Gymnosperms

where would you expect to find the Whitebark pine?

at the top of a mountain, in Colorado, California, Nevada, etc.

what are the four phylum in Gymnosperm?

Coniferophyta, Ginkgophyta, Cycadophyta, Gnetophyta

what is a gymnosperm?

refers to the exposed nature of the seeds

where are the seeds of gymnosperms produced?

on the surface of sporophylls or similar structures

T or F: gymnosperm seeds are enclosed within a fruit similar to flowering plants

F

where is the female gametophyte produced?

inside an ovule

the ovule, where the female gametophyte is produced, contains what?

a megasporangium

what is another word for the megasporangium

nucellus

the ovule is enclosed in what?

integument

the sporophytes of gymnosperms are mostly what?

trees and shrubs

are the gametophytes tiny or large?

tiny and develop within sporophytes

how many species of gymnosperms are there?

about 760 species

how many times are the seeds of gametophytes fertilized?

once

T or F: seeds of gymnosperms are the result of a single fertilization

T

T or F: fertilization of gymnosperm doesn’t not require water

T

why does the fertilization of gymnosperms not require water?

the pollen grains travel via wind dispersal, so no water is needed

list the four selective advantages to being a seeded plant.

1. the dormant state of seeds enable seed plant to survive during periods of cold winter and drought

2. the seed coat serves as a barrier against bacterial or fungal decay

3. seeds attract seed-eating animals for seed dispersal

4. seeds include food for the embryo and germinating seedling

what phylum are conifers in?

Coniferophyta

what is the distinguishing plant of conifers?

Pines (pinus)

what is the largest genus of conifers?

Pines (pinus)

how many species of conifers are there?

over 100 species

what is the world’s oldest known living organism?

Bristlecone Pines - 4,600 years old

what phylum is the oldest known living organism a part of?

Coniferophyta

describe the structure of Coniferophyta?

pines leaves are needlelike and are arranged in clusters of bundles of two to five leaves

each cluster of pine leaves is called a what?

fascicle

what does the fascicle form?

a cylindircal rod of pine leaves

where do the resin canals of coniferophyta develop?

mesophyll

what type of stomata do coniferophyta have and why?

sunken stomata to reduce water loss

most gymnosperm wood consists primarily of _________.

tracheids

Do gymnosperms have vessel elements or fibers?

no

given that gymnosperms have no vessel elements we refer to it as a _____ wood.

soft

what are associated with the roots of most conifers?

mycorrhizal fungi

are pines heterosporous or homosporous?

heterosporous

what does it mean to be heterosporous?

producing two types of spores

what is the male structure for Pine reproduction

Pollen cones (male strobili)

what do pollen cones consist of?

papery scales arranged in a spiral around an axis

what is the term for male cones shedding pollen?

microsporangiate

what do the pollen cones house?

microsporangia that develop in pairs toward the base of the scales

what is the mother male spore cell?

microsporocytes

each microspore in the pollen cone develops into what?

a winged pollen grain

pollen grain is also known as what?

immature male gametophyte

what cells does the pollen grain consist of?

two prothallial cells

a generative cell

a tube cell

• 4 cells total

is the pollen grain haploid or diploid?

haploid

what does the tube cell of the pollen grain become?

pollen tube

what is the function of the pollen tube

elongates upon germination

what enters the pollen tube?

generative cell enters the pollen tube and divides via mitosis

when the generative cell divides via mitosis in the pollen tube what does it yield?

sterile cell and spermatogenous cell

when the sterile cell and spermatogenous cell divide via mitosis what does it yield?

two sperm (no flagella)

what is the mature male gametophyte is coniferophyta?

the germinated pollen grain, with its pollen tube and two sperm

T or F: Coniferophyta form an antheridium strucutre

F

what is the female reproductive strucure of pines?

seed cones (ovulate cones/female strobili)

what do seed cones consist of?

woody scales w bracts (at maturity) arranged in a spiral around an axis

what are the fertile scales of seed cones referred to as?

ovuliferous scale

the seed scale bears what on its upper surface?

two ovules

each ovule on the seed scale consist of what?

a multicellular nucellus (megasporangium)

what is the nucellus (megasporangoium) surrounded by?

the integument

what is the opening of the ovule called?

micropyle

the megasporocyte produces megaspores through what process?

meiosis

what structure does the megasporocyte produce the megaspores within?

megasporangium

how many megaspores are produced by the megasporocyte?

four megaspores

how many functional megaspores are produced by the megasporocyte?

one

how many of the megaspores produced by the megasporocyte end up dying?

three

only _____ megaspore develops into the female gametophyte

one

how many arechonia differentiate at the micropylar end?

two or three

is the integument haploid or diploid?

diploid

is the female gametophtye haploid or diploid?

haploid

where do the pollen grains land on the female reproductive structure?

pollen chamber

how long is reproduction for pines?

about 15 months after pollination

it takes about 15 months for the tip of the pollen tube to arrive at the ________

archegonium

one sperm unite w the egg to form a ______

zygote

the zygote develops into the _______

embryo

what is the embryo nourished by?

the female gametophyte

what does the integument become?

the seed coat

the whole pine tree is which generation?

sporophyte 2n

the only part of the female gametophyte which is n is what?

megaspore

look at the pine life cycle in the slides

…..

give some examples of plants that produce naked seeds.

Balsam fir (Abies balsamea)

European Larch

Thuja

Juniper Seeds of yew (Taxus)

seeds of podocarp

what is the plant example for phylum Ginkgophyta

Gingko (Maidenhair tree)

how many living species of Ginkophyta are there?

only one → the Ginkgo biloba

what type of leaves does Ginkgo biloba have?

notched, borad, fan-shaped leaves

what arrangement are the leaves of Ginkgo biloba leaves produced?

in a spiral on short, slow-growing spurs

what are the veins of Ginkgo biloba leaves like?

No midrib or prominent veins

hair-like veins that branch dichotomously

Ginkgo trees are deciduous and dioecious. What does this mean?

their leaves drop in the winter and there are two separate trees (male and female)

what is an example of a plant in the phylum Cycadophyta?

the Cycads

what do Cycads look like?

appearance of a cross between a tree fern and a palm

What climate do Cycads grow in?

tropics

are Cycads fast or slow growing?

slow-growing plants

what types of trunks do Cycads have?

tall unbranched trunks

what are the leaves of Cycads like?

crown of largely pinnately divided leaves

how many living species of Cycads are there?

about 140 living species

are cycads dioecious or monoecious?

dioecious

what makes phylum Gnetophyta unique?

only gymnosperms that have vessels in the xylem

more than half of the 70 known species of phylum Gnetophyta are joint first in the genus:

Ephedra

Given that Gnetophyta have vessels what type of wood are they?

hard wood

most of the remaining species of Gnetophytes are in which genus?

Gnetum

what habitat to the Gnetophytes grow in?

tropics

what are the leaves of Gnetophytes like?

most are vine-like with broad leaves similar to those of flowering plants

what are the three genus of phylum Gnetophyta?

Ephedra

Gnetum

Welwitschia

the genus Welwitschia is w/n which phylum?

Gnetophyta

how many species are in the genus Welwitschia?

only one species