Transcript Tuesday January 25, 2005 BIOL L100 Indiana University Southeast

Living organisms are classified into
3 Domains
1. Bacteria
2. Archaea
3. Eukarya
4 Kingdoms in this
Domain
1
Domain Eukarya has 4 Kingdoms
1. Kingdom Protista
2. Kingdom Fungi
3. Kingdom
Plantae
4. Kingdom Animalia
2
Characteristics of Plants
A.
B.
C.
D.
E.
Eukaryotes
Multicellular
Cannot move from place to
place
Autotrophic-can
Photosynthesize
Thick cell walls made of
cellulose (carbohydrate)
3
Review of Photosynthesis
Words:
Carbon Dioxide + Water---Glucose + Oxygen
Symbols:
CO2 + H2O --------- C6H12O6 + O2
4
Evolution of Plants



The common ancestor of ALL plants is
thought to be green algae.
In the early evolution of plants, they made
the transition from aquatic to land
environments.
The most crucial ingredient for movement
to land is water and it is in short supply.
5
Special Adaptations
A.
B.
C.
D.
E.
F.
G.
Cuticle to prevent water loss
Leaves for carrying out photosynthesis
Roots to anchor and absorb water and minerals
Stems for support and transport of food, water
and minerals
Vascular tissues for transport in some plants
Most have seeds for reproduction
Alternation of generations
6
Special Adaptations




Most plants have a waxy cuticle which
covers their leaves and stems which
prevents water loss.
Cuticle is made of phospholipids.
The phospholipids head is polar and
attracted to water.
The cuticle is clear and this is important
so that light rays can reach the chloroplast
for photosynthesis.
7
Alternation of Generations
See Study guide page 2
mitosis
Multicellular
diploid organism
(2n)
Unicellular
diploid zygote
(2n)
fertilization
sporophyte
meiosis
Unicellular haploid
cells
(spores)
(n)
Unicellular
haploid gametes
(n)
Multicellular
haploid organism
mitosis
(n)
mitosis
gametophyte
8
Human life cycle
mitosis
Unicellular
diploid zygote
(2n)
Multicellular
diploid organism
(2n)
fertilization
meiosis
Unicellular haploid
cells
(gametes)
(n)
Meiosis – splitting chromosome pairs – 2n  n
Mitosis – making exact copy
9
Protists / fungi / plants
mitosis
Multicellular
diploid organism
(2n)
Unicellular
diploid zygote
(2n)
fertilization
sporophyte
meiosis
Unicellular haploid
cells
(spores)
(n)
Unicellular
haploid gametes
(n)
Multicellular
haploid organism
mitosis
(n)
mitosis
gametophyte
10
Bryophytes
 think
moss
11
Bryophytes
sporophyte
gametophyte
12
Plant Evolution
 Plants are divided into:
1. VASCULAR-special tissue
for carrying water and
nutrients
2. NONVASCULAR-diffusion
used to transport water
and nutrients
13
Plant Evolution
 The
Vascular plants are divided
into seed plants and non seed
plants (ferns)
 The Seed Plants are divided into
those with cones and those with
flowers
14
Nonvascular vs Vascular
Seedless vs Seed



Bryophytes are the non-vascular
seedless plants with our focus on the
moss
The Pterophytes are the ferns and they
are vascular and seedless
The Seed plants consist of the
Gymnosperms with cones and the
Angiosperms with flowers which are
vascular and have seeds
15
Cladogram-Vascular Tissue
Gymnosperms
Angiosperms
Seedless vascular
plants
Bryophytes
Evolution of
vascular tissue
Green algae
Evolution of specialized
cells / tissue
Evolution of cuticle
16
Vascular tissue

Set of tubes that transport materials
around plant

Allows plants to grow taller

Water travels up through xylem

Sugar travels throughout in phloem
17
Ferns live further on land



Still must be in moist areas
Sporophyte survives with vascular tissue
which helps conduct water
But sperm must still swim to egg in tiny
gametophyte
18
Fern gametophyte
19
Ginkgophyta
A division of seed plants that
have only one living species
 The leaves of the plant are fan
shaped
 For centuries it was thought to be
extinct in the wild, but is now known
to grow wild in eastern China.

