PowerPoint Presentation

Change Over TimeEvolution

Big Picture: Four Types of EvolutionCosmicChemicalOrganicCulturalKnow which we study in biology

Tsagiglala, or She Who Watches.

Key ConceptUniformity of rate across time and space: Change is typically slow, steady and gradual.James Hutton and Charles Lyell studied rock formations and changes in Earth and came to the conclusion that the Earth was very old.Challenged the idea Earth was 300,000 years old.

Key Historical FigureJames Hutton (1726 1797) Scottish geologist, physician, chemical manufacturer and naturalist.Hutton's work established geology as a proper scienceFather of Modern Geology

Key Historical FigureSir Charles Lyell, 1st Baronet,(17971875) British lawyer and the foremostgeologistof his day. Author ofPrinciples of Geology, which popularizedHutton's conceptsThe Earth was shaped by the same processes still in operation today.How old he believed the Earth was according to his studies.Challenged theories most accepted and circulated ideas about geology in England at the time.

Key Historical FigureLamarck Jean-Baptiste Pierre Antoine de Monet, Chevalier de Lamarck(1744 1829) A Frenchnaturalist who was also asoldier, biologist,academic.Was an early supporter of evolution occurring & followingnatural laws. Created terms for specialized sciences; chemistry, meteorology, geology, and botany-zoology.Book: Philosophie zoologique early 1800s

Lamarck: Core believesHis LawsThe desire to changeThe theory of use & disuseThe theory of acquired inheritance

Important because he was first to look at changes over time.

Lamarck1. The desire to changeIf an organism wants to change it can or will.Example:All elephants had short trunks. When there was no food or water they could reach with their short trunks they wanted longer trunks.

Larmarcks TheoryDesire to changeGiraffes ran out of food they could reach.They wanted food out of reach.

Lamarck2. The theory of use and disuseUse or disuse causes structures to enlarge or shrink Example:When there was no food or water they could reach with their short trunks, they stretched their trunks to reach the water and branches.The desire to changeThe theory of use and disuseThe theory of acquired inheritance

that use or disuse causes structures to enlarge or shrink

Larmarcks TheoryUse and disuseOriginal short necked ancestor.Keeps stretching neck to reach leaves higher up on tree.And stretchingAnd stretching until neck becomes progressively longer.

Lamarck3. Theory of Inheritance of Acquired CharacteristicsAdaptions to environment during life passed to offspring. Example:Offspring inherited long trunks. The desire to changeThe theory of use and disuseThe theory of acquired inheritance

Larmarcks TheoryInheritance of Acquired Characteristics The individual giraffes stretched neck will be a trait passed on to offspring via inheritance.

Key Historical FigureCharles Darwin (18091882)Englishnaturalist&geologistWorld trip via the HMS Beagle1859 bookOn the Origin of Species First published with Alfred Russel Wallace who had parallel ideas at same time.Major contributor to evolutionary theory.

Summary of Darwins TheoryIndividual organisms in nature differ from one another. Some of this variation is inherited.Organisms in nature produce more offspring than can survive, and many of those that survive do not reproduce.Because more organism are produced than can survive, members of each species must compete for resources.Because each organism is unique, each had different advantages and disadvantages in the struggle for existence.

Natural Selection

The gradual process by which heritablebiological traitsbecome either more or less common in apopulationbased on how successful the organisms reproduces survives in their environment. It is a key mechanism of evolution.

Differences Between

Differences Between

1. Lamark2. Darwin

Evidence for Evolution Primarily comes from four sources: fossil record chemical and anatomical similarities geographic distribution recorded genetic changes over generations

Fossil RecordCan show transition from one species into anotherOrigin of new physical features. Time perspective for understanding the evolution of life on Earth This perspective is not available from other branches of science or in the other databases supporting the study of evolution.

Chemical Similarities Only 7 elements are found in all life. OxygenHydrogenCarbonIronSiliconCalciumNitrogen20 different amino acidsProteinsDNAMutations (a mechanism for change)

MutationsMutations change the composition of the gene pool.New alleles are introduced, and allelic frequencies change.

Mechanism for Change

Anatomical & Embryology Similarities Same Structure same ancestor (usually ancient)Organism in similar environmental niches accumulate adaptations add up resulting in resemblance, convergent evolution.Vestigial structures are an anatomical feature no longer seeming to have a purpose in the current form of an organism. Examples:Human coccyx or tail boneHuman appendix (new research indicated may actually be used)Whales & snakes pelvis

Geographic Distribution Also known as biogeographyDistribution of species and ecosystems in geographic space and through (geological) time

Recorded genetic changes Recorded genetic changes over generationsEasily demonstrated over a 24 hour period in a petri dish of bacteriaCladogramsPedigrees

Comparing Evolution TypesDivergentprocess when a species evolves into two or more descendant or different form ConvergentTwo species become increasingly similar phenotypically in response to environment.ParallelTwo separate species in the same environment develop similaradaptationor characteristic for survival.

DivergentConvergent

Expression of different types of evolution

DivergentConvergentExpression of different types of evolution

Natural Selection

Hardy / Weinberg Law of Equilibrium(p2+ 2pq + q2= 1)The frequency (%) of an allele in a populationUse as tool to measure change Allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences.

Hardy / Weinberg Law of EquilibriumUsuallydoesnt happenin nature, these are reasons why we still use:Mutations cancel each otherProbability of selection (death) lowSome populations have little movementMake predictionsCan alter equation mathematically

Effects of Selection on Population

Darwins Finches

Cladogram of insects

Acladogram(from Greek clados "branch" and gramma "character") is a diagram used in cladistics which shows relations among organisms

Mustard Family Cladogram

Cladogram

BiodiversityThe degree of variety of the living things in any given ecosystem, biome, or the entire planet.