Animal behavior exam 1

Why evolution is so controversial

1. emphasis on variation : - previously ( old theory of typological thinking) is the idea there is a perfect type that underlies every species- species arose as perfect creations of the creator, they didn't change, they were immutable - this is like the opposite of variation - variation seemed liken noise around true signal 2. evolution is stochastic ( BLIND)? : -governed by laws of chance, ultimate source of variation, MUTATION, is probabilistic - ppl couldn't believe that such a mechanistic process could lead to "progress" or something as complex as adaptive design 3. species can change - the blending theory of inheritance posed a problem for the natural selection theory, and darwin couldn't figure out the initial source of variation

Why was evolution not immediately accepted??

1. it was a radical departure from the current way of thinking : because of the emphasis on VARIATION, the STOCHASTIC process, and idea that species can change into new species ( ESSENTIALLY, because of the controversies discussed) 2. Conflict with religion 3. darwin didnt get everything correct so, this theory was not accepted until Mendel's Modern Synthesis

assumptions

1. measure of fitness = energy maximization ******** makes sense but should be tested orb weaving spider: experimental food supplementation of webs 14/38 females produced 21 egg sacs 17 out of these 21 ( 81%) were produced follwing heavy natural or experimental prey consumption water pipit - the number of fledglings produced increased with the biomass of food delivered to them by their parents 2. does optimality matter? ****** - we do not forage optimally, animals do - refuge: get food as quickly as possible to use time for other things: finding mates, tracking offspring, not being in danger - we would feed differently if we had a high likelihood of death always 3. food items are encountered one at a time and in proportion to their abundance 4. food items can be ranked according to profitability

group selection

"for the good of the group" - old definition - NOT TRUE cheating and evolutionary stable strategies today: the differential rate of origination and/or extinction of populations on the basis of differences among them in one or more characteristics - analogous to individual selection on groups WEAK relative to individual selection: - generally operates in concert with individual selection - only in extreme cases would it be expected to work against individual selection : when the effect on the group is negative and effect is positive on individual ( like species develop cannibal feeding strategy)

DARWIN

- evolution by natural selection ( as opposed to evolution by theory of inheritance by acquired characteristics) - darwins model for evolutionary change - model for inheritance: blending/ pangenesis, was proven INCORRECT and it diminished the importance of VARIATION - natural selection assumes that organisms are varied and that within species there is natural variation - these variations lead to differences in survival and reproduction -there is excess progeny in many species so there exists competition to survive or " struggle for existence" - assuming variation is heritable, individuals that produce the most progeny will tend to have offspring that look like themselves --> species constantly evolve -over time as small changes are acquired new species can be formed from old ones

Envrionment before birth

- injecting rats with hormones impacts behaviors in the wild - inject fetuses with testosterone causes them at act differently as adults - this is relevant because in the womb the fetuses can be subjected to different levels of hormones, position in the womb can influence future behavior/ mating success: ( OM- surrounded by 2 sisters, 2M- surrounded by 2 males)- female surrounded by 2 brothers= flush of testosterone- masculinized females and were more agresseive in adulthood and wandered in larger spaces Before birth environment makes a difference

nat'l selection points

- property of POPULATIONS AND SPECIES not individuals -nat'l selection acts on relative and NOT absolute trait values ( trait doesn't need to be perfect, just better) - nat'l selection does NOT equal evolution: natl selection is a process, evolution is a record of change - Nat'l selection does NOT create perfectly adapted organisms - fighting and game theory NS does not favor a specific trait value (absolute), i.e. a particular speed. It favors any trait that is better than the alternatives (relative). A trait need not be perfect or fully formed, as in the eye, to be favored. This is a very important concept for complex trait evolution.

Design principles- Bat Sonar

- very high frequency - very high intensity - frequent sonar blips - sensitive but discriminating receiver the argument underlying this approach is that such HIGHLY developed design could not arise by accident or by some other purpose. it is hard to imagine any explanation other than natural selection building such features for this particular purpose. of course, this does not mean that the trait originally evolved for the task it now functions well at, we have already discussed this point nonetheless, (exaptation)d it is clear that nat'l selection has played a great role modifying the structure for its current purposes. bats catch insects by using sonar- sound waves - did it evolve for catching insects or for communication? look at design of system ( above): none of those factors are needed for communication so there is storng evidence that sonar is an ADAPTATION FOR CATCHING INSECTS

Pets and backyard behavior

- we didnt just capture wolves and make them into our partners-dogs: Domestication Domesticaiton: wolves started following people around realizing they left food and trash - two way street Backyard Behavior: basic behaviors allows us to make easy predictions. squirrels like to forage as efficiently as possible - will they eat the food they get up in the tree or on the ground? BOTH- determining factor for choosing which option is the proximity of predators - humans.

species

- within a locality, sympatric species are distinct entitities - across space, populations of a species may differentiate, but they must also maintain connectedness geographic variation is the norm - milk snakes : some species of milk snakes look more different than distinct species because of geographic isolation

genic selection

-selfish gene theory - t- allele : in mice artificially high levels of t allele bc of genic selection Gene level selection: T -allele confers sterility in male mice- gene frequency is artificially high - why is it high unless selection is favoring it ? - it is really just a selfish gene, not good for fitness - get distorted proportions Selected against in individual level - fundamental unit of heredity

