Overview of Plant Diversity, Structure/Function, Reproduction, Responses and Adaptations

1. Kingdom Plantae
Overview of Plant Diversity,
Structure/Function, Reproduction,
Responses and Adaptations

2. 
How many different kinds of plants can you
count on the following slide?




A. 10
B. 17
C. 34
D. Too many to count….

3. D. Too many to count

4. Plants Make the World Go Round

Life as we know it today could not exist
without plants.
Plants provide us with many essential items
other than food.

1. What are some items you use daily that are
plant products?

2. What are three things plants need from
animals, either directly or indirectly?

5. What is a Plant?

Plants are members of the Kingdom Plantae.


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Most are autotrophic.


All are multicellular eukaryotes.
All have cell walls made of cellulose.
Carry out photosynthesis using green pigments
chlorophyll a and b.
A few are saprobic (decomposers) or parasitic.
Ex: Trees, shrubs, grasses, mosses, ferns

6. What Plants Need to Survive


Plants are sessile…they don’t move around.
This makes survival on land a difficult task.
To be able to survive, they need:


1. Sunlight – they use energy from sunlight to
carry out photosynthesis.
2. Water and Minerals – all cells require a constant
supply of water. As plants absorb water, they also
absorb minerals, which they need for growth.

7. What Plants Need to Survive


3. Gas Exchange – plants require oxygen to
support cellular respiration as well as carbon
dioxide to carry out photosynthesis.
4. Movement of Water and Nutrients – plants take
in water and minerals through their roots, but make
food in their leaves. They have to have specialized
tissues to carry water upward and distribute
products of photosynthesis throughout the plant
body

8. Plant Diversity
Cone-bearing plants
760 species
Ferns & relatives
11,000 species
Mosses & relatives
15,600 species
Flowering plants
235,000 species

9. Reproduction Free From Water

Seed plants do not require water for
fertilization of gametes.


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This allows plants to live anywhere.
Adaptations that allow this include:
Cones and Flowers


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The gametophyte grows within the cone or flower.
Cones = Gymnosperms
Flowers = Angiosperms

10. Reproduction Free From Water

Pollen



The entire male gametophyte is contained in a tiny
structure called a pollen grain.
The grain is carried to the female reproductive
structure by wind, insects, or small animals.
This transfer or pollen is called pollination.

11. Reproduction Free From Water

Seeds


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A seed is an embryo of a plant that is enclosed in a
protective covering that is surrounded by a food supply.
An embryo is an organism in its early stage of
development.
A seed coat surrounds and protects the embryo.


This prevents drying out of the embryo.
Seeds can be dispersed by wind, sticking to fur, or by
being eaten and dispersed by animals.

12. Seed Structure
Seed Coat
Seed
Embryo
Wing
Stored Food Supply

13. Eat Your Seeds!

A seed contains both the embryo of a plant and
a food supply for that plant. If you have eaten
corn, you’ve eaten a seed. Do you like
hamburger buns with sesame seeds on them?
That’s another kind of seed you’ve eaten.

After you answer the following questions,
exchange papers with a partner to see how
many of the same seeds you listed.

14. 
1.
In addition to sesame seeds, what are some other seeds that
are found in or on top of loaves of bread?

2.
In addition to corn, what are some other seeds that are eaten
as “vegetables”?

3.
What are some seeds that you have eaten as snack foods?

4.
What types of nutrients are found in seeds?

5. Do seeds have the same nutritional value for plants as they
do for animals? Why?

15. Gymnosperms – Cone Bearers

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Gymnosperms are the most ancient surviving seed
plants
Conifers are the most common gymnosperms.
These include pines, spruces, firs, cedars, sequoias,
redwoods, and junipers.

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Redwoods can grow more than 100 meters in height!
Needle-like leaves are characteristic of this group,
which is believed to have been evolved for dry, cool
climates, and allows for water conservation.

16. Angiosperms – Flowering Plants


Angiosperms develop
unique reproductive
organs known as
flowers.
Advantage: attract
animals such as bees,
moths, or
hummingbirds, which
allows for efficient
pollination.
Helianthus annuus

17. Angiosperms – Flowering Plants

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Flowers contain ovaries, which surround and
protect the seeds.
After pollination, the ovary develops into a
fruit.
A fruit is a wall of tissue surrounding a seed,
which can be eaten by animals, and the seeds
are dispersed after they pass through the
animals digestive system.

