Strategies and Adaptations Flashcards
What was the main idea around Tinbergen’s work?
The idea of watching and wondering, and then asking questions.
What are Tinbergen’s 4 questions?
- How does the behaviour affect fitness?
- What is the role of evolutionary history?
- What physiological signals drive one behaviour over another?
- How does behaviour develop?
Which of Tinbergen’s questions are the ultimate evolutionary questions?
The ones that involve adaptation and phylogeny.
Which of Tinbergen’s questions are the proximate, causal questions?
The ones relating to mechanism and development.
When is estimating genetic parameters in many natural populations problematic?
If evolution by natural selection is changes in gene frequencies.
Is fitness ultimate or proximate?
It is ultimate.
What are testing of evolutionary hypotheses often based on?
They are often based on only phenotypic data as the implicit assumption is made that phenotypic data are an adequate predictor of the underlying genetics.
What is the phenotypic gambit?
Using simple haploid genetics when testing evolutionary hypotheses based on phenotypes.
What does optimal foraging use and require?
It uses optimality models to determine foraging decisions and it requires a currency and a set of restraints.
What are the two frames of reference of an optimality model graph?
- where the difference between the costs and benefits is biggest
- where the costs and benefits are equal.
When should a behaviour increase when looking at optimal utilisation of time or energy?
A behaviour should increase as long as the resulting gain in time spent per unit food exceeds the loss.
What is Marginal Value Theorem (MVT)?
It is an optimality approach to study animal foraging for resources in a patchy environment.
What is the Marginal Value Theorem used to predict?
It is used to predict how long an individual will spend in a patch and which level the individual will give up when resources deplete.
What are the Marginal Value Theorem predictions determined by?
A ratio of travel cost to foraging benefit.
What is the evidence that plants optimally forage?
A study showed that give-up time should be higher in higher-quality patches than low-quality patches in plant roots.
What is another use for the Marginal Value Theorem other than optimal foraging?
It can be applied to other ideas in animal behaviour like male mate investment.
What are the 2 main assumptions of the ideal free distribution?
- any individual settles in a habitat most ideal for them
- all individuals within a habitat have individual expected success rates.
What aspects make a good game theory model?
- simple, so rules can be easily understood
- has elements of reality
- creative
- insightful
- predictive.
What is the best response to a move by an opponent in the prisoner’s dilemma?
The best response is Tit for Tat, where you start off deflecting and then copy your opponent, so choose what they last chose.
What is the Nash Equilibirum?
It is where the payoffs of a situation are equal.
What is the concept of an evolutionary stable state?
It is the concept that playing a certain strategy is uninvadable and it is the stable state.
What is the impact of evolutionary stable strategies on game theory?
It makes games temporally and spatially dynamic.
When does the phenotypic gambit work?
It works if simple genetics are present and when phenotypes can be used as surrogate fitness.
What is a life history strategy?
It is a unique combination of investment in survival, development and reproduction.
What are some of the key life history traits?
- age at maturity
- reproductive window
- frequency of reproduction.
What can life history strategies be impacted by?
- limited resources
- physiological limitations
- microevolutionary processes.
What is life history theory concerned with?
“strategic decisions over an organism’s lifetime”.
What is a perennial iteroparity life history strategy?
Where there are multiple reproductive cycles.
What is a annual semelparity life history strategy?
Where there is reproduction and then the individual dies.
What is a perennial semelparity life history strategy?
Where it doesn’t mature for years and then dies after reproduction.
What is an example of life history strategies of animals?
- Mice invest a lot of energy into reproduction, having large numbers of offspring in one reproductive cycle.
- Greenland shark invest highly in living for a very long time.
What is an example of a life history strategy of plants?
Bamboo invests lots in development, growing quickly.
What do you get when following life histories of many different individuals?
You get lots of longitudinal cohort studies and follow key life moments and you can observe changes over time.
What is measured when looking at life histories of individuals?
When tracking individuals, they measure different physical features to look at the growth rate.
What are examples for using a cross-sectional cohort study?
- tree rings
- radiocarbon
- fire.
When are longitudinal cohort studies not possible/convenient?
They are not possible/convenient for species with a long lifespan.
For annual species, how is the absolute gain in intrinsic population growth achieved?
It can be achieved by changing to the perennial reproductive habit.
What is the absolute gain in intrinsic population growth be equivalent to for an annual species?
It would be exactly equivalent to adding one individual to the average litter size.
What is the Cole’s paradox?
The idea of why complicate your life an put is all into reproduction.
What are the assumptions of Cole’s paradox?
- no costs of reproduction
- juveniles are not fragile
- a lack of stage-specific density-dependence.
When does semelparity happen according to the reproductive hypothesis?
It happens when you get the highest reproductive success if you invest everything into reproduction.
When does iteroparity happen according to the reproductive hypothesis?
When there is a relatively high success of reproduction with not complete reproductive effort used.
How does iteroparity evolve according to the demographic hypothesis?
It evolves when you start reproducing and then you keep reproducing while mortality slowly increases.
When does semelparity evolve according to the demographic hypothesis?
It evolves when, upon reproduction, the risk of mortality shoots up to insanely high, and there is usually early maturity and lots of offspring in a short amount of time.
What are the key objectives of life history theory?
- explaining the vast variation in life history strategies across the Tree of Life
- predict which life history strategies are better suited to different kinds of environmental regimes.
What is the paradox of perennial semelparity?
It is when to reproduce, with the ultimate trade off being that reproduction is now but there is no survival later.
What is the ultimate correct hypothesis on the evolution of semelparty and iteroparity: the reproductive hypothesis or the demographic hypothesis?
