1. Plant Diversity

2. Why Plants? Plants give us food
Much of our cloth comes from plant fibers
Many types of furniture comes from wood
Paper is made from wood
Money is made from plants
Tires are made from rubber tree plants
Medicines come from plants

3. Chapter 22: Introduction To Plants

4. What Is A Plant? Members of the Kingdom Plantae
Multicellular eukaryotes
Cell walls
Cellulose
Carry out photosynthesis
Green pigment – chlorophyll a and b
Develop multicellular embryos
Not all plants have seeds – some have spores

5. Overview of the Plant Kingdom
The plant kingdom is divided into groups based on whether or not they have the following features.
Vascular Tissue
Seeds
Flowers
Plants may have all some or none of the above.

6. What Do Plants Need to Survive?
Sunlight
Photosynthesis
Water
Needed to carry nutrients
Needed for photosynthesis
Minerals
Absorbed through the soil
Gas Exchange
Need oxygen – cellular respiration
Need carbon dioxide - photosynthesis
Movement of Water
Movement of Nutrients

7. Importance of Plants Provide the base for the world’s food chain
Provide shelter and shade for many organisms
Oxygen released into the air is used by all animals and other organisms during cellular respiration
Plant remove carbon dioxide from the air

8. The First Plants
DNA sequencing confirms that plants are closely related to certain algae
The oldest fossils are nearly 45 million years old
These plants were dependent on water for their life cycles
Over time plants adapted to living on land and became less dependent on water for their life cycles

9. Plant Life Cycle Plants have 2 alternating phases
Sporophyte
Plants have 2 alternating phases
2N (diploid) phase is the sporophyte
Produces 1N spores by meiosis
Spores grow into gametophytes
1N (haploid) phase is the gametophyte
Gametophytes produce egg and sperm by mitosis
These gametes fuse to produce sporophytes
Gametophyte

11. Chapter 22-2: Bryophytes
Bryophytes have life cycles that depend on standing water for reproduction.
Sperm producing structure is an antheridium
Egg producing structure is an archegonium
Lacking vascular tissue, these plants can draw up water by osmosis only a few centimeters above the ground
This group includes mosses, liverworts, and hornworts.

12. Types of Bryophytes - Mosses
Phylum Bryophyta
Most common type bryophyte - mosses
Velvety green organism that grows in areas of abundant moisture – swamps, bogs, rainforests and streams
Mosses have a cuticle, stomata, and some simple conducting cells
Walls of the conducting cells are not as thick as they are vascular plants

13. Moss Structures and Reproduction
Mosses do NOT have true stems and leaves
They produce thin stalks containing a capsule
This is the sporophyte stage
Mosses do NOT have true roots
They have rhizoids which are long thin cells that anchor them to the ground and absorb water and minerals from the surrounding soil

14. Bryophytes - Liverworts
Phylum Hepaticophyta
Liverworts grow in mats of many individuals
Mats look like a collection of miniature flat leaves attached to the ground
These gametophytes draw up moisture directly from the soil
Some liverworts produce “umbrellas” that carry egg and sperm
They have no conduction cells, no cuticle, and no stomata

15. Bryophytes: Hornworts
Phylum Anthocerophyta
Found only in soil that is damp nearly year round
Its sporophyte looks like a tiny green horn

16. Chapter 22-3: Seedless Vascular Plants
Over time plants developed vascular tissue
Vascular tissue is used to conduct water and nutrients throughout the plant

17. Vascular Tissue: A Transport System
Xylem – transport system that carries water upward from the roots of every part of a plant
Phloem – transports solutions of nutrients and carbohydrates downward toward the roots
These transport systems can move fluids through the plant body – even against the force of gravity

18. Ferns Roots – underground organs that absorb water and minerals
Have true roots, leaves, and steams and reproduce with spores called sori
Roots – underground organs that absorb water and minerals
Fronds (Leaves) – photosynthetic organs that contain one or more vascular bundles
Veins – made of xylem and phloem
Stems – supporting structures that connect roots and leaves – carries water and nutrients between them

19. Ferns and Relatives Club Moss – Phylum Lycophyta
Seedless vascular plant
Ancient group of land plants
Grew up to 35 meters in height
Formed coals beds still used today
Club mosses today are small plants
Horsetails – Phylum Arthrophyta
Genus Equisetum
Has non-photosynthetic scale leaves
Also called scouring rush
DO NOT PRODUCE SEEDS
Ferns – Phylum Pterophyta
True vascular tissue
Rhizomes
Fronds

20. Chapter 22 – 4 Seed Plants
Plants with seeds are the most dominant group of photosynthetic organisms on land
Seed plants are divided into 2 groups
Gymnosperms
Seeds on the surface of cones
Includes conifers, pines, and spruces
Cycads, ginkgoes
Angiosperms (flowering plants)
Seeds in flowers
Grasses, flowering trees and shrubs