18. Plants
are categorized as
Annuals
Biennials
Perennials
that complete
their life cycle in
that complete
their life cycle in
that complete
their life cycle in
1 growing
season
2 years
More than
2 years

19. Seed Plant Structure
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Three of the principle organs of seed plants are
roots, stems and leaves.
1. Roots – the root system of a plant absorbs
water and dissolved nutrients.

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Roots anchor plants to the ground, preventing
erosion, and protects the plant from harmful soil
bacteria and fungi.
They also hold plants upright against wind and
rain.

20. Seed Plant Structure

2. Stems – a stem has a support system for the
plant body, a transport system that carries
nutrients, and a defense system that protects
the plant against predators and disease.

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The stem must be strong enough to support
branches and leaves.
The stem must also contain subsystems that lift
water and nutrients from the roots to the leaves.

21. Seed Plant Structure

3. Leaves – leaves are
the plants main
photosynthetic systems.

Leaves must contain
subsystems that protect
against water loss and
conserve water, while
allowing oxygen and
carbon dioxide enter and
exit the leaf.
Stem
Root
Dermal Tissue
Vascular Tissue
Ground Tissue

22. Tissue Systems

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Plants consist of three main tissue systems: dermal
tissue, vascular tissue, and ground tissue.
1. Dermal Tissue – the outer covering of a plant
consists of a single layer of epidermal cells.
 These outer cells are often covered with a thick
waxy layer called the cuticle.
 Ex: Helps regulate water loss/gas exchange in
leaves, increases surface area in roots and aids in
water absorption.

23. Tissue Systems

2. Vascular Tissue – forms a transport system
that moves water and nutrients throughout the
plant. It has two main components:


A. Xylem – tissue that carries water upward from
the roots to every part of a plant.
B. Phloem – tissue responsible for the transport of
nutrients and the carbohydrates produced by
photosynthesis.

24. Tissue Systems

3. Ground Tissue – the
cells that lie between the
dermal and vascular
tissues make up the
ground tissue.

Photosynthesis occurs in
the ground tissue of
plants.
Leaf
Stem
Root
Dermal Tissue
Vascular Tissue
Ground Tissue

25. Types of Roots

The two main types of
roots are taproots and
fibrous roots.

1. Taproot – reach far
underground for water.


Ex: Carrots, dandelions,
radishes
2. Fibrous root – helps
prevent erosion.

Ex: Grasses

26. Root Functions
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Roots have 3 main jobs:
1. Uptake of Plant Nutrients -
Nutrient
Role in Plant
Result of Deficiency
Nitrogen
Proper leaf growth and color; synthesis of
amino acids, proteins, nucleic acids, and
chlorophyll
Stunted plant growth; pale yellow leaves
Phosphorus
Synthesis of DNA; development of roots,
stems, flowers, and seeds
Poor flowering; stunted growth
Potassium
Synthesis of proteins and carbohydrates;
development of roots, stems, and flowers;
resistance to cold and disease
Weak stems and stunted roots; edges of
leaves turn brown
Magnesium
Synthesis of chlorophyll
Thin stems; mottled, pale leaves
Calcium
Cell growth and division; cell wall
structure; cellular transport; enzyme
action
Stunted growth; curled leaves

27. Root Functions

2. Active transport of minerals – by using
active transport to accumulate ions from the
soil, cells of the root epidermis create
conditions under which osmosis causes water
to “follow” those ions and flow into the root.

The minerals then flow into the vascular tissue and
are dispersed throughout the plant.

28. Root Functions

3. Root Pressure – as minerals are pumped into
the vascular tissue, more and more water
follows by osmosis.
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This produces a strong pressure that keeps forcing
water and nutrients in and up into the plant body,
and prevents the roots from filling up and
expanding with water.
Without a constant root pressure, the stem and
leaves would wither and die.

29. Stem Study

Imagine walking through a botanical garden.
You probably would see many different kinds
of plants, such as small and large trees,
flowering plants, and cacti.

1. How do the stems of trees, flowering plants,
and cacti differ?
2. How are the stems of these plants similar?


30. Stem Structure and Function

Stems have three important functions:


They produce leaves, branches and flowers; they
hold leaves up to the sunlight; and they transport
substances between roots and leaves.
Xylem and Phloem form continuous tubes
from the roots through the stem to the leaves.

The stem allows for the entire body of the plant to
be connected, so water and nutrients can reach the
leaves.

