Transcript Seed Plants Gymnosperms & Angiosperms copyright cmassengale Evolution Of Land Plants REMEMBER: • Terrestrial plants evolved from a green algal ancestor • The earliest land plants were nonvascular,

Seed Plants
Gymnosperms &
Angiosperms
copyright cmassengale
1
Evolution Of Land Plants
REMEMBER:
• Terrestrial plants evolved from a
green algal ancestor
• The earliest land plants were
nonvascular, spore producers
(bryophytes)
• Ferns were the 1st vascular, spore
producing plants
• Gymnosperms & angiosperms were
the 1st vascular, seed plants
copyright cmassengale
2
copyright cmassengale
3
Characteristics of Seed Plants
• Multicellular
• Autotrophic
• Alternation of
Generations
• Reproduce by Seeds
• Vascular tissue for
transport
• Heterosporous –
make female
megaspores & male
microspores
copyright cmassengale
4
Dandelion dispersing seeds
Reasons for Success on Land
• Waxy cuticle
• Stomata with guard cells to open &
close
• Gametes protected in tissue called
Gametangia
• Pollen tube to transfer sperm to the
egg instead of water
• Seeds protect developing embryo &
contain food
copyright cmassengale
5
Seeds and Fruits
copyright cmassengale
6
Seeds
• Seeds contain a young,
developing plant embryo
• Seeds are covered with a
protective seed coat (testa)
• Inside is stored food or
endosperm that the young
plant uses as it begins to
sprout or germinate
• Seeds form from ripened
ovules after fertilization
copyright cmassengale
7
Parts of a Seed Embryo
• Primary root or Radicle
• One or two embryonic leaves called
Cotyledons
• Plumule becomes the shoot
• Stem like portion below cotyledons
called Hypocotyl
• Stem like portion above cotyledons
called Epicotyl
copyright cmassengale
8
Parts of a Seed
copyright cmassengale
9
copyright cmassengale
10
Endosperm (3n)
Seed Coat
Cotyledon
Plumule
Epicotyl
Hypocotyl
copyright cmassengale
Radicle
11
Seed Dispersal
• Seeds must be
scattered (dispersed)
away from the parent
plant
• Testa (seed coats)
may last thousands of
years
• Seeds eaten by
animals aren’t digested
but pass out with
copyright cmassengale
wastes
12
Seed Dispersal
• Seeds may have adaptations such as
stickers, hooks, or fuzz to adhere
to animals
copyright cmassengale
13
Seed Dispersal
• Both water and
wind can scatter
seeds
Wind
Dispersal
Water Dispersal
copyright cmassengale
14
Seed Dispersal Methods
copyright cmassengale
15
Seed Germination
• Early growth of
plant embryo
• Begins when seed
absorbs water &
breaks seed coat
(testa)
• Embryo uses stored
food of cotyledons
to begin growing
copyright cmassengale
16
Fruits
• Form when ovary with ovules (eggs)
ripens
• May be dry and hardened (nuts)
• May be enlarged and fleshy
(berries, apples, tomatoes)
• Used to help disperse seeds
copyright cmassengale
17
Types of Fruits
• Simple fruits – form from a
single ovary (apple)
• Aggregate fruits – forms from
several ovaries of the same
flower (blackberry)
• Multiple fruit – forms from
several ovaries of different
flowers (inflorescence)
copyright cmassengale
18
copyright cmassengale
19
Plants with Vascular
Tissue
copyright cmassengale
20
Taxonomy of Vascular Seed
Plants
• Phylum Gnetophyta: Ephedra,
Gnetum
• Phylum Cycadophyta: Cycads
• Phylum Ginkgophyta: Ginkgo
• Phylum Coniferophyta:
Conifers
• Phylum Anthophyta: Flowering
plants
copyright cmassengale
gymnosperrms
angiosperms
21
Sporophyte
microsporangium megasporangiumx
microspores megasporesx
microgametophyte megagametophytex
antheridium archegonium
lsperm eggmm
copyright cmassengale
22
Seed plants (Ch.30)
Tiny gametophytes protected in ovules and pollen grains
Advantages of seeds
Gymnosperms have “naked seeds”
Angiosperms have seeds in fruits
Monocots
Eudicots
copyright cmassengale
23
12: Gymnosperms and
Angiosperms
• Gymnosperm
– Intro and evolution
– Life cycle and
reproduction
– Uses and significance
• Angiosperms:
Flowering plants
– Intro and evolution
– Life cycle and
reproduction
– Uses and significance
copyright cmassengale
– Monocots vs. dicots
24
Kingdom Plantae
• Evolutionary tree of plants
• From primitive more advanced
traits
Bryophytes
_______
Gymnosperms
__________
Flowers
________
Green
alga
ancestor
Vascular 
Terrestrial 
copyright cmassengale
25
GYMNOSPERMS
• Introduction – Gymnosperm means “naked
seed” (From the Greek: gymnos = naked;
sperm = seed)
• More advanced than ferns – do not have
spores, they have seeds.
