adaptationMonday, November 9, 20152:58 PM Product of evolution by natural selectionAn organism becomes adapted to environment by natural selectionTrait or feature that increases fitness of organism in environmentBetter fitness in environment Adaptation to the abiotic environmentTwo aspects of environmentAbiotic environment Without biologyNon living partSuch features as temperature, rainfallPhysical conditions of one sort or anotherSelection occur to conditions due to this aspect of the environmentCold environmentMammals with long fur - adaptation to cold environment - survive longerLong fur - adaptation to long environment Biotic component of environmentLiving part of environmentOther living thingsCan fall in 2 general categoriesNot members of your own speciesAre members of your own speciesAdaptations are rather different Other species in environment - Species don't affect you in any way - no selection pressure to adapt to another species out there that doesn't affect youSpecies competetors - eating same food your eatingPredators of yours - want to eat youOther species - mutualists - engage in positive interaction with youPlants and polinators - mutualistic relationshiAdaptations between plants and polinators that deal with that interactionCamoflauge in insectsPeppered moth case Peppered and black form of mothMoth camoflauge in environmentDeal with another species - birdsMembers of own species - For example - most of the interactions with members of your own species that is important has to do with attracting and keeping matesSexual selection - involves adaptations associated with aquiring and keeping mateAntlers on male deer (bucks) are an adaptation for fighting other males to win mates

Selection and adaptation related to other speciesAdapting to abiotic - non living Any adaptation - longer furDoesn't change abiotic environmentStill as coldBut changes better able to survive in that environmentDifferent case when environment is naother speciesDynamic evolving entityPreditor prey interactionOne is predator one is prayPreditor and pray adapting to each otherEach can be changingPray evolved to run fasterSelection on predators to run even faster to keep up with preySituations as co evolution2 species predator and prey co-evolving so change in one brings about a change in the other as well Aspects - members of own speciesSexual selectionNo difference than natural selectionSelection on features associated with aquiring matesLook at how animals aquire matesOne things we seeFemales choose males to mate withIn other cases males fight with each other - whoever wins gets right to femalesIn humans - unclear which it isLook at some examples of mating systems and what products those are in sexual selectionFemales choose what male to mate withOften time result of sexual selection are ornamentsMales in this context to be chosen by femalesMale cosen by female - genes passed on to next generationNothing attractive about him - no mate and genes don't get passed onFemales choose malesMales have a lot of ornamentation - male peacockHas giant feathery array that he displays and walks around attracting attention of females and females mate with himContrast this with where males fight with each otherAdaptations that result are not ornaments - armamentsWin fights with malesThose sorts of features selected for themAnimal - elephant sealMale elephent seal rearing up Females around himMale 4 times as largeWhere mating system worksBull elephant seals fight with each otherAnd male wins fight

Has harum of females he mates withSee in these male elephant sealsHave protruding canine teeth - rake foesSee that there is trunk like thing on elephant sealMale has but tno femaleElongated nose that elephant seal blow into to make trumpet sound - similar to elephantUsed as context of fightingFemales choose males or males fightSexual dimorphismMales and females look differentBird species

Similar kinds of environmentsProduce similar types of organismsConvergent evolutionBody shape and fins of shark dolphins and penguinesPlants in african deserts that look like the cacti of american deserts

One things you notice - look at body shape of all three - have basically submarine type of shape

Narrow at frontBroad in betweenNarrow at backParticular shape is very useful for moving through water in efficient wayBlunt front - resistance through waterSubmarines have same shape - engineers found out best way to move through water without dragPorpose and shark - fin on top to stabalizeNot really closely related at allShark - fishPenguine - birdPorpose - mammal Body shape and fin - not features because they share common ancestorFeatures they evolved independently because particular environment selected features that allow them to move through that environment in efficient way

Stem part - green often time spines on themIf we then went to deserts in africa - those are cacti - same as cactus in africaLook very similarIn fact these plants not related at allDifferent plant familiesReason they look alike Not share common ancesterBut look that way because they live in desert environmentsSelection pressures on organismAdaptations very similarOne of features of adaptationIn desert - dry and hotHow they conserve moistureVery easy to lose moisture through leavesThey lsot their leavesDon’t photosynthesis through leavesCuts down on losing waterVery suculant and if they didn't have thorns ainmal would eat them Nature of adaptations

