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58 Pages

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BIOL 1000
Nicole Nivillac

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LIGHT AND LIFE 9102012 62300 AM Evolution of EyesOrganisms from the same family but more complex eyes for eachRole of Light in Ecology and BehaviourOur planet we have diff environments darkness to bright environmentsOrganisms that live there have to adapt o Adapting to colouration o Circadian Rhythm CamouflageCircadian RhythmsBiological clockBehavioural patterns Circaaround DiemdayCR is the behavioural pattern within a organism of a 24hr time rangeControlled by an internalendogenousnatural clockCR is a clock set by the photoreceptors you use according to light and dark o Eg Jet LagIf your on Canadian time and your on European clock sleeping schedule is not rightBecause body is set to a certain time to wake up and sleep o Birds hibernating in winter and return in summerBirds know the time of yearThey know the weather and know when to fly backBirds have a daily cycle as well as yearly cycles while humans are 24hr clock onlyKeeping track is important because they give a lot of info o Plants are efficient because they make there enzymes at night because they can absorb the energy during the dayThey must do max photosynthesis during the dayDNA SYNTHESIS we do it during the evening o Less risk to be damaged o When we walk in the sun it gets damaged so we do it during the day How does it work CRClock is found in superchiasmatic nucleus of brain o Light hits retina o Gets photoreceptors o Goes through optic nerve cells to the brain o Sets biological clock in SCN o Regulates other processes in body o Also creates melatonin which is important in a humanSome ppl need to take synthetic melatonin Melatonin production depends on the BIO CLOCK o PLANTSLeaves are usually straight out during the dayAt night the leaves drop so the save energy ARCTIC circle people are exposed to artificial light o Ppl who live in the dark affects other issues o The light helps with certain hormones and people may becomes depressedsuicidal Blind Mole RateStill have photoreceptors so still can use natural light to set biological clockSame applies for blind peopleOther factors help sounds outside tempAvoiding Detection CamouflageHelps disguise the animal from its predatorBlends in with its backround PEPPERED MOTHFactories came up and trees were covered with sutLight coloured moths were seen because sut was blackLater on black moths were eaten and lighter sut was there Predator must camouflage as well or prey might run awayUsing Colour as SignalsEg Skunks stripedSnakes make a sound to warn ColourUse colours to hide attract warnColourful Warning ExamplesColours are there for other organisms NOT usOrganisms use this to surviveFlower colourPollinatorFlowers must be attractive for other organisms to come and pollinate itBirds pollinating flowers are usually red yellowBeetles small whitish or greenPerception that we see is different from what organisms see o This is called COEVUALUTION2 organisms evolvetrace simultaneously evolveadaptthose adaptions allow them to interact closely with each otherLight in Aquatic HabitatsIf you go deeper into the ocean red light cannot go that farMore at the surface its brighter and wavlengths are able to penetrate through the waterFish in the deep water have silver bellies and black backs because they try to camouflage from the top they look like the bottom and bottom up and they blend in with the lightLight PenetrationOrganisms at the surface better eyes and can see more coloursBottom ocean organisms have less developed eyes Organisms always have what they need
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