Neither is the certain ultimate correct one.
What is the observed perennial semelparity strategy observed in plants?
Reproduction begins at smaller sizes in nature and the model showed that the evolutionary stable strategy would be for the plants reproduction.
What does the evolutionary stable strategy match when taking into account environmental stochasticity?
The evolutionary stable strategy matches the absolute stable strategy.
What are the 2 key predictions from life history theory?
- constant environments select for long-lived strategies
- random variation in environmental conditions select for annual species.
When is the principle of competitive exclusion seen?
When there is greater stochasticity where there are long-lived species.
What is ageing?
It is the time passing by while getting worse, so it is the decrease of the physiological functions with time.
Are senescence and aging the same thing?
Senescence and aging aren’t the same thing in humans, but can be the same thing in other species.
Who presented the first evolutionary theory on senescence and what strategy did they come up with?
August Wiseman presented the first evolutionary theory on senescence, and came up with the make room strategy in terms of group selection.
What are classical evolutionary theories of senescence?
- Medwar, mutation accumulation
- Williams, antagonistic pleitropy
- Hamilton, mathematics of aging and the moulding of senescence by natural selection
- Kirkwood, disposable soma.
What do the different classical evolutionary theories of senescence say?
- increase in mortality and decrease in fertility are inevitable
- “protected” species should evolve longer lifespans
- lifespan correlates with timing of reproduction
- senescence begins immediately after sexual maturity.
What is the correlation between body mass and longevity?
Increasing body mass has a positive correlation with longevity.
How could you measure senescence?
By looking at the decrease in strength.
What do harsh environments do to a plants maximum lifespan?
They extend it.
What characteristics in mammals and birds increase lifespan?
- flying (more access to resources)
- being arborial
- being fossorial
- not being crepuscular
- the ability to escape extrinsic mortality
- cliff-nesting
- burrowing
- ocean-going.
What are the 2 different types of senescence
There is individual senescence and demographic senescense.
What are demographic traits that are associated with life history traits?
Rate and age-at-onset of senescence is correlated with generation time.
Is phylogenetic/taxanomic information important when looking at senescence?
Yes.
Can senescence be observed in wild species?
Yes, which is contrary to the “die before you get old” idea.
What age-specific mortality patterns are seen in Hydra?
There is constant mortality and fertility with age.
Is senescence inevitable, and if not, what other types are seen?
It is not inevitable, with there commonly being no, negligible, and negative senescence being seen.
What are the drivers of immortality?
- indeterminate vs. determinate growth
- modular vs. unitary architecture
- high vs. low cell pluriopotency/separation of germ line from soma.
When might species that do not senesce display declines in performance and ultimately die?
When they are subject to suboptimal conditions of stress.
What are the problems with some methods that are used to study age?
They can be very destructive, so new non-destructive approaches of studying age are being researched.
What is one potential challenge of humans studying senescence?
We may not be looking at the correct factors or looking at the right time in individuals.
How can longevity be defined?
It can be defined on an individual level, or if a cell lives for a long time. So, it can be defined at many different levels.
What is the economy of effort?
It is the idea that signals have their effects without direct physical force.
What is ritualisation?
The process signals being specially evolved for communication.
What is signal design classically seen as?
A series of solutions to the problems of signal detection and recognition.
What are the 4 problems of classic signal design?
- background noise
- signal degradation
- confusion with other signals
- correct recognition and response.
What are the solutions to the 4 problems of classic signal design?
- conspicuousness
- repetition
- redundancy
- stereotype
- distinctiveness
- typical intensity.
What are supernormal stimuli?
The evidence for signals as psychological drugs.
What are the steps in the arms race that is seen in signalling?
- The signal triggers a supernormal response in the receiver, so they are manipulated.
- The receiver evolves reduced sensitivity to the signal.
- Signaller escalates signal intensity.
- The evolutionary arms race ensues, with conspicuous, exaggerated signals.
What are the steps in mindreading seen in animal signalling?
- The receiver detects cues that predict the future behaviour of the emitter.
- The emitter learns this and reduces the conspicuousness of such cues.
- The receiver gets more sensitive to the signal.
- The arms race ensues based on stealth and concealment, or conspiratorial whispers where there is no conflict.
What are the 2 types of handicap in animal signalling?
- Revealing handicap/Index, where it is impossible to cheat
- Strategic choice handicap, where it is not worth cheating.
What is signal content?
How a signal is designed to contain its particular message.
What is signal efficacy?
How a signal is designed to get its message across.
What are the three properties determined by receiver psychology that can contribute to a signal’s efficacy?
- Detectability
- Discriminability
- Memorability.
What does Darwin say that sexual selection depends on?
“depends on the advantage which certain individuals have over others of the same sex and species solely in respect of competition over reproduction.
What evidence is there that sexual selection traits are costly?
There are phonotactic parasitoid flies that use the specific song features to locate male crickets and parasitise them.
What does sexual selection operate on?
It operates on the variation in individual reproductive success determined by competitive access to reproduce opportunities among members of the same sex, so it only acts on individuals of the same sex.
Why does the evolution of traits that convey competitive advantage happen?
It happens due to high variation in reproductive sex leading to more intense sexual selection on these traits.
What did Dawin look at with sex roles?
He looked at the ancestral role of ‘sex roles’, with the male pursuing females and the females being coy. He suggested it could be due to the size and quantity of gametes produced.
What is anisogamy?
Two mating types with different investment in gamete size.
What is the only stable solution to the evolution of anisogamy?
Total commitment to disassortative function, where males are dependent on females and propagate at their expense.