Champion of Evolutionary Thought

Lamarck - Change builds over time in small increments includes idea that animals are "adapted " to their environments -- leads to theory of inheritance by acquired characteristics --> this is scientifically disproven - that traits develop throughout ones lifetime and can be passed down to offspring

adaptationists programme

An approach in evolutionary biology that assumes that most traits of an organism are adaptations which have evolved solely or chiefly by means of natural selection rather than by means of other processes such as genetic drift. Under Gould and Lewontin's definition of adaptation, a trait that confers current utility today mustalso have evolved for that specificreason. must TEST theories of adaptation

how do you identify an adaptation- design principles

Design Principles says traits that match optimal theoretical design are likely to be adaptations as that high degree of specificity would be unlikely to evolve for another reason. specify a particular problem passed by the environment and then specify what the best or optimal solution is to that problem morphology and movement patterns/ foraging/ habitat choice open/closed habitats of birds and wing desin- longer wings more efficient good in open habitats sponges: perfect filtration system - water goes through and filters out nutrients, so good adaptation

foraging-biotic interactions- predation

Won't get the best food if it is in the cave with the grizzly bears Barbed swallows feed in groups out in the open to avoid predators - less food but better for safety In barn - no predators- hunt individually Stickleback - same thing as barbed swallows- feed on insects on the water- big school are best food but predators of sticklebacks see they big schools so they avoid them

the geography of speciation

a traditional and still useful way of classifying different ways that speciation can occur focuses on the geographical distributions of populations modes of speciation: allopatric - speciation through geogrpahic isolation sympatric- speciation without geographic isolation

aptation

a trait that confers CURRENT utility- high fitness today aptations = adaptations and exaptations

Exaptation

a trait that confers current utility today, but evolved for some other reason

adaptation

a trait that evolved for the SAME reason that it confers CURRENT UTILITY TODAY

the trick to defining species

accounting for differentiation between the same species while recognizing the differences that distinguish one from the other - identify populations that are interacting as separate entities - identify populations that have independent evolutionary trajectories and outcomes

Aptations examples

all of these are aptations: taxon and trait: Bird wing - modification for swimming: EXAPTATION Penguin wing- modification for swimming: ADAPTATION Bird wing- modification for flight: ADAPTATION Vertebrate forelimb- modification for flight: EXAPTATION

scientific study of animal behavior: modernity

all start with evolution. evolution: broad sense- change evolution: biological sense- population genetics, change in allele frequencies through time ( eg eye color) Darwin's evolution theory : descent with modification

Roles of genes in behavior

almost all (>90%) of animal behaviors have a genetic BASIS - species have typical behaviors and diff species act differently from one another- **genetic predisposition to act a certain way - DOGS - shepherding types like to herd ( bred to herd sheep), lab types like water and retrieving ( labs were bred to retrieve nets off of fishing boats so they have webbed feet!) evidence comes from instinctive/innate behaviors observed in nature - instinct: a behavioral pattern that appears in fully functional form the FIRST time it is performed, even though the animal may have had no previous experience with the cues - ie baby turtles heading to sea, salmon migrating back to where they were born - imprinting ( not innate) : geese is hatched and they consider the first person they see to be their mother and they follow it no matter what species -fixed action patterns: behavior that displays almost no variation, once started MUST be completed: graylag geese egg retrieval FAPS are istinctive/ innate --> not the same thing as having a genetic basis

interbreeding

an obvious connection or uniting factor between individuals/ populations is the ability to interbreed. across space the ability to interbreed allows genetic material to be exchanged this has two effects - one hand, it permits beneficial mutations to spread throughout the species - on other hand it can prevent populations from diverging too much from the rest of the species both effects act to maintain the cohesiveness of species these ideas codified by ernst mayr in 1942

Constraints on evolution - architectural

architectural constraints: the way in which organisms are constructed may provide limits on what can evolve. some things may be impossible to evolve because of the physiological limitations from existing deisgn - in other words, the presence of ONE TRAIT LIMITS the evolution of another - insects and oxygen and size: insects breathed in their skin, cant get bigger than a certain amount - surface area x volume- much more oxygen back then eg. surface to volume ratio: - volume is proportional to the amount of oxygen needed to supply all the bodys cells - surface area is proportional to the amount of oxygen that can be brought in from the outside - what if an insect DOUBLED in size without changing its shape? anti predator tactics: rapid flight vs defense - large elephants: size affects their anti predator tactics: cant jump male parental care: -birds: really good parents, males participate equally or more to females - some exclusive parental care from males - Mammals: absence of male care is normal: 0 mammals have zero mammal care ( architectural constraint - boobs)

