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Lecture

Behavioural Processes

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Department
Life Sciences
Course
LIFESCI 2D03
Professor
Brett Beston
Semester
Fall

Description
Animal Behaviour 12/09/2012 14:48:00 Midterms (Not cumulative) Oct 17 25% Nov 14 30% Final Exam is cumulative “I am an animal” “My neighbour is an animal” What characterizes animals?  Multi-cellular  Instincts – responsive to their environment, can react  Organs  Sensory processes  Feed by consuming other organisms Animals (Kingdom Animalia) – one of the 3 kingdoms of multicellular organisms  Some think humans should be placed in separate category  But within biological context, humans should be placed in Kingdom Animalia We are animals We like (some) animals We are surrounded by animals We depend on animals Research on animal behaviour is relevant behaviour Grebe Clip – mating process  Copying each other‟s movement  Synchronized dance  Gift giving What is the goal of these behaviour Grebes both contribute to rearing of offspring  Assessing each other o Work ethic o Appearance o Genes o What they can contribute to offspring Psychology Questions Don‟t always know how people will behave or think. Need to do research  Mothers talk to their younger children differently from their older children o False  Few students will confess to ruining a computer program if they didn‟t do it. o False  Most individuals will notice if a person they are talking to is replaced by another person o False  When we think about our own behaviour, we fail to recognize how narrow our attention is Spot the change picture We only see 1-2 degrees in clear focus  Visual memory fills in the gaps Animal Behaviour Objectives  Understand importance of animal behaviour  What is the function of the behaviour?  Two mechanisms that change behaviour over time o Natural selection, learning & social learning  Describe mechanisms that control and generate behaviour in most animals  Apply scientific thinking for analyzing new problems in animal behaviour  Describe the major components of behaviour that are shared by most animals o Sex, aggression, foraging o Use that to understand human behaviour Read through textbook  If talked about in lecture, read that section in textbook  Broad concept in class – look into examples in textbook How do we depend on animals? Exercise: write down at least two ways in which animals affect the apples we eat  Nutrients (manure)  Pollination  Ruin it Flowers on apple trees require pollination (by honeybees) in order to produce fruit Several insect species feed on apples  The “worms” which are insect larva  Apple Maggot Fly Several insect species feed on flies  Parasitoid wasp How do we depend on animals? Fly learning & human mental health Memory-enhancing drugs & the treatment of mental retardation in humans Tim Tully – Helicon Therapeutics  How to turn learning mechanisms to a bigger state of on  Similarity between fruit flies & humans  Several dozen flies into a chamber with an electric coil o Slight shock to flies – enough to notice, not enough to hurt, also noticing a scent o Test how well flies remember scent & tingle are tied together o Place chamber so flies can choose tubes  Flies avoid the tube with the scent associated with tingle o In order for fly to remember, has to practice repeatedly  10 training sessions crammed together does not form good memory  Must be rest interval between training sessions, but less than 24 hour rest interval o Krebb gene – turn short term into long term memory  All flies avoided tube with scent associated with tingle  Even with bad training (even after just 1 training) We learn that the style of learning between fruit fly & human is about the same  Cramming does not result in formation of long term memory  Require resting period in between Uses of animal-behaviour research Entertainment – pets, zoos, safaris Model systems for human application Protection of rare, endangered animals Control of pests and damage-reduction  Interaction between aircrafts and wildlife  Migrating geese Bird-airplane collision  Most airports employ control teams that do research on and run programs for reducing bird collision o Peregrine falcon – large bird  Other birds don‟t like to be in presence of larger birds  Israel – 500 million birds fly twice a year through their skies o Research in Israel has reduced bird-aircraft collision & damage by ~85%, saved human and bird life and over 40 million USD/year Summary of Part 1 Surrounded by animals and like to know them Research on animals help us understand humans Animal research has been useful for many human applications (eg drugs) We depend on animals Animals affect our lives Proximate Factors 12/09/2012 14:48:00 Why do animals do what they do? Animal behaviour asks what, why how. Animal behaviour also referred to as ethology  Scientists who study animal behaviour are called ethologists o Jane Goodall – 45 years studying chimpanzees Scientific approaches in animal behaviour research observe what before why  Ethologists do not attempt to describe why an animal does a behaviour before describing what the animal is doing  Eg Two Gophers o What do we see? – interacting with each other, rolling, hopping around, running to and from each other o Why? – play? Mating ritual? Aggression, defending territory? Action Patterns  Complex behaviours that are always repeated the same way by a species of animal o Sometimes no experience needed to do behaviour  We say patterns are