Green Algae and Land Plants Review

Flashcards covering ecosystem services, plant evolution, morphological adaptations, alternation of generations, and specific reproductive structures of green algae and land plants.

What are the key ecosystem services provided by plants?

Plants produce food, fuel, fiber, and medicine; provide shade and shelter; sequester carbon; produce oxygen and biomass; clean and filter water; decompose waste; build and hold soil; and influence humidity to moderate climate.

What does the monophyletic nature of land plants suggest about their evolution?

Molecular phylogenies showing land plants as a monophyletic group suggest there was a single transition from aquatic to terrestrial habitats.

What were the first morphological innovations seen in early land plants?

The first evidence includes the cuticle, spores, and sporangia, followed by major innovations like stomata, vascular tissue, roots, and leaves.

Define the two multicellular forms in the alternation of generations.

The gametophyte is a multicellular haploid ($n$) form that produces gametes by mitosis, while the sporophyte is a multicellular diploid ($2n$) form that produces spores by meiosis.

What is the function of the plant cuticle and stomata?

The cuticle is a waxy layer that prevents water loss from stems and leaves, while stomata are pores surrounded by guard cells that allow for gas exchange.

Contrast the functions of antheridia and archegonia.

The antheridium is the sperm-producing structure, while the archegonium is the egg-producing structure.

Define homosporous plants.

Homosporous plants produce a single type of spore that develops into a bisexual gametophyte which produces both sperm and eggs.

Define heterosporous plants and their specific structures.

Heterosporous plants produce two distinct types of spores: microsporangia produce microspores that develop into male gametophytes (sperm), and megasporangia produce megaspores that develop into female gametophytes (eggs).

What are the primary functions of xylem and phloem in vascular plants?

Xylem transports water and dissolved minerals from the roots to the rest of the plant, while phloem transports sugars and organic molecules from the leaves to other parts of the plant.

Contrast tracheids and vessel elements.

Tracheids are elongated water-conducting cells with pits in their secondary cell walls found in all vascular plants; vessel elements have gaps through both primary and secondary cell walls and are found in gnetophytes and angiosperms.

What characterizes Non-vascular plants like mosses, liverworts, and hornworts?

They lack xylem and phloem, lack true roots, stems, and leaves, require water for sperm to swim to the egg, and have a dominant gametophyte ($n$) stage.

What are the two major functions of fruit in angiosperms?

Fruit serves to protect the seeds during maturation and to effectively disperse the mature seeds.

What is sporopollenin?

A tough coat that helps spores resist drying when plants moved to land.

Which plant lineages produce seeds and how are they categorized?

Seed plants include Gymnosperms, which have "naked seeds" (e.g., conifers, cycads, ginkgoes), and Angiosperms, which have "encased seeds" (flowering plants).

Identify the primary photosynthetic pigments found in the Plantae lineage.

Chloroplasts in this lineage contain chlorophyll $a$, chlorophyll $b$, and beta-carotene.