Lecture 3 RH Flashcards
What replaces leaves in bryophytes, lycophytes and acacia?
Bryophytes do not have true leaves.
lycophytes have microphylls rather than true leaves
acacia have phyllotes
What are the 3 types of vascular plants (tracheophytes)?
lycophytes
manillophytes
lignophytes
Which plants don’t have true leaves?
bryophytes
lycophytes
How long ago does fossil evidence suggest the existence of ferns?
tree fern fossils evidence goes back more than 300 million years
Which trees have true leaves?
euphyllophytes
Which plants dominated carboniferous era?
manillophytes
Do bryophytes have true roots?
bryophytes have rhizoids not true roots.
Which plants produce spores?
Everything up to gymnosperms are spore bearing plants the rest produce seeds
What are the characteristics of vascular plants?
Vascular tissue
Sporophyte dominant and assimilative
Cutin or suberin on aerial parts
Body on axis (stem)
Large SA/V ratio
Increase in size made possible by conducting tissue
What are the types of seedless vascular plants?
Lycopodiophyta
Sphenophyta
Psilophyta
What is the 3rd largest group of plants?
Whisk Fern (psilophyta)
What is happening to fern diversity?
It is getting more diverse
Do lycopods have true leaves?
No they have microphylls
Do sphenophytes have true leaves?
no they have microphylls in spirals
What are plants’ role in formation of coal?
Plants get compacted over time to form coal. Specifically lycophytes.
*oil and natural gas form from marine organisms
What is the dominance of seedless vascular plants? Is the gametophyte or the sporophyte reduced?
Sporophyte dominance, gametophytes are highly reduced in seedless vascular plants
What are the features of ferns?
Earliest fossils are 390 million years old.
Dominant plants 300 million years ago
Advancements over the mosses - vascular tissue and sporophyte dominance
Tree ferns in tropics are 5 - 15 meters tall, 2 -4 meter leaves
Sporophyte generation in ferns is a perennial plant with large complex leaves called fronds
What is the shape and role of fern gametophyte?
fern gametophyte is typically heart shaped and contains the antheridia and archegonia (it is monoecious)
How do ferns prevent self-fertilization?
Gametophytes mature at different times most of the time
How do gametophytes prevent self-fertilization?
They develop at different times
What are sori?
Clusters of sporangia
What is a sporophyll?
A fertile leaf
What are the 4 phyla of ferns and allies?
Lycopods (lycophyta)
whiskferns (psilophyta)
horsetails (sphenophyta)
true ferns (pteridophyta)
What are the 5 groups of pteridophytes?
Fork-ferns (psilotum)
True ferns (Dicksonia)
Lycopods (lycopodium)
Horsetails (Equisetum)
Progymnosperms
What are the features of fork-ferns?
Fossils 400 million years before present
First land plants
Simple structure
What are the features of true ferns?
Leaves are large (megaphylls), pinnately divided (fronds), multiveined, circinnate vernation (uncoiling)
What are the features of lycopods?
Small leaves
Single vein
Spores in thick-walled sporangia on top surface of leaves. Some are specialized for spore production (sporophylls)
What are the features of lepidodendron?
diamond shaped pattern on stem.
tree form pteridophyte
heterosporous
primitive formation of leaves
What ar ethe features of horsetails?
Whorled leaves
Silicified cell wall
Ribbed stem
What are the features of progymnosperms?
Extinct species
Earliest they appeard was 390 million years before present
They are trees (Up to 20 meters)
‘Wood like gymnosperms’
Large fern-like leaves
What are the types of growth habit?
Tree
Ground
Epiphytic
aquatic
What is leave specialization?
Some ferns have leaves which carry out reproductive functions whereas others are important for photosynthesis.
What is an an indusium?
This membrane covering the sorus
What are sporangia?
Spore holding structures (10 to hundreds of spores)
What is a stomium?
Maturing sporangium with and annulus of the way
What are the features of the cells of the annulus?
Cells of the annulus have a thick cell wall
How are spores released from sporangium?
When sporangium stretches it eventually snaps and releases the spores in a dispersed manner
What is homospory and heterospory?
Homospory means only 1 type of spore is produced. Heterospory means multiple types of spores are produced
What types of spores are there?
Megaspores and Microspores
What is the difference between megaspores and microspores?
Megaspores: Large and only produce archegonia with eggs
Microspores only produce antheridia with antherizoids
what is the difference between micro and mega sporangium chambers?
Microspores are contained in one large chamber called the microsporangium.
Megaspores are contained in several large chambers called megasporangiums
What is the life cycle of the lycopod?
1) Mature sporophyte contains strobilus (false cone). Under their leaves is either a microsporangium or a megasporangium. Stem contains rhizospores
2) Sporangia walls rupture
2) Sporangium wall ruptures and produces rhizoids and archegonia in gametophyte
What is a ligule?
ligule is a modified leaf that connects the lycopod leaf to the rest of the plant
What are the characteristics of gymnosperms?
Highly reduced gametophtye
Female gametophyte is enclosed in sporophyte
Megasporangium is surrounded by integument
Megaspore develops in situ
Reproductive organs are within cones
Generally able to withstand extreme conditions
What are the dessication-resistant features of gymnosperms?
Xeromorphic (store water)
Waxy (glaucous)
Hard-leaved (sclerophyllous)
Sunken stomata
Resin
What are the extant classes of gymnosperms?
Coniferopsida
Cycadopsida
Gnetopsida
This means there are many extant monotypic genera with some genuses with single species which indicates a decline.
What are the orders of gymnosperms?
3 orders extant and 1 extinct:
Coniferales (conifers) - still expanding
Taxales (yews) - declined but stable
Ginkgoales (maidenhair tree) - monotypic
What are the “fruit” of gymnosperms and how are they different to that of angiosperms?
They are fleshy outgrowths rather than ovaries
What are cycads?
Cycads are very old trees and have manoxylic wood (wood that is made up of soft, medullary rays) their leaves are palm-like.
They produce toxic alkaloids
Where are the sporangia located in gymnosperms?
Within the cones
How are cycads pollenated?
They are beetle pollenated which is different to other gymnosperms
