Presentation on theme: "What is Evolution? AND Evolution explains BOTH"— Presentation transcript:
1 What is Evolution? AND Evolution explains BOTH changes in living organisms and their genes over timeWe KNOW based on evidence and observationsexplains how modern organisms have descended from ancient organismsEvolution explains BOTHunity of life - similarities between all living thingsANDdiversity of life - wide variety of different creatures on Earth
2 UNITY: All creatures have common characteristics How did we get GRSNERRT?DNA – codes for _______________Proteins are made of _______________Amino acids are coded for by ________The 3 bases are called _________Codons are translated using the “Universal” code - works for ALL living things!!!!!!!Determines ADAPTATIONS
3 determines Adaptations DIVERSITY - variation BOTH within a population and the wide variety of living things (remember classification – 6 Kingdoms)Sexual ReproductionTwo parents contributing genesIn Meiosis – crossing overNew combinations of parents genesMutation, mutation, mutationsometimes beneficial -determines Adaptations
4 AdaptationsTraits that help an individual survive – may not know it’s beneficialPhysical – color, structureBehavioral – instincts, courtshipBiochemical/physiological – enzymes, sweating, internal characteristicsBorn with adaptations – are NOT chosenGENES determine adaptations (remember genotype determines phenotype)
5 Adaptations NO organisms BECOME adapted They are either born adapted or they are not.
6 What determines survival? Natural Selectiontraits that help individuals survivesurvive predatorssurvive diseasecompete for foodcompete for territorytraits that help individuals reproduceattracting a matecompete for nesting sitessuccessfully raise youngAdaptationsSurvival & Reproduction of the Fittest
7 Earlier ideas on Evolution LaMarckevolution by acquired traitscreatures developed traits during their lifetimegive those traits to their offspringexamplein reaching higher leaves giraffes stretch their necks & give the acquired longer neck to offspringnot accepted as valid
8 Charles Darwin Proposed a way how evolution works 1809-1882 British naturalistVoyage of the HMS BeagleStopped in the Galapagos IslandsProposed a way how evolution worksnatural selectionWhat did Darwin say?What evidence supports Evolution by Natural Selection?What impact did Evolution have on biology?
9 Voyage of the HMS Beagle Stopped in Galapagos Islands500 miles off coast of EcuadorThe origin of the fauna of the Galapagos, 900 km west of the South American coast, especially puzzled Darwin.On further study after his voyage, Darwin noted that while most of the animal species on the Galapagos lived nowhere else, they resembled species living on the South American mainland.It seemed that the islands had been colonized by plants and animals from the mainland that had then diversified on the different islands
10 Darwin found: many unique species Different shells on tortoises on different islandsDarwin asked:Is there a relationship between the environment & what an animal looks like?
11 The finches cinched it! different beaks are inherited variations serve as adaptations that help birds compete for foodthese birds survive & reproducepass on the genes for those more fit beaksover time nature selected for different species with different beaksDarwin found:The differences between species of finches were associated with the different food they ate.Finch?Sparrow?Woodpecker?Warbler?Darwin said:Ahaaaa! A flock of South American finches were stranded on the Galapagos…Large ground finchBig seed eaterSmall ground finchSmall seed eaterInsect eaterWarbler finchLeaf & bud eaterTree finch
12 Darwin’s finches Darwin’s conclusions variations in beaks differences in beaks in the original flockadaptations to foods available on islandsnatural selection for most fitover many generations, the finches were selected for specific beaks & behaviorsoffspring inherit successful traitsaccumulation of winning traits: both beaks & behaviorsseparate into different species(speciation)
13 Modern Natural Selection Overproduction – not all offspring will surviveVariation – (3 sources) differences in adaptations (3 types)Competition – “struggle for survival”Environment (nature) determines which adaptations are the “fittest”Best adapted survive and reproduce – pass on the “fit” genes to next generationThe gene pool changes = EVOLUTION – Not the individual
14 3 Types of Selection 1. Stabilizing 2. Directional 3. Disruptive Niche – organism’s role or “job” in an ecosystemex: predator/prey, habitat, relationships with other organisms, when it is “active”ONLY ONE (1) species may occupy a niche at a time - total overlap results in “extinction” of the less fit from that ecosystem
15 Stabilizing Selection Favors the average – decreases variationExtremes are selected againstExample – spiders - too big: can be easily seen by predators; too small: can’t compete for web building sites
16 Directional Selection Favors one extreme or the otherExample – finch beaks – small or large food; also peppered moths
17 Witness to Evolution Peppered Moth 2 types: dark vs. light light
18 Peppered moth Why did the population change? early 1800s = pre-industrial Englandlow pollutionlichen on trees = light colored barklate 1800s = industrialfactories = soot coated treeskilled lichen = dark colored barkmid 1900s = pollution controlsclean air lawsreturn of lichen = light colored bark
19 Disruptive Selection Favors BOTH extremes at the same time Leads to speciation – two separate species forming to fill different nichesONLY one species can occupy a given niche in an ecosystem (increased competition leads to narrower niches)
21 Other Evidence supporting evolution 1. Fossil recordshows change over time2. Anatomical recordcomparing body structureshomology & vestigial structuresembryology & development3. Molecular recordcomparing protein & DNA sequences4. Artificial selectionhuman caused evolution