stereotyped since they occur the same way each time & through to completion  Only then do we attempt to determine why Niko Tinbergen & Beewolf Beewolfs would circle nest in an ever widening circle before flying to hunt This behaviour was an action pattern – performed the same way every time After beewolfs flew off, Niko would move landmarks around the nest  When beewolf returned it was disoriented Behaviour was done so that beewolf could find their nest Niko had to describe and investigate what before explaining why Songbirds May be trying to communicate to others Male Songbirds  to defend territory  attract mate Females  Use for defence Scientific Approaches  Function (why) vs Mechanism (how)  Ultimate (broad) vs proximate (localized) mechanisms  Adaptive significances vs machinery (genetics, physiology, neurobiology, endocrinology) Example – Male House Finches Plumage colour in male house finches  Males are most colourful o Why such large variation  What is the adaptive significance of red plumage?  How is the red colouration generated? o Red colouration comes from carotenoid pigments  Canthayanthin  Choosing to eat more carotenoid-rich food result in more red plumage Colour – comes from diet, only males  What is the benefit to these males?  What is the adaptive significance of red plumage o Positive correlation between male mating success & red- colour intensity Positive relationship between father & son plumage scores  If father has bright red colouration, so will son o Colour is based on diet, but what‟s passed along is the food seeking behaviour Artificial manipulation of red-colour intensity  Benefit for male to bright colouration o Dull colouration = last to get picked by female Advantage Health of males – choose higher food quality  Infected males with bacteria that causes eye irritation o Monitored rate at which they recovered  Males with red colouration – fast recovery, less disease o Yellow colouration – slow recovery, more disease o Females who choose yellow males may be exposing themselves to more pathogens  Females will have direct benefit from choosing better male o Brighter = higher readiness to feed their young  Benefit that a female will observe + possible survival benefit Males actively seek out this food Males who do seek these foods = better quality, healthier Females can estimate quality of males based on red colour Proximate vs Ultimate Causes Proximate – related to internal changes in animal  Hormones o Surges in testosterone = increased aggressive behaviour  Message from nervous system Ultimate – related to survival and reproductive success of animal Ground Squirrel When they reach 2 months old – leave burrow  Caused by increase in testosterone – hormonal change that triggers behaviour  In doing so – avoid inbreeding  Offspring likely to be healthier  Offspring will also inherit the trait  Pass on trait  Benefit of leaving nest = produce healthier offspring Hormone Changes High testosterone levels Low testosterone levels may be beneficial  When men become fathers – testosterone drops o When dad helps take care of child, focus on mother and children - making testosterone drop – care more, rather than think of sex, war etc Hormone Changes in new fathers  What is the change? o New fathers show lower T than non-fathers for nearly 5 years o Not just that men with low T are more likely to have children o Number of hours father commits to caring has dramatic effects on T How does a male‟s behaviour change in absence of T Experiment on mice  Males in castrated group with pups spend more time at nest o Much more than if no pups are present o And much more than those who did not have T removed Why is there a large change  Men with less T are more likely to be monogamous  More likely to care for children Memory in Rats & Hormones (Proximate)  Rats can learn landmarks to find platform location in the water maze  Stress hormones affect our ability to remember details o Corticosteroid (analogous to cortisol)  Increase in that will impair memory formation  Take half an hour to have any effect on brain  Experiment – induce corticosteroid production o Modified timing of when they put rat in maze after shocking them o We know corticosteroid takes 30 mins for circulation o Looking at pattern of swimming behaviour & record amount of time spent in quadrant  Control mouse is systematic in finding platform  Spending more time in target quadrant  Shocked mouse after 30 min – not systematic, random  Amount of time spent in target quadrant decreases Metrapon – blocks response of corticosteroids  Administer this 30 minutes before shock  Rats show no impairment Other example of Proximal Causation  Animals that seem to be more intelligent = larger brain  Spatial learning in honeybees  Humans per pound of body weight have largest brain  Look at size in certain area of in honeybees that relate to spatial learning o Mushroom bodies  Oldest honeybees go out and forage o Foragers have larger mushroom bodies  Yes they‟re older, but other part of brain (brain stem) can be used as control for relative comparison  Compaired to other brains – ratio of mushroom bodies to brain stem changes  Bigger ratio when foraging Recap What is happening? Why is that happening?  Proximate – immediate causation o Why are males are more aggressive ?– testosterone  Ultimate – functional differences o Why do males have more testosterone? 