Lecture 11: Land plants

Question 1

what are the characteristics of land plants? (6)

Answer 1

• land dwelling (some have returned to aquatic habitats)
• Eukaryotes
• Multicellular
• Photosynthetic (photoautotrophs)
• cell walls made of cellulose
• Alternation of generations

Question 2

What are the 4 main groups of Land plants?

Answer 2

1. Non-vascular plants
2. Seedless vascular plants
3. Gymnosperms
4. Angiosperms

Question 3

Why did plants gradually move to land?

Answer 3

• spacious
• unfiltered sunlight
• higher levels of oxygen
• rich source of mineral nutrients
• less predators

Question 4

how did early ancestors of plants overcome the challenges they faced?

Answer 4

through adaptations for survival and reproduction on land (natural selection)

Question 5

Adaptations to life on land:

1. what is sporopllenin?

Answer 5

• it is a tough polymer that serves as a protective layer
• in charophytes it protects the zygote
• in plants it is in the walls of plant spores

Question 6

Synapomorphies of land plants:
(shared, derived traits that are unique to only plants and not in charophytes)

2. To adapt to water conservation…

Answer 6

• waxy cuticle on the epidermis: water proofs and protects from microbial attacks
• stomata: are pores in the epidermis of leaves and other photosynthetic organs

Question 7

Synapomorphies of land plants:

3. Multicellular, dependent embryos means…

Answer 7

• zygotes retain within tissues of the female parent

- parent provides nutrients, embryo has specialized placental cells (transfer nutrients)

Question 8

Synapomorphies of land plants:

4. Resources more compartmentalized: Roots and Shoots…

Answer 8

• Roots are responsible for finding nutrients and minerals underground
• Shoots are responsible for obtaining light about ground

Question 9

What is Alternation of generations?

Answer 9

• Haploid (n) multicellular and diploid (2n) multicellular body forms alternate
• sporophyte makes spores through meiosis
• gametophytes make gametes through mitosis

Question 10

What type of plant is a Bryophyte?

Answer 10

Non vascular plant

Question 11

What do Bryophytes look like? why can’t they grow tall?

Answer 11

they are very thin, ground hugging plants

• they cannot grow taller because they rely on diffusion

Question 12

What are the characteristics of Bryophytes?

Answer 12

• most tissues are only 1 or a few cells thick
• they lack a xylem and phloem so they rely on diffusion
• very thin and waxy cuticle
• stomata fixed in the open position
• lack true vascular tissue
• do not have leaves, stems, roots, shoots

Question 13

What is there to know about bryophyte reproduction?

Answer 13

• Haploid (n) gametophytes are the most dominant phase of the life cycle
• diploid (2n) sporophytes are only present half the time and are smaller
• the entire plant is either male or female
• must live in moist places