations to assess the relationship between female age, pack size, & pack composition, while also used Poisson regression to assess the sources of variation. • Found that the sex ratio of pups at emergence was significantly biased toward males, while younger mothers had significantly more male-biased litters than older females • Indicates that males are favored due to local resource enhancement as they help more than females, while competition among females for breeding positions may also cause this male bias.

OBLH5: Describe the assumption of Conventional sexual selection as well as the potential alternative to this assumption...

• Assumes the 'best' mate is the same for everyone i.e. individual out there that will covey the highest fitness to your offspring • Provides additive benefits - fitness improved by a certain amount • Alternative of non-additive benefits e.g. if individuals have different Major Histocompatibility (MHC) complexes

OBHL 14: Identify what were the results found by Møller & Höglund (1991), inclucing what this suggests...

• Asymmetry higher in tails of males of ornamented species when compared to females, with larger range of asymmetry for the ornamented males • Very little difference in tail asymmetry between males & females from non-ornamented species • So supports prediction from hypothesis 1 as higher fluctuating asymmetry in tails of dimorphic males • Found correlation was negative in tails of males of ornamented (dimorphic) species, while very little relationship between asymmetry & tail length in non-dimorphic species • So supports prediction from hypothesis 2 as asymmetry is negatively correlated with the mean length of tail for males from dimorphic species

OBLH4: Describe an indirect benefit of female choice in sexual selection that were developed by Fisher, including the process that also occurs as a result of this...

• Attractiveness - if a female mates with an attractive male she will have attractive sons, & because of their mating advantage she will have more grandchildren • Attractive sons pass on their mother's preference for attractive ornament, so the preference & ornament spread together in a self-reinforcing positive feedback loop, AKA Fisher's Runaway Process

OBLH4: Identify the key assumptions of Fisher's theory...

• Attractiveness must be heritable • Preference must be heritable • Attractiveness and preference must covary

OBLH9: What are the essential points of Trivers-Willard?

• Based on mammals, but principle is general • Trivers-Willard very influential but hard to test • Maternal conditions affects local sex ratio • Across birds & mammals, bigger benefit results in bigger effect: Importance of strength of selection

OBLH8: Identify and describe research evidence for Fisher's Theory, including the methods used and the findings... (check)

• Basolo (1994) used Platyfish (Xiphophorus) which have 3 factor sex determination: X, Y, W • Males = XY & YY, Females = WX, XX, & WY • Bred XY & YY fathers with WX, XX, & WY mothers • Get all male from XX mother & YY father • Found rarer sexes were produced each generation until a 50:50 ratio (ESS) was reached after many generations can tell genotype from phenotype

OBLH4: Describe why do peahens pay any attention to the tail length of males?

• Because it is reliably associated with male condition & all the genes that affect condition. • Also has the benefits of having sons that are good at advertising too - the Fisher end of the sexual selection continuum.

OBLH11: Identify what should be used (instead of phenotypic correlation) to measure the cost of reproduction...

• Best method: Experimental manipulation → artificial variation. • Need to see what happens when animal does something different

OBHL 14: Describe the main issues associated with the methods used by Møller & Höglund (1991) to measure body size/length, including how these problems could be avoided....

• Biases in measurement due to two researchers taking the measurements using calipers so may not have measuring in slightly different ways due to unconscious bias • Could prevent this bias by having some training before-hand or having both individuals measure the same skin & see if their measurements are the same - if getting consistently different measurements then there is a problem • Problems or bias may also come from measurement tools e.g. different calipers may give different measurements • Could avoid this by standardising the measuring equipment to be used before-hand

OBLH9: Describe the different contexts of reproductive success (e.g. in deer)... Also, identify and describe the factors that affect the maternal condition?

• Big male offspring better than big female • Small female ospring better than small male (worst) • Big female mum better to produce big male son • Small female mum better to produce big female daughter (state dependent decision) • Predicts that good condition mum produces son, while poor condition mum produce female • Body size, dominance, reproductive history, age, food supply/nutrition, health, quality of genes (genotype), hierarchy/ dominance social status, can all affect maternal condition. • Other factors that affect condition of female: - Parasitism = reduce energy that can invest in offspring - Population size = how much food available - Age = young female may be more fertile affect maternal condition.

OBLH3: Identify and describe the research on varied sperm size in birds, including the methods used, the findings and what these findings indicate...

• Briskie et al., (1997) obtained information on rates of extrapair paternity in birds from the literature, all studies used at least one molecular method • Collected, preserved & dissected the utero-vaginal region of female bird species to obtain data on the size & number of sperm storage tubules • Sperm length, length of sperm storage tubules, & number of sperm storage tubules were measured directly from birds • Found higher rates of extrapair paternity (EPC) had a positive correlation with longer sperm length. • Indicates higher EPC rate (& higher sperm competition) selected for larger sperm storage tubles so that females can store or select sperm of preferred males • Sperm length evolve in response to larger sperm storage tubules as longer sperm are an adaptation to filling up the female's storage tubules.

OBLH1: Identify the short-term advantages to sex...

• Can produce more variable offspring, this is good because: - They can better exploit a patchy environment (lottery mode, Williams) - They can evade parasites better (red queen, Hamilton, freshwater snails only self-ferterlise if parasites not common [lit]) - It can remove synergistic deleterious genes

OBLH2: Describe why heterogamety occurs if the best sex to be doesn't change during that organisms life....

• Can't predict which is the best sex to be at birth • Use chromosomal sex determination & allow meiosis to toss the coin as to which sex to have (e.g. 50:50 X & Y sperm in mammals) • Untested theory, but no better one available

OBHL12: Identify and describe the new theory on the reasons behind the menopause, including who came up with this theory...

• Cant & Johnstone (2008) - Idea that there is conflict within group over breeding • Claim that in humans, females disperse, as new younger female joins a group & marries son of older resident female • Although the new female is not related to offspring of older female, the older female will be related through her son to offspring of younger female • ESS: New female breeds, older female helps.

OBLH3: Explain the reasons why so many sperm are produced (e.g. one ejaculate (in man) contain 100s of millions of sperm)...

• Cohen (1973): - Classic explanation is that meiosis is error-prone so there are lost of defective sperm, so you need back-ups. - True, but greater error rate in meiosis is true for egg formation too, so can't be the main reason. • Parker (1982,84): - If there's sperm competition then you stand a greater chance of winning if you have more sperm. - It's an evolutionary arms race between males.

OBLH8: Describe what happens if colonies differ in queen's mating pattern?

• Colonies differ in sex ratio: Split sex ratios • Explanation by Boomsma & Grafen (1991) that colonies differ in relatedness asymmetry • Workers have control & know asymmetry in their colony, so optimal to specialise on one sex.

OBLH2: Describe Environmental sex determination and identify the different environment mechanims that fall in this category...

• Common in reptiles, fish, plants • Includes sequential hermaphroditism, temperature, size & social factors

OBLH6: Describe how Haig's theory on genomic imprinting was tested, including the methods used....

• Comparing situations where there is high conflict (e.g. polyandrous species) with situations where conflict is low (e.g. monogamous species) • Used two closely related species of deer mouse that can hybridise: - P. polionotus = monogamous & low conflict - P. maniculatus = promiscuous, with multiple male paternity & high conflict • Bred female P. polionotus with male P. maniculatus, and also bred female P. maniculatus with male P. polionotus

OBLH8: Describe the research on Local resource competition in primates by Silk & Brown (2008), including the methods used and the findings...

• Compiled information about Birth Sex Ratios (BSRs) from a variety of sources & collected published information on the numbers of males & females born in wild & captive populations in primates from published literature. • Also collected information about dispersal patterns, body size dimorphism & group size mainly from published sources. • Found that BSRs are skewed in favour of the dispersing sex in species that do not breed cooperatively - supports local resource competition • Found ratio differs significantly across dispersal categories & that on average, BSRs are biased towards females in species in which females are the primary dispersers

OBLH7: Describe the optimal strategy, including examples...

• Considers a Static (single) decision, which might be repeated, but doesn't change over time • E.g. when to leave a patch (Margin of Value Therom), or which prey item to eat etc.

OBLH1: Describe how Meiosis causes sexual reproduction to be costly...

• Consumes more ATP (energy) than mitosis and has a higher error rate

OBLH3: Describe the use of accessory fluids by sperm, including the affect these accessory fluids are thought to have based on finding in Drosophila...

• Contain nutrients for the sperm • Also contains toxins • Chapman et al. (1995): Some toxins have been identified that seem to act against rival male's sperm • Fowler & Partridge (1989): Females who mate have a shorter lifespan & this has been shown to be due to a toxin in the male's sperm.

OBLH4: Describe the research study carried out by Norris (1993) including how this supports Zahavi's handicap theory...

• Cross-fostered Great tit chicks & found male offspring of wide-stripe males survive better due to genetics • Cross-fostering important because females of attractive males may invest more in young & that's why they survive better

OBLH1: Briefly describe what could have resulted if syngamy occured before crossing over...

• Crossing over between homologous (but not identical) chromosomes increases variation

OBLH3: Describe the use of forced copulation & rape in bean weevils as documented by?

• Crudgington & Siva-Jothy (2000) • The male has spines on its penis which wound the female & reduce her chances of mating again.

OBLH1: Describe how crossing over occurs and why it is important...?

• Cutting & pasting between homologous chromosomes • Possibly a by-product of the mechanism of double-strand repair • Promotes variation - these are the same factors that maintain sex

OBLH3: Identify the two main forms of Male-male competition...

• Darwin - traits that help males get access to females • Parker (1970) - traits help ensure male paternity after copulation through sperm competition

OBLH 10 Describe the long-term studies on parental care in Dunnocks by Davies (1990) as well as Hatchwell and Davies (1990), including the various research methods used and the findings, as well as the conflict of interest...

• Davies (1990): Used bird nets in Cambridge botanical gardens & used leg rings for individual recognition • Found in Polygynous territories: - Females share help from male - Dominant female tries to drive away other female so she can have exclusive help from male • Found in Monogamous territories: - Not stable situations - Female seeks copulations from other males, to get help from two males - So male wants to entice 2nd female so he can sire young in two nest to increase his reproductive output that year • In Polyandrous territory: - Both males that mated with female may feed all young - Can't recognise if young are their own or not - Dominant male tries to drive away other male to secure exclusive paternity • Hatchwell & Davies (1990): Carried out experimental removals from 3 trio-fed broods, with the male providing most food for nestlings being removed for about 3 days • Provisioning rates were recorded before and after removal of the male. • Found the remaining male's provisioning rate was not sufficient to compensate for the loss of the removed adult and nestling weight was reduced.

OBLH13: Identify and describe the research on how intense directional selection can cause of 'stress' to result in Fluctuating Asymmetry, including the research methods used and the findings...

• De Coster et al. (2013): looked at directional selection (due to recent shifts in habitat quality) in 4 bird species from the African rainforest • Measuring tarsus bone length (as increasing body = higher tarsus) & using X-ray photography to measure FA in the bone structures • Did this for museum specimens & for live birds captured with mist nets • Found one species showed decreased body size, the other 3 species had increased body size with this increase being due to increased FA.

OBHL12: Describe semelparity and why it is favoured in certain animals, as well as the issue with this idea...

• Death in itself not selected for, as death is consequence of high reproductive effort. • Favoured if there are increased returns i.e: 1. Current reproductive success (RS) is accelerating 2. Low probability of future reproduction • Problem as hard to test empirically

OBLH11: Define life-history theory (LHT) and describe its key features, including why it is important....

• Def: 'Distribution of major events over the lifetime of individuals' • To understand natural selection, must know entire lifespan of an organism • Not every trait can be adapted in isolation → trade offs must occur. • Important as relates to costs of reproduction

OBLH7: Describe the different possible affects that adult body size has on an individual....

• Determines food intake rate & thus metabolic rate • Influences size of territory, mating success & thus rate of reproduction • Survival affected via risk of predators & also have to grow - may be low chance of surviving to large size

OBLH5: Identify and describe the two vital roles of the Major Histocompatibility Complex (MHC) in the immune system...

• Development of self/non-self recognition: - Before birth, huge variety of T cells produce - T cells that bind too tightly to MHC molecules are eliminated as these would cause auto-immune disease. - T cells that bind too weakly are eliminated, as these are no good at recognising proteins. • Activates many components of immune system e.g: - Cytotoxic T lymphocytes (detect intracellular parasites) - Helper T cells (detect extracellular parasites) - macrophages (detect extracellular parasites) - Antibody-secreting B cells (detect extracellular parasites)

OBLH2: Describe the Consequences of two sexes (not fini)...