20
Alternation of Generations
An alternation between two
distinct forms or generations
that reproduce differently
 One generation is haploid and
reproduces sexually
 The other generation is diploid
and reproduces asexually

21
Alternation of Generations
Gametophyte and Sporophyte
Notice that
the more
advanced
plants have a
dominant
Sporophyte
and the less
advanced
plants have a
more
dominant
Gametophyte
22
Moss Life Cycle
http://intro.bio.umb.edu/111-112/112s99Lect/life-cycles.html
http://www.sumanasinc.com/webcontent/anisamples/majorsbiology/moss.html
23
Fern Life Cycle
http://intro.bio.umb.edu/111-112/112s99Lect/life-cycles.html
24
Alternation of Generations
By definition,
all plants
alternate
generations
Gametophyte
n=haploid
Sporophyte
2n=diploid
25
Cladogram-Pollen Grains/Seeds
Gymnosperms
Angiosperms
Seedless vascular
plants
Bryophytes
Evolution of
pollen grains
/ seeds
Evolution of
vascular tissue
Green algae
Evolution of specialized
cells / tissue
Evolution of cuticle
26
Gymnosperms

Think cones (any conifer like pine trees)
female ovary
male pollen cone
27
Pine tree
Gymnosperms
tiny gametophyte
inside cone
sporophyte
sporophyte dominates
28
Gymnosperm pollen strategy

Release a lot, hope some pollinate

(Meanwhile, irritating everyone else)

Pollen is the male sperm in Gymnosperms
and Angiosperms
29
OTHER ADAPTATIONS
Vascular Tissue-Used for Transport
Xylem
specialized cells for carrying water and
dissolved minerals from the roots
Phloem
cells for carrying food produced in the
leaves through photosynthesis to all
parts of the plant
Vascular Cambium
The specialized tissue that gives rise to new
Xylem and Phloem
This is the tissue that brings
about the growth of a tree
trunk
30
ADAPTATIONS
Leaf Structure in Angiosperms
•The primary function of
leaves is photosynthesis
•Most photosynthesis takes
place in the Palisade
mesophyll
•Spongy mesophyll is
loosely packed cells and
permits gases to move
between palisade cells and
the outside of the leaf
31
ADAPTATION
Root Structure
•Apical Mesistems
are found at the tips
of roots
•This is an area of
active growth
•There are also
meristems found at
the tips of
growing stems
32
Root Functions
A.
B.
C.
D.
1.
2.
3.
Anchor plants
Absorb water and minerals
May store carbohydrates (carrots,
beets, turnips, radishes)
May store water for dry periods
MINERALS ABSORBED BY ROOTS
Plant Cells use minerals, such as nitrogen and potassium
in LARGE amounts; called macronutrients
Minerals needed in SMALL amounts are called
micronutrients
Mineral deficiencies or excess minerals can kill plants
33
Transport in Plants
•Transport in a plant involves movement
of water, minerals by vascular cambium
•Xylem transports water and minerals
from the roots
•Phloem transports nutrients from the
leaves to all parts of the plant
•Root Hairs aid in the absorption of
water and minerals because it increases
the surface area of roots
34
Stomata
35
Structure and Function of
Stomata

If water enters the guard cells, they
swell up and the stomata opens

If water leaves the guard cells, they
become soft and the stomata closes
36
Angiosperm or Flowering Plant
Reproduction
The
Sporophyte is
the dominant
stage in the life
cycle of the
Angiosperms
37
Cladogram-Flowers and Fruit
Gymnosperms
Seedless vascular
plants
Bryophytes
Angiosperms
Evolution of
flowers / fruits
Evolution of
pollen grains /
seeds
Evolution of
vascular tissue
Green algae
Evolution of specialized
cells / tissue
Evolution of cuticle
38
Sunflower
Angiosperms
tiny gametophyte
inside bottom of
flower
rest of plant =
sporophyte
Sporophyte Dominates
39
Basic Flower Structure of an
Angiosperm
http://plantandsoil.unl.edu/croptechnology2005/plant_phys/?what=animationList&informationModuleId=1087230040
•Sepals protect the
flower bud from insect
damage and dryness
•The color, scent, and
nectar of flowers attracts
insects, bats, and birds
•These animals help to
transfer the pollen from
the anthers of one flower
to the stigma of other
flowers-called pollination
40
Complete and Incomplete
Flowers




