Conservation in Zoos & Seedbanks Revision Notes

• Their numbers increase, reducing the risk of extinction
• Subsequently some individuals can be released into the wild or protected areas such as national parks, to maintain or re-establish wild breeding populations
• The genetic diversity of the species is maintained

• Reintroduction programmes: these programmes endeavour to release captive bred individuals back into the wild so that natural breeding populations can be maintained or re-established

Importance of maintaining genetic diversity during captive breeding programmes:

• The problem is that some zoos can only have a small number of individuals, so inbreeding is likely to occur. This leads to:

• Reduced genetic diversity and therefore, a reduced chance of adapting to environmental change
• Increased risk of a genetic condition becoming more common in the breeding population

Techniques used to reduce inbreeding:

• Do not allow organisms to repeatedly breed with the same partner, possibly by isolating partners
• Select partner, possibly by adding another partner to a cage, IVF or inter zoo swapping
• Keep a record of individuals in captivity and their breeding history e.g. stud books so that choice of partners is controlled

Role of seed backs in conserving endangered species:

• Seeds from a variety of endangered plants can be stored in a dormant state in seed banks. Seeds, rather than living plants, are stored because:

• Less space is required so more species can be stored
• Most plants produce large numbers of seeds so collecting small samples is unlikely to damage the wild population
• Easier to store as dormant
• Most cost effective

How a seed bank can be used to conserve a rare plant species:

• Seeds collected from a number of individual plants: seeds from several plants are likely to have a greater genetic diversity
• Seeds X-rayed to check for fully formed embryos: this only allows seed that could germinate to be selected for storage
• Seeds dried to remove water: reducing water content increases the time a seed can be stored for and remain viable
• Seeds stored in the cold e.g. -20C: reducing the temperature also increases the length of time a seed can be stored and remain viable
• Some seeds periodically germinated to check viability: some are checked to see if they will still germinate
• If less than 75% germinate, those that did germinate are left to grow into a mature plant that will produce their own seeds which are then stored
• If 75% or more germinate, the remaining seeds are retained in cold storage and will be checked again for viability.