Comp Psych - morgans canon

simplest psychological process possible should be used to explain an animal's behavior animals arent consciously thinking or going through a process

optimal foraging

assumes that nat'l selection has favored feeding behaviors that maximize fitness animals like the foods that maximize fitness 2 most common application are prey choice and food patch use

anthropomorphism

attribution of human characteristics or behavior to a god, ANIMAL, or object - eg : dog looking sad- assumption - we perceive adaptations as "good" for animals, but adaptations leads to organisms that are better fit to their environment and have better reproductive fitness - there is nothing "morally good" about this - adaptation simply leads to more reproduction

developmental homeostasis vs behavioral flexibility

some behaviors are fixed- developmental homeostasis some behaviors are more flexible- behavioral flexibility tiger salamanders: when they develop thye are omnivorous, but there is a cannibal morph that also develops and eats the other salamanders. triggered by large body size, ponds with high degrees of relatedness tend to INHIBIT turning into cannibal morph ( less cannibals)

biological species concept - mayr

species are groups of actually or potentially interbreeding populations which are reproductively isolated from such other groups key is reproductive isolating mechanisms!!! post and pre mating isolation mechanisms Scientists categorize organisms into species based on their physical, genetic, and behavioral characteristics. The most common method for species differentiation is the biological species concept, which defines a species as a population of organisms that can interbreed to produce viable, fertile offspring.

allopatric speciation

splitting of one continuous population into two or more groups that are geographically isolated from each other - reproductive barriers evolve while populations are geographically isolated, although the two species may subsequently become sympatric ( live in same place but not mate bc reproductively isolated) pre and post mating isolation techniques are important for allopatric speciation but not required**** experiment: control: two pops separated and given same food- no reproductive isolation -given different food after many generations: stop mating dark dulap on lizard- better in bright habitat and vice versa to stand out and attract mates golden frog- all mating displays visual ( most frags use calls) bc lives by very noisy habitat (waterfall) 1. initial geographic separation: geology/ climate change/ sea level fluctuation 2. divergence in different areas - limited or no gene flow between areas - allows divergence 3. reproductive isolate in sympatry - if theres subsequent, secondary contact -may interbreed in narrow hybrid zone -hybrids generally have reduced fitness

How do you identify an adaptation

studies of natural selection: 1. observation- natural variation: comparisons between individuals of the same species 2. experimentation- create artificial variation: cut off fringe off of the toes of the fringe toes lizard to see if they still run as fast in the sand - vary the environmental factor : predation and behavior, food and HR size ONLY WORKS for plastic behaviors - species must be able to naturally vary the behaviors - if the species cant vary naturally, we can vary the behavioral traits or the result of them

sympatric speciation

sympatry: two populations are sympatric if individuals of each are physically capable of encountering one another with moderately high frequency - evolution of reproductive isolating barriers within a single initially random mating population ( behavorial_ requires evolution of reproductive isolation without any spatial isolation among diverging lineages two ways it can occur: - genome doubling- polyploids - disruptive selection, reduced hybrid viability and selection for mate discrimination mechanisms - assortive mating by resource use- ecological speciation - could be a magic trait

Competing Browsers hypothesis

the giraffes long neck is an aptation for getting access to tall vegetation right?? - Lamarck: yes - Darwin: yes But, giraffes dont actually browse preferentially on high vegetation during the dry season- during the most intense feeding competition- giraffe generally feed from low shrubs- and feed with their necks bent SO WHY?

Descent with modification

change over the course of generations, in the properties of populations of organisms, groups of populations ( eg. prey population becoming faster over time, lone wolf, fear of the dark- it is healthy to have this fear)

positive frequency dependent selection

common phenotype favored/ fixed different populations may become fixed for different phenotypes mullerian mimicry: several unpalatable species share a similar warning pattern batesion mimicry: one poisonous one not poisonous * in some cases there is convergence to different phenotypes in different regions due to positive frequency dependent selection - demonstrated by transplant experiments

secondary contact

consequences: 1. fusion of incipient populations back into one species 2. reinforcement 3. stable or transient hybrid zone formation 4. speciation of hybrids

constraints on evolution - developmental

developmental constraints - the developmental process of an organism is highly complex and intricate. consequently some changes are simply not possible because they would have so many effects on the developing organism. - traits are products of interacting developmental processes during embryogenesis and maturation ex. no modification of upper part of limb, lizards can only lose the end of their tails - modifications to the end of limbs happen all the time - claws, toes, etc horned beetles- 2 headed organisms only, not 3 on behavior: personality evolution: most constraints are not absolute but instead bias the evolutionary pathway because some phenotypes are easier to produce than others

testing roles of genes in behavior- studying population with genetic differences

dietary preferences in coastal vs inland garter snakes - coastal snakes eat banana slugs and inland snakes avoid slugs ( eat fish and frogs) if presented, both will eat the fish and frogs but the inland snakes will avoid slugs- why? inland populations are older and the snakes move out west and gain genetic preference for slugs. Also slugs have some toxins in them that is similar to that of leeches that inland snakes encounter so the slugs remind them of the toxic leeches and they stay away. migratory patterns of the black capped warbler - birds can orientate - inner compass at birth, but only adult birds can NAVIGATE- it is a learned behavior, babies cant navigate