9/12/2012 2:48:00 PM Charles Darwin Giant tortoise Darwin was 21 when he began his voyage Would ride the tortoise Entire foundation/idea of natural selection is based on this Animal Behaviour Self generated movement of either a body part or the whole body in animals  Trying to look at much more complex behaviours  Behaviours that might be shared among a variety of animals Major components of animal behaviour  Sex/Reproduction  Sleeping  Feeding  Nurturing  Communication  Fleeing  Fighting  Nesting Four F’s of Animal Behaviour Feeding – why are certain foods preferred over others?  What kinds of behaviours determine/influence that? Fleeing predators  Some strategies require no experience – ingrained in the animal o Climbing trees o Playing dead & giving off odour (possum) Fighting Sex  Jumping Spider (exceptional vision – like to use visual cues, can also perform audio cues) Sleep Social interactions/Communication These behaviours persist over time What is the benefit? Why is this behaviour being passed on? Elephants Females form groups Male elephants live alone in isolation – only come together for breeding season Consider ourselves as cavemen Sabre tooth tiger hunts us  We have a set of autonomic functions o Adrenaline  Run faster, hit harder, hear more accurately, think faster  May survive to live another day, possibly to reproduce Flash forward to present day  Have same set of actions with our ancestors Traffic-related death in Canada in 2004  2730 Death from snakebites in Canada in 2004  0 Snakes don‟t pose much of a threat to us but we‟re still instinctively fearful Two mechanisms that can change behaviour over time Evolution  Natural Selection Learning  Can include social learning o Convey information from one generation to the next Animals exhibit a wide variety of behaviours, all have originated through either evolution or learning Evolution A process of change in the proportion of heritable traits within a population spread over many generations  We have a bias to think of evolution as an increase in traits  This definition is non-directional o Some traits may increase in frequency o Other traits may not do so well in a particular environment & may disappear Galapagos – volcanic area Darwin observed tortoises  Tortoises closer to mainland mostly resembled mainland tortoises  Further away, less resemblance  For some reason they had diverged  Theory – something about geographic location must have been a factor in the changes Darwin didn‟t really do any scientific evolution  Just looked at what he saw  Tried to come up with a theory  Came up with theory about what force of nature was driving these changes o Any trait that causes it‟s possessor to have reproductive advantage would be favoured o That trait can be passed down across generations & increase in frequency over many generations  3 principles for Natural Selection to occur o Variation – must have differences Fitness consequences Heritability Galapagos Finches Why are there differences in these traits Peter & Rosemary Grant Evolution of larger beak size Found a relationship between beak shape & kind of food they could eat  Variation in Traits o Larger beaks – large tough seeds o Small beaks – small sees  Heritability o Offspring of parent with big beaks – offspring likely to have large beak o Offspring of parents with small beaks – offspring likely to have small beak Variation in weather and seeds between years  Dry years – few small seeds o Caltrop Fruit can persist  Wet years – small seeds are common  1977 - 1978 o drought that killed 80% of finches  Individuals with large beaks (who could crack large seeds) were more likely to survive  Evolution of beak size chart  1982 – torrential rainstorm o led to huge excess of seeds o Average size of beak depth went back to normal Natural Selection in Crickets Male crickets sing to attract females  Sound generated by rapidly scraping serrated file against side of other wing Unfortunately, singing attract parasites too  Lay eggs on back of cricket  Eggs burrow in cricket  When eggs mature – cricket dies Parasites found on 3 main islands (also home to the crickets)  Largest Parasitism is on Kauai Researchers couldn‟t see crickets on Kauai  There were still male crickets – had morphological changes  Male has modified serrated file – resembles more like what we‟d find on females o Males on Kauai have a morphological distinction from others o Don‟t sing, live longer? o Females usually attracted to males singing Not only morphological changes, but behavioural changes  On other islands, males tended to avoid other males How males respond to the sound of a cricket singing?  Normal crickets go away from sound  Flat winged male –gravitate towards the sound How close they are to the speaker  Normal males – further away from speaker  Flat wings – closer to the speaker Can confirm based on number of males found & proximity Learning – ability to acquire a neuronal representation of new information  Change in either connections in the brain/strength of connections that facilitate memory  Individual may use that information to determine subsequent behaviour What‟s learning good for? Female bird mates with a number of different males  If female can learn relationship of colour-offspring & use it o Could be favoured by natural selection o Learns that red colouration = less offspring Dukas‟ Work - Grasshoppers Learning about particular aspects of diet could affect behaviour? What do grasshoppers learn?  