What is the Bateman gradient?
It is the idea that as the number of partners increases, the total number of offspring also increases.
Is the Bateman gradient steeper in males or females?
It is steeper in males than females.
What are male and female potential reproductive rates like?
- male faster than female as they produce more gametes
- it is limited by the availability of ova
- female’s reproductive success limited by fecundity.
What does the sex experiencing the strongest sexual selection have?
It has the higher standardised variance in mating success.
What limitation does Bateman’s study suffer from?
Mating success wasn’t measured through mating behaviour, but through the offspring that were raised.
While controversial, what has new evidence indicated regarding the Bateman principles?
That the principles are a near-universal feature of sexually-reproducing taxa.
What is intra-sexual selection?
Competition among members of one sex over access to a member of the opposite sex.
What is inter-sexual selection?
Selection of reproductive partners by members of one sex among members of the opposite sex.
What can variation in mating success be caused by?
Male competition and female mate choice.
What is selected for in terms of male-male competition?
- large body size
- armaments
- social competitive ability.
What does selection on females to maximise offspring viability happen through?
It happens through the quality of the male reproductive contribution.
What leads to inter-sexual selection acting on male ornaments and courtship displays?
Female behaviours can bias variation in male copulation success, and they can have different responses to individual males that influence the probability of successful copulation.
What is the adaptive significance of female preference?
Female choice is not adaptive to the female as natural selection promotes a sensory bias that leads to preferences. There can be benefits for the female, and both genetic and non-genetic benefits for the offspring.
What does female preference and assortative mating lead to?
It leads to linkage disequilibrium between genes for male ornament and female preference for such ornament.
What does the self-reinforcing process lead to?
It leads to the evolution of more extreme ornaments and preferences.
What is the handicap principle?
The idea that sexually selected traits are costly to produce and large ornaments can only be produced by those who can afford them.
What does sexual ornament expression reflect according to the handicap principle?
It reflects genetic quality.
What is the idea of condition dependence on sexual selection?
It is the idea that there is a limited amount of resources available for allocation to fitness-enhancing traits. This means there is a trade-off between male investment in ornaments and in fitness-enhancing traits.
What does sexual ornament expression reflect in terms of condition dependence?
It reflects hereditable condition.
What can good genes include in sexual selection?
They can include parasite-mediated costs, and immunocompetence.
What is polyandry?
Females mating with more than one male within a single reproductive event, or storing sperm across multiple reproductive bouts.
What are the drivers of polyandry?
- maladaptive to females (male-driven and correlated evolution)
- selection through maternal performance (convenience, acquisition of resources, and sperm replenishment)
- selection through offspring performance (increased genetic diversity, insurance against inbreeding, and fertilisation by genetically superior males).
What does polyandry introduce?
A new source of variation in male reproductive success.
What is variation in male reproductive success driven by in monandry?
It is driven by the number of mates.
What is variation in male reproductive success driven by in polyandry?
It is driven by paternity share within clutches.
What does variation in paternity share give rise to?
It gives rise to sexual selection after mating.
What is sperm competition?
Competition of the ejaculates of different males for the fertilisation of the eggs of a female.
What is cryptic female choice?
Female traits biasing the outcome of sperm competition.
What is are some alternative mating tactics?
They include sneaker and satellite males which pretend to be a female and then also release sperm for the female as well as the parental male releasing sperm.
What does intense competition over reproductive opportunities make sexual selection?
It makes it a strong, open-ended directional process which leads to exaggeration.
What intrasexual variation do females have and why?
They have low intrasexual variation in reproductive success caused by intrasexual competition for ‘best’ mates.
What intrasexual variation in reproductive success do males have and why?
They have large intrasexual variation in reproductive success which is determined by competitive access to females and fertilation, a strong opportunity for sexual selection.
What is parental investment?
Any investment by the parent in an individual offspring that increases the offspring’s chance of surviving at the cost of the parent’s ability to invest in other offspring.
What happens when optimal parental investment differs between sexes?
Where one sex invests more than the other, the members of the latter will compete among themselves to mate with members of the former.
Why are females predisposed to a greater parental investment?
Because of ancestral greater investment in ova, the current investment reduces female reproductive success more than male residual reproductive success.
What will the sex with the greater parental investment become for the opposite sex?
It will become a limiting resource.
How is mating skew seen in parental investment?
If male mating success is strongly skewed in favour of certain males, sexual selection will push this non-random subset of males to mate rather than care.
When is stronger sexual selection seen in males?
It is seen in species with female-biased parental care and larger males.
What are the potential rates of reproduction in two sexes affected by?
The proportion of time and energy expended by male and female parents on their progeny.
What is the operational sex ratio?
The average ratio of fertilisable females to sexually active males at any given time.
What are the sex roles?
Males selected to mate multiply rather than invest in parental care and females are selected to invest in parental care and partner choice rather than mate.
What happens when ecological conditions make intrasexual competition more intense in females?
The sex roles are reversed.
What does anisogamy predispose and create?
It predisposes one sex to stronger selection, which creates divergent reproductive strategies and fitness interests in males and females.
Why does sexual conflict arise?
Because reproduction is costly and alternative reproduction opportunities are available to members of at least one sex.
Why is strict lifetime monogamy the exception?
As sexual conflict does not occur, and the fitness of an individual is aligned with that of its reproductive partner.
What are members of one sex selected to impose?
They are selected to impose their fitness interests upon members of the opposite sex.
How can males overcome female discrimination and resistance?
Through sexual harassment and coercion, which can harm females.
What can sexual cannibalism happen?
Before, during, or after mating.
What is an example of mating duration being important?