21. Seeds
Seed – an embryo of a plant encased in a protective covering and surrounded by a food supply
Embryo – early stage of development
Seed coat – surrounds and protects the embryo and keeps the contents from drying out
Some seeds have special structures to help them disperse
A seed embryo stops growing until conditions are right for growth

22. Evolution of Seed Plants
The development of the seed was extremely important for land plants
With the development of seeds they were able to survive dry conditions and extreme temperature
The first plants needed water for fertilization to occur
With the advent of seeds this was no longer necessary
It was this adaptation that allowed seed plants to spread all across the globe

23. Gnetophytes Welwitschia plant – Namibian desert An odd desert plant
Only has 2 leathery leaves
Leaves grow continuously and spread across the ground

24. Cycads A palm like plant with large cones
These plants first appeared in the Triassic Period of the Mesozoic Era
Huge cycad forests thrived when dinosaurs roamed the earth
These plants today are found in tropical and subtropical areas

25. Ginkgo Ginkgoes were also found during the time of the dinosaurs
Today ONE species survives
Ginkgo bilboa– a living fossil
May be one of the oldest seed plants alive today
These plants are very tough and resistant to air pollution

26. Conifer Conifers are the most common gymnosperms
Conifers include pines, spruces, conifers, cedars, sequoias, redwoods, junipers and yews
Conifers are “evergreens” – they retain their leaves year round.
Gametophytes found inside cones

27. Gymnosperms (Cone Bearers)
These plants reproduce with seeds that are exposed (gymnosperm means “naked seed”)
Most ancient seed plants

28. Chapter 22 – 5 Angiosperms (Flowering Plants)
Angiosperms develop unique reproductive organs known as flowers.
Angiosperm means “enclosed sperm.”
Flowers contain ovaries which surround and protect the seeds
After pollination, the ovary develops into a fruit.
Fruit is used to attract animals
By the time the seeds have passed through the digestive system they are ready to sprout
This helps expand the range by spreading seeds to other habitats

29. Flowers Bright colors Pleasant smell Unpleasant smell
90 % of all plant species reproduce with flowers
Male and female gametophytes of angiosperms – the sperm and egg – develop with flowers
Adaptations to aid in cross- pollination is:
Bright colors
Pleasant smell
Unpleasant smell
Self pollination – pollination occurs before flower opens

30. Diversity of Angiosperms
There are 2 classes within angiosperms
Monocots and dicots are named for the number of seed leaves, or cotyledons, in the plant embryo
Monocots have one seed leaf and dicots have two
A cotyledon is the first leaf or the first pair of leaves produced by the embryo of a seed plant
Other differences include distribution of vascular tissue in stems, roots and leaves

31. Plant Life Spans Biennial Perennial Annual
There are 3 categories of plant life spans
Annual
Completes life cycle within on growing season
Examples: marigolds, pansies, zinnias
Biennial
Completes life cycle within 2 years
1st year – germinates, grows roots, sometimes leaves
2nd year – grows new stems, leaves and seeds
Examples: primrose, parsley, celery
Perennial
Flower plants that live for more than 2 years
Examples: grasses, trees, sagebrush, honeysuckle

32. Chapter 23: Roots, Stems and Leaves

33. Roots Absorb water and nutrients Anchor plant and prevent erosion
Protect plant from harmful bacteria and fungi
Transport water nutrients to the rest of the plant
Help hold plants upright against forces such as:
Wind
Rain

34. Stems Support system for plant body Transport system for nutrients
Defense system that protects against predators and disease
Length – a few millimeters to 100 meters
Must be strong enough to hold up leaves and branches
Transport system must lift water from roots to leaves and carry products of photosynthesis from leaves back down to the roots.

35. Leaves Main photosynthetic system
Broad flat leaves help increase the amount of sunlight plants absorb
Protect tissue from dryness of the air
Gas exchange—pores let oxygen and carbon dioxide enter and exit the leaf.

36. Chapter 23 – 2 Roots
The two main types of roots are taproots and fibrous roots
Taproots – found in dicots
A primary root that grows long and thick while secondary roots remain small
Fibrous roots – found in monocots
These roots branch so that no single root is larger than the rest
These roots help prevent topsoil from being washed away

37. Root Vocabulary
Root Hair – penetrate the spaces between soil particles and produce a large surface area through which water can enter the plant
Cortex – spongy layer of ground tissue
Endodermis – layer that encloses the roots vascular system which is called the vascular cylinder
Root cap – protects the root as it forces its way through the soil

38. Chapter 23-4 Leaves
Leaf structure is optimized for absorbing light and carrying out photosynthesis
Leaf Structure
Blade
Petiole
Bud
Stem
Simple leaf
Compound leaf

39. Leaf Function - Photosynthesis

40. Leaf Structure and Photosynthesis
Cuticle—waxy layer that prevents water loss
Palisade and spongy mesophyll – absorbs light as it enters the leaf (photosynthesis)
Vascular bundle—xylem and phloem transport water and nutrients
Stomata – pore-like openings in the underside of the leaf that allows carbon dioxide and oxygen to diffuse in and out of the leaf
Guard Cells – open and close the stomata in response to changes in water pressure.

