Chapter 29: Plant Diversity

What are the two major groups within Archaeplastida?

Red algae and green algae + land plants.

What defines a true land plant?

Multicellular, photosynthetic organisms with cellulose cell walls and chloroplasts containing chlorophylls a and b.

What is the significance of vascular tissue in plants?

Vascular tissue allows plants to get bigger and live in a wider range of habitats.

What is a synapomorphy shared by all land plants?

Alternation of generations with multicellular dependent embryos.

What limited mosses to moist habitats?

Sperm must swim through water to fertilize eggs.

What are the three groups of bryophytes?

Liverworts, hornworts, and mosses.

What are the two main types of leaves in vascular plants?

Microphylls and megaphylls.

What innovations allowed seed plants to reduce the gametophyte stage?

Further reduction of the gametophyte stage and variation in spore size.

What are the two major clades of seed plants?

Gymnosperms and angiosperms.

What are the advantages of seeds compared to spores?

Seeds are better for dispersal, have multicellular coats, can remain dormant, and provide a food store.

How do angiosperms aid in seed dispersal?

Through fruits, which can be carried by animals.

What happens during the double fertilization in angiosperms?

One sperm fertilizes the egg to form an embryo, while the other fuses with two nuclei to form endosperm.

What are some adaptations plants have to avoid herbivory?

Chemical defenses like caffeine and nicotine, and mechanical defenses like thorns.

Why are plants crucial to the ecosystem?

They produce oxygen, food, habitat, fuel, and medicine.

What are the five key events in land plant evolution?

Multicellularity, invasion of land, vascular tissue, seed plants, and flowers.

What defines the major division between vascular and nonvascular plants?

Vascular plants have vascular tissue, while nonvascular plants do not.

What is the dominant phase in the life cycle of bryophytes?

Gametophyte phase.

What defines the flowering plants (angiosperms)?

They produce seeds contained in fruits.

What is a gametangium?

A specialized structure where gametes are produced.

What structure in seed plants allows them to live in drier habitats?

Seeds, as they contain an embryo and a food reserve and can remain dormant.

What is an apical meristem?

An area of growth located at the tips of shoots and roots.

What is the primary function of phloem?

To transport organic molecules throughout the plant.

What is meant by heterosporous in seed plants?

The production of two different types of spores: male and female.

What is the role of the endosperm in seeds?

It serves as the food supply for the developing embryo.