Organisms adapted to environmentsShouldn't imagine adaptation is perfectOrganisms can only adapt in ways that are possible for themDon't see animals with wheels - not within realm of posibilitiesSee when we look at themLook more like contraptions than elegantly designed deviceAdaptations and see how they were built from bits and pieces of things that organisms already haveMiddle ear bones of mammals

These bones very important for transmitting sound into inner ear and signals sent to brainNot know names of bonesConnects with ear drumSounds come in and hits ear drumEar drum vibratesAnd bone movesHitched to next boneAlso movesAnd hinged to next bone and that also movesCreates movement in fluid in inner earAnd movement of fluid movess little air cells in inner earAnd sends off singals to the brain and we interpret that as soundWhere do earbones come fromPretty good record how they came to be involved in hearingGo back and look at fossilsReptiles to mammalsIn course see changes in skull that create these earbonesBones already present in reptile jawJust modified to become middle ear bonesUpperleftReptilian jawOn right - color code for types of bones in jawReptiles - difficulty eatingCan't chew and tear it upSnakes can't chew - swallow whole

Adaptations in mammalsDevelopment of muscular and bigger lower jawIn course - little bones - yellow and green - hinging of reptile jaw - not hinging of mammal jawLittle bones lying around - at that point that these bones further evolved to become part of hearing aparatusContraptionPieces of what was already thereNot being used anymoreAnd therefore taken over and used for different purpose (for hearing)Ear bones - birds - constructed in different wayHear better than animalsBones built from available materials Certain compromises involvedCan't be good at everythingGood at one thing - not good at antoherTail length in male birdsNumber of speciesLong tails very attractiveSexual selectionMales have longer tails than other tales choosen by femalesToo long - can be detrament - difficult to fly vulnerable to other speciesCompromise selection for to find mate and against long tale for how it can flyVery long tale - mating displays - featured prominantlyFemale - has long tails but not near as long as maleExperiments with other speciesLengthened tale - those birds very attractive to females but downside to having long tail and can't fly as well Feathers on birdsImportant for flightBut think about how we could have evolved from something without feathers to something with feathersDifficult to see how this could evolvedEvolution of feathersNot feathers like todaySomething small and feather like - not useful for flyingEvolution of feathers - differentDidn't evolve for flightProbably evolved for keeping - reptile warmFeathers serve that function today for birdsDown blankets and pillowsInsulating properties of feathersProducts in china Reptile group related to birdsSmall feathers used for keeping warm and not of any value involved in flightOnce this adaptation occursOnce they are formed and evolved for purposes of that

Once they get large enough - now have for coasting or glidingFurther selection to improve that adaptation to improve flightExamptationFeathersNot evolved for flight but for something else and taken over and used for flightThink about organisms evolving we know that natural selection works on recombinations of genetic traitsAnd sometimes when we think about thisThink well what can selection really do to take organism down new pathwayThink of something that sorts out stuff already there and puts it together in other waysHow do we get something completely differentSome of these changes come about through mutationsTo get some changes you need to have lots of mutations or possible to get mutations on few or one gene to produce novel feature in organismDifferent kinds of genesHair is blond or brown or blackSuperficial genes - structural genesGenes - regulatory genesInvolved in developmentTurn on and turn off at certain periods of time

Right hand side - see at top - skull of adult chimpOn bottomSkull of adult humanSee there are significant differences in shapes of skullsChimp skullMutch bigger skull relative to brain case sizeHuman - larger brain case size relative to largeHow did this things come aboutGenes involved in creating different skull shapeLook at chimp and human baby skullSkulls very siilarHard pressed to know if it was from chimp or humanDuring course of development in chimpPortions that grow quite a bit - lower jaw brain area doesn't grow much at all

Human infant skull compared to adultSee that basically all portions of skull grow about same amountGreater growth in jaw area but rest doesn't grow much at allHow much each part of skull changed over timeWhat's responsible for these changes?Appears that just a few genes involved in these differencesIn chimps going from baby to adultGenes that turn on to allow jaw to growIn human those aren't turned on for that long of timeHuman adult skull blown up version of baby skullAdult chimp different than baby chimp skullChanges occur over short - hundreds or thousands of years - short timePeppered moth