Download Kingdom Plantae Ch 22

Plant Diversity
Chapter 22
Miller & Levine Text
Biology 111
Introduction to Plants
Plants…
• Provide the base for food chains on
land
• Provide shade, shelter and oxygen
for all animals
Oldest fossil evidence of plants dates
from about 470 million years ago!
What is the name of the science of
studying plants??
Kingdom Plantae
• Multicellular
• Eukaryotic
• Carry out photosynthesis using
green pigments called chlorophyll
• Include trees, shrubs, grasses,
mosses and ferns
• Most are autotrophs
• Cell Walls made of cellulose
What do Plants Need?
1.
2.
3.
4.
Sunlight
Water & Minerals
Gas Exchange
Movement of Water and Nutrients
Plant Life Cycle
• Two alternating phases, a diploid
(2N) phase called the sporophyte
generation and a hapoid (N)
known as gametophyte generation
• These alternating phases are known
as “alternation of generations”
Early Plants
• For most of Earth’s history plants
did not exist. Life was concentrated
in oceans, lakes and
streams…Oxygen came from algae
and cyanobacteria
• The first plants evolved from an
organism much like the multicellular
green algae living today.
Overview of the Plant
Kingdom
Botanists divide the plant kingdom
into 4 groups based on three
important features:
1. Water-conducting tissues
2. Seeds
3. Flowers
Types of Plants
Cone-bearing
plants 760 species
(gymnosperms)
Ferns & Relatives
11,000 species
Mosses &
Relatives
15,600 species
235,000 Flowering
Plants
(Angiosperms)
Bryophytes (Non-Vascular)
No Xylem or Phloem
• Confined to moist habitats b/c they
need water for sexual reproduction
• Commonly found in wetlands, rain
forests, and roadside ditches
• Generally less than 20cm tall
• 3 classes: mosses, liverworts, and
hornworts
Liverwort
Hornwort
Bryophytes
• Have leaflike, stemlike and rootlike
organs
• Have rhizoids (fine-like roots) that anchor
the plant
• Water and nutrients move from cell to cell
by diffusion
• Mosses are the most common and they
hold a lot of water – this sponge like
feature makes them useful in oil spills,
and potting soils
Moss
Seedless Vascular Plants
(Ferns & Relatives)
• Dominant land plant 300 million
years ago
• Most are now extinct
Seed Plants (Vascular)
• Divided into 2 groups:
Gymnosperms & Angiosperms
GYMNOSPERMS:
• The most ancient surviving seed
plants are the gymnosperms (naked
seeds)
• Seeds often found in a cone
Gymnosperms: The Conifers
• Cone bearing woody trees and shrubs
• Leaves are usually needlelike
• Most are evergreen (don’t drop their
leaves in the Autumn)
• Conifers DO shed their needles, just not
all at once – usually 2 to 4 years
• Grow in many different environments
• 600 species (pine, fir, spruce, cedar,
hemlock, sequoias
• Produce useful products, ie.
lumber/paper
Seed Plant – Angiosperms:
Flowering Plants
• There are thousands of different kinds of
flowering plants
• Angiosperms ALL produce seeds in
reproductive structures called flowers.
• Flowers contain ovaries, which surround and
protect the seed. Then, as the seeds mature,
the flower changes into a fruit.
• The name angiosperm means “covered seed”
• Mature seeds are scattered, or dispersed, along
with the fruit
Roots, Leaves, Stems &
Carnation Activity
“Principal organs of seed plants”
Roots
• Absorbs water and dissolved
nutrients
• Anchors plants to ground
• Prevents erosion
• Protection from soil bacteria and
fungus
• Transports water & nutrients
• Holds plants upright against forces
such as wind and rain
Roots – Two main types:
Plants have taproots, fibrous roots or both
#1 Taproots - Characterized by having one main
root (the taproot) from which smaller branch
roots emerge.
• Make a plant hard to pull from the ground
• Go far underground to reach water
• Ex: dandelions, carrots, beets, radish
Taproot
#2. Fibrous Roots –
• Characterized by having a mass of
similarly sized roots.
• Most monocots have fibrous root
systems.
• Ex: grasses
• Plants with fibrous roots systems are
excellent for erosion control, because
the mass of roots cling to soil particles.
Fibrous Roots - A cabbage seedling with
white, fibrous roots snaking through the soil
Root Overview
Root Cap – tough cells to drill soil,
and produces a slimy substance for
roots to move through soil
Apical Meristem (growth tissue) –
replaces cells of root cap as they
are damaged
Root Hairs – absorb water and
minerals from the soil and increase
the surface area of the root.
Pericycle – forms the lateral roots
Leaves
• The structure of a leaf is optimized
for absorbing light and carrying
out photosynthesis.
Leaves
• Photosynthetic organ of the plant,
used to convert sunlight into food
• Photosynthesis Equation:
STEMS
Stems have 3 important functions:
1. Produce leaves, branches, flowers
2. Hold leaves up to sunlight
3. Transport substances between
roots and leaves
Carnation Activity:
Most plants “drink” water from the
ground through the roots…but what
if they are cut??
Carnation Activity:
• There are 2 things that combine to
move water through plants
1. Transpiration
2. Cohesion
Carnation Lab:
• Water evaporating from the leaves,
buds and petals
(TRANSPIRATION) pulls water up
the stem of the plant
• Water that evaporates from the
leaves “pulls” other water behind it
up to fill the space left by the
evaporating water, but instead of
your mouth providing the suction it
is due to evaporating water
Carnation Lab:
• Water can move up the plant
because water is very sticky to itself
(called water cohesion) and
because the tubes in the plant stem
are small (the xylem) this process is
called capillary action/cohesion
tension theory!.
• Coloring the water doesn’t harm the
plant but allows you to see
movement through the plant 