Transcript The Diversity of Plants

The Diversity of Plants
Unit 7
Chapter 22
Nonvascular plant habitat
 Near water source
Nonvascular plant size
 Because nonvascular plants do not have
xylem and phloem, they depend on diffusion
to get water and nutrients to each cell.
 Consequently, nonvascular plants cannot be
large because cells farther away from a water
source would die..
Rhizoids
 Structures that are
similar to roots that
anchors and
absorbs nutrients
for the nonvascular
plant
Alternation of generation life cycle
 Antheridium: male structure that produces
sperm
 Archegonium: female structure that
produces egg
 Sperm + egg  zygote
Alternation of generation life cycle
 The zygote grows into a plant structure called
a sporophyte.
 The sporophyte produces spores by meiosis.
 The spores grow into a plant structure called
a gametophyte.
Alternation of generation life cycle
 The gametophytes are either male or female.


Male: antheridium
Female: archegonium
Prothallus
 The fern
gametophyte body
that develops
male (antheridia)
or female
(archegonia)
reproductive
structures
Sorus on fronds
 Structures
underneath the
frond leaflets of
fern plants are
called sorus.
 These structures
produce spores
that germinate to
form the prothallus.
Cones
 The structures that bear the male and female
reproductive parts in gymnosperms (exposed
seed, vascular plants) that produce sperm
and egg are called cones.
 Most associate cones with pine trees.
Large
cycad
cone
Pollen grains
 The male gametophytes of seeded plants are
pollen grain, which are sperm and nutrients
packaged within a protective coat.
 These structures carry sperm cells to an egg.
Pine pollen grain with
air pockets to help
the structure stay
afloat in the air
Pollen grains in flowering plants
 Flowering plants produce pollen grains within
the male reproductive structures on flowers.
Ovule in flowering plants
 The ovule is a protected structure that
produces eggs.
Seed development in flowering plants
 Sperm + egg  zygote
 The zygote develops into an embryo found
within a seed.
 The seed may have one or two structures
(cotyledons) that store food.


Monocot: plants that make one cotyledon
seeds
Dicot: plants that make two cotyledon seeds
Dicot seed germination (ex: bean)
Fruit
 Only plants that produce flowers produce
fruits.
 The fruit is a covering that either helps the
seed fly through the air or entices animals to
eat the fruit to disperse the seeds.
Evergreen vs. deciduous plants
 Evergreen: plants that
retain leaves over
winter
 Deciduous: plants that
drop leaves over winter
evergreen
deciduous
Annual plants
 produce seeds that
survive harsh
winters, but parent
plant dies after one
year
Biennial plants
 Life cycle lasts two generations (years)
 Year 1: develop root system, storing sugars
 Year 2: flowers, fruits, and form seeds
Perennial plants
 Plants that live for
multiple years,
continuously producing
viable seeds
 Usually during winter,
leaves drop but the
wood stems survive.