• The seeds of the gymnosperms lack a
protective enclosure (unlike flowering
plants which have flowers and fruit).
• Examples of gymnosperms:
• Conifers (pine trees), cycads,
26
ginkgo biloba copyright cmassengale
Evolution of gymnosperms
• Gymnosperms evolved from fern-like
ancestors
• Advancements of gymnosperms over
ferns:
• 1. __________ (plant embryo, food
storage tissue, and seed coat)
• 2. Gymnosperms do not depend on water
for fertilization (have air-borne pollen)
• 3. Have a more dominant
_______________ generation
copyright cmassengale
27
• 4. Have a more efficient vascular
• Exhibits alternation of generations
• Sporophyte generation (2n) is dominant
• Gametophyte generation (1n) is contained in and
dependent on the sporophyte generation
Gymnosperm life cycle
copyright cmassengale
28
Gymnosperm
lifecycle
copyright cmassengale
29
Sporophyte generation
• Sporophyte produces two types of spores
(heterosporous)
• Megasporangium – undergoes
meiosis to produce megaspores
(female gametophyte)
• ________sporangium – undergoes
meiosis to produce haploid microspores,
germinate to produce male gametophyte
(pollen)
• Many gymnosperms
use wind
copyright cmassengale
30
for pollination and seed dispersal
Wood produced by
gymnosperms
• Gymnosperms have a very efficient and
effective vascular system
• Usually woody plants
• Xylem  wood of a tree
• Phloem  bark of the tree
• Wood is formed
from secondary growth
copyright cmassengale
31
Primary vs. secondary
growth
• 1. Primary growth – occurs in
apical meristems of shoots and roots
• Results in increase in length
• 2. Secondary growth – derived
from secondary or lateral meristems
• Results in increase in girth (width)
• Common in trees (wood and bark)
copyright cmassengale
32
Secondary growth
• The ____________ cambium forms
secondary xylem and secondary phloem
• W______ – is secondary xylem; cells are
dead at maturity and only cell wall remains
• Bark – is secondary phloem (conducts food)
copyright cmassengale
33
Annual rings
• Annual rings – xylem formed by the
vascular cambium during one growth season
• Early Spring wood – vessel diameter is
large, xylem walls are thinner
• Late Summer wood – vessel diameter is
small, walls are thicker
• Tropical trees:
have no annual
rings, because
seasons are so
similar
copyright cmassengale
34
Vascular tissue: Trees
• Vascular tissue is located on the
outer layers of the tree.
bark
_______
Vascular
cambium
wood
________
copyright cmassengale
35
Gymnosperms
• Conifers are most important group of
gymnosperms
• Largest and most familiar group
• Bear seeds in cones
• Staminate cones – male cones
• Ovulate cones – _________ cones
• Seeds produced on an open scale
• (Do not produce flowers
or fruit)
copyright cmassengale
36
Gymnosperms
• Mainly woody plants that include
• Oldest living trees: bristlecone pine,
5000 yrs old!
• Most massive trees
(giant sequoia):
up to 375 ft. tall,
41 ft wide!
• Tallest living trees (redwoods)
copyright cmassengale
37
Conifers
• Conifers adapted to temperate to cold
regions
• Narrow leaves (needles) help to conserve
water
• Covered by resins – for protection from
predators, fire, etc.
copyright cmassengale
38
Other gymnosperms
• Cycads – short shrubs,
native to tropical regions
(look like palms)
• Ginkgo biloba –
a “living fossil”,
male and female tree,
used as a medicinal plant
copyright cmassengale
39
Other gymnosperms
• Welwitschia – a bizarre gymnosperm plant
that grows in Namib desert (So. Africa).