Early experiences/ Learning

early experiences can affect later courtship imprinting: sounds and sites Learning: - ability to learn and what you learn can be shaped by nat'l selection : eg: - prairie vs meadow voles: one is monogomous and one is polygamous- selection favors mapping abilities for polygamous species eg: Clark's nutcracker vs pinyon or mexican jays: seedbarrier- many seeds buried in thousands of caches they need to remember where they buried the seeds, so they have dramatically enhacned ability for spacial awareness

food choice constraints

energy not the only factor - vitamins and nutrients - eat a variety of foods fledglings: eat both dragonflies and bees bc they grow better if they eat both has to do with the different vitamins and nutrients present in those choices and a balanced diet matters

Role of Genes in behavior: parent-offspring regression

examines similarities between parent and offspring in the traits they posses. if the trait has a genetic basis, then there should be a correlation between the parental and offspring phenotype - migratory birds, direction of timing and departure- leave at the the time of their own species no matter what group of species they are currently in - direction fixed for species cautions? if offspring behaves like parents that doesnt automatically mean it is genetic, it can be learned through environment- so we conduct experiments to adjust for that

experimental study example 2 - zonosemata fly

experiments to test whether waving banded wings is an APTATION to avoid predation by jumping spiders - yes waving banded wings is an aptation for avoiding jumping spider predation - ineffective against other predators flies mimick predatory predatory jumping spider to deter an attack

Learning preparedness

what an animal is biologically programmed to learn- learning is only possible within the boundaries set by natural selection ( picking food based on color- animals dont pick food based on size because not all associations are equally possible)

adaptations programme example

why did t rex have short forelimbs? - for stability? -ta keep arms away from massive jaw? - to arise from a nap? - to stimulate the fame during courtship? these are just speculative just so stories unless they can be tested! theories of ADAPTATION MUST BE TESTED

testing role of genes in behavior - combined approach- carry trade offs

exploratory behavior in the Great Tit - personality matters - bold vs shy - bold birds advantage: have a lot of friends that aren't that good -shy: have a few very good friends bold birds do better in terms of finding food, shy birds do better in terms of avoiding predators behavioral alternatives carry trade offs - artificial selection and population differences

how do you identify an adaptation- historical approaches?

fossil records eg. evolution of grasslands arise and evolve and these is a change from eraqtotheream to a horse - so the CHANGE is driven by the grassland eg. octopus and squid do not have ears- hypothesize that they lost ears to avoid being stung by whales, is that what drove the evolution? no, they lost ears before whales even evolved- hypothesis falsified

reproductive isolating mechanisms: post mating

gamete mortality - no fertilization zygote mortality- embryo dies hybrid inviability hybrid sterility - baby cant mate eg. mule - horses and donkey mate make mule, mule has high fitness but it is sterile = hybrid sterility

experimental study example 3- geckos tail wave

geckos wave tails when introduced to threat in order to distract predator away from head and towards the tail- how do we test the purpose of the tail wave immobilized tail with a drug then introduce predators red tailed vanvouzar severs its own tail and it has its own nervous system that will still flail to distract predators

levels of selection

gene individual - fundamental unit of selection kin group species

Adaptation

general - outcome of a process- change in response to existing or prevailing condition physiology: physiological adjustment to a new environment: no genetic change, occurs within INDIVIDUAL - heat, cold, altitude - acclimation not adaptation acclimation does not = adaptation current utility: traits currently are favored by natural selection, benefits the organism TODAY evolutionary origin: trait evolved by nat'l selection in response to a particular selective condition and is currently maintained by natural selection for the SAME reason different from current utility definition: penguin wings have tremendous UTILITY for swimming, but is it an adaptation? NO, because they arose for flight, bow they are useful for swimming but is not a swimming adaptations. it can be useful for what you are doing but that doesnt mean it developed for that specific reason why do we see so mnay possums on the road? play dead in front of predators, cant distinguish predator from car Blue footed booby- adaptation- sticking nest material at the feet of attractive female, but blue footed boobies do not build nests- so why- because historically they evolved from nest builders and females want males who could build nests, like a relic- no longer useful

kin selection

groups of related individuals inclusive fitness: direct + indirect fitness ( those who carry your genes ** ) It is based on the concept of inclusive fitness, which is made up of individual survival and reproduction (direct fitness) and any impact that an individual has on the survival and reproduction of relatives (indirect fitness): altruism: sacrificing yourself for the good of others - alarm calls, cooperative feeding

pre mating techniques

habitat ( ecological) isolation - mates do not meet - fowlers toad ( forest adapted) and american toad (grassland adapted) - can make fertile offspring but do not because htye do not interact in nature because of their ecology preferences behavioral isolation ( ethological) - mates meet but do not mate - carolina wren, cardinal, pileated woodpecker - boobies of the galapagos: masked booby, blue footed booby, red footed booby - dont recongize as mates because of foot color mechanical (lock and key) - parts dont work

constraints on evolution - historical

historical constraints: - traits may be unable to reach optimality because evolution from current design are impossible or result in a decrease in fitness - further adaptational change or optimal adaptation may be impossible from existing design: evolution works like a tinkerer, not an engineer you cannot redesign from scratch- gotta go from where u are at adaptive landscape: ex. peak in large body size and defense for elephants--> unlikely that they would get skinnier and fast youve taken a path and maximize that adaptive peak, now hard to go back cant go from a peak to global optimum because you have to go through a valley and selection would never favor that cant evolve to another trait from the first Adaptive peaks is the idea that there are multiple adaptive solutions in an adaptive landscape. However, which peak you ascend is really chance!!!. Later you cannot switch peaks even ifone is better as it would require crossing an adaptive valley (low fitness) which would never be favored.!!!!