31. 


The region where the
leaf branches off of the
stem is called a node.
The spaces in between
nodes are called
internodes.
In flowering plants,
buds form at the nodes
in between the stem and
the leaf.
Node
Internode

32. Formation of Wood


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Most of what we call “wood” is actually layers
of xylem. These cells build up year after year,
layer upon layer.
Tree growth is usually seasonal – light colored
wood rings are called “early wood,” dark
colored layers wood rings are called “late
wood.”
These names correspond with the times of year
wood is formed, early and late in the year.

33. Formation of Bark
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Bark includes all structures from the phloem to the
outside of the tree.
As the phloem grows to accommodate the needs of
the growing tree, it forces other vascular tissues
outward.
The expansion causes the oldest tissues to split and
fragment at they are stretched by the expanding stem.
By the time these layers reach the outermost area of
the tree, they are usually dead and cracked and look
like the bark we all have seen on trees.

34. Layers of a Mature Tree
Wood
Bark
Heartwood
Phloem
Meristem Tissue
Xylem

35. Leaf Arrangements

36. Leaf Structure
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The structure of a leaf is
optimized for absorbing
light and carrying out
photosynthesis.
The blade, the large
flattened section,
collects sunlight.
The stalked petiole
attaches the blade to the
stem.

37. Internal Structure of a Leaf
Cuticle
Veins
Epidermis
Xylem
Xylem
Phloem
Spongy
mesophyll
Epidermis
Epidermis
Stoma
Stoma

38. Simple Leaves

39. Compound Leaves
Acacia cornigera

40. Leaf Functions
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There are three main functions of leaves.
1. Leaves are specialized structures for
carrying out photosynthesis.
2. Leaves lose water through stoma in a
process called transpiration. Lost water is
replaced by water drawn in through the xylem.
3. Leaves are the site of gas exchange. They
take in carbon dioxide and give off oxygen
during photosynthesis

41. Water Transport

Water transport occurs in a plant due to the following
processes:

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1. A constant root pressure makes water transport possible
2. Capillary action causes the water to rise upward in the
phloem.
3. Water is pulled through the stoma in the leaves in a
process called transpiration.
4. Excess transpiration or low root pressure causes wilting,
in which the stoma would then close to slow transpiration
and build root pressure back up.

42. Evaporation of water
molecules out of leaves.
Pull of water molecules
upward from the roots.

43. Nutrient Transport
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We now know that transpiration pulls water upward
through a plant. But most plant nutrients, including
sugars, minerals, and organic molecules, are pushed
through the phloem.
Sugar movement flows from a source to a sink.
The source can be any cell in which sugars are
produced by photosynthesis.
The sink is a cell where the sugars are used or stored.
So….the sugars essentially move from where they are
produced to where they are stored.

44. Flower Structure
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Flowers are
reproductive organs
that are composed of
four kinds of
specialized leaves:
1. Sepals,
2. Petals,
3. Stamens,
4. Carpels.
Stamen
Anther
Filament
Ovule
Stigma
Style
Carpel
Ovary
Petal
Sepal

45. Flower Variation
Nelumbo lutea
Sabatia campestris
Oenothera speciosa
Helianthus annuus
Centaurea americana
Danaus plexippus on
Cephalanthus occidentalis

46. Sepals and Petals

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Sepals – the outermost circle of floral parts.
Usually resembling leaves, they enclose the bud
before it opens, and they protect the flower while
it develops.
Petals – the floral parts directly inside of the
sepals. They are often brightly colored to attract
insects and birds.
Because these two groups are non-reproductive
parts, they are sometimes called the sterile leaves.

47. Stamens and Carpels
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Stamens – made up of the male reproductive parts, the
filament and anther.
 The filament is a long, thin stalk supporting the anther.
 The anther is the site of meiosis, producing pollen.
Carpels – also called the pistil, made up of the female
reproductive parts.
 The ovary is the site of meiosis, producing ovules.
 The style is a narrow stalk, on which the stigma sits.
 The stigma is the sticky portion on top of the style,
where pollen grains land, and travel down the style to
the ovary.