Can see flower colouration – may learn that different colour = different food  Different plant species and plant parts provide different nutrients necessary for grasshopper growth  Learn to eat a balanced diet with optimal proportions of nutrients such as carbohydrates and proteins What do they gain from learning? Experiment slide  2 dishes o d = balanced diet o b = bad diet  associated 2 food choices with different cents o d = cit o b = co one condition – everything the same learning – d kept on same side with same scent etc random – dishes switch sides & scents  cues (scents) not consistent – grasshoppers wont learn anything learning – learned to naturally prefer balanced over deficient diet  more visits to the beneficial diet food random – 50/50 for each dish Learning allowed a 20% higher growth rate  Difference in growth rates translates into fitness benefit  Size positively correlated with the number & size of eggs laid over an individual‟s lifetime Dukas showed not only that they can learn, but how that benefits them Higher growth rate typically implies higher reproductive success Social Learning Learning from other individuals  Ex how to use a tool, how to manipulate objects Social Learning in Rats  Unfamiliar food may be beneficial, or dangerous  Rats watch others eat – if they don‟t die, I wont Does social learning affect food preference in rats? Jeff Galef Rates familiar with each other were divided into “demonstrator” and “observer” groups Demonstrators – taken to another room, where some subjects fed on rat food flavoured with cocoa and some subjects fed on rat food flavoured with cinnamon Observer were then allowed to interact with demonstrator for 15 min Following 2 days, observers could choose between the 2 rat foods  Observers that interacted with demonstrators who ate cocoa, preferred cocoa  Those that interacted with demonstrators who ate cinnamon, did not eat chocolate  Observers ate the same thing as the demonstrators that they interacted with  Behaviour did persist over time What exactly are rats cueing in on?  Only time that observers would avoid the food is if the demonstrator was dead  Got human to eat chocolate and breathe on the rat o Rat ate chocolate  Carbon disulfide – particular element in breath o Tells rat that that food is safe to eat o (Used carbon disulfide as pesticide)  rats picked this up Octopus is able to observe the behaviour of other octopus and learn Individual vs social learning  Information learned by an individual is lost when it dies  Information that is learned from others can remain in the population or many generations Evolution 12/09/2012 14:48:00 Evolution by artificial selection vs natural selection Deeper look at genetic variation, heritability & inclusive fitness Evolution A change over time of the proportions of individual organisms differing genetically in one or more traits Artificial Selection – the process of humans choosing a variety of traits over others  How does it vary from natural selection?  Still have variation & heritability in traits – it‟s just that humans are the ones driving the choices in who gets to breed Nature is NOT the driving force that we observe  ex Dog Breeding It‟s not the environment, it‟s human intervention that‟s created the variety of dogs  Colour, size, friendliness, speed, work ethic, loyalty, retrieving, herding o Herding – ancestral tracking trait from wolves that now is useful for humans Origin of Dogs All of them are derived from a wolf Wolves have lived with humans for thousands of years  Domestication of dogs dates back to 10 thousand years ago Key element in breeding teacup poodles Smaller poodles are given higher success rate for fitness Fitness The success of an individual in reproducing In artificial selection humans are selectively choosing who gets to breed based on preferred characteristics Corn Teosinte (bush) – small, few seeds (one row) Corn (stalk) – much bigger, much more seeds Chicken Our version of artificial selection do not always benefit the animals Jungle Fowl/Christmas Turkey Short legs, small breastbone, can barely walk/balance/mate Evolution by artificial selection The process by which humans using selective breeding change, over time, the proportion of individuals differing genetically in one or more traits  Breeding honing pigeons back in Darwin‟s time Artificial selection is very beneficial Can see if a gene can be selected out & see how heritable that trait is Artificial selection for phototaxis in fruit flies Phototaxis – movement towards or away from light In the beginning – equal bias  Then bred extremes of each behaviour and given enough time (many generations) you can get a very distinct behaviour  After generation 20, they stopped the selective breeding = let the flies breed without any restrictions – behavioural trait went back to normal pattern The Fruit Fly Flight Club Fruit flies brawl over mates and territory. Some scientists are betting that these battles can help them unravel the genetic basis of aggression Fruit flies are close to humans genetically Why do male fruit flies flight? Why select for increased aggression? Fruit flies will spend 20% of their time engaging in aggressive behaviours After selective breeding, aggressive behaviours increase Two key differences in how a population can be separated Artificial Selection – humans choose In nature – variation of reproductive success  These are both characteristics that have nothing to do with the animals‟ ability to survive In all cases there has to be some kind of pressure  Has to be heritable, must be variation, trait corresponds to ability to reproduce The importance of fitness Fitness = lifetime reproductive success, which is a product of reproductive rate and the length of reproductive lifespan Degree of fitness benefit can have very large impact on a population Lifetime reproductive success of red deer (elk) Males are capable of holding females  Compete for access Can measure the lifetime reproductive success of males & females  In females – greatest proportion of females never produce offspring that survive over 1 year of life o And then there‟s a normal distribution – average is 8 offspring  In males – nearly 50% of all males never produce a single offspring during their life o Smaller percentage that has extraordinary success for a male (4-6 offspring) We do see dramatic fitness consequences that are associated with traits Variation in humans 1. 