how do you identify an adaptation- comparative method- comparisons among species

if the same trait has evolved in different organisms experiencing similar environments and therefore similar selective pressures, then the correlation between habitat and trait is unlikely to be an accident and instead provides proof that the trait is an adaptation to that environmental situation - kittiwake vs black headed gulls: no egg shell removal or nest cleaning behavior in kittiwakes - why? kittiwake nest- filthy nest with bird poop-remove egg shells- inaccesible for predators black headed gulls- nests on ground- broken eggs deter predators evidence for relationship between predation and egg shell removal

peripatric - kaneshero model

large main population --> choosy females selected against --> novel male trait arises a sample of larger population results in an isolated population with less males containing attractive traits - over time choosy females are selected agianst as the population increases - sexual selection drives new traits to arise, reproductively isolating the new population from the old one Peripatric speciation is a mode of speciation in which a new species is formed from an isolated peripheral population. Since peripatric speciation resembles allopatric speciation, in that populations are isolated and prevented from exchanging genes, it can often be difficult to distinguish between them.

Sexual Selection hypothesis

long necks confer advantage in male male competition- fighting - intersexual selection sexual dimporphism: necks of males are 1.7 x heavier and skulls are 3.5 x heavier males with longer necks are socially dominant females are more receptive to advances from long necked males - necks for sex hypothesis : a good story doesnt make it so : "adaptationists programme" by gould and lewontin

Scientific Study of animal behavior- Greeks

mainly aristotle. most of the work was exegesis: critical explanation or interpretation of a text/ scripture (aristotle original work has unicorn in its documentation) of , not actually studying behavior of animals

value of an optimality model

makes testable predictions: if the natural conditions follow the model, then key factors influencing an organisms behavior have been identified if not then other factors need to be investigated

we can test OFT using food acceptance

mealworms go on conveyor belt - size segments -see what birds pick follow profitability equation above to a T

behavorial ecology ( 70's 80's ) ( fitness)

more closely aligned with ethology because of the biological basis but brings in a little bit of both arises in the 70s and 80s - study of animal behavior from an evolutionary perspective -emphasizes the FUNCTION of behavior: ie how it allows an organism to adapt to the demands of their ecological and social environments - how does nat'l selection mold animal behavior? - fitness is KEY : what is fitness in theory 1. average contribution to the gene pool of the next generation that is made by individuals of the specified genotype or phenotype 2. lifetime reproductive success 3. number of succesfully reproducing progeny produced in an organism's lifetime in practice we use indirect measures or surrogates for fitness: like survivorship, number of offspring, number of matings, body size, growth rate, feeding efficiency, number of breedings seasons ( could show that only single breeding season is successful) we cant really tell how many offspring a male has, so a better measure for males is number of matings/ body size etc. - but this isnt the same as fitness so while something can appear beneficial it may not actually be Fitness: genotype/phenotype/environment interaction. not fixed property of a trait- there are many components.

scientific study of animal behavior - after 17th century

most work was still exegesis and highly anthropocentric: regarding humankind as the central or most important element of existence, especially as opposed to God or animals. asking how we USE the animals behavior to benefit us. Descartes: humans share certain characteristics with animals but humans alone have soles and are endowed with reason: automata

Reinforcement

natural selection increases the reproductive isolation between two populations of species this occurs as a result of selection acting against the production of hybrid individuals of low fitness in allopatric speciation reproductive isolation evolves as a by product of other evolutionary change -drift/selection/etc exception would be secondary contact between populations of incipient species to be prior to completion of reproductive isolation - speciation begins and the break is made in allopatry but isolation may be completed/cemented/ reinforced after secondary contact

why does the species question matter

necessary to explain the diveristy of life, how it arises necessary to identify and conserve biodiversity

nonaptation

no current utility

can animals distinguish between profitable and unprofitable prey items?

northwestern crows and whelks - prefer large whelks which give high energy gain and they are easier to break - medium sized whelks are more difficult to open and these = net energy loss, these are avoided feed exclusively on large whelks

food choice not the only behavior to maximize - height of drop

northwestern crows drops whelks when already on way back down so that it sees where it falls and beats the competition to the whelk - competition factor

adaptationists programme:

not all traits are adaptive : some arose for a different reason other than selection and adaptation spandrel - non functional architecture - decorative but we dont have the spandrel to be decorated, decoration is a byproduct not all adaptive traits are optimally designed

Genetic basis vs. genetic determinism.

