APS126 Hemmings Flashcards
How would you relate Tinbergen’s 4 questions to the behaviour of birdsong?
How does the song develop?
What causes the bird to sing?
What is the adaptive function of the song?
What is the evolutionary history of the song? (+did it evolve once or multiple times?)
Which scientist is famous for early research on birdsong?
William H. Thorpe
When a Chaffinch is raised in isolation what happens to its song?
It is recognisable but far simpler than birds raised by and around other chaffinches
When a nightingale is raised in isolation what happens to its song?
It is severely retarded
When a nightingale is raised by other species what happens to its song?
It picks up the song of the other species
In the chaffinch and most other birds, song is partly …. and partly …
innate, learned
What is the short period in which birds learn details of their songs from a tutor called?
Sensitive period
Light penetrates thin bones in birds’ … which stimulates … which cause the release of … triggering the … to start growing. The testes release …, which triggers song production.
skulls, photoreceptors, gonadotrophin releasing hormone (GnRH), gonads, testosterone
Female songbirds do not typically sing, but do if…
injected with testosterone
+ if males injected in winter they sing
Which parts of the bird’s brain are associated with song?
RA (robust archistriatum) connected to HVS (higher vocal centre) and sends nerve impulses to the syrinx
HVC is much larger in …
males
What is the proximate (extrinsic) stimulus for birdsong?
Daylength
What is birdsong produced by?
The syrinx (voice box)
What are the two main hypotheses for birdsong?
Territory defence and mate attraction
Males (sedge warblers) with a more complex song pair..
earlier - gives more time to mate with others as well
Song has evolved 3 times, in…
parrots, hummingbirds and passerines
- different song control areas in the brain
What causes eating?
Hunger
What causes hunger?
Hormones
Which hormones specifically control hunger?
Leptin and ghrelin
Where is leptin released from?
Fat cells - tell body (hypothalamus) it has enough fat - so stop eating - less hunger
If leptin levels are low, what does the hypothalamus tell the body to release, and from where?
Ghrelin from the stomach - more hunger
Hormones play a major role in the … of structures (e.g…….) that play direct/indirect roles in controlling behaviour.
Development, brain and gonads
Hormones have … effects, e.g. altering neural networks that respond to signals
activational
Hormones often underpin the timing of … when conditions are most favourable
reproduction
What are the 3 key hormones controlling the motivation to mate in birds and mammals?
Testosterone, estrogen, progesterone
In female rhesus monkeys, motivation to mate is greatest at the point in her estrus cycle where the hormone … peaks and likelihood of … is high
estrogen, fertilisation
Hunger acts as part of the process of …, whereas mating does not
homeostasis - restoring physiological balance
After female drosophila mate, … … rate increases and … … declines due to sex peptide concentration alterations during copulation
egg laying, sexual receptivity
-sex peptides in male sperm alter female behaviour as advantageous to males (wants to secure paternity)
Which part of the brain controls sexual receptivity?
hypothalamus
In green anole lizards, what brings on the sexual receptivity in females?
Courting activity by males (big red flap thing)
- causes ovaries to develop and mature and produce estrogen, priming the female brain to become sexually receptive
Just 5 minutes after …, female anoles become completely … to displaying males. How long does this last?
copulation, unreceptive
Lasts almost 2 weeks, until the female enters a new fertile period - despite still having high estrogen
Mechanical stimulation of the female anole’s genital tract during copulation stimulates the production of …, which reduces her sexual receptivity
prostaglandin
Which female hormone is most associated with low mood during the menstrual cycle?
Estrogen
Estrogen increases … production and receptivity
seratonin
What are the major effectors of changes in gonadal hormones throughout a woman’s lives
- Puberty
- Hormonal contraception
- Pregnancy and childbirth
- Menopause - 14 time more likely to suffer from depression than usual
Species with higher numbers of unique syllables in their songs are expected to have…
higher testes size and mass
In bird species where the intensity of sexual selection is higher, males produce more…..
complex songs
Testosterone promotes … production, activates … behaviour, suppresses the … …, and modulates … behaviour
sperm, sexual, immune system, aggressive
Where is testosterone produced in males?