It is important in seed beetles. Longer mating allows the male to inseminate more sperm, but the females interrupt the mating by kicking the male off with their hind legs. Due to this, males have evolved sclerotized genital spines which wound females, with the males with longer genital spines having an advantage in sperm competition.
What is sperm allocation seen in hermaphrodites?
There is conflict over sperm allocation, where each partner benefits more by fertilising the eggs of the other rather than obtaining sperm to fertilise their own eggs.
What is the example of sperm allocation manipulation in hemaphrodites?
Snails stab each other with ‘love darts’ hundreds of times during mating and these are coated with a hormone-like substance that manipulate the partner into accepting more sperm.
What happens in sperm utilisation?
Females may eject or neutralise the sperm of “unwanted” inseminations, however, males have evolved ‘copulation plugs’ which may prevent females from ejecting semen.
What is an example of manipulation of reproductive allocation?
An example is in Drosophila. The male Acp ovulin increases ovulation rates in mated females by uregulating signalling of octopamine neurons, a female regulator of ovulation rates. This stimulates the process of ovulation.
What is an example of parental care and desertion?
Penduline female tits bury their eggs at the bottom of the nest and don’t let the male in. Upon laying the last egg, she uncovers the eggs and leaves them to be look after by the male and goes off to find another mate.
When is abortion seen in the wild?
Females of different taxa may abort zygotes sired by suboptimal partners and reabsorb resources.
When is infanticide seen in the wild?
In some mammals, males that take over another male’s harem or pride kill the offspring of a female sired by previous males to indue new oestrus.
What is filial cannibalism?
It is where male or female parents can be seen to eat their own young.
What is the ‘sexual tragedy of the commons’?
It is the fact that female harm represents collateral damage of male-male competition.
What does sexual selection promote?
It promotes selfish behaviour that enables a male to outcompete rivals even if this depletes reproductive resources by harming females.
What are the consequences on females of a male-biased population?
- increased aggression towards females
- female survival decreases
- female fecundity decreases
- emigration rate of females decreases.
What is the harm adaptive strategy?
It is where individuals gain fitness because they harm the partner.
What can sexual punishment discourage?
It discourages behaviours which are costly to the punisher by imposing a fitness cost on partners.
What does male harm cause females to do?
It causes females to adaptibely modify their subsequent life histories in a way that also benefits males.
What can increase a female’s optimal oviposition rate?
Reduction in residual reproductive value of the female.
What is inter-locus conflict?
Where any mutant allele at M or F are allowing cost-free achievement of the optimal outcome for the male or female will spread.
What does sexually antagonistic selection give rise to?
An evolutionary arms-race between the sexes.
What has been seen in sexually antagonistic coevolution of fruit flies?
It found that evolving under sexual selection makes females more resistant to male and it makes males more harmful to females.
What is dicogamy?
Separation of sexual organs in time.
What is an example of dicogamy?
An example is foxgloves, where the flowers at the bottom are typically male and the top flowers are female, with the male flowers eventually becoming female.
What is herkogamy?
Separation of sexual organs in space, so parts are organised so that they will never make contact with each other.
What is dicliny?
It is sexual polymorphism. It is where plants are normally male or female, or there are unisexual flowers on the same plant, or polygamous combinations of unisexual and sexual plants.
What is self-incompatability?
A plants ability to recognise and reject their own pollen.
What is immobility in terms of plant mating systems?
It is where most flowering plants are hemaphrodite, so 100% of individuals can seed and this optimises the benefit of animal pollinators.
What is inbreeding depression?
A reduction in fitness resulting from inbreeding.
What is reproductive assurance?
Ensuring seed set when mates or pollinators are scarce through self-pollination/fertilisation or asexual reproduction.
When is optimal allocation of male and female reproductive effort particularly important?
It is particularly important in the maintenance of sexual polymorphisms.
What areas of the world are pollinator-rich regions where there is pollinator specialisation and outcrossing?
- Tropical rainforests
- Sub-tropics
- The Mediterranean
- Warm temperature regions.
What are pollinator-poor regions where there is a trend towards pollinator generalisation and selfing/apomixis?
- Boreal
- Alpine
- Deserts
- Cold temperature regions.
What is Stebbins most effective pollination principle?
A plant should specialise on the most effective and/or most abundant pollinator availability is reliable.
What is an important characteristic of the S locus and how many plants is it present in?
It is one of the most polymorphic loci and is present in around 60% of flowering plants.
What happens if the S alleles are the same?
If the S alleles are the same in the pollen and the pistil, it is rejected as it is incompatible.
What happens if the S alleles are different?
If the S alleles are different in the pollen and the pistil, it is accepted as they are compatible.
How big is the S locus?
It is usually large and can be up to 200kb.
What does the S locus contain and where is it found?
It contains tightly linked genes for pollen S specificity and pistil S specificity. It is usually located in the areas of the genome where recombination is suppressed. The S allele is a haplotype.
What is a haplotype?
It is a locus consisting of two or more tightly linked genes.
What is gametophytic self-incompatibility?
Incompatibility phenotype of pollen determined by its own haploid genome, S alleles/haplotypes are co-dominant in the pistil.
What is sporophytic self-incompatibility?
Incompatability of pollen determined by the diploid genome of its parent plant, S alleles/haplotypes can therefore show dominance in pistil and ‘in’ pollen.
What happens when S alleles are dominant over each other?
The pollen tubes act differently to when codominance is seen.
What expresses the pollen S gene?
The diploid tapetum cells which make up the tube.
What are examples of sporophytic self-incompatibility?
