Pt. 1 Flashcards
Proximate questions = …
Ultimate questions = …
How, Why
Niko Tinbergen identified four specific questions that can be asked about a behaviour. What are these? Separate them into proximate and ultimate questions.
Proximate: - Causation (mechanism) - Development (ontogeny) Ultimate: - Evolution (phylogeny) - Function (selection)
E.g. squirrels store nuts in the Autumn. Red Squirrels cash their nuts in piles in the ground. Grey squirrels hide them individually everywhere and often forget where they’ve left them. Red squirrels find these food sources again in winter when other food is scarce. Let’s go through Tinbergen’s 4 questions, starting with the causation. What is a plausible hypothesis for what causes the squirrels to store the nuts?
In Autumn, an overabundance of nuts means that squirrels are over-satiated with food so, instead of leaving the nuts for other animals to eat, they hide them away from these other animals.
How did the squirrel nut-hiding behaviour develop over the early life stages of the squirrel (ontogeny)?
Hypothesis: Instincts lead them to hide the nuts and learning hones their ability to hide the nuts in safe hiding spots
What is the evolutionary history of the squirrel behaviour (phylogeny)?
Hypothesis: The ancestors of red squirrels gathered nuts into a pile in a safe place and sat and ate them. Over evolutionary time they left the piles for longer and longer periods until they became a winter food source
What is the function of the squirrel behaviour (i.e. the selective pressure that maintains this behaviour)?
Hypothesis: individual squirrels that store nuts are more likely to survive through winter and go on to reproduce in the spring
Emperor moth/eyed hawk moth eye spots used to startle predators example:
Causation?
Presence of predator stimulates the sensory system of the animal. This provokes a reaction in the motor systems of the animal which elicits the behaviour of displaying the eyespots. This sensory-motor system is, in turn, mediated by the hormone system within the insect.
(Eyespot) Development?
The physiology, and therefore the behavioural mechanism, of the moth will have developed over time as it developed through its juvenile stages to a fully functioning adult. This development will have been determined by the insect’s genes, the interaction of the products of these genes with the environment
(Eyespot) Phylogeny and function?
This behaviour increases the likelihood of the moth surviving for long enough to enable it to transmit itself to the following generation, and the behaviour has evolved over evolutionary time, due to these fitness benefits.
The proximate and ultimate questions and their answers are often referred to as two different … of …
level of analysis.
look at table at 7:30 in lecture 1
One of Tinbergen’s classic studies for the … reasons for a behaviour was carried out on bee wolves (a type of wasp). The female bee wolf provisions her underground nest with … …. She always finds her way back to the nest. Tinbergen wanted to find out how. He found that the female covers the … before going hunting and … it a few times. Tinbergen hypothesised that she was … the … near the entrance. To test this, he set up some very obvious … (… …) around the nest and waited for the female to leave. He then … these to somewhere else, and found that the female could not locate her nest. This provided good evidence that the female bee wolf’s proximate mechanism for finding her nest is … the … of nearby …, and using them to navigate back to her nest entrance.
proximate, honey bees, entrance, circles, memorising, landmarks, landmarks, pine cones, moved, memorising, position, landmarks
Tinbergen made an …, developed a clear …, and performed a simple … of this …. This resulted in a clear …
observation, hypothesis, test, hypothesis, answer.
One of Tinbergen’s classic experiment for the … reasons for a behaviour was carried out in gull nests. Many birds remove the … … from their nests after chicks hatch and dump these somewhere else. Tinbergen suspected that the broken … …, which were highly … due to the inside of the egg shell being … rather than … like the outside, could attract … such as …. He hypothesised that egg shell removal might increase fitness as it makes it impossible for … to use egg shells as an … of a nearby nest with … in it. To test this hypothesis, Tinbergen set up artificial gull nests containing a single egg with a broken egg shell at various … away from the nest. He observed the nests and found that the … the broken egg shells were to the nest, the greater the chance of the nest being … … by crows. …% predation rate when eggs 15cm away from nest, 21% predation rate when eggs 200cm away from nest. This supports his hypothesis.
ultimate, egg shells, egg shells, visible, white, camouflaged, predators, crows, predators, indicator, chick, distances, closer, predated upon, 42, 21
A recent experiment that ties proximate and ultimate ideas together was carried out on … and … butterflies. Both species have leaf-resembling … underwings and …, … dorsal wing surfaces. Commas have a white ‘C’ on their underwings too, which may resemble bird faeces or draw attention away from the overall shape of the insect. If disturbed while resting, the … keeps its wings closed to maintain camouflage, while the … opens them to reveal large … and makes a … … by rubbing its forewings and hindwings together, which effectively deters blue tits.
