1. KEY CONCEPT Plant life began in the water and became adapted to land.

2. Land plants evolved from green algae.
Plants and green algae have many common traits.
both are photosynthetic eukaryotes
both have the same types of chlorophyll
both use starch as a storage product
both have cell walls with cellulose

3. Genetic analysis points to the common ancestor of all plants.
extinct green algae species in class Charophyceae
modern charophyceans common in lakes and ponds

4. Important plant characteristics likely originated in charophyceans.
multicellular body allowing for specialization of cells and tissues
cell division that allows for chemical communication between cells
reproduction involving sperm swimming to egg

5. True plants evolved through natural selection.
Ancestral charophyceans lived in areas of shallow water.
Those that could survive longer dry periods were favored.
First true plants probably grew at edges of water.
True plants have embryos that develop while attached to female parent.

6. True plants evolved through natural selection.

7. Plants have adaptations that allow them to live on land.
Challenges of living on land have selected for certain plant adaptations.
A cuticle allows plants to retain moisture.
waxy, waterproof layer
holds moisture in

8. Stomata are tiny holes in the cuticle.
can open and close (regulated by guard cells)
allow air to move in and out

9. collection of specialized tissues
A vascular system allows resources to move to different parts of the plant.
collection of specialized tissues
brings water and mineral nutrients up from roots
disperses sugars from the leaves
allows plants to grow higher off the ground
sugars
water and mineral nutrients

10. Lignin allows plants to grow upright.
plant cells
lignin
hardens cell walls of some vascular tissues
provides stiffness to stems

11. Pollen grains allow for reproduction without free-standing water.
pollen grains contain a cell that divides to form sperm
pollen can be carried by wind or animals to female structures

12. A seed is a storage device for a plant embryo.
seed coats protect embryos from drying wind and sunlight
embryo develops when environment is favorable

13. Plants evolve with other organisms in their environment.
Plants and other organisms can share a mutualistic relationship.
a mutualism is an interaction in which two species benefit
plant roots and certain fungi and bacteria
flowering plants and their animal pollinators

14. Plants have adaptations that prevent animals from eating them.
spines and thorns
defensive chemicals

15. 21.1 Plant Cells and Tissues
KEY CONCEPT Plants have specialized cells and tissue systems.

16. Plant tissues are made of three basic cell types.
21.1 Plant Cells and Tissues
Plant tissues are made of three basic cell types.
Parenchyma cells are the most common plant cell type.
store starch, oils and water
help heal wounds to the plant
have thin flexible walls

17. 21.1 Plant Cells and Tissues
Collenchyma cells provide support to a growing plant.
they are strong and flexible.
celery strings are strands of collenchyma.
they have unevenly thick cell walls.

18. 21.1 Plant Cells and Tissues
Sclerenchyma cells are the strongest plant cell type.
second cell wall hardened by lignin
die when they reach maturity
used by humans to make linen and rope

19. Plant organs are made of three tissue systems.
21.1 Plant Cells and Tissues
Plant organs are made of three tissue systems.
Dermal tissue covers the outside of a plant.
protects the plant
secretes cuticle of leaves
forms outer bark of trees

20. 21.1 Plant Cells and Tissues
Ground tissue is found inside a plant.
provides support
stores materials in roots and stems
most commonly made of parenchyma

21. 21.1 Plant Cells and Tissues
Vascular tissue transports water, minerals and organic compounds.
stem
leaf
root
two networks of hollow tubes
xylem transports water and minerals
phloem transports photosynthetic products

22. 21.2 The Vascular System
KEY CONCEPT The vascular system allows for the transport of water, minerals, and sugars.

23. Water and dissolved minerals move through xylem.
21.2 The Vascular System
Water and dissolved minerals move through xylem.
Xylem contains specialized cells.
vessel elements are short and wide
tracheid cells are long and narrow
xylem cells die at maturity
vessel
element
tracheid

24. 21.2 The Vascular System
The cohesion-tension theory explains water movement.
Plants passively transport water through the xylem.
Cohesion is the tendency of water molecules to bond with each other.
Adhesion is the tendency of water molecules to bond with other substances.

