Unit V - Unit V - EvolutionEvolution

I. Scientific Theories – Laws – I. Scientific Theories – Laws – Facts - Facts - HypothesisHypothesis

A. A. FactFact – in science, an – in science, an observation that has been observation that has been repeatedly confirmedrepeatedly confirmed

1. i.e. objects fall when 1. i.e. objects fall when droppeddropped

2. i.e. humans have 46 2. i.e. humans have 46 chromosomeschromosomes

B. B. HypothesisHypothesis

1. a testable statement about 1. a testable statement about the the natural world that can be natural world that can be used to used to build more complex build more complex inferences and inferences and explanationsexplanations

2. “IF…THEN…”2. “IF…THEN…”

C. C. LawLaw

1. a descriptive generalization 1. a descriptive generalization about how some aspect of the about how some aspect of the natural world behaves under natural world behaves under stated circumstancesstated circumstances

2. i.e. the path of each planet 2. i.e. the path of each planet around the sun is an ellipse with around the sun is an ellipse with

the sun at the sun at one focus one focus (Kepler’s (Kepler’s First Law First Law of of Planetary Motion)Planetary Motion)

http://www.aerospaceweb.org/question/astronomy/solar-system/solar-system.jpg

Newton’s First LawNewton’s First Law – An object at rest – An object at rest remains at rest and an object in remains at rest and an object in motion maintains its velocity unless motion maintains its velocity unless it experiences an unbalanced force.it experiences an unbalanced force.

Newton’s Second LawNewton’s Second Law – The – The unbalanced force acting on an unbalanced force acting on an object equals the object’s mass object equals the object’s mass times its acceleration.times its acceleration.

Newton’s Third LawNewton’s Third Law – For every – For every action force, there is an equal and action force, there is an equal and opposite reaction force.opposite reaction force.

Law of Conservation of MassLaw of Conservation of Mass

- mass cannot be created - mass cannot be created or destroyedor destroyed

Law of Conservation of Law of Conservation of EnergyEnergy

- energy cannot be - energy cannot be created or destroyedcreated or destroyed

http://www.google.com/imgres?imgurl=http://www.wildonesonline.faketrix.com/content/pictures/original/amazing-roller-coaster-picture.jpg&imgrefurl=http://www.wildonesonline.faketrix.com/picture-4-roller-coaster-amusement-park.htm&h=137&w=103&sz=61&tbnid=pnAXTnxGYjkJ:&tbnh=137&tbnw=103&prev=/images%3Fq%3Droller%2Bcoaster%2Bpics&sa=X&oi=image_result&resnum=1&ct=image&cd=1

D. D. TheoryTheory 1. a broad and comprehensive 1. a broad and comprehensive statement of what is believed to statement of what is believed to be be true, supported by true, supported by considerable considerable experimental experimental evidence resulting evidence resulting from many from many tests of related tests of related hypotheseshypotheses2. in everyday speech, people use 2. in everyday speech, people use

the word theory when they are the word theory when they are talking about a hunch or a guesstalking about a hunch or a guess3. really they should use the word 3. really they should use the word

“hypothesis”“hypothesis”

4. Examples of Scientific Theories4. Examples of Scientific Theories

a. atomic theory – all matter a. atomic theory – all matter is made is made of atomsof atoms

b. cell theory – all living b. cell theory – all living things are things are composed of cellscomposed of cells

c. theory of gravitation – all c. theory of gravitation – all matter matter attracts other matterattracts other matter

d. theory of plate tectonics – d. theory of plate tectonics – Earth’s Earth’s crust is made of crust is made of plates which plates which move over move over timetime

e. e. Kinetic TheoryKinetic Theory explains the three explains the three states of matterstates of matter

1) all matter is made of atoms and 1) all matter is made of atoms and molecules that act like tiny molecules that act like tiny particlesparticles

2) these tiny particles are always in 2) these tiny particles are always in motion. The higher the motion. The higher the temperature, the faster the temperature, the faster the particles moveparticles move

3) at the same temperature, more 3) at the same temperature, more massive particles move slower than massive particles move slower than less massive particlesless massive particles

f. Theory of Evolutionf. Theory of Evolution

1) species change over time1) species change over time

2) the best explanation of 2) the best explanation of biological diversity on Earthbiological diversity on Earth

5. Theories…5. Theories…

a. are well substantiated a. are well substantiated explanationsexplanations

b. are internally consistent and b. are internally consistent and compatible with the evidencecompatible with the evidence

c. are firmly grounded in and c. are firmly grounded in and based upon evidencebased upon evidence

d. have been tested against a d. have been tested against a diverse range of phenomenadiverse range of phenomena

e. explain a wide variety of e. explain a wide variety of phenomenaphenomena

6. Theories are not absolute – as 6. Theories are not absolute – as we do more experiments and we do more experiments and learn more about the world learn more about the world around us, our explanations can around us, our explanations can changechange