- Brassicaceae
- Asteraceae
- Convolvulaceae
- Betulaceae
- Caryophyllaceae
- Malvaceae.
What are examples of gametophytic self-incompatibility?
- Solanaceae
- Rosaceae
- Plantaginaceae
- Campanulaceae
- Papaveraceae
- Poaceae.
How are large numbers of S alleles/haplotypes maintained in populations?
By negative frequency-dependent selection, where fitness of a phenotype or genotype decreases as it becomes more common.
How does sporophytic self-incompatibility work in the Brassicaceae?
The female S-determinant SRK encodes serine-threonine receptor kinase spanning the plasma membrane of cells of the stigma surface. Male S-determinant SCR/SP11 encodes a small cystine-rich protein-ligand present in pollen coating that binds with SRK to initiate a signalling cascade in the papillae, which inhibits incompatible pollen growth.
How does gametophytic self-incompatibility work in poppies?
Female S-determinant PrsS encodes a small protein-ligand secreted by the stigma. Male S-determinant PrpS encodes a novel receptor protein with 3-5 transmembrane domains that bind with PrsS to trigger a calcium signalling system in incompatible pollen, which results in cell death.
How does non-self recognition happen in Coprinus cinereus?
The B mating type locus contains 3 groups of genes; each group encodes a G protein-coupled pheromone receptor and 2 pheromones. The MT mating type locus of Chlamydomonas reinhardtii exists as two haplotypes mt+ and mt-, which contain different genes that regulate cell fusion and chloroplast inheritance.
What does the MHC locus of vertebrates contain?
A set of closely-linked highly-polymorphic genes encoding cell surface proteins essential for the adaptive immune system.
What is the gametophytic self-incompatibility in RNase systems?
Female S-determinant S-RNase encodes an RNase secreted by cells of the transmitting tissues of the style that digest mRNA. Male S-determinant SLF/SFB encodes an F-box ubiquitin kinase, which recognises and binds to non-self S-RNases and targets them for degradation via the ubiquitin pathway.
How are fights commonly resolved?
The are commonly resolved through ritualised displays, signalling, and endurance rivalries.
What can the evolution of non-injurious aggression be explained by?
It can be explained by considering the costs that aggression imposes on both opponents in addition to the benefits of the winter.
What does cost-benefit analysis explain?
Why animals accept low social status, switch from competing to sharing resources, relinquish resources or territory, and do not always compete to the limit of their capacity.
What can the costs of fighting include?
- energy expenditure
- predation risk
- risk of injury
- loss of time that might be devoted to other activities.
What have aggressive displays and intense fighting been shown to increase and deplete?
They have been shown to increase rates of aerobic and anaerobic respiration, and to deplete energy reserves.
When does injurious fighting evolve?
When the benefits of winning are higher than the cost of aggression.
What is a mixed evolutionary stable strategy?
It is a model which predicts an evolutionary stable equilibrium and is is seen as long as C>V and neither strategy is an ESS>
What has led to the evolution of alternative mating tactics?
Investing preferentially in either pre-copulatory competition or post-copulatory competition.
What can maintain polymorphisms in Gouldian finches?
Frequency-dependence can, but it requires assortative mating as well.
What 2 models can we look at to understand continuous variation in aggression?
- war-of-attrition
- sequential assessment.
What will the duration of multiple contests match?
A negative exponential distribution.
What is resource holding potential?
The ability to defend resources or territories and engage with opponents directly.
What happens in the sequential assessment model?
At each time step, rivals sample their own and other’s performance to estimate difference in RHP.
What are the correlations between RHP and flight duration?
There is a positive correlation with loser RHP and flight duration, but there is no correlation between the winner RHP and flight duration.
When will an individual persist as long as pV>c?
When estimate of RHP difference tells them that this is no longer likely to be true, it gives up.
How do individuals gather information about rivals?
- animals use cues of fighting ability
- use signals that have evolved to communicate RHP
- learning through repeated encounters with specific individuals.
What is one thing that can shape current investment in aggression?
Future fitness payoffs.
Why might residents be more likely to win territorial fights?
They could have a higher RHP, and/or residents might value the resource more highly.
What is the “Dear Enemy” phenomenon?
Aggression is typically lower between neighbouring territory-holders than between territory-holders and intruders and this is thought to be due to familiarity and differences in resource potential: fitness payoff of acquiring some territory likely to be greater for intruder than for neighbour.
What does the Bourgeois strategy arise from and what does it assume?
It arises from the hawk and dove game, and it assumes they are discrete strategies, but an individual can decide whether to play hawk or dove, which can strategically change.
What happens under the Bourgeois strategy if most territories are occupied?
Individuals will become ‘trapped’ in the intruder role, and it is more likely when resources are not too rare, so there are multiple opportunities to get a territory.
What is the Desperado strategy?
It is where respect for ownership yields 0 fitness, and this is where intruders fight owners with everything they have.
What is social structuring characterised by?
A predictable asymmetry in aggression and outcome of aggressive interactions between individuals, such that one individual is consistently dominant over some and submissive to others.
What can be seen in social structuring?
- repeated interactions
- memory of previous outcomes
- some form or degree of recognition
- despotic access to resources without constant fighting.
When is establishing dominance favoured?
Only if the probability of meeting the same individuals repeatedly is high.
When will social hierarchies be cost effective?
Only in groups that are sufficiently small to foster these conditions.
What does a transitive hierarchy typically lead to?
A linear hierarchy.
What do non-transitive hierarchies lead to?
They lead to non-linearity, which is not necessarily less stable than a linear structure.
How are social dominance hierarchies established?
Through aggressive threats and pecks delivered by dominant individuals.
