1: Unifying Themes In Plants

Question 1

What is a Plant?

Answer 1

1. Defined by Characteristics
2. Requires evolution of life

Question 2

Photosynthetic Eukaryotes

Answer 2

All have chloroplasts

Question 3

Cyanobacteria

Answer 3

Carry on photosynthesis without their thylakoid membrane

Question 4

How chloroplasts evolve

Answer 4

Endosymbiosis

Question 5

Primary Endosymbiosis

Answer 5

Engulfment of photosynthetic bacterium

Question 6

Secondary Endosymbiosis

Answer 6

Engulfment of Photosynthetic eukaryotic cell

Question 7

Chlorobionta

Answer 7

Green Algae and Embryophytes (Land plants)

Question 8

Land Plants

Answer 8

Monophyletic

Evolutionary Novelties:
- outer cuticle
-specialized gametangia with protective layer of sterile cells
- sporophyte = embryo

Question 9

Bryophytes

Answer 9

Polyphyletic group

Shared characteristics:
- small organisms
- without lignin
- gametophyte = dominant phase
- sporophyte = embryo, very reduced (in size and time)

Question 10

Ferns

Answer 10

Polyphyletic group

Shared characteristics
- tracheid = vessel element with lignin
- spores
- lateral branching and roots
- secondary components

Question 11

Gynosperms

Answer 11

Monophyletic

Evolutionary Novelties:
- naked seed
- wood (sporophyte)
- gametophyte totally dependent from the sporophyte
- heterospory

Question 12

Angiosperms

Answer 12

Monophyletic

Evolutionary novelties:
- hidden seed = flower
- specialized leaf tissues
- specialized pollen
- cambium
- several independent lineages with divergent morphologies

Question 13

Common concepts in plants

Answer 13

1. they have multiple pigments with multiple functions
2. plants use water and its properties
3. plants use anabolic metabolism
4. plants have cell wall that performs variety of functions
5. plant life cycle alternates between gametophyte (n) and sporophyte (2n)
6. Meristematic activity continues throughout plants lifetime
7. Plant organs are initially made up of 3 tissues
8. Plant body consists of 4 organs (angiosperms)
9. Fruit disperse seeds through space; dormancy disperses seeds through time
10. Many plants and animals have coevolved
11. Understanding plant structure requires sense of scale
12. “primary” and “Secondary” are important concepts in plant anatomy
13. “Plant” can be broadly defined

Question 14

They have multiple pigments with multiple functions

Answer 14

Pigments are visual signals for attraction; they are responsible for bright colors in fruits, plants, flowers, and vegetables

Question 15

Plants use water and its properties

Answer 15

Since plants have no muscles, they take advantage of physical properties of water and laws of physics

Xylem cells control water movement; hydraulics

Question 16

Plants use anabolic metabolism

Answer 16

Plants are photoautotrophic

they manufacture every molecule needed for growth, no waste

Have biosynthetic pathways that synthesize toxic waste, they produce minimal toxic wate as they grow

Question 17

Plants have cell wall that performs variety of functions

Answer 17

Plants possess a non-living but biologically active cell wall made of cellulose
- enclose the protoplasm of the cells
- site of active cell secretion

Question 18

Plant life cycle alternates between gametophyte (n) and sporophyte (2n)

Answer 18

Plant life cycle: sporic
- meiosis produces spores; mitosis produces gametes

Protist: zygotic
Animals: gametic

Question 19

Meristematic activity continues throughout plant’s lifetime

Answer 19

continuous growth of plant

oldest tree have newly formed tissues every year

Primary growth; increase in length

secondary growth; increase in diameter

Question 20

Plant organs are initially made up of three tissues

Answer 20

Protoderm

Ground meristem

procambium

Question 21

Plant body consists of 4 organs (angiosperms)

Answer 21

Roots

stems

leaves

flowers

Question 22

Fruits disperse seeds through space; dormancy disperses seeds through time

Answer 22

Animals-mobile; plants - sessile

Fruits are unit of seed dispersal

Unlike animals, plant embryo can be dormant for long time allowing dispersal of next generation through time

Question 23

Many plants and animals have coevolved

Answer 23

Plant reward food and shelter

animals aid in pollination and seed dispersal

Question 24

Understanding plant structure requires sense of scale

Answer 24

Structures of interest to plant anatomists range in size over 10-11 orders of magnitude

Question 25

“Primary” and “secondary” are important concepts in plant anatomy

Answer 25

Primary and secondary Growth

Primary and secondary xylem and phloem

Primary and secondary cell wall

Question 26

Plants can be broadly defined

Answer 26

Eukaryotic, photosynthetic organisms

1. green algae
2. bryophytes
3. fern and fern allies
4. gymnosperms
5. angiospersm

Question 27

Why study plants?

Answer 27

1. photosynthesis changed the Earth
   - altered Earth’s atmosphere
   - compounds produced in the process are utilized directly or indirectly by heterotrophic organisms
2. Importance to humans:
   - agricultural plants
   - flavoring agents
   - simulating beverages
   - alcoholic drinks
   - lumber and pulp
   - plant fibers
   - plant extracts
   - euphorics and hallucinogenics
   - cultication and ornaments
   - medicinal significance