Captive breeding programs

• Difficulties keeping animals in captivity:

  • space - the organism is adapted to a natural area
  • food - simulating natural hunting is very difficult e.g. bats need live insects. Enrichment is needed.
  • inter-species relationships
  • expensive - food, cleaning, heating, vets, space
  • pathogens/parasites
  • the optimum environment/enrichment is needed so they don't express stress behaviour e.g. pacing, curled dorsal fins, hitting their heads
• Factors that inhibit species from breeding in captivity:

  • gene pool size
  • hybridisation
  • breeding habitats
  • conditions for breeding
  • Population interaction
• Issues with gene pool size:

  • small gene pools lead to inbreeding
  • This creates a lack of genetic variation and a vulnerability to disease and changes in environmental factors
• Issues with hybridisation:

  • breeding of 2 different species that produces infertile offspring
  • Similar species are often kept together due to similar ranges of tolerances
• Issues with breeding habitats:

  • species need specific habitats to breed
  • if it is not in the specific range of tolerance lead to stress behaviours so they don't breed
  • courtship displays require certain spaces
  • nesting materials need to be provided
  • migrating species live in a different habitat to the one they breed in
• Issues with conditions for breeding:

  • specific triggers are required to breed
  • e.g. temperature, day length, fat stores, light intensity
• Issues with population interaction:

  • interactions within the wider population
  • big cats are kept separate because the females are bigger and stronger so when conflicts occur with the males they are risk
  • existing offspring means the pair doesn't breed again, so eggs are removed.
  • flamingos don't breed in small numbers to avoid inbreeding so mirrors are put up in zoos to trick them into thinking there are more of them
• Methods to increase the success of breeding:

  • micro-propagation of plants
  • cloning
  • cryopreservation
  • Artificial insemination
  • embryo transfer
• Micro-propagation:

  • this is done on plants
  • micro = removal of cells or tissue sample to grow a whole individual
  • lots of organisms can be made from one plants
  • all the organisms then have the same DNA, so they are genetically identical and there is no gene pool, which makes them vulnerable to disease or sudden environmental changes
  • The population is very fragile
• Cloning:

  • extract DNA from an individual to create another one that is genetically identical to it
  • cloning is expensive ad difficult
  • there is no genetic variation and no gene pool so a large number of individuals have to be cloned
  • The Iberian Ibis was brought back from extinction

  1. Take the nucleus out of an egg of the desired species and put it in the empty egg cell of a similar species
  2. Activate the egg by an electrical impulse
  3. Implant the egg into a surrogate mother's womb that is a similar species
  4. It gives birth to a genetically identical organism to the original
• Cryopreservation:

  • the deep freezing of genetic material and/or gametes for future use
  • e.g. tissue samples, genomes
• Artificial insemination:

  • In Vitro Fertilisation - can be done in or cut out of the womb
  • often done in agriculture
  • sometimes males and females have to be kept separate so they don't kill each other
  • A stud book is a written record of which individuals are breeding with who. This is done to make sure the gene pool doesn't shrink
  • selective breeding is done on corals for resistance against acidity to reduce coral bleaching
  • Sperm can be brought from another zoo to increase the gene pool
  • e.g. Kakapo parrots
• Embryo transfer:

  • the embryo of the desired species is removed out of the womb
  • It is then placed in the womb of a similar species that acts as a surrogate mother

  Pros:

  • this makes the female free to breed again
  • the female may be ill, so already at risk
  • if the species has a high mortality rate when they give birth it is too risky e.g. apes