02 July 2016

#150 Protecting endangered species

An endangered species is one that is threatened with extinction. The best way to conserve any species is to keep it in its natural habitat.

National parks - conservation areas with strict limits to protect wildlife and the environment

  • alien animal species are removed; invasive plants are dug up and destroyed
  • restriction on human activities; tourism raises money and awareness
  • marine parks: conserve fragile ecosystems and areas at risk of overfishing, dredging, pollution

Zoos - protection for endangered and vulnerable species; provides enjoyment and interest for visitors
  • captive breeding programmes: help reintroduce animals to their natural habitats
  • problems: 
            - inbreeding, when breeding animals from a small population
            - some captive bred animals don't know how to avoid predators, find food, rear young
            - animals refuse to breed in captivity; hard to recreate suitable habitat --> animal can't                   be returned to the wild
  • for research: understand breeding habits, habitats, how to increase genetic diversity, solution in inbreeding problems

Botanic gardens
  • seeds/cuttings are collected from species in the wild and are used to build up a population of plants that can one day be reintroduced into the wild
  • sample of cells grown on agar (in sterile conditions) 
          --> cells divide by mitosis to give a mass of cells which can be cloned 
          --> cells transferred to a medium contain an appropriate mixture of plant hormones 
          --> grow stems, roots 
          --> transferred to soil
Roles of botanic gardens:
  • protect endangered plant species
  • research methods of reproduction and growth
  • research conservation methods
  • reintroduce species to habitats
  • educate the public (roles of plants in the cosystem; economic value)

Frozen zoo

Holds genetic resoures for endangered species in the form of eggs, sperms and embryos
  • more genetic diversity
  • genetic material is kept for longer periods of time
*eggs are more difficult to freeze as they are more likely damaged by freezing and thawing

Seed banks

Seeds of the same species are collected from different sites, so that the stored samples contain a good proportion of the total gene pool of that species --> genetic diversity is not lost

"Recalcitrant" seeds cannot be dried and frozen. These include seeds of economically important tropical species e.g.: rubber, coffee, cocoa. The only ways to keep the genetic diversity of these species are to
  • collect seeds and grow successive generations of plants 
  • keep as tissue culture

* seeds can be stored for a long time with little maintenance, anywhere in the world
* seeds are germinated every few years to:
  • check if seeds are still viable
  • produce new plants to collect new seeds
  • find conditions for breaking seed dormancy

  Syllabus 2016-2018

18.3 Conservation

Maintaining biodiversity is important for many reasons. Actions to maintain biodiversity must be taken at local, national and global levels. 

 It is important to conserve ecosystems as well as individual species.

a) discuss the threats to the biodiversity of aquatic and terrestrial ecosystems (see 18.1b) 

b) discuss the reasons for the need to maintain biodiversity 

c) discuss methods of protecting endangered species, including the roles of zoos, botanic gardens, conserved areas (national parks and marine parks), ‘frozen zoos’ and seed banks 

d) discuss methods of assisted reproduction, including IVF, embryo transfer and surrogacy, used in the conservation of endangered mammals 

e) discuss the use of culling and contraceptive methods to prevent overpopulation of protected and non-protected species 

f) use examples to explain the reasons for controlling alien species 

g) discuss the roles of non-governmental organisations, such as the World Wide Fund for Nature (WWF) and the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), in local and global conservation 

h) outline how degraded habitats may be restored with reference to local or regional examples

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