1. Plants
Ms. Luaces
Honors Biology

2. 2.2 – Properties of Water
Water is a neutral molecule and found over 75% of Earth’s surface
However, water is polar (a molecule in which the charges are unevenly distributed)

3. 2.2 – Properties of Water
Polar molecules like water can attract each other – known as hydrogen bonding
This accounts for many of waters special properties

4. 2.2 – Properties of Water
Cohesion: attraction between molecules of the same substance
Why drops of water form beads and why there is such a thing as surface tension
Adhesion: attraction between molecules of different substances
Causes the capillary action that draws water out of roots up into a plants stems and leaves

5. 2.2 Properties of Water
Water also has a high heat capacity – takes a large amount of heat to cause the molecules to move faster
This is why cells don’t overheat as they are carrying out the bodies processes – the water is drawing the heat out (sweat!)

6. Chapter 22: Plants
Plants have adapted so well to many environments that they dominate much of the surface of the planet
Include trees, shrubs, mosses, and even green algae!

7. 22.1 – Characteristics of Plants
Plants are:
Kingdom Plantae
Multicellular
Eukaryotes
Have cell walls with cellulose
Autotrophs (photosynthesis)

8. 22.1 – Characteristics of Plants
The lives of plants center on the need for sunlight, gas exchange, water and minerals
Sunlight: required for photosynthesis so they’ve developed broad, flat leaves
Gas exchange: require carbon dioxide and have to let go of oxygen, so they’ve developed special parts to deal with this
Water and minerals: required for photosynthesis and survival, so they’ve evolved structures that limit water loss and increase the intake of water and nutrients upwards from the soil

9. 22.1 – The History & Evolution of Plants
Ancestors of land plants were water-dwelling without leaves and roots: today’s algae
At first, algae was in Protista, but because they have cell walls and do photosynthesis, they are classified as plants

10. 22.1 – The History & Evolution of Plants
Over time, the demands of life on land favored the evolution of plants more resistant to the drying rays of the sun, more capable of conserving water, and more capable of reproducing without water.

11. 22.2 Seedless Plants
Algae: any photosynthetic eukaryote other than a land plant
Mostly aquatic
Absorb moisture and nutrients directly from their surroundings
One of the first plants to evolve billions of years ago
Can form colonies – how first plants probably arose

12. 22.2 Mosses and other Bryophytes
Bryophytes: higher degree of cell specialization and one of the first plants to become established on land.
Characteristics:
Live in damp places with plenty of water
Lack vascular tissue (roots and stems) and lignin, and therefore cannot support a tall plant body
Include mosses, liverworts, and hornworts

13. 22.2 Vascular Plants
Tracheophytes (vascular plants): have a transport system with true vascular (roots and stems) tissue
Characteristics:
Contain cells called tracheids (water conducting cells)
Contain xylem (carries water from the roots) and phloem (transports solutions of nutrients and carbs)

14. 22.2 Vascular Plants Vascular plants are split up into 2 categories:
Seed Plants: the majority of plants on earth
Seedless plants: ferns, mosses and horsetails

15. Let’s Practice!
Study Workbook A Pgs. 17 #1-4 and Pgs SKIP #4-6
Work with a buddy – one sheet of paper
Question AND Answer
You’ve got 40 minutes!!

16. 22.3 Seed Plants
Each and every seed contains a living plant ready to sprout as soon as it encounters the proper conditions for growth
A seed is a plant embryo and a food supply, encased in a protective covering

17. 22.3 The Importance of Seeds
Unlike mosses and ferns, the gametes of seed plants do not need standing water for fertilization
Adaptations that allow seed plants to reproduce without standing water include:
a reproductive process that takes place in cones or flowers
the transfer of sperm by pollination
the protection of embryos in seeds

18. 22.3 Seed Plants Gymnosperms Angiosperms
Bear seeds directly on scales of cones
Male gametophyte is in pollen grain
Pollen is carried by wind
Flowering plants
Bear their seeds in flowers inside a layer of tissue to protect the seed
Male gametophyte also in pollen grain
Pollen is carried by animals

19. 22.3 Seed Plants
Embryos can remain in dry conditions for weeks or even years because of the tough seed coat that surrounds and protects it

20. 22.4 Flowering Plants
Angiosperms (flowering plants) are the most recent in evolution of plants
Contain ovaries, which surround and protect seeds
Attract animals such as bees to carry pollen to other flowers

21. 22.4 Flowers & Fruits
Fruit contains one or more ovaries with seeds inside the walls
Helps to disperse the seeds, especially when eaten by an animal
Increase the range the plants inhabit (over hundreds of km)

22. 22.4 Angiosperm Classification
Classified according to the number of seed leaves (cotyledons) in their embryos
One seed leaf – monocots
Two seed leaves – dicots
** Recent classification has shown dicots go into a variety of different categories, and have been expanded
**Figure is a good reference!