5 behavioural or cognitive traits that vary among people 2. Do you think the variation in that trait is heritable?  intelligence/IQ (medium)  introvert/extrovert (strong)  aggressiveness (strong)  sexual tendencies (low)  laziness  criminal tendencies (strong)  curiosity  athleticism  compulsiveness  psychoses o mental disorders We have a tremendous amount of traits that all have variation  doesn‟t necessarily mean that these traits are going to be acted on by natural selection Physical traits Broad sense heritability  Low score = genetics has little to do with heritability o Handedness 30% o Diastolic blood pressure 45% o Twinning 50% o Systolic blood pressure 55% o Body weight 65% o Stature and tooth size 85% o Fertility 10-20% o IQ 60-80% Individual Variation Genetic Variation Without it, basic mechanisms of evolutionary change would not be able to take place Mutations – change in DNA itself Affects how it looks, behaves & its physiology Random; Non-directional; don‟t happen with any specific purpose in mind  Could end up being beneficial/neutral/harmful  Not all mutations matter to evolution in any way whatsoever o May not be passed down from parent to offspring (somatic mutations = irrelevant to evolution)  Only mutations that matter are those that happen to the germ line (gametes/reproductive cells) – different magnitudes of mutations o No change in phenotype o Small change – curly ears o Big change – pesticide resistance Causes DNA fails to copy accurately External influences can create mutations (ex radioactivity/chemicals), doesn‟t even have to be any unnatural conditions – dna is going to break down over time Migration – flow of genes between populations (gene flow) Sex & migration – sex = genetic shuffling Can introduce a variety of different combinations Sex – recombination of genes within a population This is going to produce a tremendous amount of variation  Ex height = symmetrical distribution o Greatest freq of individuals is found at the mean o Left & right have similar distribution  Number of finger prints that people have  Birth weight of infants  Foot size  IQ How do we identify those sources that are producing the variations we see in the environment? There are two main influences Genetic variance Environmental variance  Broad sense heritability – measures the extent to which genes vs environment contribute??? Animal Behaviourists are more interested in the heritability of characteristics Narrow sense heritability Assume behaviours are under genetic control Assume more than one gene can contribute to phenotype  Polygenic traits – more than 1 allele affects phenotype When you reproduce, only half is passed on to offspring  Not all of the alleles that contribute to a single trait are going to be passed down to offspring Measures the reliability with which the trait can be passed and expressed in the offspring Ex beak size – very strong heritability Selection differential, S The difference between the mean trait of selected parents and the population mean  mean of selected population – mean of parental population  ex 13-10 = 3 Response to selection, R Change in the mean character state of one generation as a result of selection in the previous generation  mean score of all offspring – mean score of parental generation  ex 13-10 = 3 Narrow sense heritability = R/S  Ex 3/3 = 1  All the alleles responsible for that trait will be passed on Conclusions We can quantify the heritability of traits Deeper look into genetics Most genes are polygenic  many genes are involved in the trait‟s expression Quantitative Trait Loci – genes that control polygenic traits  Helps to map out regions of the genome QTLs for emotionality (J. Flint) Experiment with field mice Used open field area When mice are anxious – stop, defecate, etc  Took a look at the genetic composition of the anxious mice  2 QTLs were identified on the mice – chromosome 1 & 12 Certain levels of emotions such as anxiety, depression and love are adaptive  Anxious people may survive more because they don‟t take more fatal risks *Paul Andrews has come up with an adaptive explanation of why it exists  Scientific American Genes and behaviour Scientists can see what genes are active during different circumstances DNA microarrays – gene chip  Square that contains number of different DNA strands o One cell = one particular DNA sequence  We inject a sample of their DNA/mRNA into each cell  If it‟s actively encoded into mRNA = we see colour changes o Can measure the intensity of colouration & infer the extent of expression in that gene Ex Bee behaviour  Changes over their lifetime depending on age/stage in life  Young nursing bees – have set of genes that are highly active & set of genes that are highly suppressed o Exactly opposite of old foraging bees  Different set of genes that are being