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Plant
Evolution
Plant Evolution
• Evolved from green algae
(450 mya)
• Green algae ancestor
– Multicellular body
– Cells w/ channels to
communicate
– Reproduce w/ sperm &
egg
• Early plants
– Low growth
(nonvascular)
Land Adaptations
• Retain Moisture
– Early plants grew near waters edge
– Cuticle: waxy coating
Land Adaptations
glucose
water
• Transporting Resources
– Vascular system: tissue to transport nutrients
• Up from the roots (ex: water)
• Down from the leaves (ex: sugars)
– Allows taller growth
Land Adaptations
• Growing upright
– Large plants need to support own weight
– Lignin: hardens cell wall; gives wood strength
Land Adaptations
• Reproduction on land
– Pollen: carried by wind/animals
– Seeds: hard coat protects embryo inside
Alternation of
Generations
X
X
X
X
X
• Diploid Stage
– zygote created from
sperm & egg
– Zygote grows into a
sporophyte
– Meiosis makes
spores
• Haploid Stage
– Male gametophyte
creates sperm
– Female gametophyte
creates egg
• Diploid stage restarts:
Sperm and egg make a
diploid zygote
• The cycle repeats
Kobe Kuiz
1) What traits do plants and plant-like protista share?
2) Name 4 adaptations that plants have for life on land.
3) Which plant adaptation allows them to carry nutrients to great
heights?
4) Which plant adaptation allows them to retain moisture?
5) What is the purpose of lignin?
6) What is the chromosome combination for the sporophyte stage?
7) What is the chromosome combination for the gametophyte
stage?
8) What does the gametophyte stage create?
9) What does the sporophyte stage create?