Evolution and Microevolution

Evolution

• Evolution is the process that creates new species, primarily driven by natural selection.
• It has resulted in the formation of Homo sapiens over billions of years from the earliest life forms.
• Evolution, especially microevolution, is an ongoing process that occurs around us.

Definition of Evolution

• Evolution refers to changes in populations, species, or groups over time.
• It involves changes in allele (trait) frequencies in populations over time.

Types of Evolution

• Microevolution: Changes in allele frequencies within a population over time due to mutation, selection, gene flow, gene drift, and nonrandom mating.
• Macroevolution: Patterns of changes in groups of related species over broad periods of geologic time, determining phylogeny (evolutionary relationships among species and groups of species).

Phylogenetic Tree

• The patterns of changes in groups of related species can be used to establish a phylogenetic tree.

Lamarck Theory

• Use and disuse: Body parts can develop or weaken with increased or decreased usage.
• Inheritance of acquired characteristics: Incorrect theory that body features acquired during one's lifetime can be passed down to offspring (only changes in genetic material can be passed down).

Darwin's Theory

• Natural selection: Survival of the fittest without luck, leading to increased or decreased allele frequencies to adapt to the environment.
• Neo-Darwinism: Synthetic theory of evolution that combines Darwin's theory with genetic influences to propose mechanisms responsible for evolutionary patterns.
• Descent with modification: Coined by Darwin, this occurs via natural selection, resulting in traits providing reproductive advantage becoming more common within a population over time and generations.

Laboratory Equipment

• Beaker: most common equipment, used for heating, stirring, and mixing, but not for measuring
• Graduated cylinder: used for basic measuring, has volume markings on it
• Test tubes: hold small volumes of liquid, used for mixing, comparing, and storing, but not for measuring
• Dropper (pasture pipette): used for dropwise dispensing, commonly used for indicators
• Erlenmeyer flask: cone-shaped, used for mixing, heating, and stirring solutions, reduces risk of spillage
• Volumetric flask: has volume markings, used in dilution experiments
• Boiling flask: has a long neck and round bottom, used for swirling and heating liquids
• Bunsen burner: produces an open flame from a natural gas source, controlled by a dial on the bottom
• pH meter: measures pH, must be calibrated first
• Digital balance: accurate and precise, use with weigh paper and tear button to measure mass

Measurement Techniques

• Reading meniscus: common in graduated cylinders, read from the bottom
• Reading burettes: uses reverse numbering system
• Precision of glassware: least precise (beakers and Erlenmeyer flasks), then comes graduated cylinders, burettes, and volumetric flasks, and most precise (pipettes)

Basic Laboratory Techniques

• Measuring mass: use weigh paper, tear button, and digital balance
• Centrifugation: separates mixture, spins at high speeds, creating centrifugal force
• Titration: performed by delivering drop-by-drop volumes from burette to Erlenmeyer flask, using stopcock and indicator
• Calorimetry: measures absorbed/released heat during experiment, uses styrofoam cup and thermometer

Laboratory Safety Protocols

• Safety shower: pull lever to activate water shower
• Eyewash machine: used to remove chemicals from eyes
• Fume hood: provides proper ventilation in enclosed space
• Fire extinguisher: used for solvent or chemical fires
• Lab coats, safety goggles, and gloves: worn to prevent skin and eye exposure to chemicals
• Broken glass container: clean up and dispose of immediately after breakage
• Disposal of solutions: follow proper procedures for disposal

Quiz on evolution, microevolution, and natural selection. Understand how species change over time through allele frequency changes.