28-1: EVIDENCE FROM THE PAST

Evolution –

·       Geologic Evolution à evolution of the _________

·       Organic Evolution à evolution of ___________

Fossils:

·       __________________ – Bacteria cannot decay organism à it is preserved (extreme conditions kill bacteria). Amber -a hard, yellow, transparent material formed by hardening of resin

·       _____________ – Shells, bones, teeth preserved (tar)

·       ________________ – Dead organism in body of water with high mineral content à organic materials dissolve & are replaced by minerals à turned to stone

·       __________– Dead organism buried by sand/mud at bottom of lake/sea à hardens into rock à shape of organism preserved in rock (organism decays)

·       _________ – Mold fills with minerals à harden to form rock

·       ____________ – Impressions remain when mud hardens to rock

Calculating the Age of Fossils

Sedimentary Rock à

·       ______________________ – Any method of determining the order in which events occurred (Grand Canyon)

Fossil Record – The history of life as determined by the relative age of fossils.

·       ______________________ – Determines how long ago an event occurred (actual age of fossil in years)

Radioactive Dating –

Ø   Certain elements have _____________________

Ø   Nucleus breaks down/ decays à changes to a _____________ ~ radioactive decay. Ex: C-14àN-14

Ø   E given off in the form of radiation

Ø   Half life:

Ø   Ex: Compare the ____________________________ to calculate fossil’s age

28-2: INTERPRETING THE FOSSIL RECORD

Correlation –

·       Cannot be used where there are no nearby rocks that are similar

·       Not viable for 2 different regions/ locales

Index Fossils – Matching __________________________ ___________________________ Permit ______________ ________________ of rocks within a narrow time span.

à Ex: Trilobytes lived 500-600 MYA. If you find these, it allows you to date other rocks/ fossils

Geologic Time Scale – ____________ of the earth’s history constructed through a ___________________________ _________________________________________.

à 4 Major Eras: Precambrian, Paleozoic, Mesozoic, Cenozoic

à _________ broken down into ___________ also

Patterns of Evolution

1.    Organisms: ______________________________

Ex: prokaryotic cells à eukaryotic cells; 1-celled organism à many-celled organism; aquatic à terrestrial

2.    ____________ in organisms occur over _____________ ______________________________ (series of gradual changes passed on from generation à generation)

3.    ______________________________________________ _____________________________________________

Extinct: When the last individual of a species dies

28-3: EVIDENCE FROM LIVING ORGANISMS

Anatomical Similarities

Comparative Anatomy –

Structural similarities = evolutionary relationship between species

·       Homologous Structures –

à Evidence of evolution from a common ancestor

à Ex: human arm, whale flipper, cat limb, bat & bird wings

·       Analogous Structures –

à Evidence for evolution along different lines (not closely related)

àEx: bird wing & insect wing

·       Vestigial Structures –

à Evidence of evolutionary relationships

à Ex: tailbone, appendix, wisdom teeth

Embryological Similarities

Similar embryological development = common evolutionary origin

More __________________ à ________________________ _____________________ during embryological development

Molecular Similarities

How similar is the genetic code (DNA) between organisms?

More biochemical similarities = more closely related

Cytochrome C à A protein molecule organisms need for ________________________.

·       ________________________ in all species

·       Differences in protein produced by ___________________ that occurred after the ancestors of living species _______________.

·       Humans & monkeys à differ by _______

Humans & fish à differ by ________

28-4: THE ORIGINS OF LIFE – EARLY HYPOTHESES

Spontaneous Generation/ Abiogenesis –

Early Experiments:

1.           Jan Baptista van Helmont (early 1600’s)

Put wheat in sweaty shirt à 21 days à wheat gone, mice present

Hypothesis:

2.           Francesco Redi  (mid-1600’s)

·       People believed that maggots developed by spontaneous generation (S.G.) from decaying meat

·       Redi’s Hypothesis:

·       Redi’s experiment:

·       This experiment only proved that meat had to be exposed to open air to develop maggots à _______ _________________________________à sealing jars “prevented necessary air from reaching meat”

3.           Redi’s Second Experiment (fig 28-16) _____________ _____________________________________________:

Spontaneous Generation of Microorganisms (Microbes)

Place hay/ soil into sterile water à microbes appearedà thought to be S.G. (controversy over next 200 years)

4.           John Needham (1745) à boiled flasks of chicken, lamb & corn broth for a few minutes to kill microbes à sealed flasks for a few days à full of microbes

Hypothesis:

5.           Lorenzo Spallanzani  à

·       He said Needham didn’t heat flasks long enough to kill microbes

·       Needham said Spallanzani heated flasks too long à destroyed “vital principle” in air needed to generate new organisms

6.           Louis Pasteur (1860) ________________________!

Hypothesis:

·       Microbes and their spores are in the air à become active & reproduce when they enter nutrient broth.

·       Pasteur’s Experiment: (fig 28-17)

·       As long as flasks are not disturbed, _______________  ________________________

·       __________________ in flasks only when flasks were tipped and some broth ran into neck & became ___________________

28-5: THE ORIGINS OF LIFE: MODERN HYPOTHESIS

Biogenesis –

But how did the first living things originate?

The Heterotroph Hypothesis (A.I. Oparin)

Natural Synthesis of Organic Compounds

·       _________ compounds à _________ organic compounds

·       E provided from:

-        _________ given off by earth

-        ______________ (decay of radioactive elements in earths crust)

-        _______________ (lightning)

-        ____ light, __________ light, X-rays from _______

·       1^st ______________, ____________, __________ formed

Stanley Miller & Harold Urey (1953) did an experiment to prove this. They mimicked the conditions of primitive earth:

·       1 week later à __________________________________ _____________ were found (complex organic compounds)

·       Organic substances could have been produced in nature under the conditions assumed for primitive earth.

·       Sidney Fox did further experiments to show ___________ ____________________________ through ____________ processes

Aggregates of Organic Compounds

Oparin propsed that:

Protein-like substances à aggregates or clusters of large

molecules (Coacervates)

Coacervates –

·       Numerous ____________________ occur in coacervates

·       Coacervates became more _____________ à developed ____________________ with capacity to release __ from various organic nutrients absorbed from the environment

·       Coacervates _______ à _______ in ½ à grew again…etc

·       ___________________________

·       “___________________” – obtain nutrients from the environment

Graham Cairns-Smith proposed that ____________________ ___________________________________________________ ___________________________________________________

·       self assemble

·       _________ in assembly à new “____________” forms with favorable properties à ____________________________

·       currently testing this hypothesis

Respiration & Photosynthesis

·       1^st organisms performed anaerobic respiration to produce E because ___________ à release ____ into environment

·       # heterotrophs___, competition for nutrients ___, ___ supply of nutrients

·       1^st Photosynthetic/ autotrophic organisms: Use _______ ___ to synthesize ATP à coupled with rxns that use _____ and ______ to synthesize _________________

·       Creates another ________________

·       Changes the ______________ à ___________

·       Aerobic Respiration à ___________________ than anaerobic respiration. Use _____ to break down nutrients and produce E

·       Aerobic organisms are ________________ to anaerobes

Environmental Changes

·       Oxygen formed the __________ (O₃) à blocked suns rays

·       ________ ¯, ¯ ____ in environment