• Live up to 2000 years in these extreme
conditions!
copyright cmassengale
40
• Only makes two leaves
throughout its life. It
takes water from sea mist
Significance of gymnosperms
•
•
•
•
•
•
•
•
•
Ecological importance:
Provide food and habitat for wildlife
Forests prevent soil erosion
Reduce greenhouse-effect gasses
Economic and commercial importance:
Lumber for wood, paper, etc.
Resins – wood, furniture, etc.
Ornamental plants (trees, landscaping)
Food – pine nuts (pesto, etc.)
copyright cmassengale
41
ANGIOSPERMS
•
•
•
•
Angiosperm means “covered seed”
Have flowers
Have fruits with seeds
Live everywhere – dominant plants in the
world
• 260,000 species (88% of Plant Kingdom)
• Angiosperms are the most successful and
advanced plants on earth
copyright cmassengale
42
Evolution of Angiosperms
• Advancements over gymnosperms:
• Angiosperms have flowers – many use
pollinators
• Fruits and seeds – adapted for dispersal
• Double fertilization of the endosperm in
the seed
copyright cmassengale
43
Angiosperm life cycle
• Flower has male and female sex
organs
copyright cmassengale
44
Flower structure
• Male sex organs: Stamens, composed of
anther – organ that produces pollen (male
gametophyte)
• Female sex organs: The carpel
• Ovary is the enlarged basal portion of
carpel that contains the ovules (female
gametophyte)
• The stigma is the
receptive portion of
the carpel for pollen
copyright cmassengale
45
grains to adhere
Flower structure
• Non-reproductive parts:
• Sepals (green) are the
outermost whorl of
leaf-like bracts
• Petals (usually colored)
are the inner whorl of
leaf-like bracts
• Both can have various
shapes and colors
• Tepals copyright cmassengale
_______________
46
Angiosperm life cycle
• Heterosporous: forms two different
types of spores (micro- and megaspores;
male and female spores)
• Male – pollen grains contain tube nucleus
and generative cell (2 sperm nuclei)
• Female – female gametophyte contains
egg and 2 polar nuclei
copyright cmassengale
47
Angiosper
m
lifecycle
Flowering plants exhibit
alternation of
generations. The large,
familiar flowering plant
is the diploid
sporophyte, while the
haploid gametophyte
stages are microscopic.
The unique feature
about the life cycle of
flowering plants is a
double fertilization that
produces a diploid
zygote and a triploid
endosperm or nutritive
tissue.
copyright cmassengale
48
Double fertilization
• Pollen grain germinates on stigma forming a
pollen tube, which grows down style to the
ovary
• Pollen has 2 haploid sperm nuclei, which
travel to the ovary
• One sperm nucleus fertilizes the haploid
egg forming the 2n zygote
• Another sperm nucleus unites with the 2
polar nuclei, forming the triploid (3n)
endosperm
copyright cmassengale
49
Seeds
• Fertilized egg grows into a
___________, which grows into plant
embryo
• Endosperm is stored food tissue – for
the embryo to grow
• Mature ovule becomes the seed coat
and/or fruit
copyright cmassengale
50
Monocot vs. dicot
• Angiosperms are divided into monocots
and dicots
• As the zygote grows into the embryo,
the first leaves of the young sporophyte
develop and are called as cotyledons
(seed leaves)
• Monocots have one cotyledon (corn, lily,
etc).
• Dicots have two cotyledons (bean, oak,
copyright cmassengale
51
etc).