Interstitial cells in the testes - in response to a glycoprotein produced in the anterior pituitary of the brain
Testosterone is responsible for certain secondary sexual characters, e.g.
cockerel’s wattles or sheep’s horns - tested experimentally by removing testes and then replacement of testosterone
Individuals with higher endogenous levels of testosterone are more likely to be ……..
aggressive and/or dominant
testosterone levels increase in anticipation of …
and testosterone … after an aggressive incident
aggression (a ‘priming’ effect)
increases
Where do females produce testosterone?
Ovaries
In dunnocks, testosterone levels were … in females competing for males in … groups than in females in monogamous relationships
higher, polygynous
… fathers have lower testosterone than … non-fathers
married, unmarried
Fathers who invest highly in parental care have … testosterone
lower
Castrated males (who can’t produce testosterone) live on average … years longer
12
In western society people compete by …
achievement - success in business and endeavour
- people prefer high-performing partners
Type A people respond much more rapidly to …
a challenge - a change mediated by the hormone noradrenaline
Intrasexual combat
In a wide range of animal species, dominant males secure more mates and matings - weigh up whether it is worth it at the start, which is why you generally only see this type of aggression between closely-matched individuals
+in ring-tailed lemurs the females are aggressive and compete
Sexual canniblism
The female eats the male, during or after copulation (e.g. in praying mantises and spiders)
In praying mantises, females that eat their males lay…
30% more eggs
Siblicide
Older chick kills or pushes younger sibling out of the nest - a method of birth control when resources are limited
Infanticide
Adults kill others’ offspring - e.g. langur monkeys - when a new male takes over a troop he kills as many babies as he can - he is not their father and for him infanticide is adaptive because the females come into estrus sooner - infanticide increases his reproductive success - not adaptive for females of their offspring, but they cannot do much about it
Children with step parents are much more likely to be … … and/or …
physically abused, murdered
How many offspring did Moulay the Bloodthirsty produce?
888
What is the record for most offspring produced by one female?
69
There are almost always more sexually active/receptive … than …
males, females
What is the inevitable consequence of the operational sex ratio?
Males must compete for females - females are the limiting sex
Sexual selection drives the evolution of many apparently … traits
maladaptive (when thinking in terms of natural selection)
Sexual competition comprises two processes:
- Male-male competition
- female choice
Sperm competition is a form of…
male-male competition
- e.g. larger testes size = more sperm = more raffle tickets
Species with more male-male competition have larger …
testes
more promiscuous females
What is polyandry?
2+ males to one female
(in dunnocks one male is slightly dominant over the other - female copulates with both so both look after young - although may mate preferentially with dominant male)
What is polygyny?
2+ females to one male
What is polygynandry?
2+ males and 2+ females in one mating group
What is parental care?
Any form of behaviour that increases offspring fitness, e.g. nest building, producing large and nutritious eggs
What is parental investment?
Any expenditure by parents on an individual offspring that reduces their potential to invest in other present and future offspring
- investment in current offspring is traded off against investment in future offspring
Parental care is only favoured when…
the benefits to the parents outweigh the costs to the parents - increase in parental fitness - if offspring survives this is positive to the parents
… offspring are usually unable to survive unless they have parental care
Altricial
Parental care tends to be favoured when environmental conditions are… or risk of … is high, or if there is … …
harsh, predation, strong competition
… care is common in mammals. Why?
Maternal.
Because they have mammary glands and only females lactate. And because fertilisation is internal, so males can abandon the female but the female cannot abandon herself.
