Chapters 14-17

Change over timeSpontaneous Generation: Living organisms

arise from non-living things.Many experiments were conducted to

disprove spontaneous generation.

SCIENTIST DISPUTED THEORY

CONCLUSIONS

Francesco Redi (1600’s)

Maggots come from rotting

meat

Maggots come from eggs laid

by flies

Lazzaro Spallanzani

(1700’s)

Microorganisms come from a

vital force in the air

Microorganisms travel in the air

Louis Pasteur (1800’s)

Boiling destroys air’s vital force

Solid particles in the air transport

microorganisms.

Redi— Spallanzani—

Pasteur--

Where did we come from?

Formation of Simple Organic CompoundsAlexander Oparin, 1923 (H2O, H2, CH4, &

NH3)Formation of Complex Organic Compounds

Amino acids formed chains in early atmosphereConcentration & Enclosure of Organic

CompoundsCoacervates & Microsphere formed

Evolution of Growth, Metabolism, & Reproduction

Approximately 4.6 – 3.5 billion years ago.First organisms – Prokaryotic cellsEukaryotic cells – 1 billion years ago

Endosymbiont Theory – Eukaryotic mitochondria evolved from bacteria & chloroplasts evolved from cyanobacteria.

We can find evidence of evolution by examining fossils & modern day organisms

Dating fossilsCarbon-datingPosition in

sedimentary rockFormation of the

Fossil RecordTypes of fossils:

MoldCastImprint

Common ancestryHawaiian honeycreepers

Homologous structuresSimilar embryologically,

but have different functionsVestigial organs

Functionless partsBiochemistry

Similar biochemical metabolismEmbryological Development

Fish, rabbits, gorilla

Jean Baptiste de Lamarck (1774-1829)Before DarwinInheritance of Acquired Characteristics“If you don’t use it, you lose it”

Natural SelectionOrganisms with favorable variations survive &

reproduce at a higher rate

Variation exists among individuals of a species.

Scarcity of resources in an increasing population will lead to competition

Individuals with advantageous variations are more likely to survive & reproduce.

CONVERGENT

EVOLUTION

DIVERGENT EVOLUTION

Type of Environment

Similar Different

Two or more species

Similar but unrelated

Related but different

Examples Cactus & euphorbia

Red fox & kid fox

The joint change of two or more species in close interaction.

Example: Plants & animals that pollinate them

PopulationAll members of the same species living in a

particular location at the same timeGene Pool

Collection of genes for all the traits in a populationAllele Frequency

Percentage of a specific allele of a gene in the gene pool

Genetic EquilibriumAllele frequencies stay the same from generation

to generation

A population will remain in GENETIC EQUILIBRIUM if all of these conditions are met:

No MutationsIndividuals neither enter nor leave a populationPopulation is largeIndividuals mate randomlyNatural selection does not occur

MutationMigration Natural SelectionGenetic Drift

A phenomenon by which allele frequencies in a population change as a result of random events or change.

Stabilizing SelectionFavors average form

(ex. Lizard)Directional Selection

Favors one extreme form (ex. Anteaters)

Disruptive SelectionFavors both extreme

forms (ex. Limpets)Sexual Selection

SPECIATIONFormation of a new species.

Geographic IsolationPhysical separation

of members of a populations

Reproductive IsolationResults from

barriers of successful breeding between population groups in the same area