Comparing monocot vs. dicot
plants
FEATURE
MONOCOTS
DICOTS
Cotyledons
1
2
Leaf venation
parallel
broad
Root system
Fibrous
Tap
Number of
floral parts
Vascular
bundle
position
Woody or
herbaceous
In 3’s
In 4’s or 5’s
Scattered
Arranged in a
circle
Herbaceous
Either
copyright cmassengale
52
Monocot vs. dicot
• Number of cotyledons: one vs. two
copyright cmassengale
53
Monocot vs. dicot
• Leaf venation pattern:
• Monocot is parallel
• Dicot is net pattern
copyright cmassengale
54
Monocot vs. dicot root
• Monocot: Fibrous root
• Dicot: Tap root
copyright cmassengale
55
Monocot vs. dicot
• Flower parts:
• Monocot: in groups of three
• Dicot: in groups of four or five
copyright cmassengale
56
Monocot vs. dicot
• Vascular bundle position:
• Monocot: _____________
• Dicot: arranged in a circle
copyright cmassengale
57
Monocot vs. dicot
• Stem type:
• Monocot: Herbaceous
• Dicot: herbaceous or woody
copyright cmassengale
58
Summary: Monocot vs. dicot
copyright cmassengale
59
Seed plants (Ch.30)
protected gametophytes
advantages of seeds
gymnosperms
angiosperms
monocots
eudicots
Fig. 30.2 Notice how
the importance of the
gametophypte
dwindles as we
move from mosses
to ferns to seed
plants. The
gametophyte of a
seed plant is
microscopic and not
green (does not
carry out
photosynthesis)
copyright cmassengale
60
Seed plants (Ch.30)
protected gametophytes
advantages of seeds
gymnosperms
angiosperms
monocots
eudicots
Lots of specialized terms are used to
describe the life cycle of see plants.
Here, we will use the fewest we can,
and simply drastically. Fig. 30.3.
This whole structure is a ovule (integument,
the cells of the megasporangium, and the
cells of the megaspore). The megaspore is
formed by meiosis, so is a haploid
gametophyte, the rest is diploid sporophyte.
copyright cmassengale
61
Seed plants (Ch.30)
protected gametophytes
advantages of seeds
gymnosperms
angiosperms
monocots
eudicots
Lots of specialized terms are used to
describe the life cycle of see plants.
Here, we will use the fewest we can,
and simply drastically. Fig. 30.3.
One of the female gametophyte cells becomes an egg
(n). The rest divide to produce the rest of the cells of the
female gametophyte. A male gametophyte (n), or pollen
grain, enters the ovule, and the nucleus of one of its cells
acts like a sperm, and
fertilizes
the egg (= zygote).
copyright
cmassengale
62
Seed plants (Ch.30)
protected gametophytes
advantages of seeds
gymnosperms
angiosperms
monocots
eudicots
Lots of specialized terms are used to
describe the life cycle of see plants.
Here, we will use the fewest we can,
and simply drastically. Fig. 30.3.
The haploid female gametophyte (minus the cell that
became the egg) becomes a mass of tissue that will
provide a food supply for the new embryo developing from
the zygote. The integument becomes a hard seed coat.
Note that
the embryo
stops developing until it germinates
copyright
cmassengale
63
thus the “baby plant” in a peanut!
Seed plants (Ch.30)
protected gametophytes
advantages of seeds
gymnosperms
angiosperms
monocots
eudicots
The advantages of seeds are pretty obvious - there is no
need for the gametophyte to live in a damp place so
sperm can swim to the egg - seed plants can, and do, live
everywhere.copyright cmassengale
64
Seed plants (Ch.30)
protected gametophytes
advantages of seeds
gymnosperms
angiosperms
monocots
eudicots
Gymnosperms are seed plants that do not
have a fruit around the seed, and thus have
“naked seeds”. Most of us think of
gymnosperms as just “pines” (or conifers), but
there is quite a diversity. Ginkos live on
campus - have you seen one? The “fruit” is not
really a fruit, but part of the ovule..
pine
gingko
copyright cmassengale
65
Seed plants (Ch.30)
protected gametophytes
advantages of seeds
gymnosperms
angiosperms
monocots
eudicots
Angiosperms do not have naked seeds,
but seeds surrounded by a n extra layer
of tissue that forms a fruit (which may be
juicy or dry). Fig. 30.8, 30.9
copyright cmassengale
66
Seed plants (Ch.30)
protected gametophytes
advantages of seeds
gymnosperms
angiosperms
monocots
eudicots
But of course,
angiosperms also have
flowers! Fig. 30.7. You
do not have to memorize
all the parts, but know
that that most flowers
have both male, pollen
producing parts, and
female ovules.