23. 23.1 Specialized Tissues in Plants
Plants move materials, grow, repair themselves, and constantly respond to the environment. They do this with 3 principal organs that produce, store, and transport nutrients:
Roots
Stems
Leaves

24. 23.1 Seed Plant Structure Roots: Anchor plants
Absorb water and dissolved nutrients
Transport these materials to the rest of the plant
Store food
Hold the plant upright

25. 23.1 Seed Plant Structure Stems: Support the plant body
Transport nutrients
Serve as a defensive system that protects the plant against predators and disease

26. 23.1 Seed Plant Structure Leaves:
Main photosynthetic organ (absorbs sunlight and creates food)
Protect against water loss

27. 23.1 Plant Tissue Systems 3 main tissue systems:
Dermal: covers the plant like skin
Vascular: forms a system of pipe-like cells
Ground: produces and stores food

28. 23.1 Plant Tissue Systems
Dermal Tissue: made of a single layer of cells called epidermis
Covered with a thick waxy layer (cuticle) which protects against water loss
The protective outer covering of a plant

29. 23.1 Plant Tissue Systems
Vascular Tissue: supports the plant body and transports water and nutrients throughout the plant. Made up of 2 types of tissue:
Xylem: transports water (also known as tracheids)
Phloem: transports dissolved nutrients (also known as sieve tube elements)

30. 23.1 Plant Tissue Systems
Ground Tissue: produces and stores sugars, and contributes to physical support of the plant
Edible portions of the plants
Composed of parenchyma cells and contain many chloroplasts for photosynthesis

31. 23.1 Plant Tissue Systems
Even the oldest trees produce new leaves because of meristems: unspecialized cells in which mitosis produces new cells that are ready for differentiation
Only located at the tips of stems and roots (apical meristems)
Act like stem cells of animals
Gradually, the cells mature and specialize through a process called differentiation

32. 23.2 Roots
Seeds put out their first root to draw water and nutrients from the soil
Adds length and surface area to take up water and nutrients
2 types of root systems: Taproot & Fibrous

33. 23.2 Types of Root Systems Taproot System Fibrous System
Primary root grows long and thick
Smaller branch roots from the main root
Ex: Oak, Dandelions
Many equally sized roots that grow separately from the base of the stem
No root is longer than another
Ex: Grasses

34. 23.2 Anatomy of a Root
A mature root has an outside layer (epidermis), and also contains vascular tissue and a large area of ground tissue
Helps to transport water and minerals

35. 23.2 Anatomy of a Root
Epidermis is involved in protection and absorption
Contains small projections called root hairs that help produce a large surface area for absorption

36. 23.2 Anatomy of a Root
Ground Tissue moves water and minerals through the cortex and stores the products of photosynthesis (such as starch)
Also contains a layer called the endodermis which works closely with vascular tissue

37. 23.2 Anatomy of a Root
Vascular Tissue helps absorb water and nutrients through the special channels xylem and phloem

38. 23.2 Anatomy of a Root
Apical Meristem contains the root cap that protects the growing region of unspecialized cells

39. 23.2 Root Functions
Roots support a plant, anchor it in the ground, store food, and absorb water and dissolved nutrients from the soil
Ingredients of the soil help define what plants can flourish there
In general, plants need large amounts of N, P, K, Mg, S, and Ca

40. 23.2 Root Functions
Active transport (where the use of energy in the form of ATP is used to move materials across membranes) help to transport water by pressure from the outside into roots, up the stems and into the leaves
Root Pressure

41. 23.3 Stems There are above and underground (potatoes!) stems
Aboveground stems have several important functions:
Produce leaves, branches, and flowers
Hold leaves up to the sun
Transport substances throughout the plant

42. 23.3 Stem Structure & Function
Stems are important water (xylem) and mineral (phloem) transport system
They also function in storage and aid in the process of photosynthesis

