Some unicellular species of green algae, many golden algae, euglenids, dinoflagellates, and other algae have become heterotrophs (also called colorless or apochlorotic algae), sometimes parasitic, relying entirely on external energy sources and have limited or no photosynthetic apparatus.
sˌʌm jˌuːnɪsˈɛljʊlɚ spˈiːsiːz ʌv ɡɹˈiːn ˈælɡiː, mˈɛni ɡˈoʊldən ˈælɡiː, jˈuːɡəlnˌɪdz, dˈɪnəflˌeɪdʒəlˌeɪts, ænd ˈʌðɚɹ ˈælɡiː hæv bɪkˌʌm hˈɛɾɚɹˌoʊtɹɑːfz ˈɔːlsoʊ kˈɔːld kˈʌlɚləs ɔːɹ ɐpəklˌoːɹˈoʊɾɪk ˈælɡiː, sˈʌmtaɪmz pˌæɹəsˈɪɾɪk, ɹᵻlˈaɪɪŋ ɛntˈaɪɚli ˌɔn ɛkstˈɜːnəl ˈɛnɚdʒi sˈoːɹsᵻz ænd hæv lˈɪmɪɾᵻd ɔːɹ nˈoʊ fˌoʊɾoʊsɪnθˈɛɾɪk ˌæpɚɹˈæɾəs.