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
Regents Biology


UNITY:
All creatures have common characteristics
How did we get G R SNERRT?

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
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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 genes

 sometimes beneficial -
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
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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What determines survival?

Natural Selection
 traits that help individuals survive
 survive predators
 survive disease
 compete for food
 compete for territory
Adaptations
 traits that help individuals reproduce
 attracting a mate
 compete for nesting sites
 successfully raise young

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
Regents Biology

Charles Darwin

1809-1882

British naturalist

Voyage of the HMS Beagle

Stopped in the
Galapagos Islands

Proposed a way how evolution works
 natural selection
Regents Biology

Voyage of the HMS Beagle

Stopped in Galapagos Islands

500 miles off coast of Ecuador
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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?
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The finches cinched it!
 different beaks are
Darwin found: inherited variations
The differences
 serve as adaptations between species of finches were associated with the different food they
 ate.

 for food
Ahaaaa!
A flock of South reproduce
QuickTime™ and a
Photo - JPEG decompressor
American finches are needed to see this picture.
finch were stranded on the
Galapagos… over time nature selected for different species with different beaks
Regents Biology

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)
Regents Biology


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


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
Regents Biology

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
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Peppered moth

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

Regents Biology return of lichen = light colored bark

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
Regents Biology

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
Regents Biology

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
Regents Biology

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

3. Biochemical Evidence

Compare amino acid sequences and 3-D structure in proteins number of amino acids different from human 1
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4. Artificial selection

We know natural selection can change a population?
 we can recreate a similar process

“evolution by human selection”
Humans create the change over time
“descendants” of the wolf
Video – Evolution in Action – Silver
Foxes
Regents Biology

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

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

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
Regents Biology

Artificial Selection gone bad!

Unexpected and often dangerous consequences of artificial selection
Antibiotic resistance Bacteria
Pesticide
(and herbicide) resistance
Insects
And
Weeds
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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
Regents Biology

Regents Biology

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
Regents Biology

Time Frame for Evolution

Gradualism

Slow, continual change due to a more stable environment
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Species
Alive today
Extinct
Period of stability
Change in environment
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Common Ancestor
Recent or now
Oldest

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
Regents Biology

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 changes
That is EVOLUTION!!!!!
Regents Biology

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. ____
Regents Biology