Topic 10 - Seedless Vascular Plants Flashcards
what is one feature for vascular plants?
- independent sporophyte
what did teh indepedent sporophyte lack?
- did not have leaves and roots, and appeared to not have vascular tissue therefore they were not vascular plants themselves.
what evidence the silurian/ early Devonian show?
- vascular tissue in the stem
- cooksonia –> the symbol in front of it means not living.
What is the oldest evidence of vascular tissue from?
- cooksonia fossil form 432 MYA
How to interpret the time-based phylogram?
- the lines where there is no long grey bars –> show that there is not living representative
- the grey bars width shows the duration of the fossil record.
what is the first characteristic of extant vascular plants?
- They have vascular tissue which allows for taller growth and thicker bodies.
what are the two types of vascular tissue?
- xyelm –> transport waters and minerals
- Phloem –> transports carbohydrates
what does xylem contain?
- it has lignin, which is a strengthening polymer in dead hollow cells called tracheids.
what is the second characteristic of extant vascular plants?
complex multicellular roots
what is the third characteristic of extant vascular plants?
complex multicellular leaves
what are the two categories that leaves are divided into?
- Microphylls –> single vein of vascular tissue and are small
-2. Megaphylls –> have a branching vascular system and are large
what does phyll mean?
leaf
what is the fourth characteristic of extant vascular plants?
- the sporophyte is dominant in the life cycle (lasts longer and is more independent)
What is NOT dominant in non-vascular plants?
- sporophytes of are NOT dominant as they are not continuously nutritionally dependent on gametophytes.
what is the fifth characteristic of extant vascular plants?
- have sporophylls (leaves that make spores)
- it is basically a modified leaves on the sporophyte that bears sporangia.
How are sporophylls arranged?
- they can be arranges in a cluster of overlapping scales, which is called a CONE
what is a sporangia?
- a capsule on top of spore
- it is a spore making structure
- vessels where meiosis takes place
what does angio mean?
vessel
what is the sixth characteristic of extant vascular plants?
- shows variation in haploid spore sizes among species
There are two spore sizes
what are the two spore sizes?
- Homosporous –> only makes one size of spore, which becomes a gametophyte that makes both eggs and sperm.
- Heterosporous –> Make two sizes of spore, in which small spore = male gametophyte, and large spore = female gametophyte
what are the two major extant linages?
- Phylum Lycophyta. (1200 sp)
a. have vascular tissue and seedless - Phylum Monilophyat (1200 sp)
a. seedless and vascular tissue.
b. necklace like structure of xylemc. usually are homosporous
what are the two characteristics of seedless vascular plants?
- Gametophytes are tiny, independent plants on or just below the soil surface. (still make own food)
- have flagellated sperm cells that must swim in a film of water to reach eggs. (common in damp habitats)
what are all members of lycophyta?
- they are all microphyllous and can be homo or heterosporous.
what is microphyllus?
- single unbranched vein, and has small leaves
what is a club moss?
- low evergreen herbs with needlelike or scalelike leaves.
- it is a small lycophyte
what is a lycophyte?
- Any of various seedless vascular plants belonging to the phylum Lycophyta and characterized by microphylls (primitive leaves found in ancient plants
What are the three extant groups of Phylum Monilophyta?
- whisk ferns (considered living once but have no roots or leaves as they were lost secondarily)
- horsetails (reduce microphylls, their common name refers to a bushy appearance, they have a genus name of EQUISETUM –> equus = horse and Seta = whiskers)
- True ferns in Devonian (they are the most successful of seedless vascular plants)
what are megaphylls?
- have large leaves with extensively branched vascular system
what are clusters of sporangia called?
- spori
Steps of Homosporous Fern Life Cycle:
- you start off with a haploid spore dispersal from sporangia.
- the multicellular haploid spore, becomes a haploid young gametophyte.
- The Haploid gametophyte is matured. It has an Antheridium. (male part), and an Archegonium (female part). Together the haploid sperm meets the egg in the archegonium.
- The egg is fertilized.
- A diploid zygote is formed in the archegonium.
- The diploid new sporophyte is formed. The gametophyte will dies and the sporophyte will become independent.
- Then a diploid sporophyte is matured where it is a nutrionally independent sporophyte.
- The diploid sporangium is formed on the leaves of the mature sporophyte.
What is a scouring rushes?
- gritty silicon dioxide on horsetail stems made them useful for cleaning cookware.
what are fiddleheads?
- young fern fronds sometimes edible.
- young stems of ferns
what is flash powder used for?
- spores produced by lyophytes abundant and rich in oils, is used as flash powder by photographer sin place of a flashlight.
what are cool swamps?
- tree-sized Lycophyta and Monilophyta
formed forests during the
Carboniferous
what is carboniferous?
producing or containing carbon or coal
what are swamps?
- dead plants accumulated as peat
– swamps and their organic matter later
covered by marine sediments
what did heat and pressure gradually converted peat to?
coal.
Enormous amounts of
CO2 by converting it into plant tissues that then didn’t
decompose, what did this leas to?
- decreased atmospheric CO
2 - this caused global cooling, glaciation and drying, causing cool swamps to be wiped out.
what is global cooling?
changes in solar radiation coming to the Earth’s surface
