1) Please turn in your Unit 9 Test Corrections on the table by the door. Staple your corrections to the

back of your test.

2) If you have not yet selected a Learning Objective for the PowerPoint assignment, please see me. Due on April 24th

• Please take your lab notebook from the table by the door.

Chapter 29 Plant Diversity

1. What are the characteristics of plants?- Photosynthetic autotrophs- Cellulose in cell walls- Starch as storage polysaccharide- PROBLEM – light, CO2 & air are above ground

- water & minerals are below ground- SOLUTION – evolution of specialized structures

2. What adaptations do plants have for survival on land?- Stomata – pores used for gas exchange- Roots – absorb water & minerals from underground- Apical meristems – tips of shoots & roots where growth occurs- Cuticle – waxy covering to prevent water loss thru leaves- Jacketed gametangia – gamete producing organ with protective jacket

of cells to prevent dehydration- Sporopollenin – polymer that formed around exposed zygotes & forms

walls of plant spores preventing dehydration- Lignin – structural polymer that provides strength for woody tissues of

vascular plants

Algae also

Chapter 29 Plant Diversity

1. What are the characteristics of plants?2. What adaptations do plants have for survival on land?

- Stomata – pores used for gas exchange- Roots – absorb water & minerals from underground- Apical meristems – tips of shoots & roots where growth occurs- Cuticle – waxy covering to prevent water loss thru leaves- Jacketed gametangia – gamete producing organ with protective jacket

of cells to prevent dehydration- Sporopollenin – polymer that formed around exposed zygotes & forms

walls of plant spores preventing dehydration- Lignin – structural polymer that provides strength for woody tissues

3. Describe alternation of generations- Alternates between sexual

& asexual reproduction- Gametophyte (n) make gametes

by mitosis- Sporophyte (2n) makes spores

by meiosis

Haploid multicellularorganism (gametophyte)

Mitosis Mitosis

Gametes

Zygote

Diploid multicellularorganism (sporophyte)

Alternation of generations: a generalized scheme

MEIOSIS FERTILIZATION

2n2n

n

n

nn

nSpores

Mitosis

Chapter 29 Plant Diversity1. What are the characteristics of plants?2. What adaptations do plants have for survival on land?3. Describe alternation of generations4. What is the evidence that plants evolved from charophytes (green algae)?

- rose-shaped complexes for making cellulose - Proteins in the plasma membrane that make cellulose microfibrils- Linear arrays found in non-charophytes- Similar %age of cellulose found in plants & charophytes

30 nm

Chapter 29 Plant Diversity1. What are the characteristics of plants?2. What adaptations do plants have for survival on land?3. Describe alternation of generations4. What is the evidence that plants evolved from charophytes (green algae)?

Similarities??- rose-shaped complexes for making cellulose

- Proteins in the plasma membrane that make cellulose microfibrils- Linear arrays found in non-charophytes- Similar %age of cellulose found in plants & charophytes

- Peroxisome enzymes - Sperm structure – flagella- Formation of phragmoplast

- Phragmoplast – an alignment of cytoskeletal elements & Golgi-derived vesicles at a dividing cell’s midline

- Used in making cell plates during cell division- Genetic evidence

- “Deep Green” Project- Nuclear & chloroplast genes have similar DNA

Chapter 29 Plant Diversity1. What are the characteristics of plants?2. What adaptations do plants have for survival on land?3. Describe alternation of generations4. What is the evidence that plants evolved from charophytes (green algae)? 5. How did plants evolve from green algae?

- Natural selection- Algae best suited genetically for a drier climate (low water in a lake)

could reproduce & pass along those genes to create a new population of better adapted “algae”

6. What were the highlights/adaptations of plant evolution?- Movement to land led to Bryophytes (mosses & worts)

- Tougher spores (sporopollenin)- Jacketed gametangia

- Vascular tissue (ferns)- Cells joined to transport water & nutrients- Lacked seeds

- Development of seeds (Gymnosperms)- More protection of embryo- Embryo w/ food

- Development of flowers (Angiosperms)- Complex reproductive structure

Figure 29.7 Highlights of plant evolution

Bryophytes(nonvascular plants) Seedless vascular plants Seed plants

Vascular plants

Land plants

Origin of seed plants(about 360 mya)

Origin of vascular plants (about 420 mya)

Origin of land plants(about 475 mya)

Ancestralgreen alga

Cha

rop

hyce

an

s

Liv

erw

ort

s

Hor

nw

orts

Mo

sse

s

Lyc

oph

yte

s(c

lub

mos

ses,

spi

ke m

oss

es,

qu

illw

ort

s)

Pte

rop

hyt

es

(fe

rns,

hor

seta

ils,

wh

isk

fern

s)

Gym

nos

pe

rms

Ang

iosp

erm

s

Table 29.1 Ten Phyla of Extant Plants