• Different selection pressures on males and females - See the later lectures on sexual selection • Sometimes beneficial to allocate resources unequally to male and female offspring (or male and female function, if hermaphrodite) - See the later lectures on sex ratio adjustment

OBLH1: Explain why there is the continual shift between diploidy and haploidy...

• Diploidy is expensive, as there is more DNA to copy & repair • Reduction division (without crossing-over) could have evolved as a facultative response to changing environmental conditions (e.g. 'when conditions become bad, turn haploid) • But, it could also have evolved to 'expose' recessive deleterious mutations to selection, removing them from the lineage

OBLH4: Identify and describe the different benefits of female choice in sexual selection, including examples of these if possible...

• Direct benefits AKA non-heritable: - Direct material resources that boost the female's current reproductive effort - E.g. a good territory, help with parental care, defence from predators or harassment from other males, etc. • Indirect benefits AKA heritable: - Advantageous traits passed on from the male's genes, so benefits are seen in offspring who inherit the male's genes - E.g. attractiveness & viability

OBLH3: Describe the male behaviour of guarding, including why it is important & what this may have resulted in...

• Direct guarding of female(s) is a common male tactic. • Guarding before copulation is important if the time of ovulation is uncertain, while guarding after copulation reduces the chances the female may mate with a rival. • Thus mate guarding has been suggested as a factor involved in the evolution of monogamy.

OBLH13: Identify and describe the other types of asymmetry, including some examples to illustrate these different types... Hint:

• Directional asymmetries: where it is normal for one side to be bigger than the other & the same directional bias is shown by most individuals • E.g. many internal organs (e.g. heart), show a directional asymmetry, as in the human heart the left atrium is bigger than the right in most people • Antisymmetry: where it is normal to have one side larger than the other but there are similar numbers of individuals of each type (in the population) • E.g. Fiddler crabs males can have dominant large claw on right or left side (about 50:50 ratio)

OBHL12: Describe the theory by Kirkwood (1977)....

• Disposable soma as even without senescence, will eventually succumb to accident/predation • Thus huge investment in repair will eventually be lost → optimal level of investment in repair not too low, not too high • Small repair means life is too short for reproduction success • Long life from larger repair but little energy for reproduction

OBLH 10 Describe the supposed conditions for biparental care to be stable as part of the pay-off matrix model...

• If female cares, male does better by caring than deserting, while if male cares, female does better by caring than deserting • These conditions must hold so that neither can do better by changing behaviour.

OBLH1: (Pluralism) Describe how these ideas can work also work together by using examples...

• E.g. parasitism can cause populations to crash, & small populations are vulnerable to Muller's ratchet • E.g. accumulation of mutations can make a population more vulnerable to disease • Thus both these factors work together N.B. The 'sexual lifestyle' we are familiar with in multicellular animals is a suite of traits that must have evolved separately and MAY not all serve the same function. And may not serve the same function now as when they evolved. So, we shouldn't expect that there is a single answer for all the features we associate with 'sex'. The best clues may come from groups such as protists, where the separate components of the normal multicellular sexual lifestyle DON'T always go together.

OBLH10: Describe the conflict of interest facing parent dunnocks...

• Each member of group prefers the others to do the work • e.g. in pair, male wants female to look after young & vice versa • Individual effort gives shared benefit but personal cost so very general tension in groups

OBLH4: Identify and describe the research evidence for offspring of attractive males being more viable (survive better), including how the influence of females was avoided...

• Evans et al. (2004). used artificial insemination of female guppies - this removes possibility of biased female investment • Found offspring of females artificially inseminated by more attractive males evaded predation better

OBHL12: Describe what is senescence and the aspects involved...

• Even under ideal conditions, get increase in age-specific death rate • Deterioration of many aspects of physiology e.g. less efficient mitosis • Decline in reproduction

OBLH2: Identify the conditions required which explains why don't all animals change sex...

• Expected life-span must be long • Has to be strong dependence of reproductive value on size/age/condition • Cost of changing sex must be low • Sex-specific experience must be relatively unimportant

OBLH8: Describe Fisher's Theory (1930), including the equation used (N.b. similar argument for females) and what this theory also relates to...

• Explained why sex ratio is 50:50 as it pays to produce the sex that has the higher mating success. • Individually advantageous to produce the rare sex e.g. males rare so produce males due to fitness advantage as sons mate more Equation: Sm = T / Nm • Mating success per male (Sᵐ) = Total mating success (T) ÷ number of males (Nᵐ) • Presumes males & females equally costly to produce • Is an Evolutionary Stable Strategy argument (40 years before Maynard Smith invented ESS) • before Game Theory invented

OBLH13: Describe the link / association between fluctuating asymmetry and fitness, including why fluctuating asymmetry is important e.g. when choosing mates....

• FA is potentially heritable & it's the level of FA experienced (rather than the direction) that is heritable • Heritable as some individuals will be more able to cope with an environment & this will be selected for • There has been a link between FA & fitness (since the 1960's e.g. Beardmore) • In the 1990's Møller did some experiments on barn swallows & pointed out that FA can tell us about 'good genes' models of sexual selection • Asymmetry is a good indicator of the quality of genes within an individual • E.g. If have individual that is very asymmetric & asymmetry is an indicator of how much stress experienced - then indicates that individual has experienced a lot of stress & not dealt with it very well • FA might be a way to find out if secondary sexual characteristics are indicating/signalling genetic quality • Depends on how symmetry is assessed by an individual - can use experiments to test if individuals choose mates based on their symmetry

OBLH7: Describe the storing of fat over a year in little birds, including the potential reasons for these fluctuations...

• Fat levels not limited by food availability with a high peak before migration • Fat not at maximum level in midwinter, as they regulate their fat • May be high when food availability is low, thus acting as a buffer against starvation

OBLH3: Define Inter-sexual selection...

• Features that aid in attracting members of the opposite sex

OBLH3: Define Intra-sexual selection...

• Features that aid in competition between members of the same sex

OBLH3: Describe the upsides and downsides to sexual selection, including an example to illustrate...

• Features that promote success in reproductive competition e.g. Tungara frog males (live in Costa Rica) croak in breeding season to attract females • May be deleterious to survival e.g. Croaks also attract bats which prey on the frogs • So Natural (viability) selection & sexual selection may act in opposition e.g. trade-off between croaking for mates & avoiding predation

OBLH3: Describe Sexually antagonistic coevolution, including the research methods and findings by Rice (1996) that demonstrates this....

• Female optimum ≠ male optimum • Drosophila in experimental coevolution versus independent evolution: - Two lab populations of Drosophila. - One population allowed to breed over many generations as normal i.e. in which males & females can coevolve with each other. - Other population, each generation he gave males & females mates from different lines, so that coevolution was not possible. - Found after several generations that females who mated with males that they hadn't been allowed to coevolve with suffered high mortality because of a toxin in the male's seminal fluid - Due to females not coevolving with males, so they can't evolve countermeasures against the male's toxins.

OBLH8: Describe the observations on fig wasps and how these lead to the development of a certain sex ratio theory, including who developed this theory....

• Female wasp enters fig to lay eggs • Male eggs hatch 1st, so males mate with females (their sisters) • Males die; females get covered in pollen & leave, thus female-biased sex ratios. • Non-Fisherian sex ratios can result when relatives interact with one another. If relatives experienced competition for resources, or benefited from the presence of other relatives, sex ratios become skewed. • Hamilton's theory: Local Mate Competition

OBHL12: Define and describe the menopause, including what it is caused by....

• Females lose reproductive ability but continue to live • Documented species include killer whale, short-fined piolet whale & humans • Physiology wise it is caused by depletion of oocytes

OBHL13: Summarise the main aspects of fluctuating asymmetry....

• Linked to developmental stability • Higher asymmetry if 'stressed' during growth • Potential indicator of 'adaptedness'

OBLH2: Describe Haplodiploid, including the organims that do this and how it is done...

• Fertilised egg = female • Unfertilised egg = male • Hymenoptera (bees & wasps), thrips, & some beetles, bugs, mites, nematodes, rotifers, & others • As female stores sperm, by releasing sperm or not as eggs are laid, she has precise control over the sex ratio of her offspring

OBLH10: Describe how Dunnocks can respond to each other and negotiate their way to a stable solution as determined by McNamara (1999) model of negotiation rules...

• Final efforts emerge from negotiation during a series of interactions, as get ESS negotiation rule instead of ESS action • Outcome not the same as for standard model as negotiation predicts less care, so not best response to partner's effort instead, best way of responding to partner's way of responding • So the stable solution from negotiation is for both parents to care for the young less than if there wasn't flexibility.

OBLH8: Describe the research findings by Werren on Nasonia vitripennis, as an example of Fisher meets Hamilton in superparasitism...

• First female to host results in local mate competition so female bias • 2nd female to infected host detects parasitism, so less bias • Small clutch = strongly male-biased • Large clutch = Strongly female-biased

OBLH13: Describe what the graphs would look like for the three different types of asymmetry, including why this is...

• Fluctuating Asymmetry - level of asymmetry with the population tends to be normally distributed with a mean (peak) around zero (0 = symmetrical) • Directional asymmetry - the trait is asymmetric as it is skewed (away from zero) while the population is still normally distributed • Antisymmetry - normal distribution with two peaks either side of the zero, as half the population have the asymmetry on the right side, while the other half have the asymmetry on the left side

OBLH2: Describe the explanation of the Evolution of the sexes using the classic theory by Parker et al. (1972), including the components involved...

• Focuses on the evolution of male- & female-ness • Uses game theory to determine an evolutionarily stable strategy (ESS) • N.B. Game theory: essential when the best thing to do depends on what other individuals are doing, so game theory becomes useful when analysing social behaviour.

OBLH8: Describe Sex differences in polygynous mammals e.g. in red deer... Also, what is the sex ratio and why is this potentially?

• For red deer males are larger & more costly than females e.g. - Greater growth rate in utero - More milk til weaning - Mother in poorer condition after bearing son than after daughter. • Sex ratios are equal, possibly due to it being hard to influence sex ratio or maybe females cost more later

OBLH7: Describe the main elements of the Optimal strategy that birds should use to maximises long-term survival...

• Forage when resources low to avoid starvation • Build up resources to get through night • But also need to cope with interruptions (e.g. bad weather when they can't forage).

OBLH7: Describe the research findings by Stearns and Koella (1986) when predicting age and size at maturity... (check paper)

• Found Maximised fitness function • Found Increase of age & decrease of body size at maturity (in poorer environment)

OBLH6: Describe where else the meiotic drive is found, including why this might be.... Also describe the two different possible reasons why this phenomenon isn't more common...

• Found in other organisms too (e.g. Drosophila & mice), & not just on sex chromosomes. • Maybe drivers on sex chromosomes are easier to spot due to the effect on offspring sex ratio A) Resistance evolves in other chromosomes (as in Aedes) B) Successful drivers, that spread unopposed, make population go extinct or, in haplodiploids turn species asexual - so don't notice effect any more

OBLH7: Describe the research findings by Kozlowski and Wiegert (1987) when predicting age and size at maturity... (check paper)

• Found opposite conclusion to Stearns & Koella (1986) as found it maximised Life Reproductive Success • Found age at maturity increases with the growth rate

OBLH6: Describe the findings from the test on Haig's theory on genomic imprinting was tested, including what this indicates....

• Found that giant babies were produced from weak polionotus mother & manipulative maniculatus father • supports theory as maternally imprinted genes in monogamous females were weak at resisting paternally imprinted genes • Found that tiny babies were produced from unmanipulative polionotus father & resistant maniculatus mother • supports theory as maternally imprinted genes in promiscuous maniculatus females were strong at resisting paternally imprinted genes

OBLH6: Describe what molecular biologists discovered when they 'de-imprinted' the genes concerned, including what a particular scientist discovered about these genes and what this suggests...

• Found the resulting foetus is fine, so imprinting isn't vital to gene, & embryo, function • Haig found that: - Male imprinted genes seem only to increase maternal investment e.g. increased placenta growth, increase insulin production in mother, so releasing energy for embryo. - Female imprinted genes seem only to reduce effects of male imprinted genes e.g. down-regulating insulin etc. • Haig (1993) realised that genomic imprinting is the result of sexual conflict

OBLH2: Give a general overview of Sex determination with examples...