22 → supports the idea of a common ancestor Types: 1. Fossil recordLayers of rock contain fossilsnew layers cover older onescreates a record over timefossils show a series of organisms have lived on EarthLink between birds and reptilesLink between land and sea animals→ supports the idea of a common ancestorTypes:
23 What do we know?Creatures have changed over timeFossil Record
24 2. Homologous structures Structures that come from the same originhomo- = same-logous = informationForelimbs of human, cats, whales, & batssame structureon the insidesame development in embryodifferent functionson the outsideevidence of common ancestor
25 2. Anatomical strucures The same bones under the skin limbs that perform different functions are built from the same bones
26 Vestigial organs Structures on modern animals that have no function remains of structures that were functional in ancestorsevidence of change over timesome snakes & whales have pelvis bones & leg bones of walking ancestorseyes on blind cave fishhuman tail bone
27 Human vestigial organs 2. t________ b_______3. w_______ t_________No longer have a function or are necessary – may have had a function at one time
28 Comparative embryology Development of embryo tells an evolutionary storysimilar structures during developmentall vertebrate embryos have a “gill pouch” at one stage of development
31 Video – Evolution in Action – Silver Foxes 4. Artificial selectionWe know natural selection can change a population?we can recreate a similar process“evolution by human selection”“descendants”of the wolfHumans create the change over timeVideo – Evolution in Action – Silver Foxes
32 But don’t be fooled by these… Analogous structureslook similaron the outsidesame functiondifferent structure & developmenton the insidedifferent originno evolutionary relationshipSolving a similar problem with a similar solution
33 Convergent evolution led to mimicry Why do these pairs look so similar?Monarch malepoisonousViceroy maleedibleWhich is the moth vs. the bee?Which is the fly vs. the bee?flybeemothbee
34 For examples of Natural Selection – 1. ID variation in the population2. ID type of variation (adaptation)3. ID source of variation4. ID selecting agent (e___________)5. individuals with advantageous variations – survive;6. THEN they get to reproduce7. State which variation increases and which variation decreases
35 Artificial Selection gone bad! Unexpected and often dangerous consequences of artificial selectionAntibiotic resistanceBacteriaPesticide(and herbicide)resistanceInsectsAndWeeds
37 Insecticide resistance Spray the field, but…insecticide didn’t kill all individualsvariationInsecticide did NOT cause the resistance – it’s the selecting agentresistant survivors reproduceresistance is inheritedinsecticide becomes less & less effectiveThe evolution of resistance to insecticides in hundreds of insect species is a classic example of natural selection in action.The results of application of new insecticide are typically encouraging, killing 99% of the insects.However, the effectiveness of the insecticide becomes less effective in subsequent applications. The few survivors from the early applications of the insecticide are those insects with genes that enable them to resist the chemical attack. Only these resistant individuals reproduce, passing on their resistance to their offspring. In each generation the % of insecticide-resistant individuals increases.
40 REVIEW - Evidence of Evolution 1. Fossils2. Comparative Anatomyh______________ structuresv____________e________________3. Comparative Biochemistry________ and p___________4. Artificial Selectionb________________i____________ and a_______________
41 Time Frame for Evolution Punctuated EquilibriumPeriods of stability followed by periods of rapid change (speciation) OR extinction due to rapidly changing environmentAdaptations must already exist in population
42 Time Frame for Evolution GradualismSlow, continual change due to a more stable environment
43 Recent or nowSpeciesAlive todayExtinctPeriod ofstabilityChange in environmentCommon AncestorOldest
44 Evolutionary Time Frame Evolution is caused by changes in the environmentNatural – caused by natureArtificial – caused by humansEx: pesticide and antibioticsEvolution is faster with organisms with short life cycles AND lots of offspringExamples – insects and bacteria
45 Natural Selection - Summary Adaptations – 3 types: p_________, b________, ph________________Born with – determined by genesVariation – 3 sources: s____, c_______ o____, m________; NOT e___________Competition – struggle for resources (food, shelter, mates) to s_________________“Fittest” or best adapted are selected for by s___________ a_________ in the e_______________If “fit” – reproduce and pass on g______Gene pool evolves (NOT the individual) from selection – 3 types: s___________, d_____________, d____________
46 Summary – One more time WAY too many offspring are produced 1. Overproduction –WAY too many offspring are produced2. Variation –3 sources -Adaptations – DO NOT get to Choose3 types -
47 Summary - Continued That is EVOLUTION!!!!! 3. Selection – selecting agentNatural – environmentArtificial – human→ “fittest” survive4. ReproductionPass on “fit” genes→Over time “fit” genes increase→ gene pool of a population changesThat is EVOLUTION!!!!!
48 Study Guide Vocab, vocab, vocab!!!!!!! Evolution – unity and diversity – p.___Darwin – Galapagos – p.____Natural Selection – p. ____OverproductionVariation in adaptations – 3 types, 3 sourcesCompetitionSurvival of fittest – 3 types of selection – p._Evidence of Evolution – 4 pieces – p. ____Time Frame for Evolution – 3 theories – p. ____
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