comma, peacock, bright, colourful, comma, peacock, eyespots, hissing noise
Peacock butterflies have two potential ways of scaring off predators: … and … …. Vallin et al. wanted to know which of these was responsible for scaring predators. various combinations and controls using black marker (to cover eyespots) and cutting parts of wing off (hind of front wing to remove ability to hiss). The butterflies were presented to blue tits in cages, and each blue tit was only given one butterfly so that it could not learn their taste. Vallin recorded how many butterflies were predated upon to determine how effective the strategies were. He found that the more effective strategy was the …. In fact, the … did not protect the butterflies from predation (from blue tits). The … alone are effective at protecting the butterfly from predation. perhaps the hissing is effective with …
eyespots, hissing noise, eyespots, hissing, eyespots, bats
Not all eyespots are for scaring predators. … … butterflies have small black eyespots near their wing tips, which instead provide a …-… target for the predator, so that the butterfly can …
Non-vital, escape
What are the 4 steps of the scientific method?
- Ask a question about an observation (e.g. observed behaviour)
- Establish a hypothesis to explain what has been seen
- Set up predictions based on this hypothesis
- Test these predictions by gathering appropriate data (field observations, experiments etc.)
… is when a bird such as a blue jay, disturbs an ant mound, allowing the ants to climb onto its body and spray the bird with defensive chemicals (formic acid). Some birds will pick up the ants and rub them into their feathers. There are two hypotheses for this behaviour:
- Formic acid kills … in the feathers, such as …
- Encouraging the ants to secrete formic acid makes them more …
Anting, parasites, lice, palatable
There are four subfamilies of Apidae bees (orchid bees, stingless bees, honeybees, bumblebees). These bees show interesting behaviours. Honeybees,, bumblebees and stingless bees are all …. Orchid bees are …. Honeybees and stingless bees are …-forming (during winter colony raises many offspring and population grows, overcrowding nest by spring. Colony rears new queen and the old queen flies away to form new colony, taking with her old worker bees. This flying swarm temporarily attaches itself to a tree branch, while … bees are sent out to find new nest sites, returning with information). Honeybees and stingless bees also exhibit … …, where a … bee returns to the hive with lots of nectar and transfers this to a … bee, who stores the nectar in a …. This is an example of … …, where a task is divided into subunits and two or more individuals are specialised to perform the different elements of the task.
eusocial, solitary, swarm, scout, nectar transfer, forager, receiver, task partitioning
What is the evolutionary history of eusociality, swarming, and nectar transfer (when, during evolutionary history, did these behaviours arise)? To answer this we need to look at the … of the bees. This is not yet known for certain, as … and … data give different results. One potential phylogeny indicates a single origin of …, as this is the most … explanation. It indicates that swarming and nectar transfer evolved …. Either that or it evolved … and was subsequently lost in … However, if the phylogeny was slightly altered, each behaviour would only have had to evolve once and not been lost at all, which is more parsimonious.
(27.00 in lecture 1)
Phylogeny, molecular, morphological, eusociality, parsimonious, twice, once, bumblebees
Animal behaviours can seem paradoxical from a darwinian evolutionary perspective. Give an e.g. of such a behaviour in humans
Humans eat unhealthy and potentially harmful amounts of sugary sweets and drinks
Why do humans eat so many sweet things?
Hypotheses:
- Contain sugar which tastes good (Proximate)
- Sugar is an energy source that keeps helps keep people alive (Ultimate)
- Our ancestors depended on sugar-rich fruits, and we’ve inherited the same tastes that they had (Ultimate)
- Our genes shape the development of nerve cells that provide perceptions of sweetness and pleasure (Proximate)
- The sensory input from taste receptors in the tongue to the selected brain cells leads to a positively reinforcing sensation of sweetness (Proximate)
… langurs live in social groups with one male, several females and young. When a male is displaced by challenging younger male, infants die and new males are most often the cause of this, called …. Females may … the new male if they see him murdering infants.
Hanuman, infanticide, attack
Why do males kill offspring? 3 hypotheses:
- …-… : e.g. social …brought on by overcrowding - male driven insane - unlikely as infanticide always occurs after a takeover and isn’t more prevalent in … groups
- Favoured by NS at … level - infanticide frees females to become … sooner (as she stops lactating and enters oestrus cycle again), so the male … offspring sooner and has more … before he is himself overthrown by another male - most likely
- Favoured by NS at … level - infanticide reduces … which would cause the group to … its food or other resources
non-adaptive (not natural selection), pathology, larger
individual, pregnant, fathers, offspring
group, overcrowding, overexploit
…-level selection is very rare
group
Group selection suggests an individual’s behaviours are adaptations that assist the survival or their group, e.g. reproducing less to avoid overexploiting resources. Groups with individuals that practice self-…, for example, survive better. The problem with this is that … selection will usually be …. Those individuals who don’t practice …-… will usually … within the group.