What is the position of an individual within the hierarchy reflective of?
Its competitive ability relative to others, and predictive of differential access to limited resources.
What are hierarchies like during establishment?
They are highly dynamic.
What are self-organising social dynamics?
They are social behaviours which are conductive to the formation of hierarchies.
How can individual properties enable transitive inference?
By using known relationships to infer unknown ones.
How can hierarchies be established?
- there can be individual properties that signal RHP
- social conventions are used
- self-organising dynamics
- individual properties enabling transitive inference.
How are hierarchies maintained?
- having signals of dominance
- having individual recognition
- social eavesdropping
- punishment and self-reinforcing behavioural mechanisms
- physiological inhibition or suppression of reproduction.
What are Post-aggression behavioural strategies used for?
They are used to reduce the social costs of aggression.
What are examples of post-aggression behavioural strategies?
- reconciliatory behaviours
- grooming
- avoidance
- subordination.
What is punishment?
An action that imposes a net cost on a recipient in response to an action by the recipient that harms the punisher.
What is policing?
A behaviour that generates public goods.
What is a peace-keeping social structure?
Where dominant individuals are more likely to intervene in conflicts and break-up fights among lower-ranking ones.
Why do individuals form coalitions?
To out-compete or challenge top-ranking members of the same group.
What is the balance between for coalitions and alliances?
There is a balance between increasing the chance of success and having to share resources.
How does dominance work in female meerkats?
Females usually give up dominance due to having died, and the other main causes of giving up position is displacement.
How does dominance work in male meerkats?
Dominant males are at risk of being displaced, dying, but also of being taken over by invading males. Being dominant is costly and typically lasts for about 5 years.
Is the presence of offspring required for a behaviour to be understood as care?
No.
What is a form of parental care for multicellular organisms and plants?
They both need resources to develop a zygote, fruit, or seed.
Why might nuptial gifts have evolved?
To supply resources to help a female produce eggs, or to evolve as a way of increasing paternity assurance.
What is viviparity, and what does it do?
It is live birth, which has evolved multiple times independently. It increases offspring survival and is surprisingly widespread across taxa.
What are the 2 main types of provisioning young after birth or hatching?
- continuous provisioning, e.g. lactation in mammals
- mass provisioning, e.g. wasps laying eggs in a caterpillar.
What is parental care seen as when offspring might be mature?
It can be seen through social assistance.
What is an example of parental care in Peruvian poison frogs?
The females produce trophic eggs to provide for tadpoles with resources, depending on where they are laid.
What is reproductive value?
The contribution to the future gene pool.
What costs continue to accumulate from care?
Every unit of investment in care potentially reduces the number or size of offspring, or the potential of finding additional mates.
What did care systems evolve as a result of?
They evolve as a result of relative costs and benefits to both species.
What does optimal investment maximise?
The difference between benefits and costs.
What are the benefits of providing care determined by?
The probability of transmitting genes to future generations, which will be particularly determined by extrinsic mortality.
What does parental investment correlate with?
It correlates wit reproductive value of offspring and within species.
What will natural selection favour when thinking about parental care?
It will favour individuals that leave descendants without paying the cost of looking after them, but this relies on someone else looking after them.
What does anisogamy lead to selection acting on with parental care?
It leads to selection acting more strongly on females to provide care, and more strongly on males to compete for mates.
What percentage of mammals cooperatively breed?
3%.
What is the only cooperative breeder in the UK and how does this work?
Long-tailed tits are the only cooperative breeder in the UK and if their offspring are eaten, they go and help relatives raise the young and they identify these kin by similar calls, but some unrelated individuals might have similar calls.
What is brood parasitism?
The laying of eggs of one species into the nest of a second species, where they receive parental care.
When can filial cannibalism be favoured?
It counts as bad care but it can be favoured to divert resources from offspring with a low chance of survival to future broods.
Why is there competition for which parent leaves the nest first in some birds?
It can sometimes pay to abandon offspring, so it’s a competition of who leaves first and gets to breed again and who has to stay and care for the offspring.
What happens in favouritism in parental care?
Some animals favour the larger offspring when in unpredictable conditions, and so the parents ignore the begging and pay more attention to size.
Why isn’t brood parasitism really seen in mammals?
Because brood parasites rely on the majority of the development and parental care taking place outside of the body.
What are the benefits of brood parasitism?
- freedom from parental care and its inescapable cost
- freedom from clutch/brood limitations
- avoid putting all their eggs in one basket, allowing for a higher chance of survival.
How is it thought that evolution of brood parasitism occurred?
It is thought that it evolved through egg-dumping, which is thought to be a precursor of interspecific competition.
How many times has brood parasitism evolved independently in the cuckoos?
It has evolved three times independently in the cuckoos.
What are examples of brood parasites other than cuckoos?
- Honeyguides, where they typically parasitise cavity or burrow nesting species.
- Viduidae, they are host-specific and are native to Africa and some imitate their host’s song.
- Cowbirds, which are ultimate generalists and are found in flocks in South and North America, and they respond to vocalisation of other cowbirds, allowing young to find and join flocks of their own species.
How do cuckoos draw birds away from the nest to allow them to lay the eggs?
They mimic a bird of prey in shape and silhouette.
What do females do to ensure there are enough hosts in her territory?
She monitors the breeding stage of her hosts and chases non-hosts out of the area to allow for hosts to live in the area.
What are cuckoo gentes?
They are highly distinct, genetically different from each other female cuckoos which prefer different hosts.
What are the results of cuckoos having gentes?
It means there will be lots of cuckoo species who specialise on their own hosts.