• Genetic e.g.: - Heterogamety (two sex chromosomes) - Multifactor (> two sex chromosomes) - Haplodiploidy (one sex chromosome) • Environmental e.g.: - No genetic difference between sexes - Temperature, size, social, etc. - Can be determined developmentally e.g. bottleneck

OBLH7: Which scientist came up with the idea that reproduction is costly and identify what animals should aim to do...

• George. C. Williams (1966) • Aim to maximize current reproduction + future reproduction

OBLH1: Describe classic theory 2 for the evolution of sex....

• Gets rid of deleterious mutations by bringing bad genes together • Fights Muller's ratchet as two individuals with 1 (or more) deleterious mutations can have sex & produce offspring with 0 (or lots) of mutations • Sex can restore a 'perfect' genome, by dumping all of the bad genes in the same offspring (who dies)

OBLH1: Describe how the separation of certain genes is a cost of sexual reproduction...

• Linked co-adapted genes that have evolve to work well together within a gene pool can be mixed & split apart • E.g. sickle cell anaemia heterozygotes have higher fitness in malaria-rich areas, but when two heterozygotes mate the offspring are less fit

OBLH4: Identify and describe the research evidence for the possibility that females may invest more into eggs of dominant males...

• Gil et al. (1999) manipulated Zebra finches' attractiveness using colour bands • Females find red attractive & green ugly • Females mated to attractive males (red band) put more testosterone into their eggs, which promotes faster growth in the young.

OBLH6: Describe another theory why the phenomenon of having the meiotic drive on other chromosomes etc. isn't more common...

• Haig & Grafen (1991) suggested recombination at meiosis (crossing over) evolved as a mechanism to stop spread of selfish driver genes • 'Drive genes' are actually two tightly linked genes - a poison & an antidote • Crossing over can separate linked genes (e.g. poison gene from antidote gene), so doesn't spread as it would kill its own chromosome.

OBLH11: Describe the internal costs of reproduction....

• Hard work associated with attracting mates or caring for young → reduces condition → increases mortality • These costs are typically long lasting

OBLH7: What are the costs of being fat for these little birds according to Witter & Cuthill (1993)....

• Harder to take off as heavier body • Also less agile in air • Thus higher energy costs of flight

OBLH10: Identify and describe the research on the effects of manipulating parental care in birds, including the methods used and the findings.... Hint:

• Harrison et al., (2009): carried out meta-analysis on 54 studies on parent or helper removal/manipulation of care efforts by birds • Found parents respond & that partial compensation occurs for a reduction in effort of mate. • Found females increase feeding efforts to similar extent regardless to type of manipulation on partner (weight vs clipped), while males only increased feeding efforts when partner was weighted (didn't if female clipped) • When considering brood size for mate removal found males have a greater increase in feeding than females

OBLH2: Describe the mating types of the ciliate Stylonichia mytilus (S. mytilus), including if this is the same as sexes...

• Has about 100 mating types • Each type can mate with any of the others but not its own type (incompatibility system) • Possibly a mechanism to avoid inbreeding • Not the same as 'sexes' e.g. Flowering plants have incompatibility systems & two sexes

OBLH3: Describe the use of sperm dimorphism in Lepidoptera (AKA butterflies), including the research methods used and the findings in relation to female anatomy discovered by researchers in 1999...

• Have two types of sperm which are the non-fertile Apyrene (no genetic material) & the fertile Eupyrene sperm that can fertilise eggs. • Thus 90% of a butterfly's sperm can be incapable of fertilisation. • Cook & Weddell (1999): used green-veined white butterfly females that were either mated to virgin or mated males & females were allowed to remate at will for up to ten days after mating. • Counted the two sperm types in the spermatheca (originating from first male), either when the female remated or after ten days if the female did not remate. • Found that females with more apyrene sperm from a previous mating delayed remating for longer. • Females have stretch receptors in their storage organs & they don't remate if the stores are full - indicates the apyrene sperm are a cheap way for the male to fill the female up.

OBLH4: Describe benefits female swallows get from choosing long-tailed males that are high quality, including the research that supports this & any associated issues...

• Heritable benefits e.g. resistance to blood-sucking mites inherited so offspring survive better • Møller carried out a half-brood fostering experiment & found parasite load of young best predicted by parasite load of genetic father • These resistant males had long tails thus viable explanation (fisher-zahavi theory) • Issue that Møller was accused of fraud, but this was cleared

OBLH5: Describe Heterozygote advantage as a potential benefit of the Major Histocompatibility Complex (MHC), including an example... Hint:

• Heterozygosity is advantageous in widening defence against multiple infections • E.g. if allele A better for resisting parasite X & allele B better for resisting parasite Y, better to be the heterozygote AB.

OBLH13: Identify and describe the research on how loss of genetic variation can cause of 'stress' to result in Fluctuating Asymmetry, including the research methods used and the findings...

• Hoelzel et al. (2002): looked at Northern elephant seal population crash at end of 19th C, measured genetic diversity & skull dimensions of seals • Found left & right sides of bones from skulls were very similar/tight correlation (left & right sides the same for any given individual) before bottleneck/population crash • Found after crash (when genetic diversity was lost), the differences between left & right sides of skulls increased markedly (more variation), thus being an increase in fluctuating asymmetry.

OBLH6: Identify and describe the research that tested this sexual conflict theory....

• Holland & Rice (1999) experimentally manipulating level of sexual conflict in Drosophila using two lines: - High conflict line where females mate polyandrously (3 males for every female), males favour offspring now over female's future fitness - Low conflict line where females mate monogamously (1 male for every female), same interests; if male damages female then reduces his future reproductive success

OBHL 14: Identify the two hypotheses by Møller & Höglund (1991) on if sexual ornaments signifying good genes, including the predictions that could be made from these...

• Hyp 1: Sexually selected traits will be more prone to developmental stress than 'normal' (naturally selected) traits • So predict FA higher in tails of males of dimorphic species than (i) females of same species (ii) tails of males of non-dimorphic species, (iii) wings • Hyp 2: High quality males can grow longer tails & resist stress (less asymmetric) • Based on this predict that asymmetry will be negatively correlated with mean length of the trait in tails of males of dimorphic species, but correlation will be close to zero in females, non-dimorphic species & wings

OBLH7: Describe the relationships between Size and energy reserves in terms of Polar bears as an example....

• If big enough reserves, can get through winter on body fat & thus could breed • Pregnant female may fast for eight months & loses 43% body mass • May not survive if smaller size as not enough reserves

OBLH1: Describe the explanation of the short-term advantage to sex by Kondrashov (1982)...

• If deleterious genes have a synergistic effect i.e. the sum of their effects together is worse than their simple sum • Then sex can pay by dumping all the bad genes together in one individual, that dies, so purging the mutations.

OBLH10: Identify and describe factors involved in the decision of whether to care for or desert offspring...

• If food is scarce, may pay to desert - can't feed both young & self (both partners benefit) • Long-lived animals shouldn't risk own life for young e.g. albatross may desert young • If food is plentiful, may also pay to desert - partner can rear young alone & leaving partner can breed again (only leaving partner benefits)

OBLH4: Describe the lex paradox...

• If ornament or genes that affect quality, are so good, & females choose them consistently, then those genes spread until everyone has them • No need to be choosy, as every potential male mate has these good genes

OBLH1: Classic theory 2 is basically group selection, explain why despite this it still explains the evolution of sex...

• If the rate of mutation from sexual to asexual is low then asexuality may do well in the short term, but sex prevails in the long term • NB: However, some organisms can do both, so there must be short-term advantages to sex

OBLH1: Describe Muller's ratchet....

• In a population those with mildly bad mutations survive • Lowers the populations fitness

OBLH2: Describe heterogamy in different organisms....

• In mammals, (& most mosses) you are female unless you possess a small section of Y-chromosome (that produces an 80 aa long polypeptide) • In Drosophila, it's the ratio of X chromosome to autosomes (non-sex chromosomes) • So an individual who is X0 (no Y chromosome) is: - male = if it is a fruitfly - female = if it is a mammal

OBLH1: Describe the two-fold cost as a reason why sexual reproduction is costly, including an example to illustrate...

• In normal sexually reproducing species only 50% of genome is contributed by each parent • If a new mutation allowed the female to produce her eggs by MITOSIS so that offspring are identical diploid copies (clones) of herself - thus mutation (& genome) passes on to 100% of her offspring READ LIT FOR CRITIQUES

OBLH10: Describe how models and real life differ in terms of negotiation...

• In typical ESS models, 'response' occurs over evolutionary time i.e. typically male & female don't respond to each other during breeding attempt • In reality, individuals respond to differences in quality of partner (don't know opponent's action in advance)

OBLH5: Identify the three hypothesised benefits of choosing mates based on the Major Histocompatibility Complex (MHC)...

• Inbreeding avoidance • Heterozygote advantage (via parasite-mediated sexual selection) • Rare alleles (via parasite-mediated sexual selection)

OBLH5: Briefly describer evidence on Inbreeding avoidance as a potential benefit based on flowering plants...

• Incompatibility systems evolved from immune defence type mechanism to prevent inbreeding • High polymorphism essential for both incompatibility systems & defence

OBLH7: Identify the predicted changes in adaptive fat levels for given time of day (using models) due to different changes in parameter... Also describe the different benefits of the previously mentioned models (e.g. optimum strategy & dynamic programming etc.).... (check - is model AFL?)

• Increase in food availability = decrease fat storage • Increase in interruptions = increase fat storage • Increase in overnight energy expenditure = increase fat storage • Increase in predator abundance = decrease fat storage • Can get daily routine of foraging • Use same approach to find daily routine of singing v. foraging • Can also find optimal annual routines

OBLH10: Describe the two levels of interaction with the rest of the population and how this influences the pay-off matrix model....

• Interaction with partner - determines pay-off from reproductive attempt under consideration • Interaction with rest of population - behaviour of other males & females determines probability of remating • So, Maynard Smith's model is only a 'game' between a male & female parents • Thus there is interaction with the rest of the population, because everyone else's care/desert decision affects ones best choice.

OBLH11: Describe how internal costs can affect non-annual breeding by comparing the breeding cycles of three species of bird to illustrate this...

• Internal as impacts animal's condition • The Black-browed albatross (4kg) breeds first at 10 yrs & breeds every year • In contrast the Grey-headed albatross (4kg) breeds first at 12-13 yrs & has biennial cycle as it skips year after successful or sometimes failed attempt. • The later it fails the more likely it is to skip breeding as the bigger the internal cost of reproduction, the bigger the probability that it won't breed next year, as can't replenish condition in time for next year. • Similarly the Wandering albatross (9.5kg) breeds every other year so cycle > 1 year. • Due to large internal cost so have to build up condition to breed again

OBHL 14: Describe the different issues associated with the specimen selection methods used by Møller & Höglund (1991)...

• Introduce bias by using museum skins & also biases in specimen selection • Due to only best specimens kept so not randomly sampled, also specimens killed due to being good quality or may have been the easiest to catch • Thus don't know whether bias is non-asymmetric due to best individuals being caught, or if bias is asymmetric due to poor individuals failing to escape • No control over how specimens were collected, while information on labels that come with specimens maybe incorrect • Can't confirm if all asymmetry observed in specimens was caused by developmental stress due to specimens being preserved from different times & using different preservation methods • Thus may have bias in the specimen skin conditions from the 3 different museums

OBLH7: Describe dynamic optimisation, including the components involved and where this idea came from....

• Introduced by Mangel & Clark (1986), as well as McNamara & Houston (1986). • Value of animals current action (cost) affects value of future action • Series of state-dependent decisions • State variables could be size or body temperature or the organism's environment etc.

OBLH11: Describe the implications of individual variation by using clutch size and laying date as examples to illustrate this...

• Lack clutch size expects parents produce most productive clutch size • Add cost to parent → smaller clutch • Lack laying date expected when most food available • Add seasonal decline → lay earlier • Each parent has different optimum, according to own condition, so best /fitest parents breed earlier & have larger clutch. • I.e. can represent variation in optimum for animals in different condition

OBHL12: Describe why the General theory for the disposable soma is complicated, including some examples and research to illustrate this...

