Audio Glossary

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  1. F1 generation: The first generation of offspring in a genetic cross. Compare P generation.
  2. F2 generation: The second generation of offspring in a genetic cross.
  3. family: The level in the Linnaean hierarchy that is above genera and therefore comprises genera, but that is below orders and so composes orders.
  4. fast muscle fiber: A type of muscle fiber that contracts quickly, but can sustain a contraction for only a short time. Compare slow muscle fiber.
  5. fat: An organic compound that consists of glycerol linked to three fatty acids. Fats are solid at room temperature and can be used by living organisms to store energy.
  6. fatty acid: An organic compound composed primarily of a long hydrocarbon chain; found in lipids and fats.
  7. feces: The solid waste product of animal digestion, which consists mostly of indigestible food and bacteria.
  8. female: An individual of a sexually reproducing species that produces eggs. Compare male.
  9. fermentation: A series of catabolic reactions that produce small amounts of ATP without the use of oxygen. Fermentation is similar to glycolysis, except that pyruvate is converted to other products, such as ethanol or lactic acid.
  10. fertilization: The fusion of haploid gametes (egg and sperm) to produce a diploid zygote (the fertilized egg).
  11. fetus: The stage of animal development from the time when most of the major organs and tissues are identifiable to birth. Compare embryo.
  12. fibrous root system: A root system in which no one root predominates and which can form dense mats that hold soil firmly in place. Compare taproot system.
  13. fight-or-flight response: A response to a potentially dangerous situation that includes increased heart rate, blood pressure, blood flow to the brain, and energy availability - all of which contribute to increased activity throughout the body.
  14. filtrate: The liquid left over after filtration.
  15. filtration: The process of removing certain substances from a liquid by passing it through a filter, such as a semipermeable membrane.
  16. first law of thermodynamics: The law stating that energy can be neither created nor destroyed, only transformed or transferred from one molecule to another.
  17. fixation: The removal from a population of all alleles at a genetic locus except one; the allele that remains has a frequency of 100 percent.
  18. fixed behavior: A predictable response to a particular, often simple, stimulus that does not involve learning. Compare learned behavior.
  19. flower: A specialized reproductive structure that is characteristic of the plant group known as the angiosperms, or flowering plants.
  20. flowering plants: See angiosperms.
  21. fluid mosaic model: A model that describes the plasma membrane of a cell as a mobile phospholipid bilayer with embedded proteins that can move laterally in the plane of the membrane.
  22. follicle: An organized group of cells that surrounds the developing ovum in the ovary.
  23. follicle-stimulating hormone (FSH): A hormone produced by the pituitary gland that works with luteinizing hormone to regulate sperm development in males and to regulate the menstrual cycle in females.
  24. food chain: A single sequence of feeding relationships describing who eats whom in a community. Compare food web.
  25. food web: A summary of the movement of energy through a community. A food web is formed by connecting all of the food chains in the community to one another. Compare food chain.
  26. forebrain: The part of the brain that consists of the thalamus, the cerebrum, and the hypothalamus and is involved in many of the conscious functions of the brain.
  27. fossil: Preserved remains of or an impression of a formerly living organism. Fossils document the history of life on Earth, showing that past organisms were unlike living forms, that many organisms have gone extinct, and that life has evolved through time.
  28. founder effect: A genetic bottleneck that results when a small group of individuals from a larger source population establishes a new population far from the original population.
  29. fovea: region of especially densely packed photoreceptors in the retina of the eye that allows for the formation of sharp images.
  30. frameshift: A change in how the information in a DNA sequence is translated by the cell that results when a deletion or insertion is not a multiple of three base pairs (a codon).
  31. friction drag: Drag that results from the inter action of a fluid with the surface of a moving object. Compare pressure drag.
  32. fruit: A mature ovary surrounding a seed.
  33. fulcrum: The point around which a lever pivots.
  34. functional group: A specific arrangement of atoms that helps define the properties of a chemical compound.
  35. Fungi: The kingdom of mushroom-producing species, yeasts, and molds, most of which make their living as decomposers.