Land Plants: Gymnosperm Diversity Flashcards
What are the 4 extant clades of gymnosperms?
Cyadophyta
Ginkgophyta
Coniferophyta
Gnetophyta
What is the angiosperm extant clade?
Anthophyta
What is a Megaphyll?
A leaf with two or more large veins either running parallel or branching apart and connected by a network of smaller veins
What is wood?
secondary xylem (produced by the vascular cambium)
What does the cork cambium produce?
bark
What is Heterospory?
Sporophytes produce spores of two different sizes and sexes
The microspore (smaller) is male and the megaspore (large) is female
What are two key features of seed plants?
continued gametophyte reduction adn airborne fertilization via pollen
Where are gametophytes contained for gymnosperms and angiosperms?
in pollen and ovules
What is ovule composed of in seed plants?
megasporangium (2n), female gametophyte or megaspore (n), and integument (2n)
What is a sperm feature of cyads and ginkgos that conifers do not have?
they have motile sperm that can swim to the egg in the ovule
conifers do not and travels to egg in ovule via a pollen tube
What is the seed?
a mature (fertilized0 ovule with a sporophyte (2n) embryo
it consists of a seed coat, embryo, and stored food
What are the advantages of the seed?
increases offspring survival
resuslts in higher germination raytes and seedling establishment than plants that release ‘naked’ zygotes and spores
How does the seed increase offspring survival?
physically protects the enclosed embryo
prevents the embryo from desiccation
source of nourishment for the embryo
What are the features of both angiosperms and gymnosperms?
micropyle, nucleus, megasporocyte, integument presence, ovule
What is the difference between the integuments in angiosperms and gymnosperms?
in angiosperms it is a double-layer
gymnsperms only a single-layer
What are features unique to the Angiosperms?
flowering
style, stamen (anther and filament), ovary wall, Funiculus
What are Cycadophyta (cyads)?
Palm-like plants in tropics and subtropics
leaves clustered at top of woody tunk
Florida one species Zamia pumila
What is difference between palm trees and cyads?
presence of cones instead of flowers differentiates cyads to gymnosperms
What does it mean to be Dioecious?
separate male and female cone-bearing plants
Cyads are Dioecious
How do cyads do pollination?
insects attracted by chemical signals in cones
after fertilization what is produced by cyads? for what purpose?
brightly coloured, fleshy seeds, attracting birds and mammals for dispersal
What is the only species of Ginkgophyta? where found?
Ginkgo biloba
preserved on temple grounds in China and Japan
introduced in North America in late 1700s not wild
What is a feature of Ginkgos that make it suitable for urban parks and city streewts?
it is resistant to air pollution
What are features of seeds etc. of Ginkgos?
dioecious, 2 ovules per short short (usually one matures), fleshy seed coat, male cones clustered at tip of short shoots
Which clade os Gentophyta sister to?
conifers
what are the 3 extant genera of gnetophyta?
gnetum
ephedra
welwitschia
What platns do Coniferophyta include?
pine, fir, spruce, redwoods …
Where are conifers dominant?
in temperate and mountain forests
What are most conifers? meaning?
evergreen so keep needles all year round
What is a unique feature of conifer xylem?
consists almost entirely of tracheids, resulting in wood that is trong fro its weight with relatively uniform mechanical properties
What are leaves like in the pine family?
reduced in bundles 1 to 8 leaves, needles like megaphylls: 2 veins
What are advantages of Pine leaves?
adapted for growth in dry habitats
thick cuticle (waxy)
hypodermis
stomata in pits
mesophyll cells with wall ridges
Endodermis
What is hypodermis?
compact layers of cells below epidermis
What do wall ridges do?
increase surface area
What makes up the bark in pine secondary growth?
secondary phloem and peridem
What is the peridem derived from?
outer layer of cortex