How does egg mimicry work in cuckoos?
Birds are very good at counting but no so good at looking at differences in size so the cuckoo just replaces an original egg. Their eggs also match that of hosts in colour, patterns, and pigmentation.
What are the fastest birds at laying eggs?
Cuckoos.
How are specific gente properties determined in female cuckoos?
The properties are sex-linked and lie in the W chromosome of the female. The gente specificity comes from the fact that female cuckoo nestlings are imprinted on by their foster host species so return to the same species for egg-laying as adults.
Why don’t male cuckoos have gentes?
They don’t have a W chromosome, so they don’t have the imprinting and host-specificity so they can mate with any female, which is what maintains the cuckoo as a species.
Why is the thickness of Cuckoo eggshells important?
It prevents host puncture and prevents breaking during the egg-laying process.
What is the Mafia hypothesis of cuckoos?
Cuckoos don’t want live offspring to be in the nest, they want eggs, so they eject all the nestlings and kill them to make the host lay again. If the host then kicks out the cuckoo egg, the cuckoo returns and eats the hosts nestlings.
Why do cuckoos and honeyguides have early hatching?
Because it allows for the chick to kick out other eggs and nestlings.
What is the honeyguides killer instinct?
For around 5 day post-hatching, the nestlings have an instinct to kill all things, both fellow nestlings and any item outside the nest.
How do cuckoos and honeyguides achieve earlier hatching?
They achieve it by keeping the fertilised egg inside them for 24 hours, which means the egg is already developed by a day and then put it into a nest of newly laid, undeveloped eggs.
What do low-virulent brood parasites exploit?
They exploit the host parents’ tendency to feed the largest young in a brood and the one that can reach the highest.
How does metabolic rate change in high-virulent brood parasites, e.g. cuckoos?
The metabolic rate is higher than non-virulent brood parasites.
Why is twitching higher in brood parasites than non-brood parasites?
It is higher as the embryos twitch their muscles more during development which is thought to develop the muscles to allow for the strength of ejecting host eggs and nestlings.
How can eggshells be described?
They are a crystalline CaCO2 shell with pores where water vapour, O2, and CO2 are exchanged for respiration.
What is it thought that brood parasites have a low rate of gas exchange across the shell?
It is potentially to allow for the nestlings to have a bigger heart.
What is the impact on the nestlings when there is a thicker shell?
It takes more effort and strength so there are more reserves in the egg to help with rapid development. There is also extra muscular strength, with a higher fibre density in the neck muscles.
What are host defences against brood parasites?
They recognise their eggs better with age and can puncture or reject eggs, however abandoning the nest is only viable if there are other options available.
How do the cuckoo chicks get enough food?
They have exaggerated, layered calls which cause a response in the parents to bring more food. Their call sounds like a large clutch of birds so the parents keep provisioning.
What are the impacts of host parents who raise a cuckoo chick?
They have decreased survivability and are less successful in the next breeding season due to the depletion of the individuals energy budgets.
What is brood parasitism?
The surreptitious addition of eggs to another female’s nest, whether of the same or different species host.
What is the coevolutionary arms race?
A trait in one species has evolved in response to a trait of another species, which trait was itself evolved in response to the first species.
What is facultative intraspecific brood parasitism?
Deposition of eggs into a common nest by several females.
What is the geometry for a selfish herd?
It is the selfish interest for the individual to seek shelter behind other individuals.
What dimensions can dilution be seen in?
One, two, three, and four dimensions.
What is stotting?
Getting someone killed by signalling your superior escape potential.
What does pursuit deterrence signalling show?
It shows how easily they can escape.
Why does vigilance always have a trade-off?
Because there is a need to forage, the more vigilant you are, the less time you have to forage.
What is perception advertisement?
Some animals have large, loud signals to inform the predator that is has been spotted, meaning it is a less good target as it is ready to escape. The prey signals that it has become alert with a conspicuous state and this causes the predator to switch to a more vulnerable prey.
What are strategies of concealment?
- hiding
- stealth
- camouflage
- countershading.
What is eucrypsis?
General colour resemblance to background objects.
What is masquerade?
A special resemblance to worthless objects.
How can camouflage be achieved?
- shape scrambling
- disruptive colouration
- shape disruption
- crypsis.
What does apostatic selection drive?
It drives polymorphisms in mimetic crypsis, but leads to limited morph number.
What does concealment based on mimicry rely on?
It relies on polymorphisms and frequency-dependence.
What is aposematism?
It is warning colouration.
What does aposematism rly on?
It relies on the idea that conspicuous prey are more memorable.
What is prey aggregation known to do?
It is known to enhance learning.
What does predator cognition drive and how?
It drives the evolution of aposematic strategies for avoiding predation by favouring conspicuousness, aggregation, and probably many other features as well.
What is mimicry?
It is where predators confuse one species, the mimic, as belonging to another, the model, because of an evolved visual resemblance.
What does biparental mating lead to?
Meiosis, recombination, segregation, and syngamy.
What is sexual reproduction?
Where two gametes fuse and then separate, giving rise to different combinations of genes because of segregation and recombination.
What does recombination change?
It changes how alleles at different loci on the same chromosome are organised.
What does segregation change?
It changes how alleles on homologous chromosomes are packed into individuals.
What does recombination break down?
It breaks down associations among alleles on the same chromosome.
What does segregation break down?
It breaks down associations between alleles at the same locus on homologous chromosomes.
What does sexual reproduction alter?
Associations among alleles.
Biparental symmetrical sexual reproduction is unique to what?
It is unique to eukaryotes.
Sex didn’t evolve sporadically but rather what?