recruited at different stages of life  Hypothesized – maybe there‟s a way that they can separate the role of behaviour and age from one another o Manipulated the kind of behaviours that a bee took on around the nest, without manipulating their age o Bee colonies will reorganize their priorities in the nest if new bees are added in o Simply adding bees to nest doesn‟t change genetic profile if their behaviour is left the same o If behaviour changes – genetic profile changes We have a distinct set of genes that is purely modified based on behaviours performed 9/12/2012 2:48:00 PM Ultimate goal of natural selection is to increase the frequency of a gene over time Genes are traits that may only be adapted in an environment with a certain set of circumstances Guppies Breeding frequency is great for allowing you to make conclusions about the changing environment Found in northern mountains of Trinidad & Tobago  Series of streams that eventually empty out into the ocean  Streams often divided by a series of waterfalls  Guppies can be found all along these streams  You can observe very distinct characteristics between guppies in different areas among the streams o What drives these differences = predators o Upstream = slight predation pressure o Downstream = greater risk of predators present Evolution of antipredator behaviour in guppies Predators  Downstream – large predators; pike cichlids o Risk to guppies no matter how big they are o Predator is seen quite often  Upstream – smaller kinds of predators; killifish o They will only feed on the smaller guppies o Predator is less frequent than downstream Differences between Guppies High Predation (Downstream)  Smaller offspring & a lot more offspring  Dull colouration  Earlier age of sexual maturity  Greater schooling  Distant predator inspection Low Predation (Upstream)  Larger & fewer offspring  Bright colouration  Later age of sexual maturity  Lower schooling  Closer predator inspection This is likely due to the fact that in high predation – guppies are at risk no matter what size they are; may be in best interest of a female to produce as many offspring to max probability of offspring reaching adult age In low predation only smallest guppies are eaten; if adult female can invest more in amount of time she gestates her offspring – may be larger, wont be as great a risk at that point Trinidad Guppies Females – drab Males – most colourful Large variation in colouration  Ranges from technicolour – dull Males that are more conspicuous stand out to the females Flashy colours may indicate health Females are also predisposed to have a tendency to look for very brightly orange coloured plants – provide them with nutrients  If male happens to resemble the plant/colour then he will stand out Colouration also has a downside – more likely to attract predators  Males have to play a balance o Low predation – much more colourful o High predation – less colourful High predation sites – females produce many small offspring; offspring usually reach an age of sexual maturity much sooner Risk of predators that they face can have effect on male colour, age of maturity, size of offspring, also see behaviour differences Schooling Behaviour Group together in a big ball Does make them much more obvious but it also reduces the risk of individuals being targeted by predators  Probability of individual surviving in a group is significantly higher than individual surviving on their own o Predator fish is less likely to target a single individual fish o As it approaches, it can easily be confused by the schooling behaviour  Greater vigilance – don‟t have to spend much time individually looking out for a predator, greater vigilance as a group Even up to more than 75% of their time, in high risk situations they perform schooling behaviours Predator Inspection Try to figure out who the predator is and what the intentions are  The closer that they‟ll get to the predator, the less fearful they are  Guppies will get much closer to predator in low risk, than high risk Usually inspect predator in groups of 2-4; usually males; cooperative behaviour – one guppy is the leader & a few others stay right behind him while not exposing them to the predator as much as the leader Take all guppies and put them in a tank with high risk predators  Guppies from high predation areas have a higher survival rate As soon as predation pressure increases – greater percent of fish that aggregate into schools  Group size = much larger in high predation environments Experimental Transfers Accidentally switched guppies & their location  Guppies from low predation (now in high predation) got killed off quickly  How well did guppies from high predation pool survive over time in low predation area o After roughly 30 generations – Guppies will start to physically & behaviourally resemble original guppies – characteristics of low predation guppy o Distinct set of behavioural traits that are favoured in one environment vs another Supposed your sister & cousin ask for an urgent $50 loan today, are you more likely to say yes to one over the other? Why? Should a parent sacrifice her life for her offspring? Is that really a benefit in most cases? Should siblings help each other? Either with survival or reproduction How can altruism evolve? Up until the 1960s Fitness = individual‟s lifetime reproductive success 1964 – William Hamilton wrote a paper trying to explain how helping others could benefit ones fitness Inclusive Fitness – there could be a benefit by helping the reproduction of individuals that are related genetically to one another From a gene‟s perspective, all it cares about is that it increases it‟s frequency in the next generation Hamilton’s Rule An action should increase in frequency if the benefit received by the donor‟s relatives, weighted by their relatedness to the donor, exceeds the direct fitness cost to the donor  rb>c Fitness Inclusive fitness of an allele is its effect on the fitness of the individual that carries it (direct fitness) and other individuals that carry the same allele (indirect fitness) Naked Mole Rats Display behaviour called eusociality  High degree of reproductive division of labour  Communal care of young  Overlapping generations existing at same periods of time Why does this occur in naked mole rats and not in any other mammals?  