Problem 20 - Biology

Question

20\. The dominant organism in fern is the __________ a. sperm b. spore c. gamete d. sporophyte

Step-by-Step Solution

Answer

The dominant organism in fern is the sporophyte. The sporophyte stage is the main and noticeable part of the fern's life cycle.

Step 1 - Understand the Question

The exercise asks to identify the dominant organism in ferns from the given options: sperm, spore, gamete, sporophyte.

Step 2 - Recall Fern Life Cycle

Ferns have two main stages in their life cycle: the gametophyte stage (haploid) and the sporophyte stage (diploid).

Step 3 - Identify Dominant Stage

In ferns, the sporophyte stage is the dominant and more conspicuous part of the life cycle, which means that the sporophyte is the main, noticeable form.

Step 4 - Select the Correct Answer

Given the options, 'sporophyte' is the correct answer as it is the dominant organism in ferns.

Key Concepts

dominant organism

In the plant kingdom, not all organisms have the same prominence during their life cycle. For ferns, the dominant organism is the **sporophyte**. This concept is essential to understanding plant life cycles, especially for ferns. The dominant organism refers to the stage of the life cycle that is the most visible and sustained. Here are some important points to consider:

• The sporophyte is diploid, meaning it has two sets of chromosomes.
• It is the stage we commonly recognize as the true fern, which includes structures like fronds and roots.
The gametophyte stage, in contrast, is the smaller, less noticeable part of the life cycle. By understanding which organism is dominant, we can better grasp the overall life cycle and characteristics of ferns.

sporophyte stage

The sporophyte stage of ferns starts when a fertilized egg becomes a zygote. The zygote grows into a new fern plant. This plant is what we typically recognize as a fern. Here’s a bit more about it:

• The sporophyte stage is diploid (2n), meaning it has two copies of each chromosome.
• It forms structures called sporangia, which produce spores by meiosis.

The spores are haploid (1n), containing just one set of chromosomes. These spores, when released, can germinate to form a new gametophyte. The gametophyte will eventually produce gametes (sperm and eggs) that fuse to form a new sporophyte. In short:

• Sporophytes are large and long-lived compared to the small, short-lived gametophytes.

plant reproduction

Ferns have a fascinating way of reproducing. They alternate between two stages: sporophyte and gametophyte. Here’s a breakdown:

1. **Sporophyte Stage**:
• This stage is when the fern plant you see grows.
• It produces spores in the sporangia.
2. **Gametophyte Stage**:
• The spores germinate into tiny gametophytes, which are usually heart-shaped and small.
• These gametophytes produce gametes (sperm and eggs).

Understanding plant reproduction in ferns involves knowing both stages and how they relate.

Ferns rely on water for fertilization. The sperm swims to the egg, and once fertilization occurs, a new sporophyte begins to grow, continuing the cycle. This unique system of alternating generations allows ferns to spread and colonize various environments.