• Intuitive prediction if population size is stable • But high extrinsic mortality (independent of condition) → low optimal level of maintenance (eg predation) • E.g. Opossums on islands (predator-free) age more slowly than same species on mainland • E.g. Keller & Genoud (1997) found very low extrinsic mortality for queens of eusocial species, compared to solitary species • Also found lifespan (similar body mass) for eusocial was 10 yrs, while for solitary was 0.1 yrs. • E.g. Weaver ants: large workers outside nest have shorter life as more predation risk, while small workers inside nest have a longer life

OBLH1: Describe how diploidy must have evolved and the benefits that this has resulted in...

• Involved two identical sets of chromosomes. • Provides back-up copy to cover mutations • Allows DNA repair (Bernstein et al 1985) - one copy can be used as a template to repair 'double-strand' damage

OBLH2: Describe Sequential hermaphroditism including an organism that does this as an example...

• Is where an individual changes sex during their lifetime - clearly here sex is not determined genetically. • E.g. blue-headed wrasse (Thalassoma bifasciatum) - starts life as female, & then can become male later in life

OBLH5: Describe why inbreeding is a problem?

• It reduces the amount of heterozygosity in the offspring produced • This can expose deleterious mutations or bad alleles (reduce fitness of offspring)

OBHL 13: Identify and describe the reasearch on if symmetry preference (e.g. by females when choosing mates) is a by-product, including the research methods used and the findings...

• Johnstone (1994): Used computer model involving neural networks trained to prefer some patterns & avoid others • i.e. trained to recognize images representing a bilaterally symmetrical tail that exhibits varying degrees of fluctuating asymmetry • Used various patterns & some had 'left-bigger' & 'right-bigger' forms • Found networks prefer symmetrical patterns even if they've never seen them before, because symmetrical is the average of all patterns that it was trained to prefer • Thus preference may come about due to other computational processes of the brain

OBLH9: Identify and describe the research on natural variation in host size, including the (good) experimental methods used and the findings...

• Jones (1982): introduced 15 female & 10 male wasps per dish to host larvae, the host larvae were different sizes as they were either aged 11, 13, 15, 17, & 19 days • In the experiments kept superparasitism to a minimum as densities were controlled at ~20 eggs per female wasp • After 24 hours removed the wasps & counted the sex ratios as the progeny emerged. • Found negative correlation between proportion of male offspring and the age (i.e. size) of the host - indicates that females adjust the sex ratio of eggs • Found produce females when host 5+ size - does follow step function so indicates relative size of host is important

OBLH9: Identify and describe the research experimenton the affect of territory quality on the sex of the offspring produced, including the research methods used and the findings...

• Komdeur et al., (1997): looked at Seychelles warblers, collected blood samples from nestlings (from breeding pairs without helpers) & from adults. • A total of four breeding pairs from low-quality territories and three breeding pairs from high-quality territories on Cousin were transferred to Cousine and Aride • On the new islands they remained paired and occupied high-quality territories. • All the eggs produced by these pairs pre- and post transfer resulted in a nestling, that were the blood-sampled & sexed based on analysis of DNA (via PCR) extracted from the blood samples • Territory quality was expressed as mean insect prey available within a territory, as adult survival & reproductive success correlated with this, & the quality was measured each month • Found unhelped breeding pairs on low-quality territories (LRC) produce 77% sons, so produced less daughters (23%) • Found unhelped pairs on high-quality territories (LRE) produce 13% sons, so produced more daughters (87%) • Found breeding pairs that were transferred from low- to high-quality territories switched from the production of male to female eggs

OBLH9: Identify and describe two research examples on if dominance in ungulates has an impact in reproductive success... Include the different research methods used and the findings...

• Kruuk et al., (1999): measured the density of the number of females older than one, within the study area (Isle of Rhum), as could recognise the individual deer in the study population. • Monitored the population daily during the calving season, to determine number of females that calved & the sex of the offspring. • Used observations of interactions between pairs of individuals to calculate the age-corrected dominance rank for each female • Also classified whether or not females reared a calf the previous year that survived to six months • Found dominant females were more likely to produce sons than subordinate females • Found dominant females are in better condition, so found they breed earlier, live longer, have higher lifetime reproductive success & have a stronger effect of rank on sons • Lloyd & Rasa., (1989): recognised individual Cape mountain zebra via their unique stripe patterns & took photographs of the left & right sides of the body of each animal. • Used long-term qualitative observations of antagonistic interactions with herds to determine dominance in mares. • Created data cards for each individual including the name of the animal, its photographs, date of birth or introduction, identity of parents for foals born in the reserve, date of leaving maternal herd, date of joining breeding herd, sex & birthdate (to within 1 week of birth) of offspring & date & cause of death (where applicable). • Found dominant females produce significantly more daughters than sons • Also found that the mothers status positively correlated with dominant status of her female offspring (but didn't relate to the status of her sons) e.g. high rank mothers have high rank daughters.

OBLH11: Identify and describe the research on optimum clutch size, including the methods used and the findings.... How does this support Williams idea and what issue does this research have?

• Lack (1947; 1954; 1964 etc.): Carried out various long term studies (mainly on tits) by observing & manipulating clutch sizes • Found when too many young → do badly, fewer survive • Found when too few young → not as many genes passed on • Predicted that birds have optimum clutch sizes AKA 'Lack clutch size' • Indicates/supports a trade off for number of offspring verses their success to maximise productivity • However observations typically show optimum clutch size is smaller than the predicted (optimum) 'Lack clutch size'

OBLH9: Provide examples of facultative (optional) responses of a mother as part of individual adjustments, in terms of the value of sons & daughters...

• Local mate competition • Local sex ratio • Maternal condition etc. • Absence of helpers. -> can all lead to a skewed sex ratio

OBLH7: Identify and describe the how birds decisions in relation to adaptive fat levels could be modelled , including the researchers behind this....

• Look at bird decisions from start to end of day, many possible sequences → too hard to analyse • Instead use dynamic programming & work back from time where relationship between fitness & state of bird is known • McNamara & Houston (1993)

OBLH8: Describe the research by Herré, including the findings as an example of Fisher meets Hamilton... (check)

• Looked at 13 species of fig wasp & the sex ratios of broods with one or two females • Found moves towards Fisher sex ratio • Predictions for given no. of females are more accurate if species is likely to encounter that no.

OBLH5: Describe the study by Ober et al. (1997)...

• Looked at closely at inbred religious group communities in the states called the Hutterites • Found that Hutterites' marriages are more 'MHC-different' than expect by chance

OBLH10: Describe the use of a research model by Houston and Davies (1985) for the optimal parental care of young by dunnocks, including the aspects considered and the findings...

• Looked for an outcome at which neither male nor female can gain from changing effort • Model used to compare data on polyandrous mating combinations where only the alpha male mated with females & where both alpha & beta males mated & fed the brood • Found conflict as females actively encourage beta males to copulate & attempt to avoid the close guarding of alpha males, as cooperative polyandry has greater reproductive success for females • Found polyandrous trios where two males fed the brood produced significantly more young per season than trios where only the alpha male fed • Found cooperation is unstable because an alpha male cannot enforce a limit on the beta male's share of paternity i.e. conflict between males, so if beta male's paternity below a critical level then it won't help rear the brood (as both want full paternity)

OBLH13: Identify the different genetic causes of stress that can result in fluctuating asymmetry....

• Loss of genetic variation • Hybridisation • New mutations of major effect • Intense directional selection

OBLH5: Describe the original function of Major Histocompatibility Complex (MHC) and how additional uses have developed over time...

• MHC probably evolved first for parasite & disease resistance, which selects for high polymorphism. • Then the polymorphism made it a good marker of individual identity

OBLH5: Describe how the Major Histocompatibility Complex is thought to affect body odour....

• MHC proteins are large & non-volatile • Possibly influences bacterial flora on skin • Although they are large these MHC proteins can still be detected • Humans can also potentially differentiate between MHC peptides

OBLH5: Describe mate choice via Major Histocompatibility Complex (MHC) in comparison to mate choice via sexual selection, including the research by Von Schantz et al. (1998)....

• MHC-based choice is about finding a compatible partner (best for you), classical sexual selection is about finding the best partner in absolute terms within a population • Looked at spur length in pheasants • Found females like long spurs • Also found MHC genotype associated with spur length & viability of male • Suggests MHC are the 'good genes' the handicap signals i.e. spur signals viability & signals MHC genes

OBLH5: Describe a use of Major Histocompatibility Complex (MHC) odour other than for mate choice, including different research examples as evidence...

• MHC-based odour can be used for kin recognition (nothing to do with inbreeding avoidance) e.g. • Manning et al. (1992) found mice rear pups preferentially with sisters, recognised sister's pups via odour (increases fitness) • Olsen et al. (1998) found Atlantic char (fish) grow faster when with kin, & recognise via MHC odour

OBLH13: Describe what is thought to be the amount of variation in fluctuating asymmetry when surveying the literature...

• Magnitude of FA in secondary sexual characteristics is about 10% (Møller & Hoglund '91; Møller '92) • I.e. 10% variation in asymmetry within a population in something that is sexually selected, while there is about 1% of the normal morphological trait • So 10 fold change in the degree of these asymmetries in sexually selected characteristics • However others have suggested this isn't the case (Balmford et al. '93)

OBLH3: Describe forced copulation and rape as a male behaviour, including why it occurs....

• Male damage to female, pays male if value to female of future reproduction is reduced in an accelerating fashion (Johnstone & Keller 2000 - game theory) • I.e. Adaptive to the male if, by reducing the female's chances of surviving & mating in the future, she favours investing more in her current (YOUR) brood

OBLH3: Describe the use of various different male behaviour to aid sperm competition in different species, including why these methods are good tactics...

• Male dunnocks peck at the female's cloaca before mating so she then might eject any sperm from a previous male. • Parker suggested that internal fertilisation itself evolved as a tactic to increase certainty of paternity. • Prolonged copulation ensures other males can't mate, e.g. brimstone butterfly remains in copula for a week, as the male himself acts as a 'plug'. • If sperm isn't stored, repeated copulation reduces chances that another male might mate at the crucial time when a female ovulates E.g. Lions copulate 100 times a day for a week when the female is in oestrus.

OBLH10: Explore sex difference in parental care by using some different bird types as examples to illustrate this.... Hint:

• Males & female may differ in care • E.g. for birds of prey the male hunts, while the female stays with young & prepares the food. • E.g. the Sandgrouse (which is desert-living) varies their expenditure based on the offspring stage & parent's sex • The female's expenditure is greatest during laying & incubation as she has less time for foraging & so looses some condition • The male's expenditure is greatest during chick rearing stage as he brings water to the nest by using specially modified belly feathers to carry water

OBLH10: Identify and describe the problems with this pay-off matrix model in terms of bi-parental care...

• Males have chance of breeding again, but females don't • Probability (aka p) that male remates is a fixed parameter, so p should depend on behaviour • If all females are caring, then p = 0 as no free females to be the male's second mate • Maynard Smith's model, is not internally consistent as for males to be able to breed again, there must be free females around, but if all the females are caring for young, there won't be any & so there is no point in males deserting • For internal consistency of the model, the probability of remating on desertion should depend on everyone else's care/desert decision because this determines whether there are any available mates.

OBLH1: Describe how finding a mate causes sexual reproduction to be costly...

• Males of sexual species spend inordinate amounts of time fighting with each other & showing off to try to impress females • Females waste lots of time & energy being choosy • An asexual female just reproduces where & whenever she wants, without the costs.

OBLH9: Describe what are the problems with using natural variation, including an example...

• Many factors covary as may think effect is due to x when it's really y, or actually x & y cancel each other out, e.g. • Increase condition -> ♂ • Increase condition -> decrease litter -> decrease food -> ♀

OBHL 12: Describe the benefits of imposed semelparity for Velvet Spider (Stegodyphus lineatus).... Also, identify and describe the research on this Spider, including the methods used and the findings....

• Mating starts in April, females dead by end of summer as after hatching, mother feeds young, later they eat her • If brood dies or doesn't hatch, female will lay more eggs. • Schneider & Lubin (1997): Carried out experimental manipulation as for experimental grouos removed mothers from brood, thus causing these mums to reproduce again • Measured value of care & success of second brood (compared to controls groups with mothers not removed) • Found semelparity is better as first brood (control groups) does better • High risk of predation means females have low chance of second brood.