not the same thing basis: gene has impact on the likelihood that animal performs a particular behavior. correlation- doesnt mean that their arent other important factors determinism: gene has absolute control over a behavior

economic decisions and optimality

optimality theory : adaptations have greater cost to benefit ratios than the putative alternatives that have been replaced by selection

species selection:

origination/ extinction of groups of related species - clades macroevolutionary trends NOT important for explaining the evolution of traits in an individual Species level selection should never be invoked to explain the evolution of traits at the individual level. conclusion: use theories of individual selection as a default hypothesis, and only consider genic, kin, or group selection as alternative hypotheses when arguments based on natural or sexual selection are not a satisfactory explanation of behaviors

do animals make distinctions between food items with differing levels of profitability ?

oyster catchers - medium ,iscles eaten because they are easier to open than large (large have barnacles encrusted), and have more meat then small going after over a certain size ( energy gain) and most profitable size lying within that distribution

magic trait

phenotypic traits involved in both local adaptation AND mating decisions traits already important for mate recognition come under DIRECTIONAL selection beak size - trait for adaptation ( food choice- seeds) is also mate preference mechanism ( leads to mate isolation) - part of sympatric speciation - specifically ecological speciation Magic trait is a trait that is already used for 1. mate recognition and mating cues comes under divergent or disruptive selection for another ecological/habitat reason independent of mating. The resulting divergence has the effect of creating two species without selection ever acting for mate isolation.Magic trait -basically get two selection impacts (both respective to env and mating) at once Is magic trait part of sympatric speciation? IT IS SYMPATRIC SPECIATION - specifically specific part of ecological speciation ( disruptive selection (beaks for seeds- big or small- one of the two extremes -)- if this trait is also how u distinguish mates -MAGIC TRAIT) Ecological speciation part of sympatric speciation^ diff environments leads to reproductive isolation ( usually has to do with eating diff foods - hawthorn and apple flies example)

gene flow does not keep populations from diverging

populations occupying the same niche would be favored to stay the same, even int he face of some gene flow, whereas populations in different niches would diverge, even in the presence of gene flow. taken to the extreme this view would suggest that gene flow is irrelevant gene flow does matter and selection matters - they both keep populations from diverging

Optimal foraging and prey choice

prey size: rules 1. never eat anything larger than your head 2. eat items that lead to highest energy gain/ profitability PROFITABILITY = ENERGY GAIN/ HANDLING TIME

ecological speciation

process by which barriers to gene flow evolve between the populations as a result of ecologically based divergent selection between environments ecologically based divergent selection for different habitats - foods/resource acquisition - leads to the creation of reproductive barriers food choice leads to ecological/habitat isolation in a nutshell FOOD CHOICE LEADS TO SPECIATION apple flies vs hawthorn flies - hawthorn flies started eating apples when they moved into apple orchards instead of hawthorns and evolved into new species when they stopped mating with each other morphologically evolve for the different feeding

negative ( inverse ) frequency dependent selection

rare phenotype favored - scale eating cichlid

biological species concept challenges

reproductive compatibility seems easy but not always : pre vs post mating isolation mechanisms theoretical - asexual species - hybrids: in nature and out - hybridization in the lab, natural hybrids

moose feeding ecology

requires a minimum daily dose of sodium - they get sodium from the water plant habitat, even thought water plants are lower calorie so land plants are higher in energy ( calories) but to get their required dose of sodium moose need to feed in both environments diet that strikes balance with combination of required sodium (fulfilling dietary requirements) and maximal energy

food constraints TOXINS

Still maximizing energy just have other requirements for diet Toxins: eating dirt - birds eat nuts high in toxins but dirt has stuff that neutralizes the toxins- max energy Eat toxic nuts + dirt Howler monkeys: The more common a tree species the less likely they are to feed on it Only take leaves from 12 of 149 trees Prefer scarcer smaller tree leaves They often feed wastefully as well MOST common tree species have high alkaloids and tannin Poison and hard to digest ( handling cost) for howlers They discard most poisonous parts of leaves and eat least toxic - wasteful howler monkeys maximize energy given the constraints they are presented with

alternatives to nat' selection as explanations for the evolution of particular traits

1. no selection - trait is a non-aptation: drift, founder effects ie. color of blood - red not because of adaptation but because of other things that were selected for ( hemoglobin etc) 2. correlated consequence of selection on another trait - pleiotropy -genetic linkage -droopy ears and domestication go together but droopy ears are not selected for **** 3. non genetic differences - this phenotypic plasticity may well be adaptive but the different phenotypes observed in the different populations do not represent separate adaptive evolutionary change. - red wing black birds - correlation between wing length and temperature: colder climates, shorter wings ( not genetic adaptation- environmental) - acclimation? 4. historical legacy- anti swerve adaptation - possums play dead 5. gene flow 6. trade-off: one trait is adaptive for one thing or not for another, could have net + 7.functional equivalence species may differ in some characteristic but the difference does not represent adaptation to different environments. they are equal adaptive solutions to the same problem. - two different forms are EQUALLY adaptive, not adapted for different functions ie. one horned vs two horned rhinos in asia and africa - leads to non adaptive differences : like people driving on different sides of the road Non-aptive or non-adaptive differences (could also be functional equivalence)Picking a side shows an adaptive decision to avoid running into each other but the choice of either side is insignificant. Doesn't matter which side, just pick one. genetic drift + time + divergence = historical flukes!!!!!!! 8. non-adaptive differences

Modern synthesis

1. phenotype = genotype + environment 2. acquired characteristics are NOT inherited 3. genes do NOT blend 4. ultimate source of variation is MUTATION 5. environmental factors can affect the rate of mutation but not the direction

is there a reason why an animal would even accept a less profitable item?

