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Glaucophyta (algae)
PLANTAE
Rhodophyta (red algae)
Bio100 (Dr Paddack) Lecture 16 (10/24/16)
GREEN ALGAE
GREEN PLANTS
 Lecture Quiz #4
I. Phylogenetics
A. Phylogenetics
B. Constructing phylogenetic trees
C. Dating Evolutionary events
II. Plant Evolution & Diversity
A. Plant evolutionary history
B. Plant adaptations for life on land
1. Maintaining moisture
2. Obtaining resources from 2 locations
3. Working against gravity
4. Reproduction & dispersal
Descendents
(here, species)
Ulvophyceae
Coleochaetophyceae
Charaphyceae (stoneworts)
Common ancestor
to all green plants
NON-VASCULAR PLANTS
LAND PLANTS
Hepaticophyta (liverworts)
Bryophyta (mosses)
Ability to live on land
Anthocerophyta (hornworts)
SEEDLESS PLANTS VASCULAR PLANTS
Bacteria
Archaea
Lycophyta (lycophytes)
Psilotophyta (whisk ferns)
Eukarya
Equisetophyta (horsetails)
PLANTAE
Vascular tissue
Pteridophyta (ferns)
GYMNOSPERMS
SEED PLANTS
Cycadophyta (cycads)
Four nested
monophyletic
groups of plants
Ginkgophyta (ginkgo)
Redwood group (junipers et al.)
Pinophyta (pines et al.)
Seeds
Gnetophyta (gnetophytes)
ANGIOSPERMS
Anthophyta (flowering plants)
Campbell: Figure 13.5A
Establishing evolutionary relationships:
Building phylogenies: homologous structures
1. Fossil record
Pakicetus (terrestrial)
Humerus
Rodhocetus (predominantly aquatic)
Pelvis and
hind limb
Dorudon (fully aquatic)
Radius
Ulna
Carpals
Metacarpals
Phalanges
Human
Cat
Whale
Bat
Pelvis and
hind limb
Balaena (recent whale ancestor)
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But, similar structures aren’t always homologous!
3. Molecular biology
Compare DNA regions
or proteins
Analogous structures
- Structures that are
similar, but not due to
close common ancestry
Due to Convergent
Evolution
Two desert plants
Figure 15.17
Crane Paddack Nelson, Abelson, Bernardi (2016).
J Ocean Sci Foundation 21: 10–17.
Outbreak of a stony coral
Dating Evolutionary Events:
Carbon-dating & Molecular ‘clock’
Genetic analysis
mitochondrial gene cytochrome oxidase 1
(CO1)
Genus Montipora, species unidentified
Falalop Men’s House
July 2012
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Carboniferous Period (from ~360-to 299 mya)
• Intense plant growth (lots detritus ->peat -> coal)
• Changed global CO2 levels, thus climate
Plants!
Gymnosperms
(“naked seeds”)
eg. Pines, ginkgo
Angiosperms
(“contained seeds”)
Flowering plants
Why move to land?
Major challenges
• More light energy
• Preventing water loss
• Much higher concentration of CO2
• Gas exchange
• Lots of mineral nutrients
• Protection from UV radiation
• Few herbivores/pathogens on land
• Upright growth
LOTS of opportunities for adaptive
radiation
• Moving water/nutrients
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Key adaptations for
plants to move to land:
• Flavonoids
• Cuticle
• Stomata
• Vascular tissue
UV radiation
• UV damages DNA
(may cause mutations)
• UV energy attenuates quickly
in water
• 1st plants evolved flavonoids
(UV absorbing compounds)
Preventing water loss
• Cuticle: waxy coating on stems and leaves
Water loss and gas exchange
• Pores and stomata: openings that allowing
gas exchange and control water loss
– Guard cells control opening
Upright growth
• 1ST plants: low to ground in wet
areas (but still vertical…)
• More vertical growth: more
access to light
• BUT Need to support vertical
growth and move water/nutrients
Plant adaptation for life on land:
Gravity & moving resources up/down
1. lignin: complex
organic polymer
Component of wood
2. Vascular tissue
(vessels)
Rigid water
conducting
cells/vessels
• Solution to both:
vascular tissue
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Reproduction in Dry Conditions
Innovations
1. Spores: encased in tough coating to
resist drying
Lecture 16 (10/24/16): Study Questions
Phylogenetics:
8. Why is molecular data so useful for constructing
phylogenetic trees?
9. Define & briefly explain the molecular clock.
Plants:
1. The oldest plant fossil is _________ million years old.
2. What caused plants to leave the aquatic environment &
colonize land?
3. Briefly describe the conditions during the
Carboniferous Period that allowed so much plant growth.
4. How & why did this plant growth change the global
climate?
Reproduction in Dry Conditions
Innovations
2. Gametangia
Lecture 16 (10/24/16): Study Questions
Phylogenetics:
1. How is a classification system for species useful?
2. Define: phylogenetics, phylogenetic tree, common
ancestor, lineage.
3. List the 3 resources biologists use to construct
phylogenetic trees.
4. The fossil record does indeed provide a substantial
chronicle of evolutionary change, but it is limited.
How/why is it limited?
5. Define homologous structures. Provide an example.
6. Define analogous structures & provide an example.
7. Define convergent evolution.
Lecture 16 (10/24/16): Study Questions
Plants:
5. Define fossil fuels. What is the source of coal? What is
the source of oil & gas? Are they renewable?
6. What is the key difference between Gymnosperms &
Angiosperms?
7. List the evolutionary adaptations that allowed plants to
handle each of the following challenges of living on land:
maintaining moisture (2 adaptations); dealing with
increased UV radiation; handling gravity (ie, staying
upright – 2 adaptations); reproduction.
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