Unusually high degree in relatedness in the naked mole rats  Probability of sharing dna = 90% o More like identical twins vs siblings Is the high relatedness sufficient explanation for their altruistic behaviour?  NO  Regardless of degree of relatedness, have to use Hamilton‟s Law  We need to evaluate the benefit of helping vs cost??(slide changed) o But the benefit of helping as a group (in naked mole rats looking for food) far outweighs the cost of doing it on your own Simple fitness measure of lifetime reproductive success s may not be sufficient for own direct fitness or indirect fitness Adaptation A trait that provides an individual with the highest fitness relative to other traits in other individuals in a given environment Purely reliant on the environment that the animals are in When environment changes, not all of the same traits may be adaptive  Ex Wood ducks = habitual egg dumpers  Lay their eggs in nest boxes (cavities in trees); 12-14 eggs on their own – 1 egg/day for 2 weeks – laying an egg takes ~30mins to do – beyond that 30min females will forage for food – nest is unattended for a majority of the day  Egg Dumping o Other females will lay eggs into others‟ nest (this is called intra-specific brood parasitism)  On average – 10 eggs in nest in tree cavities  Over 4 year period, 75% of all females served as a host to parasitic eggs  At least 50% of the females have deposited eggs in someone else‟s nest  Roughly 1/3 rdwill have a nesting site, but will also distribute their eggs into the nest of another female  In the artificial nesting cites – found as many as 40 eggs – coming from parasitic females  Is egg dumping adaptive? o May reduce predation on all eggs  If one nest site gets preyed on, other wont  This was not a real sever risk – fairly low  Even lower in those that don‟t participate this behaviour o Maybe they‟re forced to parasitize other nests because they don‟t have their own  No. When artificial nest sites were added – more egg dumping o Maybe they‟ve lost their own nest so they‟re forced to egg dump o May benefit from placing their eggs in nests of relatives  Indiscriminately dump their eggs o Could increase reproductive success  Parasitized nest have lower success  Higher percent of parasitized nests – lower percent of eggs hatching  Eggs at bottom don‟t get proper incubation, probability of successful hatching is low o Given the current environment, by adding artificial nests – egg dumping is no longer adaptive o When nesting sites were rare – that behaviour was adaptive because nesting sites were hard to spot, hidden in trees  Frequency of parasitism remained low o By adding more sites to dump eggs – became too available to them – just decided to dump their eggs o This trait might have been adaptive when nests were hidden o To make this trait adaptive – nesting boxes are high up in trees, far apart, camouflaged o Cryptic sites – hidden nest boxes  Number of eggs laid remains stable  Because less parasitism going on  Fewer parasitism = greater chance of egg surviving  This is a good example of how traits cannot be adaptive depending on environmental circumstances  We have to work with the environment to make sure traits stay adaptive Learning 12/09/2012 14:48:00 MIDTERM INFO 20-25 m/c  fact based 4-6 short answer  explaine concepts discussed in class  particular experiments  concept – evidence from experiment to understand – make conclusion to allow to understand concept  not methodology 1 hour LEARNING Innate behaviour  Behaviour determined by the hard-wiring of the nervous system  Built into the species – not acquired by practice o Ex taxes (movement towards/away) o Reflexes o Instincts (heritable) Vast majority of animals don‟t learn – usually just innate behaviours Instincts  Inflexible, inborn behaviour  More complex than reflexes Opossum playing dead & secretes dead odour Sea turtles immediately navigate after the are hatched – move towards ocean 7 breed two – hybrid bird particular way of collecting things to make nest 8 size & how they carry – grab bark, tucks into tail 9 peach – shorter strips tuck into tail fischer – longer in size & carry in mouth hybrid – strip in beak is mid length  fail to tuck – complete behaviour is not there  do not learn  reliably do it over again – frustrated to tuck into tail, uses mouth 10 -experts without experience -learning takes practice, time, effort, failure, resources benefit -learning from innate behaviour  innate biases – preferences for navigating to diff coloured food  repetition (of relevant info)  emotional (fear, joy) tells us what is important/significant 11 Relatives – share genes & will be passed on What‟s required for creating role of relationship  Vagus nerves  Oxytocin  Frontal love of brain 12 - -how do innate experiences continue to create learning experiences? 