1. search time 2. core profitability vs profitability when found (energy gain small)/ handling time > (energy gain large)/ (search time + handling time) if the first part is greater you will eat the less profitable item key = abundance of the MORE PROFITABLE ITEM ( dont look at the less profitable item to figure this out at all)

problem with the biological species concept : operational

1. species hard to recognize - short toed and common treecreepers reproductively isolated but look very similar 2.hard to know whether two forms will interbreed 3. species that are allopatric - dont co occur - species are groups of actually or POTENTIALLY interbreeding.....so bring them in in lab - mallard and pintail: in lab these two ducks will mate but not in nature - liger - male lion and female tiger hybrid- very large -kodiak bear -tiger snake mainland vs chappell island - judgement call

two key predictions of OFT

1. the acceptability of a food item depends on the abundance of more profitable food items and is independent of its own abundance 2. as high ranking items become more common, less profitable items will be eliminated from the diet

Evolution by natural selection ( variation, heritability, survival of the fittest )

1. variation: there must be variation that leads to differences in survival and reproduction 2. heritability: variation must be genetically inherited 3. "survival of the fittest" : the ability of an orgnaism to survive and reproduce, the essence of natural selectoin BEst traits with highest fitness will get acquired

FITNESS

1. viability - probability of survival to reproductive age 2. mating success- making viable offspring 3. fecundity - reproductive potential /sexual selection Many traits lead to an increase in one and decrease in another : peacock has high fecundity if it has lots of eye spots on the tail for males, but more eye spots means it is less viable because of predators Bull frog: bigger frog/ deeper call - higher viability and higher fecundity bc a deeper call is more attractive

bears are fussy eaters

Bears are in fact picky eaters as OFT would predict for animals that require a lot of energy prior to hibernation.-They eat a lot of foods because of seasonal abundance not because they are unfussy. We see this perfectly displayed when they eat salmon, only eating the best parts when abundantOverall, the lesson from OFT that we can apply here is that food matters and specifically, optimal or favorite foods matter. Even with a bear who seems to eat everything, threats to favorite foods can/will significantly affect fitness in terms of survival/reproduction or both and put the population in potential peril.

Scientific study of animal behavior - Sumerians

Clay tablets > than 5000 years ago had descriptions of species ( animals doing typical behaviors): 100 bird species, 50 fish species

comparative method

Comparative method (way of gaining evidence for adaptation): if the same trait has evolved in different organisms experiencing similar environments and therefore similar selective pressures, then the correlation between habitat and trait is unlikely to be an accident and instead provides proof that the trait is an adaptation to that environmental situation - convergent evolution between very different species lineages ^ adaptation not aptation Cautions for comparative method : Analogous vs homologous traits- remember looking for independent evolutionary events Analogous: traits that are similar as a consequence of independent events: convergent evolution ***** USED IN COMPARATIVE METHOD Homologous: traits that are similar as a consequence of common ancestry: ONE DATA POINT Looking at the results of nature's experiments Divergent evolution between similar groups : kittiwake and black headed gulls Use comparative method for this example: Kittiwake- no egg shell removal or nest cleaning - no mobbing - because NO ground nesting - not a lot of predation threat Black headed gulls - mobbing - because predation, to protect eggs - egg shell removal ^DIFFERENCES IN BEHAVIOR BC DIFFERENCES IN ENVIRONMENT Convergent evolution between different groups: GULLS and SWALLOWS Diff species in same environmental pressure- colonial nesters with high predation-both will adapt mobbing mechanism looks at analagous traits, not homologous

Ethology vs Comp psych

Ethology (europe) - the biology of behavior of animals, behavior under natural conditions -nature -variety of organisms -nature- genetics (imprinting, honey bee dance, etc... instinctive behaviors) - Ultimate ( asks why?) - OUTSIDE Comp Psych (NA)- comparative studies on the development and causation of behavior of humans - learning and physiological basis -lab -model organisms -nurture - learning (pavlov, stimulus-response, maze boxes, etc.) - Proximate ( asks how?) -INSIDE early comp psych was really interested in understanding humans while ethology was about the animals

foraging- biotic interactions - competition

Red shanks- dig up worms- if they dig up huge worm- they set it down and walk away- it is the best item in terms of nutrients and energy but they discard- they say no bc COMPETITION (biotic interactions ) - seagulls are watching and will steal big worms burn more energy trying to run away from seagulls -interspecific Older individuals and younger individuals hunt differently Older and younger individuals can fight -intraspecific