OBLH8: What does the equation below represent and what would the equation be for Fisher's condition....? rⓜ x (Sⓜ/Cⓜ) = rⓕ x (Sⓕ /Cⓕ)

• Mating success/cost equation: - r = relatedness - S = mating success - C = cost • (Sⓜ/Cⓜ) = (Sⓕ/Cⓕ )

OBLH13: Identify and describe the research on how new mutations of major effect can cause of 'stress' to result in Fluctuating Asymmetry, including the research methods used and the findings...

• McKenzie & Clarke (1988): An insecticide (Diazinon) was used in Australia to control blowflies, but they evolved resistance due to a single mutation - this is a 'mutation of major effect' in that it had a big effect on fitness (survival of a poison). • Found when resistance first evolved FA went up in resistant flies as the homozygote for the resistance gene has higher FA than the heterozygote, which has higher FA than the wild type homozygote. • The idea is that development was destabilised by this new allele with big effects. • However, soon a modifier evolved which re-stabilised development, & FA went down

OBLH11: Describe how reproduction costs could be possibly measured via phenotypic correlation, including the issue with this and the main three possible problems with the observed data....

• Measure current reproduction & future success in natural population • More reproductive effort → the lower the survival, but it might not show cost of reproduction e.g. 1. Might get no variation - if every animal at optimum then can't see costs of deviating from this. 2. Pattern may reflect adaptive variation - animals vary in some unmeasured quality so good-quality animals both survive better & reproduce better. 3. Problems with correlation - other factors involved that are not measured

OBLH7: Describe Fitness in terms of the optimal strategy....

• Measure performance of a behavioural strategy based on number of descendants left by individuals • Can also measure it by number of offspring produced over lifetime of an individual (lifetime reproductive success)

OBHL12: Describe the accumulation of late-acting mutations as part of the evolutionary theories for decay, including who came up with this idea...

• Medawar (1952) • Force of natural selection declines with age thus discrimination between alternatives is less strong • Build up mutations over lifetime & pass these on to offspring • If breed before arisen then mutation not selected for in offspring

OBLH6: Describe what can occur in populations of mosquito Aedes when meiotic drive genes etc. are prevalent, including why this occurs....

• Meiotic drive is bad for genes on X chromosome, & the autosomes • So resistant X chromosomes have evolved in populations where driver genes are common. • Example of ANTAGONISTIC COEVOLUTION between genes on different loci.

OBLH3: Describe the use of forced copulation & rape in hermaphrodite marine flatworm as documented by?

• Michaels & Newman (1998) • Sperm is injected directly into the body cavity (where the eggs are). • This can cause infection through the wound, so it is better to take the male role & fertilise other individuals first before taking the female role & accepting sperm later on • So they 'penis fence' to try & inject sperm in each other without receiving an 'injection'. • Some species inject enzymes that cool the body

OBLH2: Describe how temperature determines sex in different reptile groups & identify the potential issue with this in the future...

• Mississippi alligator & some lizards: - Female lays eggs in nest; covers with vegetation - Incubation temperature determines sex as eggs hatch female if very cool, but male if very warm • Many turtles: - Produce males when cool • Crocodiles & snapping turtles: - produce males if warm, females if very warm or cool • Climate change could skew the sex ratios

OBHL 12: Discuss if selection could have influenced the evolution of the menopause by using our human ancestors as an example....

• Modern hunter-gatherers first reproduction at 15 yrs old & 50% survive to 45 yrs old • Thus quite likely to live till menopause • Prehistoric (extinct) populations maybe didn't survive long enough to experience menopause • Conclusion - not clear.

OBLH5: Identify and describe the research review on the study findings by Wedekind et al. (1996)...

• Penn & Potts suggested if there is a disease in the population, this is going to effect the development of the embryos • Could result in differential spontaneous abortion of these more homozygous embryos • While heterozygous zygotes/embryos were more likely to make it to full term

OBLH4: Describe the modern view of the theories AKA the Fisher-Handicap continuum (Kokko et al. 2003), including using tail length as an example....

• Most real-life examples probably have elements of both theories • Important that MARGINAL COST of optimum investment (e.g. to make peacock tail slightly larger) is greater for low quality males than high quality males. • Optimum tail length brings more reproductive success, but doesn't cost unduly in components of fitness.

OBLH8: Describe equality of investment evidence from different species of wasps....

• Mother packs cells with food • Volume is proportional to Investment • In species where investment in females > males, sex ratio is male-biased • In species where investment females = males, sex ratio is equal.

OBLH9: Describe the hypothesis by Trivers and Willard (1973) for the reason behind the local sex ratio...

• Mothers should base their sex ratio on their condition, i.e. individuals selected to invest in sex ratio based on ability to raise offspring. • Assumptions include: 1. Condition of young after investment depends on condition of mother 2. Condition of young after investment influences adult reproductive success e.g. poor mum = poor young 3. Males gain more from improved condition. - pays to invest in good quality male & pays for males to be big in red deer -> bigger harem & more mating success • Silver spoon effect = life-long reproductive advantage (i.e. increased fitness) enjoyed by an individual that had access to abundant resources during the early part of its life.

OBLH13: Identify and describe the research on how parasites can cause of 'stress' to result in Fluctuating Asymmetry (as part of environmental causes), including the research methods used and the findings...

• Møller (1992): Used 3 treatments for swallow nests wich were (i) added 50 blood-sucking mites, (ii) untreated control, or (iii) disinfected (killed mites). • Then measured tail length the following year (after moult in African wintering grounds) when they returned to Denmark to breed (captured birds in mist nets & sweep nets) • Found male tail FA affected, not females' tails - interpretation is that sexually selected male tail is more susceptible to stress.

OBHL13: Identify and describe the research investigating if symmetry is assessed, including the various methods used to test this and the findings of this study... Hint:

• Møller (1992): manipulated male swallows tails by cutting &/or sticking with 8 treatments in total • Shortened tail treatments - increased asymmetry, decreased asymmetry, or control (same asymmetry) • Elongated tail treatments - increased asymmetry, decreased asymmetry, or control (same asymmetry) • Controls for capture & cutting - control 1 with tails unmanipulated & conrol 2 tails just cut & glued back again • Looked at length of times for males to pair up & mate with females • Found males with long, symmetrical tail streamers (aka decreased asymmetry) paired in the shortest time (earlier than others) • Found males with short asymmetrical tail streamers took the longest time to pair with a mate • Found males with long symmetrical tails fledge more offspring as females put in more effort to raise offspring (but male flight is probably affected) • Found males with short asymmetrical tails flege less offspring as females put in less effort

OBLH2: Describe the advantages of Simultaneous hermaphroditism (both sexes at once)... (not fini)

• N.b. to a botanist, a hermaphrodite has male & female parts in the same flower • Only successful in angiosperms (flowers) • Low density advantage: - Even if self-sterile, can mate with everyone - Many weeds & internal parasites are hermaphrodites • Similar benefits to asexuality: - So when genetic similarity to parents is beneficial, self-fertilisation is good - BUT most simultaneous hermaphrodites have mechanisms to avoid self-fertilisation

OBLH7: Describe the affect of Size and energy reserves on small birds in winter and the methods they use to survive....

• Need to store fat but are limited in amount of excess weight they can carry around • In winter nights are cold & long so they spend more energy, while days are short causing foraging constraint • Roost in groups (long-tailed tit, goldcrest) to conserve heat • Some lower body temp. at night to cause hypothermia to generate energy (e.g. willow tit) • Others store more fat.

OBLH2: Discuss if it is male or female heterogamety...

• No idea • No obvious phylogenetic constraint - some closely related lizards have one system & some the other • May not matter, & either mechanism is an Evolutionarily Stable Strategy (ESS)

OBLH9: Identify and describe / explain the various limitations of the idea by Trivers-Willard, including some examples....

• No simple equation, so hard to make quantitative predictions. • Not even easy to make qualitative predictions! • Leimar argued that can't simply count grandchildren, & what matters is ability to leave descendants far into the future, i.e. reproductive value, not numbers • If mothers have strong effect on offspring quality & fathers have no effect then can be optimal for high quality mother to prefer daughters (even though their reproductive success is lower) • Several effects might be present as mother's condition could influence size of son or rank of daughter • Also sex of offspring might influence competition & sex ratio, but doesn't consider clutch size (number of offspring) ->Life history theory

OBHL13: Describe the interest in facial attractiveness in humans...

• Not surprisingly, lots of interest in whether symmetry is assessed in human mate choice - particularly facial symmetry. • Morphing allows easy manipulation & can create attractive face composites for use in research

OBLH8: Identify and describe another example that demonstrates Local Mate Competition....

• Not whole population interacting (Fisher) Mites have female-biased sex ratio • Mate inside the mother & leave when mother bursts. • Only need 1 male to mate with females

OBLH8: Describe the basis of Local Mate Competition by using fig wasps as an example....

• Not whole population interacting, so female gets diminishing returns from investing in males • As brothers compete for mates before the females disperse, results in a female-biased sex ratio to reduce this competition

OBLH11: Using birds as an example, describe when in a season should they breed, and the factors that affect breeding timing....

• Obvious answer is when food most abundant as less effort • But young born earlier in year do better (more time before winter) & birds that lay early produce large clutches • Trade off between chick survival & food abundance as parents have to get into condition before able to lay eggs • E.g. more reserves → bigger clutch, but delay to gain reserves → lower successfor each offspring • High quality birds can lay sooner & produce larger clutch.

OBLH3: Describe Sperm competition including the many different ways that it can occur an examples of this...

• Occurs if there is the potential for more than one male's sperm fertilising any one egg • External fertilisation e.g. - Female salmon lay eggs & males eject sperm into water over eggs • Internal fertilisation e.g.: - Delay between copulation & fertilisation - Sperm storage - Multiple mating - Extra-pair copulations (EPCs)

OBLH10: Identify some of the benefits of parental care...

• Offspring do better - but benefits likely to decrease as offspring grow (diminishing returns) • Mate has reduced costs - profitable if breeding again with same mate as mate will be in better condition. (e.g. swans paired for life).

OBLH10: Describe how hormones can be used by certain species and how the levels of hormones change....

• Often used by socially monogamous bird species • Testosterone high during territory & mate acquisition • The level drops afterwards • When artificially elevated testosterone: less care → more song, aggression, etc.

OBHL 14: Summarise the important reserch by Møller & Höglund (1991), including its merits....

• One of the first papers testing possible link between FA & sexual selection • Published in a top journal • In many ways, a perfect example of how to write a scientific paper • Tail length in birds as male long-tailed widowbird have much longer tail than female

OBLH1: Describe why the classic theory 1 for the evolution of sex only applies to groups with certain features...

• Only a benefit in large populations, & with mutations of small benefit • Sex speeds evolution only if different individuals with different beneficial mutations are around at the same time • In small populations &/or when mutations are highly beneficial, then they spread to fixations so rapidly that it is unlikely that different beneficial mutations are present, in different individuals, at any one time

OBLH7: Describe the findings by McNamara & Houston (1993) when modelling bird decisions based on fat reserve levels...

• Optimal strategy dependent on time of day & energy reserve state • If bird is above optimal strategy threshold then it should rest, but if below then it should forage • Highest proportion of food can be foraged in the morning but this reduces during the day

OBHL 14: Describe why fluctuating asymmetry (FA) is interesting....

• Optimum is no (i.e. zero) asymmetry. • Deviations from symmetry are caused by developmental 'errors' • 'Errors' increase if there is developmental stress (e.g. due to nutrition, parasites, weather etc.) • Symmetry may be a sign of 'good genes', so may be assessed in mate choice (sexual selection) • Can assess FA quite easily by measuring either side of an individual

OBHL 13: Identify the review and describe the problems it explores in terms of publication bias, including the data that would be expected and what is actually observed... Hint:

• Palmer (2000): funnel graphs (scatterplots of effect size vs. sample size) help reveal the extent of selective reporting • Look at measure of 'effect', the strength of relationship (e.g. correlation coefficient between two variables of interest) against sample sizes • Expect there to be papers published with low sample sizes & high sample sizes, while the size of effect that is measured is going to be different for different papers - effect influenced by sample size • Expect those with small samples to have a noisy estimated effect, while those with larger samples should have an estimated effect that is closer to the true value (need larger sample size to detect smaller effects). • Observe for published studies that majority have very small sample sizes but have demonstrated an effect much larger than expected - evidence for publication bias as people getting the predicted result with small sample sizes rush to publish • Thus over reporting of fluctuating asymmetry • Also observe lower number of studies with small effect sizes (correlations) for small sample sizes than would be expected • This type of publication bias is known as the 'file drawer problem' as lots of unpublished non-significant data with small sample sizes.