13 what is learning? – relatively permanent change in behaviour  very vague  what is relatively permanent?  Some animals live for short periods of time Learning – ability to acquire a neuronal representation of new info  An individual may use that info to determine subsequent behaviour 14 behavioural trait modified over time 15 detection receptors – amino acids, sugars, toxins send messages tell to go straight, or random direction then straight sample environment – reflects learning? 16 ability of animal to change behaviour based on experience/environment 17 is it learning?  Depends – ability to acquire neuronal activity… 18 19 fixed action pattern – behavioural pattern that is full? 20 smooth & near nest – must be an egg put a billiard ball – they also rolled it into the nest egg doesn‟t have to be white or round  put wooden cube around – did the same behaviour means that the real egg is never ignored even if they make mistakes 21 22 bower bird makes a nest (mini hut) collects lots of resources  places certain things & groups/categories continues to work even if you‟re near there, as long as you‟re not moving more impressive collection of treasure & properly arranged – less need for bright feathers for mate flowers –collect if they can find use them as interior décor decorate them with nicer colours – bright pink, purples depends on taste of female 23 begging behaviour in gulls instincts that are modified over time  instinct - learning base red spot – important in releasing instincts in gull chicks 24 -normal baseline result - -red dot removed – less response -illusion of more than one spot – greater response 25 actually changed over time based on experience during life 26 which chicks preferentially pecked parental – top line non parental – bottom line response of model changes -couple more days of experience “learn” over time innate can be modified based on experiences had 27 28 processing chemical stimuli in water like odour cues to alert them about danger – live in ponds both clamshelfish & minnows are eaten by pike pike – use vibration cues to know where prey are – flies stop movement so pike can‟t detect them damselflies – sensitive to cues like pike eating prey – chemicals released – translates to novel opportunities 29 30 3 – typically not found in ponds, damselflies would not have encountered in ancestrial history take pike out – put cues in 31,32 odour cues – chemicals released 3 diff groups in 3 diff tanks observe behaciour 33 34 35 + movement -movement -average amount of movement with no food or chemical cues feel threat; something is wrong; everything is decreased – completely unaware of chemical cues 36 *need multiple environmental cues, not just pike – need adaptive cue to know when its on the hunt – combo of cues why didn‟t reduce activity when smelled pike + dead mealworms? Did not possess innate response to mealworm stimuli – why not?  Evolved in environment with no mealworms Why did flies reduce activity when smelled pike + dead mealworms?  Flies possess innate antipredation behaviour to these chemical stimuli 37 38 39 some chemical cues? 1-Exhibited response 3-same cue but no response 40 novel scenario aware; can respond to new cue + determine the threat 41 never translate innate response to novel scenario if no innate experience 43 Learning and evolution Beneficial – learning 44 fitness consequences associated with animals that can learn more 46 fruit flies most important animals in biology 47 quinine - reacts very strongly in ourselves & fruitflies & other animals 48 training even numbered – should be going to orange recognize undesirable then go to pinapple – opportunity to learn environment 49 break expect behavioural preference 50 test should have more eggs (pineapple) presumed learned behaviour artificial selection 51 training switched – pineapple + quinine eliminate preference for food 53 test key elements? Training (period 1) learning + Memory test (2), selective breeding only of the flies who demonstrated good learning memory (end of period 3) 54 measure learning by # of eggs laid on orange even should lower; odd should increase GRAPH  0-13 – lots of overlap; exhibiting same behaviour  13 onward – bias being developed  took ~ 25 generations to reflect learning + distraction  dig in graph – accidentally introduced insecticide 55 conclusion 2 the evolution of learning indicates that there is heritable variation in having ability in flies – similar heritability variation in learning ability… don‟t see good learning by default 56 – SKIP UNTIL LEARNING AS AN ADAPTIVE TRAIT Learning as an adaptive Trait Not all animals learn To learn or not to learn 1 When would it be better to just act off instincts 2 present in one season, not in another – varying resources within resources – within an animals lifetime 3 consistency of resource 4 learning costs a lot –resources + time bad scenario no benefit from learning; go with innate behaviour low x low – does not help/benefit  so little consistency; will work one gen, may not in the other - varying low x high  whatworked good in one gen will work in next – good scenario 5 high x high  consider benefit of learning  environment of nest = predictable in life high predictability between and with lifetime  egg rolling – ignore experience – works 99% to learn or not to learn high x low predict where resources/predators are day by
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