25. 21.2 The Vascular System Water travels from roots to the top of trees.
absorption occurs at roots
cohesion and adhesion in xylem
transpiration at leaves

26. 21.2 The Vascular System
Transpiration is the loss of water vapor through leaves.
water vapor exits leaf stomata
helps pull water to the top branches

27. Phloem carries sugars from photosynthesis throughout the plant.
21.2 The Vascular System
Phloem carries sugars from photosynthesis throughout the plant.
Phloem contains specialized cells.
sieve tube elements have holes at ends
companion cells help sieve tube elements
unlike xylem, phloem tissue is alive

28. 21.2 The Vascular System
The Pressure-flow model explains sugar movement.
plants actively transport sugar from the source
sugar flows to the sink due to pressure differences
sugars
phloem
xylem
water
Water moves from the xylem into the phloem by osmosis, due to the higher concentration of the sugars in the phloem. The water flow helps move sugars through the phloem. 2
Sugars move from their source, such as photosynthesizing leaves, into the phloem. 1
The sugars move into the sink, such as root or fruit, where the are stored. 3

29. 22.1 Plant Life Cycles
KEY CONCEPT Reproduction of flowering plants takes place within flowers.

30. Plant life cycles alternate between producing spores and gametes.
A two-phase life cycle is called alternation of generations.
haploid phase
diploid phase
alternates between the two
fertilization
meiosis
SPOROPHYTE
PHASE
GAMETOPHYTE

31. 22.1 Plant Life Cycles
The spore-producing plant is the mature sporophyte.
sporophyte phase is diploid
begins with fertilized egg
spores produced through meiosis
The gamete-producing plant is the mature gametophyte.
gametophyte phase is haploid
begins with spore
gametes produced through mitosis

32. Flowers contain reproductive organs protected by specialized leaves.
22.2 Reproduction of Flowering Plants
Flowers contain reproductive organs protected by specialized leaves.
Sepals and petals are modified leaves.
Sepals are outermost layer that protects developing flower
sepal

33. 22.2 Reproduction of Flowering Plants
Petals can help to attract animal pollinators
petal

34. 22.2 Reproduction of Flowering Plants
A stamen is the male structure of the flower.
stamen
filament
anther
anther produces pollen grains
filament supports the anther

35. 22.2 Reproduction of Flowering Plants
The innermost layer of a flower is the female carpel.
carpel
style
stigma
ovary
stigma is sticky tip
style is tube leading from stigma to ovary
ovary produces female gametophyte

36. Flowering plants can be pollinated by wind or animals.
22.2 Reproduction of Flowering Plants
Flowering plants can be pollinated by wind or animals.
Flowering plants pollinated when pollen grains land on stigma.
Wind pollinated flowers have small flowers and large amounts of pollen.

37. 22.2 Reproduction of Flowering Plants
Animal pollinated flowers have larger flowers and less pollen.
many flowering plants pollinated by animal pollinators
pollen grains
pollination occurs as animal feeds from flower to flower
animal pollination more efficient than wind pollination

38. Fertilization takes place within the flower.
22.2 Reproduction of Flowering Plants
Fertilization takes place within the flower.
Male gametophytes, or pollen grains, are produced in the anthers.
male spores produced in anthers by meiosis
each spore divides by mitosis to form two haploid cells
two cells form a single pollen grain
pollen grain

39. 22.2 Reproduction of Flowering Plants
One female gametophyte can form in each ovule of a flower’s ovary.
four female spores produced in ovule by meiosis
one spore develops into female gametophyte
female gametophyte contains seven cells
one cell has two nuclei, or polar nuclei
one cell will develop into an egg

40. 22.2 Reproduction of Flowering Plants
Pollination occurs when a pollen grain lands on a stigma.
pollen tube
sperm
stigma
one cell from pollen grain forms pollen tube
other cell forms two sperm that travel down tube

41. 22.2 Reproduction of Flowering Plants
Flowering plants go through the process of double fertilization.
female
gametophyte
ovule
egg
sperm
polar nuclei

42. 22.2 Reproduction of Flowering Plants
endosperm
seed coat
embryo
Flowering plants go through the process of double fertilization.
one sperm fertilizes the egg
other sperm unites with polar nuclei, forming endosperm
endosperm provides food supply for embryo

43. 22.2 Reproduction of Flowering Plants
Each ovule becomes a seed.
The surrounding ovary grows into a fruit.