OBLH4: Describe the parasite theory and some of the affects it can have...

• Parasites can have strong effects on fitness • Problem found everywhere • Evolve antagonistically • Resistance genes under negative frequency-dependent selection • Condition-dependent ornaments can signal heritable resistance to disease (by the handicap -- optimal investment -- argument)

OBLH10: Describe the past ideas about parental care and thus the old models used for it...

• Parental care in past modelled as a simple foraging problem to search for food & feed the young • Optimisation: Simple foraging models prey choice, foraging in patches => Individuals making decisions in isolation • E.g. parent bird flies out from a nest, searches in a foraging area, makes decisions about the food that it collects, & then flies back to feed chicks. • Can construct models based on rate at which parent delivers food to young (cf. models of prey choice and patch use)

OBLH10: Describe how desertion varies for different species, including some examples...

• Parental care is left to one parent in many species but both parents in others • When there is uni-parental care which sex deserts varies depending on the species • Male tends to desert for mammals & birds (ducks, grouse, hummingbirds etc.) • Female tends to desert for fish (often male cares for young) & some birds (e.g. jacana, & some shorebirds).

OBLH6: Identify what 'psr' stands for and describe how it acts as a Sex ratio distorter and a genetic parasite...

• Paternal sex ratio is found in Nasonia is a gene attached to the (haploid) male's chromosomes, which doesn't code for useful proteins • When an egg is fertilised, it breaks down the paternal chromosomes that it is attached to, so turns zygote from diploid to haploid, & so turns it into a male. • Then attaches to remaining haploid chromosomes, & by converting a lineage to all-male, favours its own spread (in short term) • Affects viability so bad in long term

OBLH10: Describe the pay-off matrix and what Maynard Smith found from his models...

• Pay-off matrix (current + future) with 4 ESS behaviours: both care, both desert, F care & M desert, M care & F desert • Four possibilities, representing the four possible combinations of caring or deserting for both parents. • Found all four possibilities could be evolutionarily stable outcomes (depending on environment & payoffs)

OBHL12: Describe the possible different reasons why the body does decay (as part of senescence), including the flaws with some of these....

• Physiological theory (proximate explanation) that its due to inevitable 'wear & tear' possibly via shortening telomeres & accumulation of mutations • But some organisms don't age e.g. Creosote bush ( in Mojave desert) is > 11,000 years old • Evolutionary theories (ultimate explanations) that individuals don't die for the good of the species & instead decay depends on how mutations accumulate & trade-offs

OBLH3: Describe sperm size in Drosophila as an example of sperm evolving large size to block up female storage tubules...

• Pitnick et al. (1995) anesthetized male flies that were used for measurement of sperm and thorax length (all fly species raised under standardized conditions) • Found the fruitfly, produces sperm that is twenty times the male's own body length • It only produces one sperm per ejaculate.

OBLH5: Describe research on Inbreeding avoidance as a potential benefit of the Major Histocompatibility Complex (MHC), including the methods, findings, and what this indicates... Also, what are the problems with this study?

• Potts (1994) Used mice in semi-natural enclosures & these were allowed to breed • Found not MHC heterozygosity itself that is important in relation to fitness • Found fitness of mice in enclosures related to overall heterozygosity (AKA all other genes too) • Suggests MHC-influenced odour is just a marker for overall heterozygosity • Issue of populations being relatively small & already quite inbred, with few parasites - thus inbreeding is still a big problem in small populations

OBLH11: Identify and explain why the predicted Lack clutch size was wrong, based on the idea by Williams....

• Prediction ignores the future reproductive success • E.g. large clutch size → parents work more→ bigger cost • Parent might reduce clutch size to avoid this as working hard now means less success in the future • Due to life-history theory as assumes trade-off between current & future reproductive success, which implies there is a cost to reproduction.

OBLH8: Describe what happens when one sex is more costly than the other as part of Fisher's Theory of equal investment and why this occurs.... (check)

• Predicts equal investment in males & females (not necessarily equal numbers of the two sexes) The expected sex ratio is the ratio of allotted investment between the sexes • E.g. males x2 costly as females, so produce 2 females for every male, but then males have x2 higher mating success • Success ÷ cost ratio must be equal, so sex ratio inversely proportional to costs. Do see equal investment in both sexes by parents Nmales/Nfemales=Cfemales/Cmales

OBHL12: Identify the models related to patterns of reproduction and death, including the potential pros and/or cons of these models....

• Prey choice [rate of energetic gain]: + simple, quantitative, & easy to test • Life history [LRS]: + Better explanation - complicated, qualitative, & hard to test.

OBHL12: Identify and describe the criticisms made and issues discovered by various reseaechers on the early model of menopause

• Problem from suggesting that benefits of stopping do not outweigh costs • Mace (2000): argues it treats a female as though she could reproduce at same rate as young woman • I.e. ignores age-related decline in female survival & reproduction • Shanley et al., (2007): Analysed data from long-term study in the Gambia to look at deaths while giving birth & if grandmothers provide any benefits • Found no support for risk from death in childbirth increasing with age • Found some evidence of benefit of care by grandmothers, but effect not large compared to benefit of reproduction.

OBLH13: Describe the reasons why Fluctuating Asymmetry is interesting, and how can it be useful.... Hint:

• Provides information about the individual as is caused by 'stress' during development • A failure of the normal developmental programme as it is affected by this stress • As the optimum in a population is known, can make predictions about what has occured to cause this (unlike directional or anti-symmetry) • Can use it as an assay of environmental stress, with researchers using it in environmental monitoring • Absolute magnitude of FA is a good way to assess (via assay) an individual's ability to cope with developmental stress • Also useful in evolutionary biology

OBLH6: Describe the first cloning attempt including the results from these and explain what this suggests... Hint: 0 + 0 = ( o _ o ) & no _((_ v.s. ~º + ~º = (o_o) & __( (__

• Put two nuclei from same individual into an egg, but it failed: - If both haploid nuclei were maternal in origin, the foetuses had no placenta & big heads - If both were paternal in origin, the foetuses had a huge placenta & tiny heads. • Indicates that some genes have to have come from a sperm (dad), some from mum. • Some genes are 'imprinted' as being from father, or from mother (only seen in mammals & flowering plants)

OBLH4: Identify and briefly describe the forces that maintain genetic diversity despite females selecting for good genes in the lex paradox...

• Recurrent deleterious mutation: - Mutation rate per locus is low, but lots of genes affect 'condition' (traits affecting fitness) • Host-parasite coevolution: - By Hamilton & Zuk (1982) - Parasites etc. may have a central role in the evolution of sex & sexual selection

OBLH4: Describe how the research by Milinski & Bakker supports both Zahavi's Handicap Principle and the Parasite Theory of Sexual Selection....

• Red colour of stickleback male indicates physical condition/health e.g. redder males had greater mass per unit length • Infecting the prefered bright red males with parasites causes their condition & red intensity to decline - so females no longer prefer them • Thus red colour is cheat-proof signal of quality/health • Males with high red intensity are more helathy & may be more resistant to parasite infection

OBLH10: Identify some of the costs of parental care....

• Reduced locomotor performance e.g. pregnant snakes, lizards, bats, also birds with eggs • Increased predation risk. • Time & energy costs e.g. lost opportunities (e.g. to get more matings), energy spent; takes time to replace this, reduced success in future breeding, more vulnerable to parasitism etc.

OBLH 8 What happens if more than 1 queen?

• Relatedness asymmetry (rf/rm) of workers goes down • Predict more equal sex ratios as relatedness to sisters goes down • Across 25 species of polygynous ants (>1 queen), investment in daughters is 0.44. (not sig diff from 0.5.)

OBLH8: Describe how does relatedness asymmetry vary between single and multipy mated colonies?

• Relatedness asymmetry higher than average in single mated colonies = Specialise on females • Relatedness asymmetry lower than average in multiply mated colonies = Specialise on males • E.g. Sundström (1994): found that single-mated wood ant colonies specialise on females

OBLH11: What did Williams say (in the past) about costs of reproduction?

• Reproduction will be costly • So trade off between current & future reproductive success of parents

OBLH11: Describe the new theory by Williams (2018), including the key features and how this contradicts his previous idea...

• Reproductive trade-offs only expected under food stress, but food abundant in Spring & Summer so costs of reproduction might be quite rare • Previously thought parental care represents high intensity work • Now think parental care is not as hard work as: - Intense activity short-lived - High quality individuals can tolerate costs - Individuals might modulate costs

OBLH5: Identify and describe the findings of research studies investigating Heterozygote advantage as a potential benefit of the Major Histocompatibility Complex (MHC)...

• Research on mice by Potts (1994) found fitness & MHC heterozygosity not related • Research by Paterson et al. (1998) on soay sheep (inbred) population & nematodes found one genotype provided better resistance, not heterozygosity • Malarial resistance research in humans by Hill et al. (1991) found that one genotype provided better resistance, not heterozygosity

OBLH5: Briefly describe the research and findings of Havlicek & Roberts, (2009) in terms of mate choice based on Major Histocompatibility Complex (MHC) odour....

• Review of other research on human MHC choice • Didn't find strong evidence for preferring disimilar MHC & suggested bias due to varying sample sizes

OBHL 14: Describe the main issues associated with the samples used by Møller & Höglund (1991)....

• Sample size of 10 was slightly too small / not large enough, all though the time & resources to carry out experiments may limit this e.g. maybe difficicult to find bird skins (so 10 is a reasonable sample size) • May not actually be measuring asymmetry (caused by developmental stress) as may actually be measuring the seperate areas specimens came from, that when considered independently have no correlation between asymmetry & mean length • E.g. area rich in food so birds both grow long tails & are more symmetrical (no developmental stress), while other birds from area with harsh conditions/ little food, so tails are short & asymmetrical. Should absolute or relative asymmetry be analysed? Could there be confounding variables when comparing between species (i.e. not just the strength of sexual selection)?

OBLH9: Describe some examples where time in breeding season affects reproductive success...

• Seal species: - early in season, pups have longer to suckle so produce more sons. • Kestrel: - male bias early in season, female bias late - Probability of breeding as yearling; female = constant, but male = decreases with birth date - Model predicts decrease in % sons. - Mostly correlation evidence

OBHL13: Describe what the results by Swaddle & Cuthill (1995) on face symmetry indicates, and the issues that relate to this....

• Seems reasonable to think that highly asymmetric faces might signal some developmental problem • But most faces are fairly symmetrical so could symmetry be used as a cue to finding the best mate? • Problem of how to judge symmetry when a head is moving & not head-on • Unclear if symmetry preference is a by-product of how humans learn categories • Little overall consensus - mixed results in the literature.

OBLH 12: Distinguish between Semelparity vs. iteroparity, and provide examples for each....

• Semelparity ― single all-out bout of reproduction, followed by death • e.g. Antechinus males, Pacific salmon • Iteroparity ― several bouts of reproduction • e.g. most mammals & birds

OBLH5: Define and describe the Major Histocompatibility Complex....

• Set of vertebrate genes that are crucial to the function of the immune system • Highly polymorphic (>100 alleles at a locus), so all individuals unique for which alleles they have • Ancient - all mammals have different combinations of the same alleles • Allows one to make choices about other individuals e.g. mice can assess quality of each other

OBLH3: Describe the findings by Short et al. on testis size as a comparative test of sperm competition theory...

• Showed that relative to body size, primates where females mate with multiple males have far larger testes than those which mate with one male. • E.g. Chimpanzees, with promiscuous mating, have huge testes • E.g. Gorillas, with stable harems & one dominant male who gets all the matings, have tiny testes.

OBHL12: Describe the non-adaptive explanation of the evolution of the menopause...

• Side-effect of living for longer than we did in 'evolutionary' environment

OBLH11: Identify and describe some examples of the different possible external costs of reproduction...

• Signals to attract mate may attract predators e.g. male guppies are brightly coloured to attract females but are more obvious to predators, so are dull in high risk areas (Endler., 1978) • Deaths & injuries due to male fighting e.g. male white-tailed deer sometimes get seriously injured (Michael., 1968) • Predation risk for parent caring for/feeding young e.g. birds such as sparrows, robins & starlings are often caught by hawks & other birds of prey (Hamerstrom., 1951)

OBLH1: Describe classic theory 1 for the evolution of sex....

