Question

A seedless plant phylum that is included in the informal group known as bryophytes is a. liverworts. b. hornworts. c. mosses. d. All of the above phyla are included in the bryophytes. e. None of the above is included in the bryophytes.

Short answer

The correct answer is - All of the above phyla are included in the bryophytes.

Step-by-step solution

Understand the Characteristics of Bryophytes

Bryophytes are a group of non-vascular plants meaning they don't have structures for water transportation like xylem and phloem. They don't produce seeds and can include various phyla such as liverworts, hornworts, and mosses.

Matching the Choices with Bryophyte Characteristics

Checking each choice, we'll find that all three phylas (liverworts, hornworts, and mosses) are included in bryophytes. This is because they all share the same characteristics of bryophytes: they don't produce seeds and lack vascular tissues.

Select the Correct Choice

Based on the analysis in previous steps, it's evident that all the options constitute the phylum of bryophytes. Therefore, the correct choice is - All of the above phyla are included in the bryophytes.

Key concepts

Non-vascular plants

Non-vascular plants are a category of plants that do not have specialized structures like xylem and phloem to transport water and nutrients. Unlike their vascular counterparts, non-vascular plants depend on diffusion and osmosis for internal transport. This means they generally grow in damp and shady environments, which helps them absorb the needed moisture directly from their surroundings.

• Non-vascular plants lack true roots, stems, and leaves. Instead, they have simple structures that perform these functions.
• These plants are vital to ecosystems as they often serve as pioneer species, aiding soil formation.
• Reproduction in non-vascular plants usually involves spores, as they do not produce seeds.

As primary producers, non-vascular plants play an essential role in food chains and are also crucial for various soil processes like fixation and erosion prevention.

Seedless plants

Seedless plants are a diverse group that reproduces without the use of seeds. This includes both vascular and non-vascular plants. For those in the bryophyte category, like liverworts, hornworts, and mosses, reproduction occurs through spores.

• Spores are single-celled reproductive units capable of developing into a new organism without the need for fertilization.
• Seedless plants can occupy various habitats, but bryophytes particularly thrive in moist conditions.
• These plants contribute substantially to their ecosystems, holding and regulating moisture in the environment.

Understanding seedless plants helps us appreciate how diverse plant reproductive strategies can be successfully adapted to different environmental conditions.

Liverworts

Liverworts are recognized as some of the oldest land plants, with a simple and flattened structure. They belong to the group of bryophytes, sharing common traits such as being non-vascular and seedless.

• There are about 9,000 species of liverworts, and they are usually found in myriad habitats ranging from tropical to polar regions.
• Liverworts primarily reproduce through spores, though some can also reproduce asexually via small structures called gemmae.
• They are crucial for studies in plant biology due to their simplicity and evolutionary significance.

By forming dense mats over soil surfaces, liverworts aid in preventing erosion and contribute to soil health.

Hornworts

Hornworts, another fascinating group of bryophytes, are named for their horn-like sporophyte structure. They are distinctive because of their complex sporophyte that remains attached to the gametophyte and grows upright.

• The "horns" are actually the spore-producing structures, which means that hornworts continue to grow and release spores over time.
• They often colonize open, wet areas where competition from larger plants is minimal.
• Hornworts have a unique symbiotic relationship with cyanobacteria, which fix nitrogen, thereby enriching the soil they inhabit.

Their ability to sustain in harsh conditions where few other plants thrive highlights their resilience and ecological importance.

Mosses

Mosses are perhaps the most familiar members of the bryophytes. They are small, soft plants that typically form lush green carpets or clumps in moist environments. Mosses have a significant role in the world of bryophytes due to their widespread distribution and ecological functions.

• There are over 12,000 species of mosses globally, making them one of the most diverse groups of non-vascular plants.
• They can reproduce both sexually and asexually, with spores playing a key role in their life cycle.
• Mosses are highly effective at retaining water, which makes them important for moisture regulation in ecosystems.

They serve as habitat for microfauna and improve soil quality by slowly building humus through the decomposition of their own plant material.