43. 23.3 Stem Structure & Function
Stems contain all 3 tissue systems:
Dermal: thick layer of cell wall and waxy covering
Vascular: xylem and phloem
Ground: specialized mesophyll cells to carry out photosynthesis

44. 23.3 Stem Structure & Function
Stems also contain nodes (attach leaves) and buds (apical meristems)

45. 23.3 Growth of Stems
The growth of most plants isn’t precisely determined like our growth is
Adding length to the plant is called primary growth
Occurs in all seed plants and is a result of elongation of cells in the apical meristem

46. 23.3 Growth of Stems Adding thickness is known as secondary growth
Occurs mostly in pines and dicots, not in monocots
Allows plants to grow to great heights because the width supports the weight

47. 23.3 Growth of Stems
In conifers and dicots, secondary growth takes place in the meristems called vascular cambium and cork cambium
Vascular: produces vascular tissue and increases thickness
Cork: produces outer covering

48. 23.4 Leaves
Photosynthesis uses CO2 & H20 to produce sugar and oxygen  The structure of a leaf is optimized to absorb light and carry out photosynthesis

49. 23.4 Leaf Structure & Function
A leaf has a flat shape that helps maximize light absorption – the blade
Top and bottom surfaces are covered by epidermis (dermal tissue) that have thick outer walls that resist tearing and a waxy cuticle to waterproof

50. 23.4 Leaf Structure & Function
The vascular tissue is made of xylem and phloem tissue bundled in leaf veins to transport water and nutrients

51. 23.4 Leaf Structure & Function
Ground tissue makes up the area between leaf veins – known as mesophyll
Sugars produced here move to the leaf veins for transport in the ________?

52. 23.4 Leaf Structure & Function
Stomata are small openings in the epidermis that allow CO2, H20 & 02 to diffuse in/out of the leaf
Transpiration is the loss of water through the leaves
Helps to keep it cool on hot days but can lead to water loss

53. 23.4 Gas Exchange & Homeostasis
Photosynthesis
02  Leaves  CO2
Plants use food (Cellular Respiration)
CO2  Leaves  O2
All through the stomata openings

54. 23.4 Gas Exchange & Homeostasis
Plants maintain homeostasis by keeping their stomata open just enough to allow photosynthesis to take place but not so much that they lose excessive water
Guard cells surround the stomata and control opening/closing

55. 23.4 Gas Exchange & Homeostasis
When there is a lot of water, guard cells will open the stomata
Vice versa when there’s little water
Typically, stomata are open during the day (why?) and closed at night (why?)

56. 23.4 Gas Exchange & Homeostasis
Wilting results from the loss of water (therefore pressure)
When it wilts, the stomata will close (why?)

57. 23.5 Transport in Plants
Remember that active transport and root pressure cause water to move from soil into plant roots
Major force of water transport is provided by transpiration

58. 23.5 Water Transport
Capillary action (combines cohesion and adhesion forces) and transpiration work together to move water through the xylem tissues in the plant

59. 23.5 Nutrient Transport
Phloem transport works through pressure-flow hypothesis
Active transport moves sugars through phloem
Water follows by osmosis

60. Let’s Practice! Study Workbook A 23.3 & 23.4 Pgs. 276- 280
23.3 #1-5, 7, 10-15
23.4 # 1-17, 19
Work in pairs, one sheet of paper, answers only!

61. Study Workbook A Pg. 268 #9-13 Pg. 284 ALL Pg. 288-289 #17-27
YES, you must draw the flower and label the parts!
UNTIL EVERYONE HAS FINISHED, WE CANNOT TAKE OUR TRIP!!

62. Rooftop Garden
Sketch 2 of the plants and include their name at the top of the page. Include the following:
How many nodes the plant has
What kind of root system is it
Leaf classification, arrangement, and shape
If there are any flowers, what kinds of pollinators would be attracted?
If you had to name the plant yourself, what name would you come up with and why? (use Pg. 7 of your packet)

63. Leaf Drawing Contest
If you had gone on the Magic School Bus, how would you have drawn the inside structure of a leaf?
Include in your sketch the following: the cuticle, ground tissue (including mesophyll cells), vascular system (both xylem and phloem), dermal tissue, and stomata.
Label all of the above parts
The best sketch that has identified ALL the parts above will get to choose from the coupon book 

64. Sample Sketch