Plant Diversity Pt.2 Flashcards
Chapter 30
when did seed plants originate
360 million years ago
seed
embryo and nutrients surrounded by protective coat
when were plants domesticated?
8,000 years ago
what factors are common to seed plants
- reduced gametophytes
- heterospory
- ovules
- pollen
the ancestors of seed plants were likely ____sporous
homosporous, while seed plants are heterosporous
megasporangia
give rise to female gametophytes
microsporangia
give rise to male gametophytes
what does an ovule consist of?
megasporangium, megaspore, 1+ protective integuments
how many integuments do gymnosperm megaspores have?
one
how many integuments do angiosperm megaspores have?
two
what evol. advantages to seeds provide over spores?
- remain dormant until favorable conditions
- supply stored food
- transported long distances
progymnosperms
late Denovian plants that began to acquire adaptations that characterized seed plants
when did angiosperms begin to replace gymnosperms
near Mesozoic
angiosperms today…?
dominate terrestrial ecosystems
conifers
cone-bearing gymnosperms that dominate in northern latitudes
four phyla of gymnosperms
- cycadophyta
- ginkgophyta
- gnetophyta
- coniferophyta
cycadophyta
large cones, palm leaves
–> thirved during Mesozoic but few today
gingkophyta
one living species: Gingko biloba
—> high tolerance to air pollution/population ornamental tree
gnetophyta
three genera
- vary in appearance deserts to tropics
coniferophyta
largest of gymnosperm phyla
- most evergreen and photosynthesis year-round
oldest living organism
bristlecone pine
three features of gymnosperm life cycle
- dom. sporophyte gen
- dev. of seeds from fertilized ovules
- transfer of sperm to ovules by pollen
small pine cones
produce pollen grains w/ male gametophyte
large pine cone
contain ovule that produce megaspores (female gam.)
how long from pine cone production to maturation?
three years
most widespread and diverse plants
angiosperms
phylum of angiosperms
anthophyta
two adaptations of angiosperms
- flowers
- fruits
four leaves of flowers
- sepals
- petals
- stamens
- carpels
sepals
enclose flower
petals
brightly colored attract pollinators
stamens
produce pollen
carpels
produce ovules
anther
sac where pollen is produced
stigma
where pollen is recieved
fruits
consist of mature ovary, protect seeds and can be dry if mature