Evolution and Diversity of Green and Land
Plants
Viridiplantae or Chlorobionta – Green plants
•Have cells w/ membrane bound
organelles
•Cell wall made of Cellulose
•Microfibrils – fiber-like units that is
composed of cellulose that is secret
outside the plasma membrane
•Chloroplast – organelle that functions
in photosynthesis
•Chlorophyll b – pigment for light
capture, present in algae
•Thylakoids – chlorophyll containing
membranes
•Grana – pancake-like aggregations
composed of Chlorphyll
•Starch – storage product
•Endosymbiosis – intercellular
cohabitation of a prokaryote inside a
eukaryotic cell
2 sister group of Viridiplantae:
1. Chlorophyceae – chlorophytes
2. Streptophyceae –streptophytes
Haplontic (haplobiontic) life cycle:
•Fertilization of 2 gametes produces a
zygote (diploid 2n)
•It then divides into 4 haploid spores
•Each spores may develop into a new
individual
•The new individual then forms more
gametes
•Oogamy – the egg is larger than the
sperm cell
•Plasmodermata – allows the transfer
of compounds between cells
Embryophtes – Land Plants
•Major innovation of land plants was
the evolution of:
1. Embryo – immature sporophyte
2. Sporophyte – diploid multicellular
stage of the life cycle
3. Cuticle –protective layer that is
secreted to the outside cells of the
epidermis, covered by the cutin
•Cutin – functions as sealant and
prevents water loss
4. Parenchyma – most common plat
tissue
•Apical meristem – tissue of actively
dividing cells
•Middle lamella – binds adjacent cells
together
5. Antheridium – contains the
sperm-producing cells
6. Archegonium – female
gametangium
•Venter – outer layer of the
archegonium consisting sterile cells, it
also surrounds the egg that extends
outward as a tube-like neck
•Ventral canal cell – above the egg
•Neck canal cells – above the ventral
canal cells
Haplodiplontic (diplobiontic) life cycle:
•Consists of both a haploid
gametophyte and a diploid sporophyte
•This results in the alternation of
generations
•Gametophyte – haploid, gamete-
producing part of the life cycle