7. How do scientists arrive at a 7. How do scientists arrive at a theory?theory?a. make observationsa. make observationsb. try to explain these observationsb. try to explain these observationsc. make predictionsc. make predictionsd. use modelsd. use modelse. test proposed predictions, etc.e. test proposed predictions, etc.f. communicatef. communicateg. revise predictions/explanationsg. revise predictions/explanationsh. test revisionsh. test revisionsi. Test validity and reliabilityi. Test validity and reliability

8. Scientific Method of 8. Scientific Method of InvestigationInvestigation

a. Identify the Problema. Identify the Problem

b. Researchb. Research

c. Develop Hypothesisc. Develop Hypothesis

d. Design Experimentd. Design Experiment

e. Conduct Experiment/Make e. Conduct Experiment/Make ObservationsObservations

f. Draw Conclusionsf. Draw Conclusions

g. Communicate Findingsg. Communicate Findings

II. The Mystery of Life’s OriginII. The Mystery of Life’s OriginA. Divine CreationA. Divine Creation

1. relating to a God or Gods1. relating to a God or Gods2. Cannot be proven by science2. Cannot be proven by science

B. Spontaneous OriginB. Spontaneous Origin1. life developed by itself through 1. life developed by itself through natural chemical and physical natural chemical and physical processesprocesses2. Primordial Soup Model2. Primordial Soup Model

a. large amounts of a. large amounts of organic organic molecules molecules were in a “warm were in a “warm little pond”little pond”

b. eventually formed living b. eventually formed living thingsthings

3. the Bubble Model3. the Bubble Model

a. processes took place a. processes took place within within bubbles on the bubbles on the ocean’s surfaceocean’s surface

C. ExtraterrestrialC. Extraterrestrial

1. origin outside of the Earth1. origin outside of the Earth

III. Evolution by Natural SelectionIII. Evolution by Natural Selection

A. Voyage of the Beagle A. Voyage of the Beagle

B. Darwin’s TheoryB. Darwin’s Theory

1. individual organisms differ – 1. individual organisms differ – some traits are heritablesome traits are heritable

2. organisms produce more 2. organisms produce more offspring than can surviveoffspring than can survive

3. because more are produced 3. because more are produced than can survive, they compete than can survive, they compete for resourcesfor resources

4. some organisms possess 4. some organisms possess advantages that help them advantages that help them survive and reproduce over survive and reproduce over other organisms – this causes other organisms – this causes species to change (natural species to change (natural selection)selection)

5. today’s species have descended 5. today’s species have descended with modifications from with modifications from ancestral species ancestral species

IV. Evidence for EvolutionIV. Evidence for Evolution

A. FossilsA. Fossils

1. traces of once living 1. traces of once living organismsorganisms

2. Imprint2. Imprint

a. a film of carbon a. a film of carbon remains after the remains after the other other elements of an organism have elements of an organism have

decayeddecayed

Ammonites in matrix - http://www.fossils-facts-and-finds.com/; imprint dragonfly - http://www.units.muohio.edu/dragonfly/skeletons/

3. Mold3. Mold

a. an impression of the a. an impression of the shape or shape or track of an track of an organismorganism

4. Cast4. Cast

a. sediments fill in the a. sediments fill in the cavity left by cavity left by a fossil a fossil moldmold

Trilobite cast and mold pair - http://scientificsonline.com/product.asp?pn=3081439&bhcd2=1205787201

B. Geographic Distribution of B. Geographic Distribution of Living SpeciesLiving Species

B. Geographic Distribution of B. Geographic Distribution of Living SpeciesLiving Species

http://en.wikipedia.org/wiki/Lion; http://en.wikipedia.org/wiki/Jaguar; http://en.wikipedia.org/wiki/Cougar

C. Homologous StructuresC. Homologous Structures

1. structures that are 1. structures that are embryologically similarembryologically similar

D. Vestigial OrgansD. Vestigial Organs

1. structures or organs that 1. structures or organs that seem to have no useful purposeseem to have no useful purpose

2. examples2. examples

a. human tailbonea. human tailbone

b. snakes with pelvic b. snakes with pelvic and limb and limb bonesbones

http://en.wikipedia.org/wiki/Ostrich

E. Embryological DevelopmentE. Embryological Development

1. embryos of some species 1. embryos of some species develop almost identically develop almost identically during early stagesduring early stages

E. Embryological E. Embryological DevelopmentDevelopment

http://www.pbs.org/wgbh/evolution/library/04/2/pdf/l_042_03.pdf

F. Biochemical F. Biochemical

1. same complex biochemical 1. same complex biochemical compounds (ie- DNA) govern compounds (ie- DNA) govern same functions in vastly same functions in vastly different organismsdifferent organisms

