BIOL 1020 and BIOL 1021 - Lecture 15
- Plants-1 -
Assigned Readings in Textbook:
Chapter 33 (section 33.1) – Plant Diversity: An Evolutionary Overview (pages 688 to 690)
Use the following wireframe outline to make notes on the content presented in Lecture 15
Refer to Chapter 33 in your textbook and the Chapter 33 resources on LaunchPad to supplement
your notes and aid in studying this material.
1. How did plants evolve?
Plants colonized land about 500 million years ago (with fungi)
Plant ancestors diverged from protists about 1.5 billion years ago from branch shared with
fungi and animals
(a) what problems did plants have in moving onto land and how did they solve them?
Problem Solution
More temperature extremes - Stomata controlled by guard cells
1
Reduced water availability - Development of xylem
- Development of roots/rhizoids
2 - Presence of sporopollenin (in spores)
- Protected gametangia / gametes
Greater nutrient availability - Development of xylem and phloem
3 - Seeds with food reserves
- Apical meristems
Light fluctuation - Apical meristems / reinforced cell walls
4
Gravity - Reinforced cells walls (with lignin)
5
Exposure to UV radiation - Have protective flavonoids / pigments
6 - Protected gametangia
Higher evaporation rates (wind) - Develop waxy cuticle
7 - Stomata controlled by gaurd cells
1
- Plants-1 -
Assigned Readings in Textbook:
Chapter 33 (section 33.1) – Plant Diversity: An Evolutionary Overview (pages 688 to 690)
Use the following wireframe outline to make notes on the content presented in Lecture 15
Refer to Chapter 33 in your textbook and the Chapter 33 resources on LaunchPad to supplement
your notes and aid in studying this material.
1. How did plants evolve?
Plants colonized land about 500 million years ago (with fungi)
Plant ancestors diverged from protists about 1.5 billion years ago from branch shared with
fungi and animals
(a) what problems did plants have in moving onto land and how did they solve them?
Problem Solution
More temperature extremes - Stomata controlled by guard cells
1
Reduced water availability - Development of xylem
- Development of roots/rhizoids
2 - Presence of sporopollenin (in spores)
- Protected gametangia / gametes
Greater nutrient availability - Development of xylem and phloem
3 - Seeds with food reserves
- Apical meristems
Light fluctuation - Apical meristems / reinforced cell walls
4
Gravity - Reinforced cells walls (with lignin)
5
Exposure to UV radiation - Have protective flavonoids / pigments
6 - Protected gametangia
Higher evaporation rates (wind) - Develop waxy cuticle
7 - Stomata controlled by gaurd cells
1