Parental investment (PI):
The relative amount of investment by each sex
- about trade-offs. It is assumed individuals have a finite amount of resource (effort/energy) to invest: the more they invest in offspring x the less they can invest in offspring y
PI determines..
how much competition and how much choosiness there is in a particular species
Give two examples of sex-role reversal in animals?
Seahorse (fish)
Mormon cricket - male gives spermatophore (weighing 1/4 of male’s body mass - huge investment and male can generally only mate once - female can produce several batches of eggs - males are limiting sex)
How do male mormon crickets choose the best females?
Look at how many eggs the females are carrying - the more eggs the better - wants to fertilise the maximum number of eggs
In polygynous mating systems where the female invests more, male colouring/plumage tends to be much more elaborate than females, e.g…
in peafowl
When species are monogamous and the male and female invest similarly, they tend to be very similar in appearance and both rear offspring, e.g…
in mute swans
In polyandrous mating systems where males invest more, females tend to be brighter to compete for males, e.g…, although this is relatively rare
in Jacana birds
What is double clutching (e.g. displayed in temminck’s stint)?
Female lays two clutches in quick succession - she looks after one, male looks after the other
- can lay more clutches and have several males looking after one each
… care is common in species where the offspring are highly altricial and require a lot of care
Biparental (both parents)
St. Peter’s fish is a …-… cichlid
mouth-brooding (either the male or female - usually male as females take longer to recover after care and produce fewer offspring after mouth-brooding - costs are higher for females)
In st peter’s fish when does female mouth-brooding become more common?
When the population is female-biased (more females than males) - males can increase fitness by finding other females (can’t do this when male-biased pop. as costly trying to find mate)
What do cuckoos do?
Brood parasitism (interspecific)
Cuckoos can mimic other species’ … and …
eggs, calls
Female cuckoos retain the…..
fully-formed egg in her reproductive tract for an extra 24hours (at body temperature) - develops more rapidly - headstart in development so hatch before others and can push them out of the nest.
In … … adoption is adaptive as females prefer males which already have eggs
fathead minnows - males may eat eggs from previous males after securing a mate
In order for communication to occur, you require a … of a …, and a … of that …
sender, signal, receiver, signal
- evolve if overall benefit - even if one party faces cost
Animals use … … to engage in communication
sensory modalities
- visual
- acoustic
- chemical/olfactory
- tactile
- electrical
Female spotted hyenas possess a very realistic …
pseudopenis (actually enlarged clitoris)
In mammals the … and … develop from the same embryonic tissue
clitoris, penis
A penis develops when the embryonic tissue is exposed to high concentrations of …
androgens (male sex hormones)
When females are pregnant they produce very high concentrations of …, which causes developing female embryos to grow a pseudopenis
androgens
Cumulative selection means…
lots of small changes over time (rather than big evolutionary leaps)
Female hyenas main cost is the fact that they must give birth through their …, with complications in …% of females often leading to death of the mother
pseuodopenis, 10-20%
What are the hypotheses about why the female pseuodopenis evolved in spotted hyenas?
- Because of selection on having high levels of male sex hormones in the young to allow killing siblings (due to higher aggression)
- Because of selection on having high levels of male sex hormones that made females larger as adults - social hierarchy of dominance in females of this species - alpha female rather than alpha male
–> nowadays the female penis has also evolved as a means of signalling to other hyenas
Ground-nesting birds have begging calls with a … frequency than those of tree-nesting birds, as……
higher, these higher frequency calls do not travel as far and leave the birds less vulnerable to predation
Why have begging calls evolved?
Loud noise provides honest signal to parents about how hungry they are, as well as how fit and healthy they are (worth investing in).
+ more noise drives parents to work harder (shown in studies)
Cuckoos mimic the begging calls of…
an entire brood of host chicks, not just a single chick - so parents bring more food to grow the cuckoo
Great tit parents can convey very specific calls about … to their offspring
predators - so chicks can react appropriately
crows - stay still and low
snake - escape!