It has persisted for most of the evolutionary history of eukaryotes.
What is the complexity of the cellular processes regulating syngamy, meiosis, and gametogenesis and what do they require?
They are extremely complex and require 100s - 1000s of genes.
If all else is equal, what should an asexual mutant do?
It should spread and outcompete sexuals.
At carrying capacity, what will a sexual female replace?
A sexual female will replace herself.
What will an asexual female replace?
She will replace more than herself.
How fast can an asexual population reproduce in comparison to a sexual population?
It can reproduce at least twice as fast.
What is the cost of meiosis?
It is a 50% reduction in relatedness between parent and offspring, in comparison to asexual reproduction.
What is the cost of mating?
It is searching for mates and mating.
What is the cost of breaking down coadapted gene complexes?
Genetic shuffling caused by sex breaks down favourable allele recombinations and creates less favourable recombinations.
What did the paradox of sex require?
An adaptive explanation.
What are some general considerations for understanding adaptive explanations?
- linkage equilibrium
- epistasis
- origin vs. maintenance
- short-term vs. long-term effects.
What is linkage disequilibrium?
The non-random association of alleles of different loci.
What is epistasis?
Where the phenotypic expression of a mutation gene depends on the presence of mutations in other genes.
What is positive epistasis?
Where the combined effect of the mutations is more beneficial than the sum of the effects of each individual mutation.
What is negative epistasis?
Where the combined effect of mutations is more detrimental than the sum of the effects of each individual mutation.
What might sex have evolved from?
It may have evolved from asymmetric transfer of DNA as genetic elements that are copied and transferred to other individuals can spread in a population, as long as they infect new cells and after that they kill their host or otherwise reduce fitness.
When is variance beneficial in the short-term?
Only if the average fitness of extreme genotypes is higher than that of intermediate genotypes.
When is variance beneficial in the long-term?
If selection is directional, because adaptation occurs more rapidly with more variance.
What do modifiers do and when?
Modifiers increase the frequency of sex, and recombination will spread when the genetic associations in a population have the opposite sign to the current form of epistatic selection.
What do coevolving parasites eliminate and how?
They eliminate fitness advantage of asexual reproduction by adapting to infect locally common clonal genotypes.
What can fluctuating epistasis for fitness produce in parasites?
It can produce two or more loci under parasite-mediated, negative frequency-dependent selection, and linkage disequilibrium among alleles.
What is antagonistic coevolution that is seen in parasites?
Parasites are selected to infect the most common host genotypes.
The Red Queen Hypothesis says what is required for fluctuating selection to favour sex?
Highly virulent parasites and rapid changes in epistasis over a few generations.
What is evidence for the Red Queen Hypothesis?
- the cline of sea snails, where shallow waters had sexual reproduction whereas deeper waters didn’t.
- female flies which were infected with bacteria produced a higher proportion of recombinant offspring.
When is positive disequlibrium generated by migration?
When some sites experience stronger selection than other sites or when alleles are favourable in some locations and unfavourable in others.
What does the influx of extreme genotypes from migration cause?
It causes the disequilibrium to rise above that expected on the basis of local fitness interactions.
What might happen in a population if the disequilibrium becomes positive?
A population might find itself in a situation where there is a mismatch between the genetic associations that are present in a patch and the form of selection.
What does the rate of sex evolve towards in populations maintained in either type of homologous environment?
The rate of sex evolves rapidly towards 0.
What is the sex of rate in populations maintained in spatially heterogenous environments?
There are higher rates of sex evolving in these populations.
What happens to the proportion of sexual reproductions in harsh environments?
It increases more than sexual reproduction.
What is Williams’ lottery model?
It is the idea that sex is a bet-hedging strategy, where the production of viable offspring is associated with a higher geometric mean fitness. Sexual reproduction would be more common in temporally viable environments and asexual reproduction would be more common in stable environments.
What did Bell propose in 1982?
He proposed that asexual reproduction is associated with unpredictable and temporary habitats.
What is the tangled bank hypothesis?
The idea that genetic polymorphism could be favoured in spatially heterogeneous environments if different genetically determined morphs were favoured in the different habitat types.
What is the Ruby in the rubbish idea?
It is the idea that in sexual populations, deleterious mutations have little effect on the fate of beneficial mutations. It suggests that drift causes negative disequilibrium and that selection slows down because it is unable to distinguish between the different intermediate genotypes.
What is Hill-Robertson Interference?
The idea of selective interference between loci, with selection becoming less efficient whenever linked loci are also under selection. It happens when, by chance, advantageous alleles become associated with deleterious alleles at linked loci.
What is Muller’s Ratchet?
It is where an asexual organism inevitable accumulaltes deleterious mutations, and this increase of the mutational load results in an inexorable, ratchet-like loss of the least mutated class.
What is Kondrashov’s Deterministic Mutation Model/Muller’s hatchet?
The idea that high deleterious mutation rate and negative epistasis under which each additional deleterious mutation leads to a larger decrease of relative fitness.
What is the Fisher-Muller Hypothesis/Vicar of Bray Hypothesis?
The idea that uniting beneficial alleles from different lineages facilitates adaptation.
What did experimental evidence for the Fisher-Muller hypothesis show?
That outcrossing has often been found to increase the rate of adaptation to a novel environment relative to asexual reproduction, particularly so in larger populations.
What are most hypotheses for sex based on?
The notions that sex promotes genetic variation because segregation and recombination break down genetic associations, and that genetic variation is beneficial.
What do most individual hypotheses for the maintenance of sex often suffer from?
They suffer from fundamental constraints in their relevance.
