Seedless Plants Lecture Review

A set of question-and-answer flashcards covering key terms, concepts, and evolutionary milestones from the lecture on seedless plants and early plant evolution.

What key ability distinguishes vascular plants from non-vascular plants?

Vascular plants can transport water and nutrients through xylem and phloem, whereas non-vascular plants cannot.

Which plant group includes mosses, liverworts, and hornworts?

The bryophytes.

Why do bryophytes remain small and hug the ground?

They lack vascular tissue, so they cannot move water high above the substrate and rely on surface moisture.

By what reproductive cells do seedless plants propagate instead of seeds?

Spores.

How does a spore differ from a seed?

A spore lacks a food supply and thick waterproof coat, while a seed contains stored food and a protective coat for the embryo.

What is meant by "alternation of generations" in plants?

A life cycle that alternates between a haploid gametophyte generation and a diploid sporophyte generation.

Which generation in alternation of generations is haploid?

The gametophyte generation.

What does a gametophyte produce?

Gametes—sperm and eggs—by mitosis.

What does a sporophyte produce?

Haploid spores by meiosis.

In mosses, which generation is the dominant, visible form?

The gametophyte generation.

In ferns, which generation is dominant and conspicuous?

The sporophyte generation.

What plant structure specifically produces spores?

The sporangium (plural sporangia).

What are structures that produce gametes in plants called?

Gametangia.

Name the male and female gametangia in plants.

Antheridium (male) and Archegonium (female).

What adaptation helps early land plants reduce water loss from tissues?

A waxy cuticle covering their surfaces.

Why do bryophytes and ferns still need free water for fertilization?

Their sperm are flagellated and must swim to reach the egg.

What two types of vascular tissue evolved in ferns?

Xylem and phloem.

What is transported by xylem?

Water and dissolved minerals upward from roots to leaves.

What is transported by phloem?

Sugars (food) produced by photosynthesis to all parts of the plant.

Which polymer strengthens xylem walls, allowing taller growth?

Lignin.

Give one example of a lycophyte.

Club moss (or spike moss).

What are sori on the underside of fern fronds?

Clusters of sporangia that produce spores.

What is a strobilus in seedless vascular plants?

A cone-like structure containing sporangia (e.g., on club mosses).

Why are mosses useful indicators of air quality?

They absorb water and nutrients directly from the air, so pollutants accumulate in their tissues.

State one ecological role of pioneer species like mosses.

They stabilize soil/slow erosion, store water, and create habitat for other organisms.

Which plant group first evolved pollen and seeds?

The gymnosperms.

Biologically, what is pollen?

A male gametophyte that carries sperm cells.

How does a seed improve offspring survival compared with a spore?

It provides a protective waterproof coat and a food supply for the embryo, enabling long dormancy and successful germination.

Which plant group invented flowers and fruits?

The angiosperms (flowering plants).

What evolutionary advantage do flowers provide?

They attract pollinators, ensuring efficient and targeted pollen transfer.

How do fruits aid in seed dispersal?

Animals eat the fruit and later deposit the enclosed seeds elsewhere, often with fertilizer.

List two challenges plants faced when moving from water to land.

1) Risk of desiccation; 2) Need for structural support against gravity (others include reproduction without water).

Give two advantages of life on land for early plants.

Abundant sunlight and atmospheric CO₂, and initially few herbivores or pathogens.

What are apical meristems?

Regions of undifferentiated cells at root and shoot tips that enable continuous (indeterminate) growth.

Define rhizoids.

Root-like anchoring structures in bryophytes that do not conduct water.

What does the term "bryophyte" collectively refer to?

Mosses, liverworts, and hornworts.

Why are seedless vascular plants usually found in moist, shaded habitats?

They still rely on water for sperm to swim during fertilization despite having vascular tissue.

Approximately when did bryophytes first colonize land?

About 475–480 million years ago.

Roughly when did vascular tissue evolve in plants?

Around 425 million years ago.

What does the word "gymnosperm" literally mean, and why?

"Naked seed" because their seeds are not enclosed within fruit.