Lecture 3 DA Flashcards
Are vascular plants sporophyte or gametophyte dominant?
Sporophyte.
Do aerial plants have cutin or suberin?
Yes.
How are vascular plants classified (2)?
By dispersal - via spores (unicellular) or by seeds (multicellular).
By sperm transport - H20 or pollen
What are the seedless vascular plants (4)?
Ferns
Lycopodiophyta
Sphenophyte
Psilotophyta
Do ferns have true leaves? What about lycopodiophyta?
Ferns have true leaves, lycopodiophyra dont, they have microfils.
What are some advantages that ferns have over moss (2)?
Has vascular tissue
Dominant sporophytes
What is the gametophyte of ferns like?
Small, and shortlived, can be photosynthetic.
Only a few cell layers thick.
What is a source of carbon for fern gametophytes?
Has an association with a fungus, provides carbon.
Do fern sperm require water?
Yes, needed to swim to the egg.
When a fern egg is fertilised, where does it grow?
The zygote grows out of, and becomes independent from, the gametophyte.
Do ferns grow on other plants?
Yes, but are not parasitic.
What can be found on the underside of ferns? What do they release?
Structures called sori (sorus singular).
Produces haploid spores.
What do fern spores do when released?
They germinate into gametophytes.
Where are fern gametophytes found?
On the underside of fern leaves.
What is a rhizome, and what grows out of it?
Its an underground modified stem. True stems shoot out of it.
What are pteridophytes?
Ferns and allies.
Where are xylem and phloem found relative to each other?
Phloem is found on the outer edge, whereas xylem is on the inside.
What is the diameter of xylem relative to phloem?
Xylem has a larger diameter.
What did xylem and phloem development allow for in vascular plants? What is an advantage of this?
Allowed for crown development. Meant their leaves could be out of the reach of herbivores.
What is secondary thickening? What does it do?
Cells lay down a primary wall. Within it, they lay down a secondary wall, mainly lignin. Gives support and rigidity.
What is wood moslty made of?
Dead xylem cells.
What are the main groups of pteridophytes (5)?
Fork ferns True ferns Lycopods Horsetails Progymnosperms
What were the first land plants?
Fork ferns.
Do fork ferns have leaves or roots?
They lack true leaves or roots.
How are fork ferns branched? Are they vascular?
Dichotomously branched. They are vascular.
What are the leaves of true ferns called? Are they true leaves?
Has true leaves called fronds. They are large, called megaphylls.
How are true fern leaves divided? How many veins do they have?
Pennately divided. Are multiveined.
What shape do true ferns have?
Circinnate vernation. Theyre uncoiling.
What are lycopods like?
Small leaved, with single veins.
What are horsetails like?
Whorled leaves, that are silicified. They have ribbed stems.
Do progymnosperms exist?
No, theyre extinct.
What are progymnosperms like?
Are spore-forming trees with fern-like leaves. They have gymnosperm-like wood.
Can leaves be specialised? What is the difference between sterile and fertile leaves?
Yes, ferns can specialise their leaves.
Some are sterile, which are true leaves, or fertile, which are false leaves.
What is an annulus, and what are they found on?
Most true ferns have them, found on sporangia. Has thick cell walls. Thicker on the inside than the outside and is water-filled.
What is a prothallus?
Gametophyte.
What does a prothallus have on it?
Archegonia and antheridia which produce gametes.
What do sporangia have in them besides an annulus?
Spores.
Where can sporangia be found?
Axial surface of leaves.
What is meant by homo and heterosporous?
Homosporous - only one type of spore majority. Heterosorous have more than one.
What is a megaspore?
Large, produces only archegonia which make eggs.
What is a microspore?
Small, only produce antheridia, which make sperm/antherozoids.
What do megasporangia produce?
4 megaspores, 3 of which degenerate.
What do microsporangia produce?
Masses of microspores/sperm.
What do gymnosperms have that ferns and allies dont?
Advanced vascular tissue, particularly xylem.
Are gymnosperms sporophyte or gametophyte dominant?
Sporophyte dominant. More highly reduced gametophytes.
What is a female gymnosperm gametophyte enclosed in? What does this form later on?
Enclosed entirely in a sporophyte, produced in a sporangium. surrounded by an integument. Forms a protective seed coat in a mature seed.
What is a male gymnosperm gametophyte enclosed in?
Pollen grain.
Where do gymnosperm megaspores develop?
Within megasporangium.
Where are gymnosperm reproductive organs found?
Within cones, male and female cones respectively.
What features of gymnosperms makes them dessication resistant (5)?
Have a waxy surface (glaucous) Are xeromorphic Hard leaved (sclerophyllous) Sunken stomata Resin
What are the classes of gymnosperms (3)?
Coniferopsida
Cycadopsida
Gnetopsida
What is the living tissue of conifer wood like?
Only has living tissue in the core. Wood is layered in rings.
Do gymnosperms produce fruit?
No, only angiosperms produce fruit. Some have false fruit (yew).
What is a fruit?
Mature ovaries.
What is the leaves and wood of Cycadopsida like? Is it cone bearing? What are its defences?
Leaves are palm-like.
Wood is manoxylic.
Is cone bearing.
Produces toxic alkaloids.
Where are the pollen sacs and ovules of Cycadopsida found?
Male cones have pollen sacs at their base, which are the microsporangia, will produce microspores.
Female cone shave ovules within them.
What is the reproduction of gymnosperms like in general?
They take a long time to develop.
