24 Angiosperms Part 2

These flashcards cover key concepts from the lecture on angiosperms, including their evolutionary timeline, unique features, and classification.

What did Darwin refer to as 'an abominable mystery' in relation to angiosperms?

The sudden appearance of angiosperms in the fossil record.

What are the oldest simple vascular plants mentioned in the evolutionary timeline?

Rhyniophytes.

During which geological periods did ferns and lycophytes thrive?

Devonian and Carboniferous periods.

What key relevant fossils did Caytoniales and Bennettiales contribute to angiosperm evolution?

Caytoniales had cupules similar to carpels, and Bennettiales had flower-like bisexual strobili.

What hypothesis suggests that gnetophytes are the closest relatives of angiosperms?

Anthophyte Hypothesis.

What are some unique features of angiosperms?

Flowers, fruits, double fertilization, sieve-tube elements, companion cells in phloem.

What is the first well-preserved angiosperm discovered, and how old is it?

Archaefructus sinensis, approximately 125 million years old.

What type of pollen do early angiosperms have compared to gymnosperms?

Monocolpate pollen with a single aperture.

What percentage of Anthophyta is made up of monocots and eudicots?

97%.

What distinguishes monocots from eudicots?

Monocots have a single cotyledon, while eudicots have tricolpate pollen.

What types of angiosperms are considered basal angiosperms?

Amborellaceae, Nymphaeales, and Austrobaileyales.

What unique characteristic do Amborellaceae possess?

They lack vessels in their xylem.

How are Nymphaeales and Austrobaileyales adapted to their habitats?

Nymphaeales are herbaceous aquatic plants, while Austrobaileyales are shrubs or small trees in low light.

What is a key feature of magnoliids regarding their flower structure?

They have numerous, spirally arranged flower parts.

What is a primary difference in the flowering structure of monocots compared to basal angiosperms?

Monocots retain some basal angiosperm features like monocolpate pollen and typically have 3-merous flowers.

What significant impact did the discovery of Archaefructus have on previous theories of angiosperm evolution?

It upset theories that early angiosperms were similar to magnoliids with large, showy flowers.