Anthophyta (part 1)

characteristics, evolution and life cycle

Outline

Introduction

a.k.a., angiosperms, Magnoliophyta (after Magnolia), flowering plants

~1/4 million spp

dominant land plant for last 20-30 million yrs

Characteristics

improved vascular tissue -- vessel members, sieve tube elements, companion cells

unique life cycle -- double fertilization

flowers

• ovules enclosed in closed carpels
• insect pollination the norm

fruits -- seed enclosed in modified ovary wall

Evolution

early fossil evidence -- poor

• 130 mya -- pollen
• 120 mya -- wood, flowers, leaves

early angiosperms:

• woody shrubs, small trees
• tropical uplands of Gondwanaland -- large supercontinent with harsh interior climate
• flowers an early feature, sieve tubes later
• able to tolerate harsh conditions
  • small tough leave
  • deciduous habit
  • tough seed coat
  • efficient conduction of water
  • efficient reproduction
  • some evolved herbaceous habit -- annuals
  • secondary compounds vs herbivores

continental drift and early habitats -- adaptation and diversification

• initial conditions on Gondwanaland harsh -- demanded efficiency
• 120-90 mya -- Gondwanaland breaks up -- smaller continents with milder, maritime climates moderated by oceans
• allowed diversification of efficient angiosperms
  • Ceratophyllum
  • eudicots
  • magnoliids (woody magnoliids and paleoherbs)
  • monocots
• by 80 mya most modern families present
• allowed dominance by "superior" angiosperms

Life cycle

[see class notes]

compare and contrast with life cycle of pines (gymnosperms)

Vocabulary

click here to go to Anthophyta vocabulary