copyright cmassengale
67
Seed plants (Ch.30)
protected gametophytes
advantages of seeds
gymnosperms
angiosperms
monocots
eudicots
Almost all angiosperms
fall naturally into two
groups, monocots (one
cotyledon, or seed leaf)
and dicots (two
cotyledons). A few
dicots don’t form a
clade, but the huge
majoroty that do are
called true dicots, or
eudicots. Fig. 30.12
(p. 603)
copyright cmassengale
68
Seed plants (Ch.30)
protected gametophytes
advantages of seeds
gymnosperms
angiosperms
monocots
eudicots
Fig. 30.13. Angiosperms and
animals have evolved very intricate
mutualistic interactions involving
pollination - interactions that
benefit both.
copyright cmassengale
69
Learning goals: Lecture 3, Biological Diversity
(Plants and Fungi)
Readings: Chapters 29, 30, and 31 (read all of these, but the
parts covered in lecture are most likely to be on a test ).
Land plants II - Seed plants (Ch.30)
Land Plants I- how land plants
colonized land (Ch. 29)
Tiny gametophytes protected in
ovules and pollen; advantages of
Land plants evolved from green
seeds; Gymnosperms have “naked
algae; terrestrial adaptations;
seeds”; Angiosperms have seeds in
alternation of generations;
fruits; Monocots, Eudicots
bryophytes dominated by
gametophyte generation; ferns Fungi (Ch. 31)
dominated by sporophyte
Characteristics; fungi reproduce by
spores; fungal origins and
relationships; importance
copyright cmassengale
70
Lecture 3 specific reading. The ent ire reading is Chapt ers 29, 30, and 31
Fig. 28.3, p. 568 – read just figure legends – note that comlex algae like Ulva seem very
“ plant -like”
Fig. 29.3. p. 574, Genetic Evidence
Fig. 29.5, p. 576, (top), p. 576, (also p. 574, Adaptat ions enabling the move to land.
Fig. 29.5 (bot tom), p. 576, Alternation of generat ions
Fig. 29.8, p. 581, also p. 580, Bryophyte gametophtes
Fig. 29.12, p. 585
Fig. 29.14, p. 587, take a look at the club moss and horsetail photos, similar to one shown
in lecture
Fig. 29.15, p. 588, read Significance of seedless vascular plants (even though not
discussed in lecture)
Fig. 30.2, p. 592
Fig. 30.3, p. 593, also p. 592 Ovules and Product ion of Eggs, Pollen and Produciton of
sperm, p. 593, the Evolut ionary advantages of seeds
Fig. 30.7, p. 598, Flowers
Fig. 30.8, p. 598, p. 598-599, Fruit s
Fig. 30.9, p. 599, more fruits.
Fig. 30.12, left side, p. 603, focus on cotyledons and leaf venat ion, but read all charcters
that dist inguish monocots and dicot s.
Fig. 30.13, p. 604
Fig. 31.2, p. 609
Fig. 31.6, p. 611
Fig. 31.7, p. 611
Fig. 31.5, p. 611. If you want to understand about t he heterokaryot ic stage, you may
want to read p. 610-611, Sexual reproduction
Fig. 31.23, p. 621-622, Lichens
Fig. 31.25, p. 622-623, Pathogens
Fig. 31.26, p. 623, P ract ical Uses of Fungi
copyright cmassengale
71
Pine Life-Cycle
copyright cmassengale
72
pollen cone
male or
pollen
cone
Female or ovulate cone
ovulate cone
copyright cmassengale
73
male cone
microsporophyll
microsporangium
copyright cmassengale
74
ovule
.megasporangium
female cone
scale
“megasporophyll”
copyright cmassengale
75
seeds
scale
copyright cmassengale
76
Coniferophyta
Yew
Juniper
copyright cmassengale
77
Coniferophyta
Bristlecone
Pine
copyright cmassengale
78
Coniferophyta
Giant Redwood
or
Sequoia
copyright cmassengale
79
Hemlock
Coniferophyta
Spruce
copyright cmassengale
80
Coniferophyta
Bald Cypress
copyright cmassengale
81
Douglas Fir
Coniferophyta
Fi
r
copyright cmassengale
82
copyright cmassengale
Cycadophyta
: cycads 83
Ginkgophyta:
Ginkgo biloba
copyright cmassengale
84
Gnetophyta:
Ephedra
mormon tea
copyright cmassengale
85
Gnetophyta:
Gnetum
copyright cmassengale
86
Gnetophyta:
Welwitschia
copyright cmassengale
87
Leaves:
Many different sizes, shapes. (Pine
needles, cabbage, oak, etc.)
