Transcript 1 -Plant Diversity & Life Cycles I

Plant Diversity
and Life Cycles
Plant Kingdom Characteristics
1)Multicellular
2)Eukaryotic
3)Cell Walls
4)Autotrophic
Question:
What
adaptations
were needed
for plants to
live on land?
1)Absorb nutrients from
surroundings
2)Prevent water loss
3)Dispersal (of
offspring) on land
Charyophyte (Green Algae)
Homology to modern plants:
1. Chlorophyll B & Beta Carotenes
2. Chloroplasts have grana
3. Biochemical – Cell Wall Similarities
4. Mitotic Processes
5. Sperm Structure
6. DNA
Cuticle
All plants undergo a life cycle that takes
them through both haploid and diploid
generations.
The multicellular diploid plant structure is
called the sporophyte, which produces
spores through meiotic (asexual) division.
The multicellular haploid plant structure is
called the gametophyte, which is formed
from the spore and give rise to the haploid
gametes.
The fluctuation between these diploid and
haploid stages that occurs in plants is
called the alternation of generations.
Plant Life Cycle:
Alternation of
Generations
Vascular tissue
is composed of
xylem and
phloem, which
function in the
transport of
water and
dissolved
substances.
Vascular Tissue
Xylem - Conduct
water and dissolved
minerals
• Support
Phloem - Conduct food
and other organic
substances
Vascular Versus Nonvascular Plants
Transport
system
Can grow tall
Cannot survive
without water
Need
light
photo
synth
esize
No transport
system
Grow close to
the ground
Can go
dormant during
drought
Take a deep breath in and then let it out.
Breathing to you is a very natural function that you usually do
without even thinking about it.
When you breathe, you are taking in oxygen and releasing
carbon dioxide.
Plants 'breathe' too, but they do it through tiny
openings in leaves called stomata (singular:
stoma).
Stomata open and close to allow the intake of
carbon dioxide and the release of oxygen.
Bryophytes
3 Groups of Bryophytes
1)Moss
2) Liverworts
3) Hornworts
Pteridophytes
Pteridophytes
Pteridophytes are a phylum of plants.
They are the vascular plants (those having xylem
and phloem tissues) that reproduce by releasing
spores rather than seeds, and they include the
highly diverse true ferns and other graceful,
primarily forest-dwelling plants.
There are about eleven thousand different
species of pteridophytes, making them the most
diverse land plants after the flowering plants
(angiosperms).
3 Groups of Pteridophytes
1) Ferns
2) Horsetails
3) Club moss
Gymnosperm
Gymnosperms are seed-bearing vascular
plants, such as cycads, ginkgo, yews and
conifers, in which the ovules or seeds are
not enclosed in an ovary.
The word "gymnosperm" comes from the
Greek word “gymnospermos”, meaning
"naked seeds".
Gymnosperm seeds develop either on the
surface of scale or leaf-like appendages of
cones, or at the end of short stalks.
4 Groups of Gymnosperm
1) Ginkgo
2) Gnetophytes
3) Cycads
4) Conifers
Angiosperm
Angiosperm
Angiosperm, any member of the more than 300,000
species of flowering plants (division Anthophyta), the
largest and most diverse group within the kingdom
Plantae.
Angiosperms represent approximately 80 percent of all the
known green plants now living.
The angiosperms are vascular seed plants in which the
ovule (egg) is fertilized and develops into a seed in an
enclosed hollow ovary.
The ovary itself is usually enclosed in a flower, that part of
the angiospermous plant that contains the male or female
reproductive organs or both.
2 Categories of Angiosperm
1) Monocot
2) Dicot
A comparison of monocots and dicots

The embryo of a monocot

Has a single cotyledon (one embryonic seed leaf
)
Pericarp fused
with seed coat
Scutellum
(cotyledon)
Coleoptile
Endosperm
Epicotyl
Hypocotyl
Coleorhiza
(c) Maize, a monocot. Like all monocots, maize has only one
cotyledon. Maize and other grasses have a large cotyledon called a
scutellum. The rudimentary shoot is sheathed in a structure called
the coleoptile, and the coleorhiza covers the young root.
Figure 38.8c
Radicle

The embryo of a dicot

Has two cotyledon (two embryonic seed leaves )
Seed coat
Epicotyl
Hypocotyl
Radicle
Cotyledons
(a) Common garden bean, a eudicot with thick cotyledons. The
fleshy cotyledons store food absorbed from the endosperm before
the seed germinates.
Figure 38.8a
The flower is the defining reproductive adaptation of
angiosperms
Flowers are made up of four types of modified leaves 
sepals, petals, stamens, and carpels.
a. Stamens are the male reproductive organs
b. Carpels are female reproductive organs
The structure of a
flower.
A fruit is a mature ovary
Protect dormant seeds.
Fruit aids in seed dispersal.
- Wind dispersal
- Attachment and transportation
- Consumption – berries contain seeds to be
passed in feces
Fruit adaptations that enhance seed dispersal
 Fruits

are classified into several types
Depending on their developmental origin
Carpels
Flower
Ovary
Stigma
Stamen
Stamen
Ovule
Raspberry flower
Pea flower
Carpel
(fruitlet)
Seed
Stigma
Ovary
Stamen
Pea fruit
(a) Simple fruit. A simple fruit
develops from a single carpel (or
several fused carpels) of one flower
(examples: pea, lemon, peanut).
Raspberry fruit
(b) Aggregate fruit. An aggregate fruit
develops from many separate
carpels of one flower (examples:
raspberry, blackberry, strawberry).
Figure 38.9a–c
Pineapple inflorescence
Each
segment
develops
from the
carpel of
one flower
Pineapple fruit
(c) Multiple fruit. A multiple fruit
develops from many carpels
of many flowers (examples:
pineapple, fig).
Angiosperms dominated the earth at the end of the
Mesozoic era
The spread of angiosperms represents the transition from
Mesozoic to Cenozoic
Angiosperms and animals have affected one another’s
evolution
Coevolution is the mutual influence on the evolution of two
different species interacting with each other and reciprocally
influencing each other’s adaptations.
e.g., Pollinator-plant relationships
Plants and Human Welfare
Agriculture is almost totally dependent on angiosperms.
Plant diversity is a non-renewable resource.
Many medicines are obtained from plant materials.
Deforestation is an
international practice
Deforestation
in the United
States
Fragmentation
of a forest
ecosystem
A sampling of
medicines
derived from
plants