restraint, individual, stronger, self-restraint, prosper
See diagram at 10:00-13:00 lecture 2
Group selection will only be favoured if groups are relatively …-… in relation to the lifespan of the individuals and if … … is important to the group’s survival
long-lived, intergroup competition
Meerkats live in social groups with a dominant … and ….. Pregnant females will kill all the pups of other females. Infanticide of a newly born litter of dominant and subordinate females is more likely if another female is pregnant (survival of offspring lower). This is because other litters would…
females, subordinates, compete for resources and decrease survival and (reproductive) quality of their own litter
When a worker honeybee stings something, she leaves the barbed sting behind, known as sting …, and subsequently ….
autotomy (casting off of body part), dies
The honeybee sting exhibits a complex adaptive behaviour, even when detached. The sting contains muscles, nerve ganglion, a … sac and an … … gland. The muscles and nerves cause the drilling of the 3 sting … into the flesh and the pumping of …. The … …, a volatile compound, disperses within the environment and guides other worker bees to the intruder and increases their likelihood of …. This means that the intruder is likely driven away before being able to…
venom, alarm pheromone, stylets, venom, alarm pheromone, stinging, reach and damage the nest and bees within
The venom injection and pheromone release are most effective when…
the sting is detached from the bee
Why do worker bees sacrifice themselves for the good of their nestmates?
Honeybee workers do not normally reproduce directly, instead rearing their siblings. This reproductive altruism is selected for because workers normally rear close relatives with whom they share many genes - kin selection at work - self-sacrifice actually protects genes
In the honeybee sting example what are the proximate and ultimate explanations?
proximate - sting venom and pheromones more effective when detached
ultimate - increases chance of relative’s survival
In Anthias fish, when a dominant male dies…
a female will change into a male to “fill his space”, growing a new set of gonads, which takes time and energy. This increases her fitness when she is a large female.
Male spiders are often much smaller than females. How does the male garden spider avoid being eaten by a female when approaching her on her web?
Waits near web until she is mature and very carefully approaches her, plucking strands of web as he goes to let her know he is not food - not always successful as occasionally male mistaken for meal and eaten
Male crab spiders have a different strategy:
He grabs the female by the legs and waits until she stops struggling before tying her down. Once she is trapped he manoeuvres underneath her and copulates with her, then running off, leaving her to untangle herself and unable to eat him
Some male spiders give the female a … …
nuptial gift
Redback spiders: females much larger than males, live longer. Males mature at … …. There are many males per female (can be up to 6 males in a female’s web trying to mate). Females mate with multiple males. Males deliberately…
younger age, place themselves in a female’s jaws during copulation.
What is the male Redback’s fitness benefit to sacrificing himself to the female?
If the first male is cannibalised, 67% of females reject a second male. If the first male is not cannibalised, only 4% of females reject a second male
- The female is less likely to relate if she cannibalises the first male - less competition for paternity
As copulation duration increases, … … paternity increases
second male (after first male has been consumed)
Males that are not cannibalised copulate for around … seconds, and gain only about … of paternity, whereas cannibalised males copulate for around … seconds and gain over … paternity
11, 50%, 25, 90%
Female bean weevils that have mated have significantly more damage to their … … than females that have never mated. Females that … successfully dislodged males earlier in mating - significantly less damage to reproductive tract. No difference in … between females that had experienced one damaging mating and two damaging matings (this would not be advantageous to male fitness) - damage does, however, decrease her …. Genital damage incurs no fitness cost to …, but does to …
reproductive tract, kicked, fecundity, lifespan, males, females (males currently winning battle of sexes)
Predators and prey are often locked into a …-… struggle
co-evolutionary
- over time predators will evolve adaptations that help them to find or catch prey and prey will evolve adaptations that make them harder to find or catch
Tinbergen observed that when a new type of … appeared in woodlands, songbirds (passerines) rarely brought it to their nests. But once a few had been located, the birds collected them at…
caterpillar, a greater rate
- The birds had come to recognise the caterpillars and had formed a search image - come to recognise subtle characteristics and learned them
- like where’s wally
Animals tend to take longer to build up a … …
search image
- built up as repeatedly find food item
Blue jays were shown slides of … … of either the same or 2 different species with different … … and … …. The birds improved their recognition over … … when presented with … species but not when given …
cryptic moth, colour patterns, resting positions, repeated trials, one, both
- good evidence that they build up search image
- and evidence that it is difficult to build up search image of two things simultaneously
Striped skunks are … foragers and find foods by …. They form the equivalent of a search image but for … (… search image). Young skunks were allowed to forage in an outdoor enclosure. Food was found at greater … as they gained experience (judged by a pose they use when they detect food)
nocturnal, odour, smells, olfactory, distances