2. unlikely that almost 2. unlikely that almost identical compounds would identical compounds would have evolved independently in have evolved independently in widely different organismswidely different organisms

V. Patterns of EvolutionV. Patterns of Evolution

A. Divergent EvolutionA. Divergent Evolution

1. two or more related species 1. two or more related species becoming more and more becoming more and more dissimilardissimilar

2. ie – red fox (farmlands and 2. ie – red fox (farmlands and forest) vs. kit fox (plains and forest) vs. kit fox (plains and deserts)deserts)

3. adapted to their 3. adapted to their environmentenvironment

Kit fox - http://www.americazoo.com/goto/index/mammals/247.htm; red fox - http://animals.nationalgeographic.com/animals/mammals/red-fox.html

B. Convergent EvolutionB. Convergent Evolution

1. unrelated species become 1. unrelated species become more and more similar as they more and more similar as they adapt to the same kind of adapt to the same kind of environmentenvironment

2. ie – cactus (US) vs euphorbia 2. ie – cactus (US) vs euphorbia (African desert)(African desert)

Euphorbia (rt) - http://www.desert-tropicals.com/Plants/Euphorbiaceae/Euphorbia_abyssinica.html; cactus (left) - http://www.desertusa.com/july96/du_saguaro.html

C. CoevolutionC. Coevolution

1. the joint change of two or 1. the joint change of two or more species in close more species in close interactioninteraction

2. ie – birds and flowers2. ie – birds and flowers

http://en.wikipedia.org/wiki/Hummingbird

VI. Genetic EquilibriumVI. Genetic Equilibrium

A. SpeciesA. Species

1. a group of individuals that 1. a group of individuals that look similar and whose look similar and whose members are capable of members are capable of producing fertile offspring in producing fertile offspring in the natural environmentthe natural environment

B. HybridB. Hybrid

1. the offspring of 1. the offspring of two morphologically two morphologically

dissimilar organismsdissimilar organisms

C. Variation of (polygenic) Traits C. Variation of (polygenic) Traits in a Populationin a Population

1. Bell Curve1. Bell Curve

http://classes.kumc.edu/sah/resources/sensory_processing/images/bell_curve.gif

Phenotypes for Single-Gene TraitsPhenotypes for Single-Gene Traits

Polygenic traitsPolygenic traits

-traits governed by more than -traits governed by more than one set of allelesone set of alleles

D. Hardy-Weinberg PrincipleD. Hardy-Weinberg Principle1. = Genetic Equilibrium1. = Genetic Equilibrium2. a population will remain in 2. a population will remain in genetic equilibrium IF:genetic equilibrium IF:

a. no mutations occura. no mutations occurb. Individuals neither enter b. Individuals neither enter

nor leave the population through nor leave the population through migrationmigration

c. the population is largec. the population is larged. individuals mate d. individuals mate

randomlyrandomlye. natural selection does e. natural selection does

not occurnot occur** for evolution to occur, something ** for evolution to occur, something

must upset genetic equilibriummust upset genetic equilibrium

E. Changes in Genetic EquilibriumE. Changes in Genetic Equilibrium

1. Natural Selection1. Natural Selection

a. organisms with a. organisms with favorable traits or adaptations favorable traits or adaptations survive and reproduce at survive and reproduce at greater rates than those greater rates than those without these traits without these traits

http://animals.nationalgeographic.com/animals/mammals/zebra.html

b. Directional Selectionb. Directional Selection

1) proceeds in one direction1) proceeds in one direction

c. Stabilizing Selectionc. Stabilizing Selection

1) eliminates the extremes1) eliminates the extremes

d. Disruptive Selectiond. Disruptive Selection

1) selects against the average1) selects against the average

e. Artificial Selectione. Artificial Selection

1) nature provided the 1) nature provided the variation, and humans selected variation, and humans selected those variations that they those variations that they found usefulfound useful

http://soilcrop.tamu.edu/photogallery/cornsorghum+/pages/corn%20ears.htm

2. Migration2. Migration

a. movement of organisms into a. movement of organisms into or out of a populationor out of a population

http://www.pgc.state.pa.us/crep/lib/crep/two_white_tailed_deer.jpg

3. Genetic Drift3. Genetic Drift

a. the change in gene a. the change in gene frequency frequency

b. result of the laws of b. result of the laws of probability and chanceprobability and chance

4. Isolation4. Isolation

a. separation of populations into a. separation of populations into groups that no longer interactgroups that no longer interact

b. rivers, mountains, and b. rivers, mountains, and canyonscanyons

5. Mutation (GCU5. Mutation (GCUCCU)CCU)

6. Nonrandom Mating6. Nonrandom Mating

a. mating with like/selfa. mating with like/self

b. decrease genetic variationb. decrease genetic variation

c. increase homozygous traitsc. increase homozygous traits

http://www.hawaiipictures.com/pictures/oahu/mountains4-1.jpg

The End The End