• Slow process for beneficial mutations (genes) to occur in the same asexual lineage • Sex speeds up evolution as these beneficial mutations can be brought together faster

OBLH6: Describe evidence for Inter-locus conflict potentially leading to evolution of sex chromosomes....

• Small region of mammalian Y chromosome that crosses over with X, is furthest from sex determining gene (sry). • The nearer to sry, the more genetically different the genes on X & Y are, suggesting they stopped crossing over further back in time. • Thus the region of the sex chromosomes that doesn't cross over has gradually expanded.

OBLH13: Describe fluctuating asymmetry (FA), including various examples to illustrate this... Hint:

• Small, random deviations from perfect symmetry in a trait which is normally (bilaterally) symmetrical • Many external features of most organisms are normally bilaterally symmetrical e.g. leg length etc. • But within a whole population, there would be some individuals with the left side longer/bigger than the right, & others with vice versa • Big asymmetries would be rare, so the population distribution would be roughly normal (Gaussian) thus being FA.

OBLH2: Describe the explanation of the Evolution of the sexes using the classic theory (II) on genomic conflict by Hurst & Hamilton (1992), including the components involved...

• Some organelles have own DNA e.g. mitochondria • When two cells fuse, competition between these organelles (& endosymbiotic bacteria) for precedence in cytoplasm e.g. Chlamydomonas • Cytoplasmic conflict is costly to nuclear genes • So a nuclear gene that suppresses its own cytoplasmic genes can spread provided its own cell fuses with a cell with an unsuppressed (i.e. functional) cytoplasm • A polymorphism results: 'suppressor' types that fuse only with 'non-suppressor' types AKA two gamete types

OBLH11: Describe non-annual breeding, including its key features and an external cost example to illustrate this...

• Species where breeding cycle takes < 1 year • Means that environmental conditions have a big impact as an external cost • E.g. Ural owl breeding is affected by vole abundance which follows three-year cycle • In good years 75% breed, but in poor years 21% breed.

OBLH5: Briefly describe the research and findings of Kamiya et al., (2014) in terms of mate choice based on Major Histocompatibility Complex (MHC) odour....

• Study was a meta-analysis of animal MHC mate choice • Found mild female trend for MHC dissimilarity, but that it does differ significantly between species.

OBHL13: Identify and describe the research on if symmetry is assessed, including the research methods used to investigate this, and the findings... Hint: Asymm R=G⃤ L=O⃤ X.Asym R=O⃤ L=G⃤ Symme R=G⃤ L=G⃤ male v1 R=G⃤ L=O⃤ male v1 R=G⃤ L=O⃤ male v1 R=O⃤ L=O⃤ Asymm R=O⃤ L=G⃤ X.Asym R=G⃤ L=O⃤ Symme R=O⃤ L=O⃤ male -2 R=O⃤ L=G⃤ male -2 R=O⃤ L=G⃤ male -2 R=G⃤ L=G⃤

• Swaddle & Cuthill (1994): Put the zebra finches in a choice chamber & Manipulate leg band symmetry, whilst holding total colour constant • Female is in the middle of the choice chamber & different males are in the four separate arms of the chamber, with a partition between the two so males & females can't access each other • Female will hop around looking at all the males & record the amount of time the female spends hopping up & down in front of a certain male as females will spend a longer time with the males that she finds attractive • 6 different treatments for male leg bands which are asymmetric (2 green right leg & 2 orange left leg, & then vice versa), cross-asymmetric (right leg orange top green bottom & left leg green top orange bottom, & then vice versa), & symmetric (right leg green top orange bottom & left leg green top orange bottom, & then vice versa) • Found females spent more time looking at males with symmetrically arranged leg rings, especially those with orange at the top of the legs

OBHL13: Identify and describe the research on if symmetry is assessed by Humans to judge attractiveness, including the various methods used and the findings from this...

• Swaddle & Cuthill (1995): used morphing to assess effects on human facial attractiveness, including attractive faces being made less attractive, & unattractive faces being made more attractive • Presented the 16 male & 16 female face pictures to 82 zoology students (37 male, 45 female) • Found symmetrical faces less attractive as perfectly symmetrical faces looked a bit odd - TOO perfect. • Found an interaction between original (natural) symmetry of face & the effect of making the face symmetrical. • Found naturally attractive faces were less attractive when made perfectly symmetrical, but the LEAST attractive faces did have their attractiveness enhanced by making them symmetrical.

OBLH13: Identify and describe the research on how dietary changes can cause of 'stress' to result in Fluctuating Asymmetry (as part of environmental causes), including the research methods used and the findings...

• Swaddle & Witter (1994): carried out short-term food deprivation during the weeks when (captive) starlings were undergoing moult. • Had 4 treatment groups; (i) control, (ii) morning food deprived, (iii) afternoon food deprived, & (iiii) variable-time food deprived (unpredictable - either in morning or afternoon with probability ½) • Found asymmetry in primary (i.e. flight) feathers was highest in the unpredictably food-deprived birds compared to the other treatments • Also found the fixed-time food deprived groups exhibited higher levels of asymmetry than the control group

OBLH4: Describe the knock on affects that resulted from the experimental research by Møller (1988 onwards)...

• Tail-lengthened males less likely to return from migration the following year • Tail-lengthened males have more 'fault bars' (sign of stress) in tail feathers Expected from a condition-dependent handicap

OBLH13: Identify the different environmental causes of stress that can result in fluctuating asymmetry...

• Temperature • Chemical • Population density • Parasites • Dietary

OBLH1: Identify and describe the explanation of the short-term advantage to sex by Williams (1966)...

• The 'lottery model' - the environment is patchy, with different genotypes better suited to different patches. • Asexual reproduction is like buying 100 lottery tickets with the same number, but sex is like having 100 different numbers. • If the environment is spacially unpredictable then sex can have an advantage.

OBLH1: Identify and describe the explanation of the short-term advantage to sex by Hamilton (1980)...

• The 'red queen' - the driving force for sex is parasites and disease. • When an organism adapts to resist parasites and diseases, this puts selection pressure on the parasites to evolve too - to attack better. • Common genotypes are at greater risk because the current parasites have evolved to attack them better. • Therefore having genetically different offspring (to you), & genetically varied offspring, is good.

OBLH1: Briefly describe what could have resulted if crossing over occured before syngamy...

• The 2 chromosomes would have been identical, so doesn't create much variation (but still good for DNA repair) Restores heterozygosity back?

OBLH 10 What shapes the optimal solution in game theory vs optimisation?

• The optimal solution is depends on what others are doing e.g: • if animal feeding alone → optimisation • but if not alone → game theory.

OBLH13: Describe how the research by Møller (1992) demonstrates that secondary sexual ornaments are particularly sensitive indicators via fluctuating asymmetry....

• The tails on the swallows are secondary sexual organs & are indicators of developmental stress due to only the tails of male's FA being affected (males with mites had the highest FA) • Wing feathers are not sexually selected - found that the level of asymmetry in wing length for males & females with different levels of parasitism weren't affected by the manipulation .

OBLH8: Describe the essential point for sex ratios...

• There can be conflict over the sex ratio if relatedness differs between interested parties.

OBLH3: Describe how sperm size affects sperm competition, including two pieces of research as examples to illustrate this, including the research methods used and the findings...

• There is a trade-off between how many sperm you produce & how big they are. • Stockley et al., (1997): used data from published literature on sperm number per (stripped) ejaculate, sperm length, sperm concentration, volume of (stripped) ejaculates, & sperm longevity. • For each fish species classified the intensity of sperm competition at mating. • Found fish species with external fertilisation & more sperm competition had more sperm but smaller sperm. • Gage (1998): captured non-threatened species of butterflies, & measure male body size & testis size. • Used (dark-field phase contrast) microscopy to measure the sperm lengths. • Found species with multiple male mating had larger sperm with longer tails as more sperm competition • So sperm for species with internal fertilisation (no sperm storage) is larger with more mitochondria to swim faster hence a larger body size

OBLH3: Describe Cryptic female choice as the 7th benefit of mating, including two research examples that provides evidence for this...

• There is evidence that females choose between sperm • Pizzari & Birkhead (2000): - Chickens were shown to exercise some crude level of choice as if mated by a subdominant male, females were more likely to eject the male's sperm • Olsson et al (1996): - In sand lizards (inbred population) females who mated multiply had non-random fertilisation of their eggs by the sperm of the males they mated with. - This may have been due to fertilised eggs from genetically similar mates having lower viability. - Thus by mating with a range of female, a female increases the chances that some of the males are genetically different from her.

OBHL13: Describe the behaviour of Zebra finches towards leg bands....

• They find particular coloured ones attractive (Burley '85, etc.) as they prefer red & don't like green - can affect mate choice • Preferences in choice chamber correlate with 'free' mating patterns

OBLH2: Describe how Size and social factors determines sex in Slipper limpets as an example...

• They live piled on top of each other • Females are large ones at bottom, males are small ones on top • Change sex as they grow (male to female) • If you remove the largest female, the largest male changes sex

OBLH1: Describe what the three ideas by Williams (1966), Hamilton (1980), & Kondrashov (1982) share in common...

• They rely on the fact that sex (including crossing-over) increases the variance in fitness of one's offspring. • Different theories emphasise which end of the distribution matters, but the principle is the same.

OBLH5: Describe rare alleles as a potential benefit of the Major Histocompatibility Complex (MHC), including what this type of hypothesis this would be...

• This is a 'Red Queen' hypothesis • Advantage to have rare genotype/alleles as current diseases/parasites will be adapted to attack currently common genotypes (Negative frequency dependent selection) • E.g. if risk passing diseases/parasites via vertical transmission to offspring, it's better to have offspring with different MHC genotypes from parent.

OBLH7: Describe how age and size at maturity affects reproduction in various ways...

• Trade-off between advantages of early & late reproduction • Early reproduction: shorter generation time, higher growth rate, higher survival to maturity • Late reproduction: higher fecundity, lower juvenile mortality

OBLH7: Describe the use of Adaptive fat levels, including in terms of dynamic programming...

• Trade-off between two sources of mortality as increased fat = low starvation, but high predation • Best long-term strategy will minimise starvation & predation, but maximise survival • Sequence of decisions at various times through the day e.g. forage vs. rest • Decisions are state-dependent e.g. energy reserves affect decisions • Foraging is stochastic (random) as may not always get food or may be interrupted (e.g. weather)

OBLH6: Identify and describe the research on the use of Sex ratio distorters by another parasitoid wasp as an example of conflicts between genes in the same body.....

• Trichogramma genus has some species that are asexual (all female) • Stouthamer et al. (1991) gave asexual species antibiotics • Found 50% males produced, while treatment over several generations turned population permanently sexual • Due to the sex ratio distorter is a bacterium like msr, so antibiotics killed it

OBLH10: Describe the use of models by various researchers to try to explain caring verses deserting of offspring by parents...

• Trivers (1st model parental care as a "game") looked at conflict of interest between male & female • Maynard Smith (1977) used classic game-theory model of care vs. desertion, which involved concept of Evolutionary Stable Strategy (ESS) as cannot be 'invaded' & no other strategy can spread by natural selection. • Two parts to Maynard Smith's analysis: 1. Establishing pay-offs (Biology of organism) 2. Finding stable outcome given pay-offs • Each parent has two options of care or desert (one shot model, no switch) • These decisions affect number of eggs female lays, survival of eggs, & chance male mates again.

OBLH6: Describe a Intra-locus sexual conflict, including examples and how this could lead to evolution of sex chromosomes....

• Two alleles on a single locus • One allele has beneficial effects when in a male (e.g. more testosterone) • Other allele has beneficial effects when in a female (e.g. reduced testosterone). • So conflict between expression of genes at one locus. • This initially limits rate of adaptive evolution in either sex (neither is at optimum for its sex) which affects offspring viability • But if costs are high, then favours evolution of sex-limited expression e.g. one allele is expressed only when in a male, the other only when in a female

OBLH6: Describe a Inter-locus conflict, including examples and how this could lead to evolution of sex chromosomes.... Hint: Y: [[[[[[[x]]]]]]]]]]]]]]]]]] X: [[[[[[[[[[[[[[[x]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]

• Two different loci, one with alleles that do better in males, other with alleles that do better in females. • Favours a sex-determining gene linked to the sex-specific-advantage genes e.g. gene near female-beneficial locus (that caused it to be female) is favoured due to linkage with genes with sex-specific effects • Accumulation of other favoured genes with sex limited effects near the sex-determining gene as less likely to be lost during crossing over • Favours evolution of reduced crossing over near sex determining gene to prevent genes with sex-limited effects ending up in 'wrong' sex • Results in specialised sex chromosomes, that do not cross over with each other

OBLH10: Describe the current ideas about parental care and thus the model required for this...

