| L L L L L | letter |
| Lac operon | chapter 18 | bio 113 | heading |
| Lack of ambiguity in the triplet code | chapter 17 | bio 113 | heading |
| Lactose | chapter 5 | bio 113 | heading |
| Lagging strand | chapter 16 | bio 113 | heading |
| Lamarck, Jean Baptiste | chapter 22 | bio 114 | heading |
| Landscapes, adaptive | chapter 24 | bio 114 | heading |
| Law of addition | chapter 14 | bio 114 | heading |
| Law of multiplication | chapter 14 | bio 114 | heading |
| Law of segregation | chapter 14 | bio 113 | heading |
| Layers, germ | chapter 32 | bio 114 | heading |
| Layers, germinal | chapter 32 | bio 114 | heading |
| Leading strand | chapter 16 | bio 113 | heading |
| Leaflet, membrane | chapter 8 | bio 113 | term |
| Learning | chapter 51 | bio 114 | heading |
| Learning, associative | chapter 51 | bio 114 | heading |
| Learning, insight | chapter 51 | bio 114 | heading |
| Learning, observational | chapter 51 | bio 114 | heading |
| Level, trophic | chapter 54 | bio 114 | heading |
| Lichens | chapter 31 | bio 114 | heading |
| Life cycle | chapter 13 | bio 113 | heading |
| Life cycle | chapter 18 | bio 113 | heading |
| Life cycle of a fern | chapter 29 | bio 114 | heading |
| Life cycle of a moss | chapter 29 | bio 114 | heading |
| Life cycle of a pine | chapter 30 | bio 114 | heading |
| Life cycle of an angiosperm | chapter 30 | bio 114 | heading |
| Life cycle, lysogenic | chapter 18 | bio 113 | heading |
| Life cycle, lytic | chapter 18 | bio 113 | heading |
| Life cycles, algal | chapter 28 | bio 114 | heading |
| Life history | chapter 52 | bio 114 | heading |
| Life, origin of | chapter 26 | bio 114 | heading |
| Ligand | chapter 11 | bio 113 | heading |
| Ligase, DNA | chapter 16 | bio 113 | heading |
| Ligase, DNA | chapter 20 | bio 113 | heading |
| Light reaction of photosynthesis | chapter 10 | bio 113 | heading |
| Light, wavelength of | chapter 10 | bio 113 | heading |
| Lignin | chapter 29 | bio 114 | heading |
| Limited resource, allocation of | chapter 52 | bio 114 | heading |
| Limiting nutrient | chapter 54 | bio 114 | heading |
| Limits on population growth | chapter 52 | bio 114 | heading |
| Linkage | chapter 15 | bio 113 | heading |
| Linkage, sex linked | chapter 15 | bio 113 | heading |
| Linkage, X linked | chapter 15 | bio 113 | heading |
| Linkages, phosphodiester | chapter 5 | bio 113 | heading |
| Linnaeus, Carolus | chapter 22 | bio 114 | heading |
| Lipid bilayer | chapter 8 | bio 113 | heading |
| Lipids | chapter 5 | bio 113 | heading |
| Liquid, water as a | chapter 3 | bio 113 | heading |
| Lobe-finned fish | chapter 34 | bio 114 | heading |
| Local regulator | chapter 11 | bio 113 | heading |
| Loci (plural of locus) | chapter 13 | bio 113 | heading |
| Locus | chapter 13 | bio 113 | heading |
| Locus, fixed | chapter 23 | bio 114 | heading |
| Logic of Darwinism, The | chapter 22 | bio 114 | heading |
| Logistic growth | chapter 52 | bio 114 | heading |
| Low temperature stability | chapter 6 | bio 113 | heading |
| Lumen | chapter 7 | bio 113 | heading |
| Lumen protein, secreted protein, and membrane-protein synthesis | chapter 7 | bio 113 | heading |
| Lyell, Charles | chapter 22 | bio 114 | heading |
| Lysogenic life cycle | chapter 18 | bio 113 | heading |
| Lysosomes | chapter 7 | bio 113 | heading |
| Lytic life cycle | chapter 18 | bio 113 | heading |