Problem 63 - Objective Biology for NEET

Question

Sexual reproduction of oogamous type is found in (a) Red algae (b) Green algae (c) Brown algae (d) All of these

Step-by-Step Solution

Answer

All the given types of algae i.e., Red algae, Green algae, and Brown algae show oogamous type of sexual reproduction. Hence, the correct answer is (d) All of these.

Step 1: Understand the terminology

The first step is to understand what 'oogamous' means. In oogamous organisms, there is a high degree of specialization in the size and behavior of male and female sex cells or gametes. The female egg cell is large and non-motile while the male sperm cell is small and motile.

Step 2: Identify which algae show this type of reproduction

Once one knows the basis of what oogamous signifies, it's important to pair it off with the correct type of algae. Red algae (Rhodophyta), green algae (Chlorophyta), and brown algae (Phaeophyta) all show oogamous sexual reproduction.

Step 3: Match the type of algae with the options

So, now we have to match the algae type with the options given. Since all the three types of algae show oogamous type of reproduction, the correct answer should be option (d) All of these.

Key Concepts

Red Algae

Red algae, or Rhodophyta, are primarily marine organisms and are known for their reddish color. This characteristic coloration is due to the presence of phycoerythrin, a type of pigment that helps in absorbing blue light effectively. These algae are usually found in deeper waters, where light penetration is limited. They can thrive at such depths because phycoerythrin absorbs blue light and reflects red.

• Red algae are significant contributors to marine ecosystems; they are key builders of coral reefs.
• They play a crucial role in the production of agar and carrageenan, substances used in food and industrial applications.
• Red algae generally exhibit oogamous reproduction, which involves highly specialized gametes.

In the oogamous reproduction of red algae, the large, non-motile female gametes, or egg cells, are fertilized by the smaller, motile male gametes. This reproductive strategy is advantageous in stable environments where the egg can anchor itself and increase the likelihood of successful fertilization.

Green Algae

Green algae, or Chlorophyta, are fascinating organisms that are often found in freshwater environments, although some species live in marine or terrestrial habitats.

• They possess chlorophyll, giving them a green hue and allowing them to perform photosynthesis efficiently.
• Green algae can be unicellular, multicellular, or exist in colonies or as filamentous forms.

In the context of reproduction, many green algae are oogamous. This means that their reproductive system involves the fusion of a large, non-motile egg and a small, motile sperm.
This form of sexual reproduction enhances genetic diversity, which is vital for adaptation and survival. Green algae serve as important primary producers in many aquatic ecosystems and provide a base for the food chain. Their ability to photosynthesize and produce oxygen makes them crucial for both aquatic life and the global carbon cycle.

Brown Algae

Brown algae, commonly known as Phaeophyta, are primarily marine organisms. They are often found in cool, temperate coastal waters. Their brown color is due to the presence of the pigment fucoxanthin, which, along with chlorophyll, assists in photosynthesis.

• Brown algae include kelps and other large, complex forms that can form underwater forests providing habitats for marine life.
• These algae are important in coastal ecosystems for both their role in the ecosystem and their economic uses.

Oogamous reproduction is common in brown algae, characterized by the union of non-motile eggs with motile sperm. This method increases the chances of successful fertilization.
Brown algae can be immensely large, with some species like Macrocystis (giant kelp) reaching over 60 meters in length. They provide critical ecological services, such as carbon sequestration and serving as food and habitat for marine organisms.