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What are the two main groups within Viridiplantae?

Green Algae and land plants

When do the first green algae appear in the fossil record?

725-1000 million years ago (precambrian)

What is still under investigation regarding green algae and land plants?

Which group of green algae is most closely related to land plants.

What types of nonvascular land plants are there?

Liverworts, mosses, and hornworts.

When do the first land fossil plants appear?

Around 475 million years ago.

How did the first land plants adapt to life out of water?

They developed sporopollenin, a cuticle, and UV-absorbing compounds.

What is sporopollenin?

A durable biopolymer that encases spores and prevents dying.

What is the dominant generation in nonvascular land plants?

Gametophyte (haploid) dominant.

Why do sperm need water in nonvascular land plants?

To swim to archegonia for fertilization.

When do the first vascular plants appear in the fossil record?

Around 420 million years ago.

What significant event happens around 360 million years ago concerning ferns?

Adaptive radiation of ferns and their relatives.

What facilitated the evolution of vascular systems in land plants?

The evolution of lignin and secondary cell walls.

What materials make up the primary and secondary cell walls of vascular plants?

Primary cell wall: cellulose; Secondary cell wall: lignin.

What advantage does vascularity give to land plants?

It provides rigidity.

Do vascular land plants still need water for reproduction?

Yes, sperm still need water to swim.