Lecture 3 Flashcards
When did angiosperms come around
at the end of the dinosaurs, 130 million years ago
What are the unique characteristics of angiosperms
flowers, closed carpels, double fertilization, 3-nucleate microgametophyte, 8-nucleate megagametophyte, stamen with two pairs of pollen sacs, sieve tubes with companion cells in phloem
What are the characteristics of angiosperms ancestor
lacked flowers, closed carpels, fruits, pollen with single aperture
What percent of angiosperms are not monocots and eudicots
3%
What are the two types of angiosperms that are not monocots or eudicots
magnoliids and orchids
What the three small, isolated families that arose prior to monocots and eudicots
waterlilies, amborellaceae, austrobaileyales
What was the name of the first angiosperm fossil
archaefructus
What are some characteristics of archaefructus
seeds enclosed in carpels/fruit, stood in shallow water, no sepals or petals
How did petals evolve
modified leaves that specialized to attract pollinators, or from stamens that became sterile
What often fuses on a flower
the petals to form tubular corolla, and sometimes stamens and/or sepals
Sepals have the same number of vascular bundles as what
leaves
How many vascular bundles do sepals have
one
How many vascular bundles do petals have
can have one or multiples
What is not distinct on a perianth
does not have distinct petals or sepals
How were early carpels unspecialized
no stigma area, not fused, usually more ovules than contemporary families
What are the flour evolutionary trends among flowers
1) few to many parts indefinite in numbers to few parts that are definite in number, 2) floral axis has become shortened so can’t see spiral arrangement; parts often fused, 3) ovary from superior to inferior, perianth now differentiated, 4) radial symmetry to bilateral symmetry
What are some characteristics of Asteraceae
it is a eudicot, small epigynous flowers, inferior ovary, 5 stamens usually fused, 5 petals fused, sepals absent or pappus
What pattern do flowers mature in
a spiral
What are the two different flower shapes
disk or ray
What are the names of the two specialized families
Asteraceae and Orchidaceae
What are some characteristics of Orchidaceae
monocot, 3 fused carpels, inferior ovary, thousands of minute ovules, 1 stamen fused with style and stigma, modified petals and sepals, bilaterally symmetrical, huge range in size, clone for commercial use, some myco-heterotrophs
What is myco-heterotrophs
is a symbiotic relationship between certain kinds of plants and fungi, in which the plant gets all or part of its food from parasitism upon fungi rather than from photosynthesis
How does a closed carpel benefit a plant
protects it from herbivores
What type of pollination causes the most floral evolution
animal pollinators
