What is Evolution?

1. What is Evolution? • changes in living organisms and their genes over time • We KNOW based on evidence and observations • explains how modern organisms have descended from ancient organisms • Evolution explains BOTH • unity of life - similarities between all living things • AND • diversity 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. DIVERSITY - variation BOTH within a population and the wide variety of living things (remember classification – 6 Kingdoms) • Sexual Reproduction • Two parents contributing genes • In Meiosis – crossing over • New combinations of parents genes • Mutation, mutation, mutation • sometimes beneficial - determines Adaptations

4. Adaptations • Traits that help an individual survive – may not know it’s beneficial • Physical – color, structure • Behavioral – instincts, courtship • Biochemical/physiological – enzymes, sweating, internal characteristics • Born with adaptations – are NOT chosen • GENES 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 Selection • traits that help individuals survive • survive predators • survive disease • compete for food • compete for territory • traits that help individuals reproduce • attracting a mate • compete for nesting sites • successfully raise young Adaptations Survival & Reproduction of the Fittest

7. Earlier ideas on Evolution • LaMarck • evolution by acquired traits • creatures developed traits during their lifetime • give those traits to their offspring • example • in reaching higher leaves giraffes stretch their necks & give the acquired longer neck to offspring • not accepted as valid

8. Charles Darwin • 1809-1882 • British naturalist • Voyage of the HMS Beagle • Stopped in the Galapagos Islands • Proposed a way how evolution works • natural selection

9. Voyage of the HMS Beagle • Stopped in Galapagos Islands • 500 miles off coast of Ecuador

10. Darwin found: many unique species Different shells on tortoises on different islands Darwin asked: Is there a relationship between the environment & what an animal looks like?

11. Finch? Sparrow? Warbler? Woodpecker? The finches cinched it! • different beaks are inherited variations • serve as adaptationsthat help birds compete for food • these birds survive & reproduce • pass on the genes for those more fit beaks • over time nature selected for different species with different beaks Darwin found: The differences between species of finches were associated with the different food they ate. Darwin said: Ahaaaa! A flock of South American finches were stranded on the Galapagos… Large ground finch Big seed eater Small ground finch Small seed eater Warbler finch Insect eater Tree finch Leaf & bud eater

12. Darwin’s finches • Darwin’s conclusions • variations in beaks • differences in beaks in the original flock • adaptations to foods available on islands • natural selection for most fit • over many generations, the finches were selected for specific beaks & behaviors • offspring inherit successful traits • accumulation of winning traits:both beaks & behaviors • separate into different species(speciation)

13. Modern Natural Selection • Overproduction – not all offspring will survive • Variation – (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 generation • The 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 ecosystem ex: 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 variation • Extremes are selected against • Example – 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 other • Example – finch beaks – small or large food; also peppered moths

17. Witness to Evolution • Peppered Moth • 2 types: dark vs. light light Peppered moth

18. Peppered moth • Why did the population change? • early 1800s = pre-industrial England • low pollution • lichen on trees = light colored bark • late 1800s = industrial • factories = soot coated trees • killed lichen = dark colored bark • mid 1900s = pollution controls • clean air laws • return 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 niches • ONLY one species can occupy a given niche in an ecosystem (increased competition leads to narrower niches)

20. Relationship between species (beaks) & food

21. Other Evidence supporting evolution • 1. Fossil record • shows change over time • 2. Anatomical record • comparing body structures • homology & vestigial structures • embryology & development • 3. Molecular record • comparing protein & DNA sequences • 4. Artificial selection • human caused evolution

22. 1. Fossil record • Layers of rock contain fossils • new layers cover older ones • creates a record over time • fossils show a series of organisms have lived on Earth • Link between birds and reptiles • Link between land and sea animals • → supports the idea of a common ancestor • Types:

23. What do we know? • Creatures have changed over time Fossil Record

24. 2. Homologous structures • Structures that come from the same origin • homo- = same • -logous = information • Forelimbs of human, cats, whales, & bats • same structure • on the inside • same development in embryo • different functions • on the outside • evidence 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 ancestors • evidence of change over time • some snakes & whales have pelvis bones & leg bones of walking ancestors • eyes on blind cave fish • human tail bone

27. Human vestigial organs • 1. a_________________ • 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 story • similar structures during development all vertebrate embryos have a “gill pouch” at one stage of development

31. 4. Artificial selection • We know natural selection can change a population? • we can recreate a similar process • “evolution by human selection” “descendants” of the wolf Humans create the change over time Video – Evolution in Action – Silver Foxes

32. But don’t be fooled by these… • Analogous structures • look similar • on the outside • same function • different structure & development • on the inside • different origin • no evolutionary relationship Solving a similar problem with a similar solution

33. Convergent evolution led to mimicry • Why do these pairs look so similar? Monarch male poisonous Viceroy male edible Which is the moth vs. the bee? Which is the fly vs. the bee? fly bee moth bee

34. For examples of Natural Selection – 1. ID variation in the population 2. ID type of variation (adaptation) 3. ID source of variation 4. ID selecting agent (e___________) 5. individuals with advantageous variations – survive; 6. THEN they get to reproduce 7. State which variation increases and which variation decreases

35. Artificial Selection gone bad! • Unexpected and often dangerous consequences of artificial selection Antibiotic resistance Bacteria Pesticide (and herbicide) resistance Insects And Weeds

37. Insecticide resistance • Spray the field, but… • insecticide didn’t kill all individuals • variation Insecticide did NOT cause the resistance – it’s the selecting agent • resistant survivors reproduce • resistance is inherited • insecticide becomes less & less effective

39. Antibiotic Resistance

40. REVIEW - Evidence of Evolution • 1. Fossils • 2. Comparative Anatomy • h______________ structures • v____________ • e________________ • 3. Comparative Biochemistry • ________ and p___________ • 4. Artificial Selection • b________________ • i____________ and a_______________

41. Time Frame for Evolution • Punctuated Equilibrium • Periods of stability followed by periods of rapid change (speciation) OR extinction due to rapidly changing environment • Adaptations must already exist in population

42. Time Frame for Evolution • Gradualism • Slow, continual change due to a more stable environment

43. Recent or now Species Alive today Extinct Period of stability Change in environment Oldest Common Ancestor

44. Evolutionary Time Frame • Evolution is caused by changes in the environment • Natural – caused by nature • Artificial – caused by humans • Ex: pesticide and antibiotics • Evolution is faster with organisms with short life cycles AND lots of offspring • Examples – insects and bacteria

45. Natural Selection - Summary • Adaptations – 3 types: p_________, b________, ph________________ • Born with – determined by genes • Variation – 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 • 1. Overproduction – • WAY too many offspring are produced • 2. Variation – • 3 sources - • Adaptations – DO NOT get to Choose • 3 types -

47. Summary - Continued • 3. Selection – selecting agent • Natural – environment • Artificial – human • → “fittest” survive • 4. Reproduction • Pass on “fit” genes →Over time “fit” genes increase → gene pool of a population changes That is EVOLUTION!!!!!

48. Study Guide Vocab, vocab, vocab!!!!!!! Evolution – unity and diversity – p.___ Darwin – Galapagos – p.____ Natural Selection – p. ____ Overproduction Variation in adaptations – 3 types, 3 sources Competition Survival of fittest – 3 types of selection – p._ Evidence of Evolution – 4 pieces – p. ____ Time Frame for Evolution – 3 theories – p. ____