Angiosperms 2 Flashcards
Pollination by water
rare and Pollen floats on the water’s surface drifting until it contacts flowers
Wind pollinated species release a ___ amount of pollen
large
Most angiosperm species reply on
animals for pollination
The ____ of floral morphology is related to the modules of pollination
morphology
__ are the most important insect pollinators
bees
Coevolution
the joint evolution of interacting species in response to selection imposed on each other
The shapes and sizes of flowers often correspond to
pollen transporting parts of their animal pollinators
Plants evolve
more elaborate methods to attract animal pollinators
Animals evolve
more specialized body parts and behaviors to obtain the reward (nectar, pollen)
Darwin’s orchid
Moth-pollinated plant with “nectar spurs” or tubes that are the exact length of the hawkmoth tongue
Asexual reproduction results in a
clone of the genetically identical organisms (called vegetative reproduction)
Fragmentation
separation of parent plant into parts that develop into whole plants
Apomixis
the sexual reproduction of seeds from a diploid cell
Asexual reproduction can be beneficial to
successful plants in stable environments
Sexual reproduction generates
genetic variation that makes evolutionary adaptation possible
Some flowers can _____ to ensure every ovule will develop into a seed
self-fertilize
Self-fertilization
pollination occurs in the same flower or between flowers in the same plant
Self-compatible is advantageous when
when plants are isolated or pollinators are rare
Self-incompatible
pollination of the same or a closely related individual does not lead to fertilization
__ of angiosperm species are self-incompatible
50%
Self-fertilization is prevented by
genetic mechanisms, and structural mechanisms
genetic mechanisms to prevent self-fertilization
Recognition of pollen with identical or near-identical alleles of self-incompatible genes triggers signaling pathways that lead to the blocking of pollen tube growth
Structural mechanisms to prevent self-fertilization
incomplete flowers reduce self-fertilization
incomplete flowers in self-fertilization
Incomplete flowers lack one or more floral organs,
e.g. stamens or carpels
types of incomplete flowers
monoecious and dioecious
monoecious
male and female flowers on the same
individual plant
dioecious
male and female flowers on different individual
plants
Huge adaptive radiation of angiosperms occurred in the
cretaceous
How angiosperms have contributed to rapid adaptive radiation
modified xylem vessels, high rate of speciation, and quick reproduction
Modified xylem vessels
support higher rates of transpiration, which permits high rates of photosynthesis and growth
High rates of speciation
coevolution of plants and pollinators causes rapid divergence between plant populations, leading to speciation.
How angiosperms can reproduce so quickly
small female gametophyte with less use of resources; no development of seed storage reserves (endosperm) without double fertilization
Rapid reproduction allowed angiosperms to
diversify into short-lived habitats, e.g. annual species that reproduce quickly
Ancestors of angiosperms and gymnosperms diverged about ____
305 mya
Bennettitales
extinct seed plants with flower-like structures that may have been related to angiosperms
amborella
living basal species of flowering plants
Amborella traits
mixed pollination, replying on both insect pollinators and wind, Incomplete flowers with parts in whorls of 5-13 (more derived angiosperms have fixed numbers of flower parts), Flowers have undifferentiated petals, Xylem tissue resembles gymnosperms, Egg formation in Amborella resembles that of gymnosperms, Ovules enclosed by two integuments (one in gymnosperms)
Angiosperms divided into two main groups
monocots and dicots
Monocots form a ____ group
monophyletic group
dicots form a ____ group
paraphyletic group
Clades of dicots
eudicots (monophyletic), basal angiosperms, and magnoliids
Basal angiosperms
less derived and include flowering plants belonging to oldest lineages (<0.1% of angiosperm diversity)
three basal angiosperms lineages
Amborella family, including umbrella trichopoda, water-lily family, Star anise and relatives
Magnoliids
Evolved after basal angiosperms, 2% of angiosperm diversity, more closely related to monocots and eudicots than to basal lineages
____ of angiosperm species are monocots
25%
Major families of monocots
orchids and grasses
___ of angiosperm families are eudicots
eudicots
major families of eudicots
daisies and legumes
A eudicot embryo consists of
an embryonic axis attached to two cotyledons (seed leaves)
A monocot embryo contains
one cotyledon, and a large endosperm
One cotyledon is a _______ trait for clade monocots
shared, derived
