Biology Ch. 29: Gymnosperms Flashcards
gymnosperm
“naked seed” plants
perennial
grow and reproduce year after year
monoecious
each plant has some “male” flowers with only stamens and some “female” flowers with only carpels
dioecious
given plant produces flowers having only stamens or only carpels
strobilus
cone
group of sporangia put together on top of leaves
pollen cone
male strobilus
relatively small and delicate
consists of many small scales, which are specialized leaves called sporophylls
seed cone
develops higher in the tree than male cones
cone scales bear ovules
-each ovule contains a spore mother cell called a megasporocyte
microsporangium, pollen sac
cycads and conifers have 2 pollen sacs on the abaxial side of the cone
microspore
undergo mitosis and develop into pollen grains
microsporocytes undergo meiosis and give rise to haploid microspores
pollen grain
male gametophyte
produce 2 sperm
walls reinforced with polymer sporopollenin
nonmotile
pollen tube
pollen grain develops into a pollen tube after pollination and grows toward the female spore mother cell
spropollenin
polymer that reinforces pollen grains
microgametophyte
sperm-producing gametophyte
in heterosporous plants
tube cell
cell from which the pollen tube grows
generative cells
cell that divides to give rise indirectly or indirectly to sperm
prothallial cells
BOOK
ovule
structure in which a female gametophyte develops
enclosed within a ovary
in conifers each ovule contains a spore mother cell called a megasporocyte
seed
structure that forms when the ovule matures after a pollen grain reaches it and a sperm fertilizes the egg
3 basic parts
-embryo sporophyte
-tissue around it containing carbohydrates, proteins and lipids
-tough, protective outer seed coat
integument, seed coat
layer of tissue that surrounds the megaspores in the progymnosperm
foundation for an ovule that would develop into a gymnosperm seed
integument develops into a protective seed coat by the time the ovule is mature
micropyle
where the pollen tube enters the ovule prior to fertilization
between the integuments
megasporangium
formed within ovules
surrounded by protective tissue in one or two layers called integuments
nucellus
name for the megasporangium in the gymnosperms
megaspore
female gametophyte
megagametophyte
egg producing gametophyte
archegonium
outside layer of cells (single layer) that surround gametangia that produce the egg
egg, sperm
respective gametes
suspensor
transfers nutrients from the partent plant to the embryo
descendants of the basal cell that form a simple row of cells
cotyledon, seed leaf
cotyledon
-embryonic leaf
seed leaf
-another name for the cotyledon
cycadophyta distinguishing characteristics
dioecious -separate pollen and ovule producing plants monocot rough stem microsporangia develop on abaxial side pollen grains develop in sporangia -non-flagellated sperm
coniferophyta distinguishing characteristics
native to northern hemisphere leaves are needelike or scale-like adapted to cold/dry -have small survace area for their volume -thick cuticle -few stamates -stomates are sunken below the surface 2 pollen sacs/scale 2 ovules/scale non-flagellated sperm
gnetophyta distinguishing characteristics
“leafless” shrub of desert areas
similar to angiosperms
-some have vessels in their xylem
-some have pollen and ovules in the same cluster of strobili
-some use both sperm in a given pollen tube
-non-flagellated sperm
ginkgophyta distinguishing characteristics
large diciduous trees leaves spur shoot dichotomous venation thick, fleshy seed coat -releases butanoic acid when smashed
conifer adaptations for dry habitats
small surface area for their volume
thick cuticle
few stomates
stomates are sunken below the surface
why do many conifers require mycorrhizal fungi for normal growth?
BOOK
what advantages are there in the “seed habit” for life on the land?
way to move gametes without free water
- opens during times of the year that are not wet
- opens geographical areas
what makes gymnosperms “nakes seed” plants?
seeds are unenclosed by an ovary or fruit
angiosperms have ovary
