Vascular Plants Flashcards
When were most seedless vascular plants established by?
Devonian
What are the seedless Vascular plats called?
Pteridophytes, with the classes Lycopsids, Spenopsids and Ferns
When did they appear?
420 mya
What distinguishes them from bryophytes?
Sporophyte dominant, not dependent on gametophyte, and vascular system developed.
What did branching allow?
More complex bodies, greater diversity
What happened as a result of more complexity?
increased competition for sunlight and space, may have driven evolution further
What are the derived traits of vascular plants?
Transport in xylem and phloem
Roots
Leaves
sporophylls and spore variation
What is the Xylem?
conducts water and minerals, cells are lignified
What are tracheids?
Tube shaped cells that carry water and mineral up from the rooys
What is the phloem?
cels arranged into tubes that distribute sugars, amino acids
What are the advantages of lignified tissues?
Allow plant to grow taller, as provides support
What are roots?
Lignified tissue below ground, absorb water and nutrients from the soil, anchoring plants
What is the advantage of having leaves?
increase the surface area of the plant
What is the role of the leaves?
Main photosynthetic organ of the plant,
What are microphylls?
Small, usually spine shaped leaves supported by a single strand of vascular tissue
What are megaphylls?
Leaves with highly branched vascular systems, with greater SA and productivity
Which plants have microphylls?
Most of the older lineages, and all lycophytes
What are sporophylls?
Modified leaves that bear sporangia
What are the sporophyte in ferns?
Known as sori, usually on the underside
What are strobili?
Cone like structures, the sporophytes present in many gymnosperms and lycophytes
What are homosporous species?
Have one type of sporangium that produces one type of spore, develops in to a bisexual gametophyte
What are heterosporous species?
Has two types of sporangia and produces two types of spores
What are microsporangia?
Female, structure where megaspores are formed
Where are female gametophytes produced?
In megasporangia on the megasporophylls