Perfect Flowers: have both male
and female reproductive
structures.
Imperfect Flowers: have either
male or female structures
Complete flowers: have four basic
structures: petals, sepals, a stamen
and a pistil
Incomplete flowers: have one or
more of these structures lacking
41
Advertising in UV color
42
Pollen Tube Growth and
Fertilization in Angiosperms
•The Pollen grains are
transferred to the Stigma
where the pollen grain produces
a Pollen tube
•The pollen tube grows down
the style into the ovary where it
fuses its nuclei with the
nuclei of the ovule
•The fertilized ovule becomes
a seed and the ovary
develops into the fruit of the
plant
43
Pollen grains


Hard covering around sperm, light weight
allows travel by wind
Removes water requirement for
fertilization
44
Fruit



Typically collects sugar to attract animals
Seeds survive animal digestive system,
pooped out far away from parent with free
fertilizer!
Some are not eaten by animals, just help
wind carry seed (dandelion)
45
After fertilization, ovary
becomes fruit
46
Cladogram-Fruit and Flowers
Gymnosperms
Seedless vascular
plants
Bryophytes
Angiosperms
Evolution of
flowers / fruits
Evolution of
pollen grains /
seeds
Evolution of
vascular tissue
Green algae
Evolution of specialized
cells / tissue
Evolution of cuticle
47
Plant Responses
Example: Sensitivity to pressure or touch
This can be protective for the plant
48
Phototropism
Positive
Phototropism:
the plant is
bending
toward the
sunlight
49
Phototropism




Phototropism is illustrated by the
movement of plants in relation to light
source direction
Light causes the hormone auxin to move
to the shaded side
The auxin causes the cells on the shaded
side to elongate
As a result, the plant bends toward the
light and exhibits positive phototropism
50
Thigmotropism

Thigmotropism is a plant growth response to
touching a solid object

Tendrils and stems of vines, such as morning
glories, coil when they touch an object

Thigmotropism allows some vines to climb other
plants or objects, thus increasing its chance of
intercepting light for photosynthesis.
51
Geotropism or Gravitropism
52
Gravitropism
 Gravitropism
is a plant growth
response to gravity
 A root usually grows downward
and a stem usually grows upward
 Roots are positively
gravitropic and stems are
negatively gravitropic
53
Plant Hormones




Auxin-This hormone promotes cell
elongation
Auxin is found in the apical meristems of
plants
Gibberellins help the plants to grow
taller
Gibberellins also increase the rate of
seed germination and bud development
54
Angiosperms are Divided into
Monocots and Dicots
55
Monocots and Dicots Again
56
Monocot and Dicot Seed
Structure
57
Monocot and Dicot Leaf
Veins
58
Monocot and Dicot Flower
Pedals


Monocot-pedals in groups of three or
multiples
Dicots-pedals in groups of 4s or 5s
59
Monocot and Dicot Stem


Monocots-vascular
tissue scattered
Dicots-vascular
tissue around edge of
stem
60
Examples of Monocots and
Dicots
 Monocots
include: grasses, oats,
wheat, orchids, lilies and
palms
 Dicots include: shrubs, trees
(except conifers) wild flowers
and some garden flowers
61
Monocot and Dicot Seed
Anatomy





Food is stored in the
cotyledon for the
embryo
The seed coat
functions as a
physical barrier
Epicotyls becomes
the leaves of plant
Hypocotyls
becomes the stem
Radicle becomes
the root
62
Seed Germination
Requirements for
seed germination
include:
•Enough water to
activate the
metabolism of embryo
•Sufficient oxygen
for respiration
•Suitable
temperature for
growth of that species
63
Seed Dispersal


Seeds dispersal is
completed by birds,
small animals, wind,
and water
The tough, fibrous
outer covering of a
coconut provides
protection as well as a
floatation device
64
Seed Germination
Seeds are stored food with an
Embryo
Some species need unusual conditions
for Germination:
Pass through acidic environment of
an animals digestive system
 Some require freezing temperatures,
extensive soaking in water (rice),
exposure to fire (conifers/pines), or
certain day lengths

65
Genetic Engineering of Plants

Plants can be genetically engineered to:
 Be
more tolerant of different
climates & soils
 Produce more fruit
 Be more nutritious
 Be more resistant to insects and
herbicides (chemical that kills
weeds).
66