Problem 125 - Objective Biology for NEET

Question

Vascular plants which do not bear seeds is (a) Angiosperms (b) Pteridophytes (c) Gymnosperms (d) None of these

Step-by-Step Solution

Answer

The vascular plants which do not bear seeds are Pteridophytes

Step 1: Understand the classifications

Vascular plants are a large group of plants that have specialized tissues for conducting water, minerals, and photosynthetic products. This group can be divided into different categories based on their reproduction methods. Angiosperms and Gymnosperms are seed-bearing plants and Pteridophytes are non-seed bearing plants.

Step 2: Identify the correct category

From the given options, considering the exercise is asking about vascular plants which do not bear seeds, Pteridophytes appears to be the correct choice as they are non-seed bearing vascular plants.

Key Concepts

Vascular Plants

Vascular plants, also known as tracheophytes, are a crucial component of the plant kingdom because they have developed a complex system for transporting water and nutrients. This system comprises two main types of tissues: xylem and phloem.
Xylem is responsible for transporting water and dissolved minerals from the roots to various parts of the plant, while phloem distributes the sugars and other nutrients produced by photosynthesis.

• Xylem: Carries water and dissolved minerals upwards.
• Phloem: Transports nutrients such as sugars throughout the plant.

These specialized tissues allow vascular plants to grow much larger and taller compared to non-vascular plants.
Additionally, vascular plants are further classified based on their reproductive structures, particularly whether they produce seeds or not. The two main groups within this classification are seedless vascular plants, such as pteridophytes, and seed-bearing vascular plants, like gymnosperms and angiosperms.

Pteridophytes

Pteridophytes are an interesting group of seedless vascular plants that typically include ferns, horsetails, and clubmosses. They are an ancient group, with a lineage dating back hundreds of millions of years, making them one of the earliest colonizers of land environments.
Unlike seed-bearing plants, pteridophytes reproduce through spores instead of seeds. These spores are typically found on the underside of their leaves or fronds in structures called sporangia.

• Spores: Reproductive units formed in sporangia, not seeds.
• Sporangia: Structures on the leaf undersides where spores are produced.

Pteridophytes are mainly found in moist and shaded environments which provide the necessary conditions for spore germination and growth.
Their reliance on these specific conditions limits their habitat range compared to seed-bearing plants, which can often thrive in a wider array of environments.

Seed-Bearing Plants

Seed-bearing plants hold a distinct and essential place in the plant kingdom as they have evolved to use seeds as their primary form of reproduction. This adaptation allows them to thrive in a wide variety of environments.
The two main types of seed-bearing plants are gymnosperms and angiosperms, each with their unique characteristics. **Gymnosperms** - Gymnosperms, like pines and spruces, have seeds that are not enclosed in fruit. Instead, they are typically found on the scales of cones.
**Angiosperms** - Angiosperms, the most diverse and numerous group of plants, produce seeds that are enclosed within fruits. This group includes flowering plants, which have developed various mechanisms for attracting pollinators.

• Environmental Adaptability: Seeds allow for survival in diverse conditions.
• Diversity: Angiosperms are the most diverse group of plants.

Seeds, due to their protective nature, can withstand harsh conditions until they find a suitable environment for growth, offering a significant advantage over spore reproduction seen in pteridophytes.