Evolution by Natural Selection - PowerPoint Presentation

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Evolution by Natural Selection

Chapters 14-18

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Charles

Darwin

, DOB 1809, On the Origin of Species by Means of Natural Selection, HMS Beagle – 1831-36Greeks – life arose in water and more complex followed simpler onesLater Aristole said life was fixed (ps. he’s wrong)Judeo-Christians agreedMid 1700s fossils of “strange animals” were foundJean Baptiste de Lamark suggested acquired traits were inherited. Used = got better, Unused = go away. (ps…he’s half wrong)

History

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Dad wanted him to get into medicine, then he went to become a priest – Met John

Henslow

– took a cruise.While on the boat he read Principles of Geology by Charles Lyell. “mountains rise cm by cm” The way the rain falls today is the same way it fell 1billion years ago.UNIFORMITARIANISMLearned about Thomas MalthusHuman population should be huge but - War, Disease, Famine limits the populationHistory

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So Darwin is on a cruise…

Finds sea animal fossils thousands of feet above sea level

Finds FINCHES similar to the mainland but 600miles out to sea GALAPAGOS ISLANDS Realizes that kids look like parentsAfter his trip, he thinks about this stuff for a little while…like 20yearsAlfred Wallace sends him a paper that is the same idea that he has come to and Darwin quickly publishes. The conclusion…? History

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Organisms that exist today are modified versions of older organisms.

The environment chooses the organisms that are best fit to reproduce (natural selection).

The better fit the organism the more babies it will produce, the more of those genes are in the gene pool.Traits that help an organism survive better and make more babies are ADAPTATIONSDescent with Modification

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1. Fossils

2. Biogeography

3.Homologous/Analogous Structures4. Embryology5. Molecular Biology (macromolecules)6. Vestigial StructuresEvidence – 6 pieces

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Traces of long dead organisms

Sediments

Law of superposition:Which happened first, tree falling or it snowed?Fossil Record:The theoretical ‘stack’ of all fossils, in order1. Fossils

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Align and fix the locations in place. Answer the following questions:

Which locality is the oldest? How do you know?

Which locality is the youngest? Where might you find this in the Earth’s crust?Approximately how many years are represented in your localities? Are there any huge gaps?Why aren’t all the fossils in the same place?Is there a pattern to the complexity of the fossils?How do fossils form? What does this tell you about the organisms that we find as fossils (or what about the one’s we don’t find)?Do you think fossils are strong evidence for evolution? Why or why not.Fossil Lab

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Organisms that are relatively close (NJ and PA) are more alike than organisms that are far apart.

More pouched animals in

AustrailiaGalapagos Finches2. Biogeography

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‘Homo’ means … so these are parts in different species of animals that are the same.

Analogous – same function but different structure

3.Homologous/Analogous Structures

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Figure 13.11

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In the early stages

of development,

many species are similar.4. Embryology

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Large compounds in organisms are sometimes similar

Protein

HemoglobinStarch5. Molecular Biology (macromolecules)

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Remnants of structures that served a purpose in ancestral organisms but have little or no function now.

Appendix

Wisdom teethTails6. Vestigial Structures

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The organism that is best fit to the environment makes the most babies and passes on the most genes.

DEPENDS COMPLETELY ON GENETIC MAKEUP

Individual variation (longer legs, sharper teeth, darker color)If its not the environment choosing but people we call it ARTIFICIAL SELECTIONCowsSheepBacteriaChemicals - ddtNatural Selection

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Gene pool – all of the genes in a population

Population – a group of mating individuals in the same place at the same time.

We can identify if evolution is taking place based on the Hardy-Weinburg Equationp2 + 2pq + q2 = 1Certain events can cause evolution to occur more quicklyBottle neck eventFounder eventGene flow – immigration, emmigrationMutation

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Figure 13.22

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Figure 13.23

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Sometimes evolution occurs in a specific pattern

Directional Selection

Disruptive SelectionStabilizing Selection

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Names and groups organisms according to their characteristics and evolutionary history

Carolus

Linnaeus (1707-1778)Binomial NomenclatureSpecies identifierVarieties- peach and nectarineSubspecies – different areaA species is defined as organisms that can reproduce and form fertile offspring.Taxonomy

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Systematics – classification in the context of evolution

Fossil record

MorphologyPhylogenic treeCladistics – derived charactersCladogramsWeird relationshipsSystematics vs Cladistics

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Domains –

Eukarya

BacteriaArchaeaKingdomPhylumClassOrderFamilyGenusSpecies

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Animalia

Plantea

FungiProtistaEubacteriaAcheabacteriaKingdoms (Modern Bio p348-9)

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What is living?

Order

Regulation/HomeostasisGrowth and DevelopmentEnergy UtilizationRespond to the environmentReproductionEvolutionSpontaneous Generation- living things from nonliving things (frogs came from mud)Francesco REDI 1650: Disproved spontaneous generation with meat, flies, jarsLazzaro SPALLANZANI 1750: Disproved spontaneous generation with boiled broth, new story-vital forceLouis PASTEUR 1850: Disproved both spontaneous generation and vital force with s-shaped flaskStory of Life

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Miller and Urey Experiment on how life began

Water + ammonia +

CO2 + Nitrogen =Organic compounds!PROKARYOTESEndosymbiosis-Lynn Margulis 1950One or a few microorgsLiving together becameour organelles =EUKARYOTESStory of Life

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Found everywhereKingdoms Bacteria,

Archaea

Mostly unicellular and very smallNo nucleus or organellesShapes: Bacilli, cocci, spirochetePhotoauto/heterotroph- Chemoauto/hetero- how they eatPathogenProkaryotes

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Lynn Margulis

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endosymbiont theorySmaller prokary climbed inside larger prokay and was happy togetherKingdoms Protista, Plant, Fungi, AnimalsLarger cells, have nucleus and organellesVERY diverseEukaryotes