This thesis compares two samples of emission line galaxies, selected on the basis of the strength of their O III and/or H-beta emission lines. The distant sample has been drawn from the 4-Shooter transit survey undertaken by Schmidt, Schneider and Gunn (1994, AJ, 107, 1245 and references therein), and consists of 370 galaxies with emission line equivalent widths in excess of 50A and fluxes above well-defined wavelength-dependent limits. This survey the moderate resolution spectra taken to identify the emission line. The nearby sample has been taken from the first CfA Northern Sky Redshift Survey, and consists of 81 galaxies from Burg (1987, Ph.D. thesis, MIT, Cambridge, MA) with O III EW ≥ 23.75A and an additional 26 Seyfert galaxies fbeen observed on the 1.5m Oscar Meyer telescope using the Echelle Spectrograph in a low-resolution, long slit mode (McCarthy, 1988, Ph.D. thesis, Caltech, Pascovers the emission lines of interest such as H-beta, O II. These data have been used both to classify the 107 galaxies from their line ratio diagnostics as well as to model the spatial and spectral light distributions on the plane of the sky for a comparison of how each would appear in the distant survey as a function of redshift. Maximum redshifts in both the nearby and the distant survey have been determined for each CfA galaxy, and predicted number counts, based on both a no-evolution model as well as a model incorporating density evolution, have been made from the corresponding ratio of accessible volumes in the two surveys. Corrections were made to the predicted counts to account for sample incompletenesses and the overdensity of the CfA survey relative to the average density of galaxies in the "local" universe. These predicted counts were comclass. The results from this cono-evolution model for emission line galaxies out to z~0.5, and do not support the conjecture (Broadhurst et al., 1988, MNRAS, 235, 827; Colless et al., 1990, MNRAS, 244, 408) that there is an evolving population of dwarf star-forming emission line galaxies.