Animal cells have neither cell walls nor chloroplasts, whereas plant cells have both. Fungal cells are somewhere in between; they have cell walls but lack chloroplasts. Are fungal cells more likely to be animal cells that gained the ability to make cell walls, or plant cells that lost their chloroplasts? This question represented a difficult issue for early investigators who sought to assign evolutionary relationships based solely on cell characteristics and morphology. How do you suppose that this question was eventually decided?

Transcribed Image Text:

VERTEBRATES Whale Rabbit Chicken Cat Cobra Salamander Human Cow Frog Goldfish PLANTS Barley Lotus Earthworm Alfalfa Insect Bean Clam INVERTEBRATES Chlamydomonas Nematode PROTOZOA Paramecium