Regents Biology

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

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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!!!!!!!

UNITY: All creatures have common characteristics

Determines ADAPTATIONS

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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 genesMutation, mutation, mutation

sometimes beneficial -

determines Adaptations

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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)

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AdaptationsNO organisms BECOME adaptedThey are either born adapted or they are not.

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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

Survival & Reproduction of the Fittest

Adaptations

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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

Earlier ideas on Evolution

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Charles Darwin 1809-1882 British naturalist Voyage of the HMS Beagle Stopped in the

Galapagos Islands Proposed a way how

evolution works natural selection

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Voyage of the HMS Beagle Stopped in Galapagos Islands

500 miles off coast of Ecuador

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Darwin found: many unique speciesDifferent shells on tortoises on different islands

Darwin asked:Is there a relationship

between the environment & what an animal

looks like?

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QuickTime™ and aPhoto - JPEG decompressor

are needed to see this picture.

Finch? Sparrow?

Woodpecker? Warbler?

The finches cinched it!

Large ground finch

Small ground finch

Warbler finch Tree finch

Big seed eater Small seed eater

Insect eater Leaf & bud eater

Darwin said:Ahaaaa!

A flock of South American finches

were stranded on the Galapagos…

Darwin found: The differences between species of finches were associated with the different food they ate.

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

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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)

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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 generationThe gene pool changes =

EVOLUTION – Not the individual

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3 Types of Selection 1. Stabilizing 2. Directional 3. DisruptiveNiche – 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

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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

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Directional Selection

Favors one extreme or the other Example – finch beaks – small or large

food; also peppered moths

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Witness to Evolution Peppered Moth

2 types: dark vs. light

Peppered moth

light

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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

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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)

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Relationship between species (beaks) & food

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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

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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:

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What do we know? Creatures have changed over time

Fossil Record

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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

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2. Anatomical strucures The same bones under the skin

limbs that perform different functions are built from the same bones

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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

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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

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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

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3. Biochemical Evidence Compare DNA base sequences and

chromosome banding patterns

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3. Biochemical Evidence Compare amino acid sequences and 3-D

structure in proteinsnumber of amino acids different from human 1

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We know natural selection can change a population? we can recreate a similar process “evolution by human selection”

4. Artificial selection

Humans create the change over time

“descendants” of the wolf

Video – Evolution in Action – Silver

Foxes

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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

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Convergent evolution led to mimicry Why do these pairs look so similar?

Monarch malepoisonous

Viceroy maleedible

fly bee moth bee

Which is the fly vs. the bee?Which is the moth vs. the bee?

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For examples of Natural Selection –

1. ID variation in the population2. 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 reproduce7. State which variation increases and

which variation decreases

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Artificial Selection gone bad! Unexpected and often dangerous

consequences of artificial selection

Antibiotic resistance

Pesticide (and herbicide)

resistance

Bacteria

InsectsAnd

Weeds

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Insecticide resistance Spray the field, but…

insecticide didn’t kill all individualsvariation

Insecticide did NOT cause the resistance – it’s the selecting agent

resistant survivors reproduceresistance is inherited insecticide becomes less & less

effective

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Antibiotic Resistance

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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_______________

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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

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Time Frame for Evolution Gradualism

Slow, continual change due to a more stable environment

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Current Theory

Oldest

Recent or nowSpecies

Alive today

Extinct

Period ofstability

Change in environment

Common Ancestor

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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

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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____________

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Summary – One more time 1. Overproduction –

WAY too many offspring are produced

2. Variation – 3 sources - Adaptations – DO NOT get to Choose

3 types -

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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 changesThat is EVOLUTION!!!!!

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Study GuideVocab, 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. ____