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What is Evolution? AND Evolution explains BOTH

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1 What is Evolution? AND Evolution explains BOTH
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 determines Adaptations
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 Proposed a way how evolution works 1809-1882
British naturalist Voyage of the HMS Beagle Stopped in the Galapagos Islands Proposed a way how evolution works natural selection What 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 Islands 500 miles off coast of Ecuador The 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 islands Darwin 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 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. Finch? Sparrow? Woodpecker? Warbler? 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 Insect eater Warbler finch Leaf & bud eater Tree finch

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

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 → supports the idea of a common ancestor Types:
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
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 Video – Evolution in Action – Silver Foxes
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 The 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.


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 Common Ancestor Oldest

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 WAY too many offspring are produced
1. Overproduction – WAY too many offspring are produced 2. Variation – 3 sources - Adaptations – DO NOT get to Choose 3 types -

47 Summary - Continued That is EVOLUTION!!!!!
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. ____

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