52 terms

Biol 104 Lecture 15

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A diploid sporophyte stage alternates with a ___ ____ ___
haploid gametophyte stage
Haploid spores produced via ____
meiosis
Haploid gametes produced via ____
mitosis
Zygotes formed by the fusion of ......
two haploid gametes
This biphasic life cycle that plants demonstrate is referred to as an?
Alternation of generations
The life cycle of a plant from?
zygote to sporophyte to spore to gametophytes to gametes and back to zygote
Green algae called ____ are the closest living relatives of plants
charophytes
Four key adaptations for life on land distinguish the main lineages of the plant kingdom
Generation of lifecycle that is dominant; lignified vascular tissues; seeds; flowers
Bryophytes
lack conducting structures
Rhizoids
attachment structures
Limited size
lack of vascular tissue and ligin
Reproductive structures
archegonia
antheridia
water!
archegonia
produce eggs
antheridia
produced swimming sperm
A Moss
The short, leafy green plants are haploid gametophytes; the reddish brown stalks are diploid sporophytes
Life cycle of a moss
The leafy green gametophyte is the haploid generation that produces sperm and eggs. The sperm must swim through a film of water to the egg. The zygote develops into a stalked, diploid sporophyte that emerges from the gametophyte plant. The sporophyte is topped by a brown capsule in which haploid spores are produced by meiosis. These are dispersed and germinate, producing another green gametophyte generation.
Vascular plants have conducting vessels that also provide support
Lignin adds extra support, so plants grow taller than nonvascular plants
Sporophyte stage is larger, more conspicuous and persists longer than the gametophyte
The Seedless Vascular Plants Include the Club Mosses, Horsetails, and Ferns
Produce swimming sperm, so water is essential for reproduction
Club mosses and horsetails - presently, not diverse
Ferns - most diverse seedless vascular plants
Broad leaves unlike other seedless vascular plants
Sporangia produce spores on special leaves
The biphasic life cycle sporophyte (2n) and gametophyte (n)
.....
Sporophyte
a diploid structure that will generate sporangia that contains reproductive cells which divide by meiosis to give rise to haploid cells called spores
Spore
a haploid cell born in a sporangium that germinates into a gametophyte
Germinate
to grow and develop through repeated mitotic divisions
Gametophyte
the haploid plant that develops from a spore which will come to contain gametangia and gametes
Gametangia
a structure on a gametophyte that contains the sperm or egg
Gametes
sperm or egg cells usually found in structures called gametangia
Zygote
the unicellular diploid product of the fusion of the egg and sperm
Coal, oil, and natural gas are
fossil fuels
Pollen
transport the sperm without water; dispersed by wind or animals
Seeds
plant embryo, food supply, and protective coat
Gametophytes are microscopic
male gametophyte (pollen grains) and female gametophytes (found within the ovules of the ovary)
The Gymnosperms includes the
Cycads, Ginkgo, Gnetophytes, & Conifers
Conifers
adapted to dry, cold conitidions
Ginkgos and Cycads represent less common groups of
gymnosperms
What is the function and structure of the flower?
Flowers are the part of the sporophyte generation in flowering plants that is dedicated to sexual reproduction.
Insect and vertebrate pollination is ____ efficient than wind pollination.
more
Plant adaptations
that put more efforts into mechanisms to attract the animals (i.e. nectar, odoriferous compounds, appearance and etc.) ensured the success of those flowering plant lineages.
Wind pollinators are largely responsible for the pollen that causes ____ _____
"hay fever"
A complete flower contains all four floral parts (whorls) that make up the
sepals, petals, stamens and carpels
Stamens and carpels are composed of two to three distinctly different parts.
-Stamens contain an anther and filament
-Carpels contain a stigma, style and ovary
An incomplete flower is
any flower that lacks one or more of the four floral parts
Pollen develops within the
anther of the stamen
Pollen contains the
male gametophyte also called the microgametophyte this gametophyte is haploid
Immature male
gametophyte contains generative cell and tube cell nucleus
mature gametophyte
contains two sperm cells and one tube cell nucleus
generative cell
becomes the two sperm cells when it matures
the female gametophyte
is sometimes called the embryo sac or megagametophyte this gametophyte is haploid
Pollination of the flower leads to fertilization
1.) To recap pollination is when a pollen grain lands on the stigma of a flower's carpel.
2.) The pollen generates a tube to transfer the sperm from the male gametophyte to the female gametophyte.
3.) In flowering plants we see a double fertilization from the fusion of the sperm to specific cells of female gametophyte.
4.) This double fertilization gives rise to a zygote and endosperm.
5.) When the female gametophyte develops in the manner previously illustrated (polygonum type), which is the most common, the double fertilization gives rise to a (2n) zygote and a (3n) endosperm.
Fruits Help Disperse Seeds
Explosive fruits allow shotgun dispersal
Lightweight fruits allow wind dispersal
Wind-dispersed fruits
Floating fruits allow water dispersal
Water-dispersed fruit
Clingy or tasty fruits allow animal dispersal
The cocklebur fruit uses hooked spines to hitch a ride on furry animals
The colors of ripe fruits attract animals
How do seeds germinate and grow?
Seeds need moisture and warmth to germinate. If conditions are not within the required range the seed will go into a period of dormancy. Its metabolic activity will slow while it waits for the appropriate environmental conditions to germinate. This strategy allows seeds to persist through times of adverse environmental conditions.
The developing embryo must be nourished. Its nourishment comes from the endosperm which feeds the seed leaves (cotyledons) of the embryo.
The embryo, upon germination, begins to develop into an embryonic shoot. This shoot is composed of two parts the hypocotyl and epicotyl
The cotyledons nourish the developing plant
Hypocotyl
the region directly above the root system, but below the cotyledons.
Epicotyl
everything above the cotyledons.
Wind pollinators are largely responsible for the pollen that causes ____ _____
"hay fever"