experimentation example

STUDY: effects of food supplementation on home range size, reproductive success, productivity and recruitment in a small population of iberian lynx - in this study we assess the utility of providing aritificial food to reduce home range size and to increase productivity survival and recruitment in a scenario of low lynx density as compared with reference data from the same population in the absence of extra food. food supplementation produced a significant contraction of core areas, but not of complete lynx HR's --> must be other factors such as refuges, water, mates why would we want to reduce HR size- killing people, better conservation management, also relevant when thinking about captivity how big of a space does an animal need ( food and mates are available in large areas, but if you change these parameters to make them more -mates and food- closely available then the amount of space they need will adapt and change

testing roles of genes in behavior- artificial selection experiments

drosophila mating experiments can selectively breed for fast or slow maters, so if you select for a behavior and the population moves, their must be a genetic underpinning

role of genes in behavior- genetic mutants

drosophila yellow morph - bad dancers -yellow morph of drosophila loses ability to dance bc of one mutant gene- links between morphology and behavior (genetic and functional) Morphological trait - yellow color- causes change in behavior- bad dancer : drosophila Morphology ( color/ look) and behavior coupled - mating behavior : coitus interruptus vs stuck male -both situations caused by gene mutations because usually drosophila mate for 20 minutes -drosophila learning deficiencies -through gene mutations learning disabilities arise- the dunce line also amnesiacs (learn and immediately forget) - fosB gene mutation in rats:- if they have this mutation they dont nurse their own offspring links between morphology and behavior: can be genetic or functional genetic: domesticated dogs have floppy ears and wild dogs have ears that stand up functional: bright tail in lizard to scare away enemies

stabilizing selection

selection against phenotypes that deviate in either direction from the optimal value for a character (eliminates extremes) curve becomes narrower -mean value of trait maintained -decreases variation ( if heritable) -predominant selective force in nature clutch size and parental investment: very specific within species, number of eggs optimal for species eg. weening !!!!! jamaican croaking gecko: big is better but undergoing stabilizing selection - become more vulnerable to predators (owls) stabilizing selection often involves 2 opposing directional selection forces!!! eg selection on different components of fitness: gecko body size- gain territory/ mates (mating success) vs exposure to owls ( viability)

directional selection

selection for a higher or lower value of a character whole curve shifts to the right favor one extreme or the other - mean value of a trait is shifted -selection leads to a response -NO change in variance predominant force for evolutionary change aspects of male fitness: multiple aspects of male fitness operated together - mate acquisition - larger bigger chest cavity/ deeper call =more mates -egg laying - hes the caregiver -egg/juvenile survival - bigger size better for protecting offspring BULL FROG - big boy

disruptive selection

selection for two or more modal phenotypes and against those intermediate between them - pushes graph out and near the ends - starts to flatted curve to the ends - soft disruptive selection -if its strong leads to a binodal phenotypes ( two peaks) -important for speciation eg. african seed cracker Morphs were found to have divergent diets and feeding efficiencies on their principal food, sedge seeds (Scleria), with small-billed birds specializing on softer-seeded species than the large-billed birds (two extremes small bills and big bills) The seedcracker is now considered a textbook example of disruptive selection in the wild in which intraspecific niche partitioning has arisen through a single trait polymorphism. -increases variation if heritable -mean value of trait may not change

oscillating selection

selection reverses directions regularly medium ground finch: depending on rainfall selects for small/large seeds drought --> big seeds more abundant --> absorb moisture --> develop bigger beaks kind of looks like stabilizing selection but it isnt - it is more directional ( in the short term looks directional)

frequency dependent selection

selection that changes through time - fitness depends on phenotype frequency when the selective value of an allele is affected by its frequency within the population - negative : common form at a disadvantage 1. predator search images - for cryptic prey - look for common pattern, especially for camouflage lizards - predators will prey on patterns/ tones/ colors most common - if you have a rare color there is a reduced chance u get eaten 2. differences in resource use 3. rare male advantage positive (common form has advantage): 1. predators notice different individuals - select the ones that stick out 2. warning -aposematic- coloration ( monarch ) - mullerian (both poisonous) vs batesian mimicry (one poisonous) *** Natural selection may favor non-poisonous butterflies that have the same color pattern as poisonous butterflies. This system is called Batesian mimicry. When they are rare, birds will tend to avoid the mimics, because they will have already have encountered a poisonous butterfly of the same appearance. But when the non-poisonous type is common, the previous encounters of birds with butterflies of their appearance are more likely to have been rewarding; the birds will not avoid eating them, and their fitness will be lower. The fitness of the mimics is negatively frequency-dependent. ut with negatively frequency-dependent fitnesses (as in Batesian mimicry), it is possible for natural selection to maintain a polymorphism. When a genotype is rare, it is relatively favored by selection and it will increase in frequency; as it becomes more common, its fitness decreases and there may come a point at which it is no longer favored. At that point, the fitnesses of the different genotypes are equal and natural selection will not alter their frequencies: they are at equilibrium. The sex ratio is another case in which selection is frequency-dependent.