* Capture sun’s energy for photosynthesis
* Structure of a leaf:
- Upper surface cells
- Chloroplasts
- Veins with xylem and phloem
- Underside surface cells
- Stomata
(“stoma” in Greek means “mouth”, opening)
copyright cmassengale
88
The
Structur
e of a
Leaf
copyright cmassengale
89
Cuticle
Upper Epidermis
Palisade mesophyll
Vascular Bundle
Spongy mesophyll
Lower Epidermis
copyright cmassengale
90
copyright cmassengale
91
VENATION
copyright cmassengale
92
Transpiration = process of evaporation from leaves.
* Too much evaporation and the plant shrivels and
dies
* Closing the stomata helps slow down transpiration.
copyright cmassengale
93
Stems: support the plant and carry substances
between the roots and leaves.
* Some stems also store food (starches) like in
asparagus.
* They vary in size and shape:
- Boabab tree has a huge stems.
- Cabbage have short, hidden stems.
copyright cmassengale
94
copyright cmassengale
95
* Structure of stems:
- Herbaceous (soft) [dandelions,tomato plants]
- Woody (hard) like trees and rose bushes
- Both have xylem and phloem,
but woody stems have extra layers:
Outer Bark
Inner Bark (phloem)
Cambium (to produce new phloem and xylem)
Sapwood (active xylem - still transporting)
Heartwood (inactive xylem); just gives
strength
copyright cmassengale
96
Pith (center storing food & water in young
Parts of a Woody Stem
copyright cmassengale
97
Annual Rings = xylem rings
* Spring Xylem is wide & light brown (grows rapidly)
* Summer Xylem is thin & darker (grow slower)
* Each pair of light & dark rings = one year’s growth.
copyright cmassengale
98
copyright cmassengale
99
Roots:
(Anchors. Absorbs water & nutrients from soil)
* Two Types
1. Taproot = deep into soil
2. Fibrous Roots = several branching main
roots
* Root structure
- Root Cap the rounded tip containing dead
cells.
- Root hairs increase surface absorption area
- Cambium produces xylem and phloem tissues.
copyright substances
cmassengale
100
- Xylem transports
up to the plant
Fibrous Roots
Tap Root
copyright cmassengale
101
Root:
Internal
Structure
copyright cmassengale
102
Roots do not absorb water and minerals through a
smooth Epidermis. Tiny, hairlike projections called
ROOT HAIRS on the epidermis absorb water and
dissolved minerals from the soil. Root Hairs also
INCREASE the Surface Area of the Plant Roots.
copyright cmassengale
103
Epidermis
Cortex
Pith
Xylem
Phloem
Endodermis
Dicot Root
Monocot Root
copyright cmassengale
104
Gymnosperms
Gymnosperm = seed plant that produces naked seeds.
* Many have needlelike or scalelike leaves and deep
root systems.
* Note the book says fossils indicate there were
many more gymnosperms in the past than today.
This is because the global flood 4,000 years ago
wiped out many plants.
(The dates given by many books of millions of years
are false guesses. See the booklet by Dr.
copyright cmassengale
105
Humphreys.)
Types of Gymnosperms:
- Cycads (look like palm trees with large
cones)
- Ginkgo (only the Ginkgo biloba survives
today)
- Gnetophytes (found only in deserts
- Conifers (largest & most common, pines,
cedars, etc.)
[Conifers are evergreens: keep needles all year]
copyright cmassengale
106
Oldest living organism – Bristlecone Pine
About 4,000 years old = just after Noah’s
Flood.
copyright cmassengale
107
Reproduction of Gymnosperms:
* Cones – covered in scales, both male and female
cones are produced.
- Pollen is produced by male cones, and pollen are
tiny cells that later become sperm cells.
