lecture 15 Flashcards
what percent of all plant species does angiosperms represent?
90%
when did angiosperms first appear?
300 million years ago
when did angiosperms become common?
100 million years ago
5 characteristics that made angiosperms so successful
large broad leaves - high photosynthetic rate
short life cycle - quick dispersal
advanced vascular tissue - efficient transportation
flowers
fruits
what percent of all angiosperms likely resulted from polyploidy?
50-70%
what facilitated the evolution of adaptations in angiosperms
duplication of the genomes as well as hybridization
mangrove trees ae adapted for what?
high salt, low oxygen and hot climate
how are mangrove trees adapted for high salt, low oxygen and hot climate?
roots block salt uptake
leave reduce water loss
roots are adapted to lift trees out of water
aerial roots are adapted to taking in extra oxygen
drought adaptations:
silver-grey hairs reduce water loss
deep root system
seeds that only germinate in favorable conditions
small spines
water storage in stem
thick waxy coating
dormancy in extreme conditions
mechanical defense:
spines
chemical defence:
anti-herbivory compounds that make them taste bad
(alkaloids, glycosides, tannins)
camouflage against predation:
developed growth form and colour
indirect defence:
mutualistic relationships with insects that deter herbivores
tolerance to predation:
apical meristems at the base of the leaves
what is the driving force behind speciation?
co-evolution between herbivores and host plants