48. Comparing Wind-pollinated and
Animal-pollinated Plants
Characteristics
Wind-pollinated
Plants
Animal-pollinated
Plants
Pollination method
Wind pollination
Vector pollination
Relative efficiency of
pollination method
Less efficient
More efficient
Plant types
Mostly gymnosperms and
some angiosperms
Angiosperms
Reproductive organs
Cones
Flowers
Adaptations that promote
pollination
Pollination drop
Bright colors, sweet
nectar

49. Pollination

Most gymnosperms are wind pollinated, whereas
most angiosperms are pollinated by animals.
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
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Ex: insects, birds, bats
The work insect pollination would cost humans if we
had to do it ourselves would cost billions of dollars a
year.
Botanists suggest that insect pollination is the factor
largely responsible for the displacement of
gymnosperms by angiosperms during the last 100
million years.

50. Seed Dispersal

Dispersal by animals – seeds contained in
sweet, fleshy fruits are eaten by animals.
 The tough coating of seeds protects them
from digestive enzymes.
 The seed sprouts in the nutrient rich feces of
the animal, often in areas where there is less
competition with the parent plants.

51. Seed Dispersal

Dispersal by wind and water – these seeds are
typically lightweight, allowing them to be carried in
the air or float on the surface of the water.


Wind examples: Maple seeds twirl as they fall from tree;
tumbleweeds break off at roots and tumble across the
plains.
Water examples: Coconuts are buoyant and allow seeds to
float.

Water dispersal is one reason for the success of this species
reaching remote islands.

52. Seed Germination



Seed germination is the early growth stage of
the embryo.
When seeds germinate, they absorb water,
causing the seed tissues to swell, which cracks
open the seed coat.
The young root them emerges through the
crack and begins to grow, as the shoot grows
in the opposite direction.

53. Different Types of Seeds
Germinating Bean
Corn
Pea

54. Plant Responses


Tropism is the responses of plants to external
stimuli.
There are three main plant tropisms:

1. Gravitropism – the response of a plant to
gravity.

This causes the shoot of a germinating seed to grow out
of the soil – against gravity, and the root of the
germinating seed to grow down into the soil – with
gravity.

55. Plant Responses

2. Phototropism – the response of plants to light.


Causes the plant to grow toward a light source. This
response can be so quick that young seedlings reorient
themselves in a matter of hours.
3. Thigmotropism – the response of plants to
touch.
A plant that is touched often can become stunted in
growth.
 Vines twist as they touch objects and twirl around them
to have something to anchor themselves to as they
continue to grow.


56. Phototropism Example
Control
Tip
removed
Opaque
Cap
Clear
Cap
Opaque
Sheath over
base

57. Photoperiodism
Short-Day Plant

Photoperiodism in
plants is responsible for
the timing of seasonal
activities such as
flowering and growth.

Different types of plants
flower more when
exposed to differing
amounts of light and
darkness.
Long-Day Plant
Midnight
Noon
Long Day
Midnight
Noon
Short Day
Midnight
Noon
Interrupted Night
Chrysanthemum
Iris

58. Plant Adaptations

Aquatic Plants – able to
tolerate mud that is
saturated with water and
nearly devoid of oxygen.
 Expansive roots allow
for maximum nutrient
intake.
 Seed pods float when
mature and shoots grow
very quickly after
germination to reach the
water’s surface
Nelumbo lutea

59. Plant Adaptations

Desert plants – plant
adaptations to a desert
climate include extensive
roots, reduced leaves, and
thick stems that can store
water.



Roots reach far into soil to
reach water.
Leaves sometimes modified
into spines to reduce water
loss.
Thick stems allow for
maximum water conservation.

60. Nutritional Specialists

Plants that have specialized
features for obtaining
nutrients include
carnivorous plants and
parasites.
 Carnivorous plants, such
at pitcher plants and
Venus’ flytraps, trap
insects and secret
digestive enzymes that
allow for absorption of
the animal.
 These plants usually live
in bogs, or wet/acidic
environments that allow
for little nutrients in the
soil.
Pitcher plant
Venus’ flytrap

61. Nutritional Specialists

Parasitic plants attach to
a host plants and extract
water and nutrients
directly from the host
plant.

Plants such as this attach
to their host plant and
can eventually kill the
host as they leech all the
nutrients and water out
of the host.
Cuscuta gronovii

62. Nutritional Specialists

Epiphytes – plants that are
not rooted in the soil, but
instead grow directly on the
bodies of other plants –
these are not parasitic.



Most are found in the
rainforests.
They gather their own
water and nutrients in their
specialized bodies.
Over half of all orchid
species are epiphytes.