- Ovule is a structure containing an egg cell.
Pollination = transfer of pollen from male structure to
female part.
(Pollen falls from a male cone to a female cone and
fertilizes an ovule, which develops into a seed, with the
zygote as the embryo part of the seed. It can take two
years for seeds to mature,
then the cones open & wind
copyright cmassengale
108
carries the seeds off.)
The Life
Cycle
Of a
Gymnosperm
copyright cmassengale
109
Angiosperms
Angiosperms – Two characteristics:
1. flowers
2. fruit
(To remember, think: “Angie” likes flowers, but “Gym” does
not.)
* They produce seeds inside a fruit.
* Flower = angiosperm reproductive structure
* Fruit starts copyright
as ancmassengale
Ovary =
where the seeds develop
110
Flower Structure:
Not all flowers have same
parts. Some have only male parts.
* Sepals = leaf-like structures covering a bud.
* Petals = colorful structures of an open flower.
* Stamens = male parts (stalks topped by knobs)
* Pistils = the female parts in the center of the
flower.
- Stigma = sticky tip of the pistil
- Style = tube connecting stigma to ovary.
copyright cmassengale
111
copyright cmassengale
112
copyright cmassengale
113
The Structure of a Flower
copyright cmassengale
114
Flower Structure
Stigma
Filament
Style
Anther
Ovary
Receptacle
Petal
Sepal
Ovule
copyright cmassengale
115
Life Cycle
Of an
Angiosperm
copyright cmassengale
116
Reproduction of Angiosperms:
* Pollination = Pollen falls on a stigma when wind, bees, or
bats carry it. (Sugar-rich nectar in the flower attracts bees
or bats.)
* Fertilization = sperm & egg join together in the flower’s
ovule.
- The zygote develops into the embryo part of the
seed.
- The ovary around the seed develops into a fruit.
(Apples, cherries, tomatoes, squash, etc. are all fruit.)
* Dispersal – animals eat the fruit and the seeds come out
the other end.
copyright cmassengale
117
Two types of Angiosperms:
1. Monocots – have only one seed leaf (cotyledon)
(grasses, corn, wheat, rice, lilies, tulips)
(flowers have either 3 petals or a multiple of 3 petals)
(long slender leaves with veins parallel like train rails)
(vascular tissue scattered randomly in the stem)
2. Dicots – have two cotyledons
(roses, violets, plus oak, maple, bean, and apple trees)
(flowers have 4 or 5 petals or multiples of these
numbers)
(leaves are wide, with veins branches off one another)
(vascular tissue bundles arranged in a circle)
Angiosperms are used for food, clothing (cotton),
copyright cmassengale
Michael’s medicine (digoxin)
118
Seed Structure Examples:
copyright cmassengale
119
9.4 Plant Responses and Growth
Did God make plants like the bladderwort and venus
fly trap to eat insects?
copyright cmassengale
120
Tropism = a plant’s growth response toward or
away from a stimulus.
* Positive tropism is when it grows toward a
stimulus.
* Negative is when it grows away from it.
* Stimuli can be light, touch, and even gravity.
- Touch (thigmotropism)
[vines coil around anything they touch.]
- Light (phototropism)
[leaves, stems, etc, grow toward light.]
- Gravity (gravitropism)
(Positive) roots grow toward gravity’s pull
(Negative) stems grow away from its pull
copyright cmassengale
121
Hormones = a chemical that affects how the plant
grows and develops, & make tropism possible.
* Hormones also control germination, formation of
flowers, stems, and the shedding of leaves and
ripening of fruit.
* Auxin is an important hormone that speeds up
plant cell growth rate.
- If light shines on one side of a stem, auxin
moves to the shaded side and causes that side
to
grow faster so the stem bends toward the
light as
it grows.
copyright cmassengale
122
Life Spans of Angiosperms:
* Annuals = complete a life cycle in one year.
(pansies, wheat, tomatoes, cucumbers, etc)
* Biennials = complete life cycle in two years.
(Second year they produce flowers and seeds.)
(Parsley, celery, etc)
* Perennials = live for more than two years
(Oak tree, honeysuckles, etc)
(Roots and stems survive the winter)
copyright cmassengale
123
copyright cmassengale
124