Ex Situ Conservation

Ex situ conservation refers to the conservation of components of biological diversity (like species, genetic material) outside their natural habitats.

The question asks to identify which of the listed techniques are included under advanced ex situ conservation methods.

Let's analyze each technique:

• i. Cryopreservation of gametes: This involves preserving gametes (sperm and eggs) or embryos at very low temperatures (typically in liquid nitrogen at -196°C). This technique allows for long-term storage of genetic material from endangered species outside their natural environment. This is a well-established ex situ technique, often considered advanced due to the technology involved.
• ii. Plant tissue culture method: This involves growing plant cells, tissues, or organs in a sterile nutrient medium under controlled laboratory conditions. It is used for micropropagation (rapid cloning) and germplasm conservation of plants, especially those difficult to conserve by seed or that don't produce seeds. This occurs outside the natural habitat and is an ex situ technique.
• iii. Seed bank: This involves collecting seeds from various plant species and storing them under controlled conditions (low temperature and humidity) to maintain their viability for long periods. This is a crucial method for conserving plant genetic diversity outside its natural habitat. It is a primary form of ex situ conservation for plants.
• iv. In vitro fertilisation (IVF): This technique involves fertilizing an egg with sperm outside the body, in a laboratory setting ("in vitro"). While often associated with human fertility treatment, it is also used in conservation programs for endangered animals to assist reproduction and preserve genetic diversity, conducted outside the natural reproductive environment. This is an ex situ reproductive technology.

All four listed techniques – cryopreservation of gametes, plant tissue culture, seed banks, and in vitro fertilisation – are valid and recognized methods used in ex situ conservation programs. They represent various strategies employed outside the natural habitat to preserve species and genetic diversity.

Therefore, the correct statement is that all i, ii, iii, and iv are included in ex situ conservation practices.

Comparing this to the options:

• Only ii
• i & ii
• i, ii, iii, iv
• None of the above

The correct option is i, ii, iii, iv.