Download 20.2 Classification of Plants

20.2 Classification of Plants
Bell Ringer
• Find your lab from yesterday
• Get your lab log book and complete it for
yesterday’s lab.
20.2 Classification of Plants
KEY CONCEPT
Plants can be classified into nine phyla.
20.2 Classification of Plants
Mosses and their relatives are seedless nonvascular
plants.
• Nonvascular plants grow close
to the ground to absorb water
and nutrients.
• Seedless plants rely on freestanding water for
reproduction.
• Liverworts belong to phylum
Hepatophyta.
– often grow on wet rocks or
in greenhouses
– can be thallose (looks like
lobes of a liver flat on the
ground) or leafy
20.2 Classification of Plants
• Hornworts belong to phylum Anthocerophyta.
– found in tropical forests and along streams
– flat, lobed body with little green “horns”
20.2 Classification of Plants
• Mosses belong to phylum Bryophyta.
20.2 Classification of Plants
– most common seedless nonvascular plants
– sphagnum moss commonly used by humans as “peat”
–Peat does not decay when it dies, has antibacterial
properties, and was formerly used as diapers and
bandages.
-Do not have true leaves
-Very tolerant of harsh weather and low nutrient soil
-One of the 1st plants to colonize bare land and begin soil
making process in the early stages of primary succession.
20.2 Classification of Plants
Question
• Why can’t nonvascular plant grow tall???
20.2 Classification of Plants
Club mosses and ferns are seedless vascular plants.
• A vascular system allows club mosses and ferns to grow
higher off the ground.
• Both need free-standing water for reproduction.
• Approximately 300 mya shallow swamps were home to
enormous seedless vascular plants. Overtime the dead
remains of these plants were pressed and heated
underground where they turned into coal. This is why
they call coal fossil fuel.
• Club mosses and ferns are seedless vascular plants.
They still depend on water for reproduction.
20.2 Classification of Plants
• Club mosses belong to phylum Lycophyta.
-not true mosses
-oldest living group of vascular plants
20.2 Classification of Plants
• Ferns and their relatives belong to phylum Pterophyta.
frond
fiddlehead
– whisk ferns and horsetails are close relatives of ferns
– ferns have large leaves called fronds
– Newly forming fronds uncurl as they grow and are called
fiddleheads
20.2 Classification of Plants
• Whisk ferns grow mostly in
tropics and subtropics
• Lack true roots and leaves
• Horsetails grow in wetland
areas along rivers and streams.
20.2 Classification of Plants
Question
• Why do most seedless vascular plants live in moist
areas?
20.2 Classification of Plants
Bell Ringer
 Pg. 622 #1 and #2
 Then look over terms for vocabulary quiz!
20.2 Classification of Plants
Seed plants include cone-bearing plants and flowering
plants.
• Seed plants have several advantages over their seedless
ancestors.
– can reproduce without free-standing water, via
pollination
– pollination
occurs when
pollen meets
female plant
parts
– seeds
nourish and
protect plant
embryo
20.2 Classification of Plants
– Seeds allow plants to disperse to new places
- Ex: wind, water, or animals carry seeds far from the
individual plant. (maples seed’s “wings”)
– Seeds cans survive for many months, even years, in
a dormant state and can withstand harsh conditions
that would kill and adult plant.
– Plants can be grouped according to whether their
seeds are enclosed in fruit.
20.2 Classification of Plants
• Gymnosperms do not have seeds enclosed in fruit.
– most gymnosperms are cone-bearing and evergreen.
– the cone is reproductive structure of most
gymnosperms.
– pollen is produced
in male cones.
– eggs are produced
in female cones.
– seeds develop on
scales of female
cones.
20.2 Classification of Plants
• Cycads are gymnosperms in phylum Cycadophyta.
– look like palm trees with
large cones
– grow in tropical areas
– Many species are
endangered because of
their slow growth and loss of
habitat in these tropical
areas.
20.2 Classification of Plants
• Ginkgos are gymnosperms in phylum Ginkgophyta.
– only one species alive today, Ginkgo biloba
– grown in gardens and used in urban landscaping
– Native to China
– It may be the oldest living species of seed plants.
20.2 Classification of Plants
• Conifers are gymnosperms in phylum Coniferophyta.
– most common
gymnosperms alive
today
– includes pines, spruce,
cedar, fir, and juniper
– Needle like leaves
20.2 Classification of Plants
• Angiosperms have seeds enclosed in some type of fruit.
– A flower is the reproductive structure of angiosperms.
– A fruit is a mature ovary of a flower.
-Fruits vary from a
juicy peach to the fluff
surrounding dandelion
seeds
• Angiosperms, or flowering plants, belong in phylum
Anthophyta.
20.2 Classification of Plants
Common misconception
• Our culture tends to divide produce into fruits and
vegetables, yet the distinction between the two is often
artificial, based on taste or appearance more than on
botanical classification. For example you may think of a
tomatoes as a vegetable and grapes as a fruit when in
fact they are both fruits.
• In botany a fruit is simply the ripened ovary of any
flowering plant. This means that peppers, tomatoes,
squash, green beans, eggplant, watermelon, apples,
bananas, cherries, peaches, cucumbers are all fruits.
Even though in cuisine we refer to some as vegetables.
• Vegetable really refers to the edible leaves, stalks, flower
buds, or roots of a plant.
20.2 Classification of Plants
Question
• What adaptation of seed plants allows sperm to reach
and fertilize an egg in the absence of water??
20.2 Classification of Plants
Question
• What are the 9 phlya covered in section 2?