Question

a. Create a list of organisms the represent the evolution of major groups of plants starting from the earliest protist relative: The list should include i. the type of plants (group name),

1. the key adaptation that makes that group unique

Answer 1

I. NON VASCULAR BRYOPHYTES:

Hornworts - tall and thin sporophyte, a large chloroplast that helps in photosynthesis , found in damp places , no vascular tissue and roots absent instead rhizoids present that helps in absorption of water and nutrients from substratum.

Liverworts- plant body is thallus with underground structures known as the rhizoids, do not have vascular system, leaves or stem, reproduction by Gemma cups.

Mosses - multicellular rhizoids that facilitate absorption of water and nutrients efficiently and they have stomata that help in gaseous exchange.

II. VASULAR SEEDLESS PLANTS

Club mosses - true stem and thick leaves called strobilli present but flowers and seeds absent.

Ferns- seedless , vasculature absent , true stem , leaves and roots present , apical meristem present , Young parts of stem, young leaves, petiole and rachis of mature leave possess hairs or scales called ramenta. Ramenta protect them from mechanical injury and desicca­tion , sperms and embryo present.

III. VASCULAR SEED BEARING PLANTS

Gymnosperms -  do not have an outer covering or shell around their seeds , do not produce flowers and fruits , wind pollination ensures seed dispersal .

Angiosperms - well developed flower, seeds with covering and fruits present.