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evolution of land plants - Coggle Diagram
evolution of land plants
early land plants
high CO2 and low O2 atmosphere
evidence of early plants in fossils, plants such as spores, cryptospores, and trilete marks
innovations that evolve over time
stomata for gas exchange
tetrads/dyads
vascular tissues (trachieds) for water and sieve cells for food
indeterminate growth
leaves
roots
seeds (gymnosperms and angiosperms)
flowers
early land plants -->gametophyte dominant
later vascular plants--> sporophyte-dominant
first fossils --> liverworts and cooksonia
liverwort fossil
nonvascular plants
no true roots, leaves, or stems
has rhizoids (hair like structures that anchor them and attract water)
cooksonia fossil
simple rootless stems, leafless
contains simple vascular tissues like tracheids
one of the first vascular plants and capable of water transport
structural changes in plants
evolution of the stomata
allows for CO2 to come in and O2 to come out while minimizing water loss
some early functions of a stomata
likely aided sporophyte desiccation and not full gas exchange
possible not yet capable of the opening and closing of the stomata
intercellular spaces
called pseudostomata that lacked true intercellular air spaces
functions mainly in diffusion of minerals and water between gametophyte and sporophyte
stomatal canals developed to enhance exchange
some considerations
guard cell control
photosynthetic dependency
water use efficiency
stomatal diversity
monocots
linear, ordered rows between long files of epidermal cells
asymetrical and symetrcal divisions
eudicots
randomly scattered among epidermal cells
asymetrical cell divisions
vascularization
development of specialized conducting tissues, "vascular tissues"
xylem
vascular tissue that moves materials around like water and nutrients, main function is water transport and support
phloem
vascular tissues that move materials around like sugar and hormones and food
roots absorb water and minerals from the soil, xylem transports them upwards towards stem and leaves, leaves perform photosynthesis to make sugars, phloem distrubutes those sugars throughout the plant
vascular bundles
xylem and phloem together, eudicots it forms a ring and monocots it is just scattered
wood
forms from secondary growth which only occurs in plants with a vascular cambium
early wood cells are larger and conducts a lot of water quickly
late wood cells are smaller and provide more structure and support