• Two parents feeding the young, the amount of food the young get depends on both parents' efforts. • Parents share 'payoff' (the growth & survival of the young), as depends on what both parents do • Parents don't share costs (effort expended, food given to the young rather than eaten itself), so there is potential conflict of interest over how much effort each parent should expend on young. • Parental Care: males & females interact => need to use game theory

OBLH2: Describe how gene suppression could occur to prevent the genomic conflict, including evidence that supports this...

• Unilateral destruction of cytoplasmic genes prior to fusion • Or making gametes so small that there's no room for cytoplasmic genes (i.e. sperm) • Ciliates with isogametes (no true sexes) only pass nuclear DNA down a tube • Peritrich ciliates, with secondarily evolved full fusion, have two sexes

OBHL 14: Describe the experimental methodology that was use by Møller & Höglund (1991)...

• Used 16 pairs of bird species (so 32 species in total) & each pair were within same family (so phylogenetically close), but one species is ornamented & the other not • Visited 3 museums with 'birds' were dead as they were 'bird skins', measured right & left sides of tail & wing feathers of 10 males & 10 females of each species, to nearest 0.1 mm using calipers • Did paired tests on hypotheses by using tests for absolute (difference between left & right side) & relative asymmetry between: - Dimorphic vs. non-dimorphic male tails - Male vs. female tails - Tails vs. wings • Paired tests on difference in correlation between asymmetry & mean length for individuals (i.e for ornamented vs. unornamented species, males vs. females, & tails vs. wings)

OBLH4: Describe the research by Norris (1993) including how it provides evidence for Fisher's theory...

• Used Cross-fostering of Great tit chicks by exchanging complete, partially incubated clutches between pairs of nests (n = 64 nests). • Nests within each pair were matched as closely as possible for clutch size & laying date before all eggs in each clutch were exchanged, thus the cross-fostering design resulted in parents raising unrelated young, but experiencing no significant change in their breeding circumstances. • Compared the stripe size of male offspring with the stripe size of their putative & foster fathers (both are raising foster clutches). • Found there was a significant correlation between the stripe size of cross-fostered male offspring & the stripe size of their putative father • So breast stripe width is heritable (& also females prefer wide stripes)

OBLH8: Describe the research and findings by Macke et al. (2011), including what this means...

• Used Spider mites (Tetranychus urticae) with 3 condition levels of: - 1 foundress - 10 foundress - >100 foundress • Found 1 foundress = female bias, but when >100 foundress = 50:50 ratio • Supports both Hamilton's and Fisher's theories

OBLH4: Describe the research by Wilkinson & Reillo (1994), including how this provides evidence for Fisher's theory...

• Used Stalk-eyed flies as in the wild wider eyed males attract more females & have higher mating success • Used pairs of males with same body-length but differing eye-spans as artificially selected for one line with long/wide eyes spans & another line with short/narrow eye-spans • Used these males in four experiments to determine female mate choice in the absence or presence of male interactions, within clear plastic cages with hanging strings. • In the first experiment the males could interact, but competition was excluded for experiments 2-4 by using clear acetate partitions to separate the two different lines of males (the females could still get through these partitions). • Experiment 2 used unselected females, while in contrast experiment 3 used females from the long/wide line, & experiment 4 used females from the short/narrow line. • Found females from long-eye span group & control group prefered males with wider eyes • But females from short-eye span group prefered males with shorter eyes • Provides evidence for attractiveness & preference covarying

OBLH5: Describe the research by Milinski et al. (2013) on the detection of the Major Histocompatibility Complex....

• Used functional magnetic resonance imaging to look at which brain areas were activated when individuals 'smelt' MHC-linked peptides that came from their own group or others • Found there was a difference, suggests a direct olfactory component, despite humans not having a vomeronasal complex

OBLH4: Describe the experimental research by Møller (1988 onwards) as evidence for the parasite theory...

• Used tail manipulations to investigate female choice in swallows • 4 treatments to tail: shortened, lengthened, control of cut & re-glued, & control of just capture/release • Found long tail males pair sooner than short tailed males • Long tailed males fledge more young as females invest more in offspring • Also long tailed males had more extra pair copulations (EPC) with the females from short tailed males • Indicates female choice affects fitness components

OBLH4: Describe the research methods and findings by Bakker (1993), including how this provides evidence for Fisher's theory...

• Used three intensive red males & three pale red males as fathers & crossed these in a full-sibling/half-sibling breeding design with 14 females • Quantified the maximum red colour intensity of the males throats (2 weeks after the completion of the first nest) • Found redder fathers on average produced significantly redder sons - i.e. intensity of red colouration of son correlated with red intensity of his father • Investigated preference of female offspring for redder males by using a simultaneous choice design, as ripe females were given the choice between two courting males that differed in red intensity • Found most females were consistent as they always preferred the redder male or showed no preference on both days (via ANOVA) - i.e. daughters of red males prefered red males, while daughters of dull males showed no preference • Provides evidence for preference being heritable

OBLH4: Describe another indirect benefit of female choice in sexual selection, including the other process this relates to and who it was developed by...

• Viability - a choosy female's offspring have higher viability due to the ornament being a signal of the quality of the rest of the male's genes • This is associated with Zahavi's Handicap Process as only males with the best genes can cope with the cost of more attractive ornaments

OBLH3: Describe penis shape morphology as an adaptive response to sperm competition, including other features and examples...

• Waage (1979) Found Damselfly's penis has bristles & spines which act like a loo-brush to remove sperm of any other male from female's reproductive tract. • Arnqvist (1998) showed that diversity of genitalia shape is 2x greater in species which mate multiply, much of this diversity being adaptations for sperm competition. • Many species also use plugs & 'chastity belts' e.g. Ghost crab males inject glue

OBLH5: Identify and describe the research that suggests that humans may use scents to accentuate their own Major Histocompatibility Complex (MHC) odour...

• Wedekind & Milinski (2001) • Asked students to rank 36 different perfume compounds based on whether they would like to wear them on themselves, or on a potential partner • Found if for use on 'self' then showed strong correlation with own MHC & different groups of some of the scents • But found no correlation when considering whether it should be on a potential partner

OBLH5: Identify and describe the famous/classic studies on Major Histocompatibility Complex (MHC) odour of human males...

• Wedekind et al. (1995) • Got 44 male students to sleep in the same t-shirt for a couple of days & then stuck the shirts in jars • Then got female students to smell the jars & rate which ones they prefered • Found that females who weren't on the pill or menstruating prefered odour of MHC dissimilar males • But females on the pill (tricks body to think its pregnant) prefered MHC similar males • 1997 study used t-shirts from 4 males & 2 females, also found similar results

OBLH5: Identify and describe the famous research on rare alleles as a potential benefit of the Major Histocompatibility Complex (MHC)...

• Wedekind et al. (1996) had a hepatitis outbreak in lab mouse colony • Noticed during outbreak females started producing more heterozygous offspring, despite having the same mates • Suggested due to sperm selection by the egg in the female • Or due to a biased 2nd meiotic division where sperm genotype is recognised & so meiosis is biased to mismatch to get heterozygosity

OBLH2: Describe the theory of sex allocation as an explanation of Protogyny, including an example to illustrate this...

• When born female first is best e.g. blue-headed wrasse: • Reproductive value increases with age or size or condition, but effect of size is greater for males as thet need to fight for territories • So, females have higher values when small or young, but males have higher value when large or old. • Have highest LIFETIME FITNESS by starting out female, changing sex at the age/size (where the lines cross) & ending up male

OBLH2: Describe the theory of sex allocation as an explanation of Protandry, including an example to illustrate this...

• When born male first is best e.g. slipper limpet: • Effect of size is greater for females than males as in this case female fecundity is strongly dependent on body size. • Males have higher values when small or young, but females have higher value when large or old. • Here the highest LIFETIME FITNESS by starting out male, changing sex at the age/size (where the lines cross) & ending up female.

OBLH8: Describe what causes Local resource competition, including an example species this occurs in...

• When competition between siblings or parents is greater for one sex, then an excess production of the other sex is favored • E.g. African bushbaby: - At independence, males disperse, but daughters stay on the maternal territory - Daughters compete with mother so are a cost throughout life - Male-biased sex ratio

OBLH7: Identify what should be accepted when starvation is likely, including why there should be caution when looking at relationships based on rates...

• When starving should accept predation risk to get food & the mortality through predation • Starvation rate doesn't reflect importance of food availability, while Predation rate doesn't reflect importance of predation risk.

OBLH13: Identify and describe the research on how hybridisation can cause of 'stress' to result in Fluctuating Asymmetry, including the research methods used and the findings...

• Wilsey et al. (1998): looked a leafs from pure & hybrid birch tree species by measuring the width of the right & left halves from the midrib to the leaf margin • Found the leaf asymmetry was higher in the hybrids.

OBLH7: Identify and describe the research on cost of fat, including the methods used and the findings....

• Witter, Cuthill & Bonser (1994) trained starlings to fly through maze of padded poles • Added different masses to the birds • Found the higher the mass the worse the performance • Indicates reduced fat = performance better, while predation likely to increase with fat

OBLH9: Describe some examples of local sex ratio...

• Woodchuck: - Many females killed as control strategy - Surviving females produced more daughters (the rarer sex). • Humans (Trivers "Social Evolution"): - In both world wars, male-biased mortality - After war, male-biased sex ratio

OBLH10: Identify and describe the research on manipulating parental care of offspring in birds, including the various methods used and the findings...

• Wright & Cuthill (1989): manipulated starling pairs during nestling feeding phase, with three treatment groups of (i) male parental feeding reduced; (ii) female parental feeding reduced; & (iii) control pairs. • Added small lead weight (each weighing 1 or 2 g) to the base of a bird's three central tail feathers with Superglue to slow the rate of feeding of that individual • Also varied the number of weights added as individuals were weighted to a total of 4g (3 birds), 6 g (3 birds), or 8 g (2 birds) • Measured the response of partner in terms of feeding rate & consequences for chick growth (empirical test) • Found when neither bird had a weight attached (control), both parents fed equally • Adding weights to male reduced his work-rate, female increased her work-rate a little in response, but not to the same extent as the male reduction • Also, adding weights to female reduced her work-rate, & while male compensated to some extent, his increase did not match the decrease by the female • Consequently, chicks received less total food when either partner was handicapped, as there was some compensation, but it was incomplete • Reduced total food delivery resulted in reduced chick weight at fledging, which will lead to reduced over-winter survival - indicates mutual benefit to cooperate instead

OBLH5: Identify and describe the evidence for mate choice using the Major Histocompatibility Complex (MHC) in mice and rats....

• Yamazaki et al. (1983), Penn & Potts (1998) • Can discriminate individuals based on one MHC gene difference (very inbred so little difference between individuals) • Can also discriminate different human individuals based on MHC • If given a choice test where they choose mate, they will go for MHC dissimilar mates, based on odour • Used Cross-fostering experiments & found they learnt family odours from siblings in litter ("familial imprinting") - look for odour different to self (increase offspring fitness)

OBLH13: Identify and describe the research on how population density can cause of 'stress' to result in Fluctuating Asymmetry (as part of environmental causes), including the research methods used and the findings...

• Zakharov et al., (1991): measured skull & bones etc of common shrews over different years • Found that FA was higher in years when breeding density was high (in cyclic populations)

OBLH13: Identify and describe the research on how chemicals can cause of 'stress' to result in Fluctuating Asymmetry (as part of environmental causes), including the research methods used and the findings...

• Zakharov et al., (1997): looked at the skulls of grey seals & ringed seals (from Baltic sea) & compared the skulls from the pre-pollution sample (1877-1936), high pollution sample (1964-1975), & low pollution sample (1986-1990). • Found FA higher in the "high pollution years", while being low in the "pre-pollution period" & in the "low-pollution period"

OBLH10: Briefly identify some examples of forms of Parental care...

• provide food, water, heat • defend from predators • teach skills