41. Transpiration

42. Gas Exchange
Leaves take in carbon dioxide and give off oxygen during photosynthesis
Plants keep their stomata open just enough to allow photosynthesis to take place but not so much that they lose an excessive amount of water
Guard cells open and close in response to water pressure
Water pressure high - stomata opens
Water pressure low – stomata closes

43. Chapter 24 – Reproduction of Seeds

44. Why Seeds?
Protection – seed coat protects the embryo from drying out and from injury and disease
Nourishment – most seeds have large cotyledons that supply organic nutrients to the embryo as it starts to grow
Dispersal – many seeds have structures that help wind, water, or animals carry them away from their parent plants. Dispersal prevents competition for resources
Delayed growth – an embryo in a seed is in a state of suspended animation. Most seeds don’t germinate until conditions are favorable. This allows seeds to survive unfavorable periods such as droughts or cold winds

45. Structure of Flowers
Flowers are reproductive organs that are composed of four kinds of specialized leaves:
Sepals
Petals
Stamens
Carpels

46. Flower Vocabulary Sepals – outermost circle of floral parts
Encloses the bud before it opens
Protect the flower while it developes
Petals – often brightly colored are found just inside the sepals
Attract insects and other pollinators
Stamen – structure that produces male gametophytes
Filament – long, thin stalk that supports an anther
Anther – oval sack where meiosis takes plance
Carpels (pistils) – produces female gametophytes
Style – carpels narrows into a stalk
Stigma – sticky portion on top of the style
Ovary – contains one or more ovules where female gametophytes are produced

48. Fertilization in Angiosperms
Pollen grain land on the stigma of a flower
Grows into a pollen tube
Pollen tube contains nucleus and 2 sperm nuclei
Pollen tube grows into the style and reaches the ovary and enters the ovule
Inside embryo sac a diploid zygote formed
Zygote grows into a new plant embryo
Endosperm – food rich tissue which nourishes the seedling as it grows

49. Chapter 24 -2: Seed Development and Germination
As angiosperm seeds mature, the ovary walls thicken to form a fruit that encloses the developing seed
Fruit – a ripened ovary that contains angiosperm seeds
Examples of fruits include:
Apples, grapes, strawberries
Peas, corn, beans, rice, cucumbers, and tomatoes

50. Seed Dispersal Dispersal by Animals Dispersal by Wind and Water
Seeds eaten by animals are covered with tough coating to protect them from digestive chemicals and allow them to pass through the animal unharmed
Seeds are contained in fleshy nutritious fruit
Dispersal by Wind and Water
Seeds dispersed by wind or water are typically lightweight allowing them to be carried by water or wind

51. Pollination Benefits
Pollen provides a dependable source of food for insects and other animals
Plant pollen is transferred from flower to flower
Insect pollination is more efficient than wind

52. Seed Dormancy Many seeds will not grow when first mature.
Instead they enter a period which the embryo is alive but not growing
Length of dormancy varies in different plant species
Environmental factors such as temperature and moisture can cause a seed to end dormancy and germinate
Most seed germinate in the spring when conditions are best
However, some seeds need high temperatures to active them and then germinate (example: pines)

53. Seed Germination Germination – early growth stage of an embryo
When seeds germinate, they absorb water
Water causes food-storing tissue to swell
Swelling cracks open the seed coat and the young root emerges and starts to grow
Seed leaves
(monocot – 1, dicot – 2)
Monocots – the single cotyledon remains underground
Dicots – cotyledons can emerge above ground

54. Leaf Adaptations Cactus – spines for protection
Pea plant – tendrils climb nearby supports
Carnivorous plants – catch and digest insects to obtain essential nutrients

55. Plant Responses to the Environment
Plants bend toward the light
Auxin (discovered in 1920) is the plant hormone that causes plants to bend
Cells on one side grow longer that other side
Response is called - phototrophism

56. Plant Responses Which part of a seed is the top? Bottom?
Seeds have no top or bottom
No matter how you place them the roots will grow down toward gravity and stems will grow away from gravity
Response to gravity is called gravitrophism

57. Plant Response Thigmotrophism – response to touch
Plants grow tendrils around wire is positive thigmotrophism