ESS Topic 3 Case Studies

Speciation - Galápagos Finches

Speciation - Galápagos Finches

- adapted to local conditions of each of Galápagos Islands fill many of the niches
- Different selection pressures led to evolution of different species, each adapted to local environment

Mass Extinction

- fossil record shows there have been 5 periods of mass extinction in the past
- Causes: sudden changes in natural global cycles (plate tectonic activity by volcanic activity), or catastrophic events (asteroid impact)
- 65 million years ago, asteroid strike believed to cause extinction of dinosaurs
- perceived 6th mass extinction is the first to be caused by biological impacts (human causes)
- Rapid change to the planet do not allow time for species to adapt & evolve, increases extinction rates

Invasive Species - Grey Squirrel

- Introduced from North America into Europe
- red competing with grey for food
- led to decreasing population of indigenous red squirrel

Extinct Species - Falkland Islands Wolf

- Only native land mammal of the Falkland Islands
- Diet consisted of ground-nesting birds (such as geese and penguins), grubs, insects.
- Went extinct because:
- Settlers considered the wolf as a threat to their sheep
- Huge-scale operation of poisoning and shooting
- very rapidly, because of the lack of forests & the tameness of the animal
- Impact on the rest of the food chain (e.g. increase in population of its prey).

Critically Endangered Species - Golden Lion Tamarin Monkey

- Conservation status has been improved by intervention
- Under threat because:
- 90% of original forest habitat in Brazil has been cut down
- Remaining habitat is small & fragmented
- Only found in 1 small area of Brazil, (prone to extinction)
- Were killed as believed to spread human diseases
- Ecological role is omnivore, they eat fruits, insects & small lizards
- Loss of species would mean the following:
- Seed dispersal of plants that have fruits eaten by the monkeys would be affected
- Species at lower trophic levels would become more numerous
- Shortened food chains would produce imbalances in the forest food web
- Being restored through captive breeding programmes and wildlife reserves

Back From Brink of Extinction - American Bald Eagle

Natural Area of Biological Significance - The Great Barrier Reef

Evaluating Success of A Protected Area - Danum Valley Conservation Area (DVCA)

- Malaysian Borneo
- Major threat from commercial logging, until late 1980’s
- Collaboration in research between Yayasan Sabah (logging company) and the Royal Society in the UK
- Success:
- Corridors to other conservation areas allowed for the movement of animals
- Hotels, ecotourism, both helped local economy
- Employment and educational opportunities for local community
- High international profile and key research held over long period of time, one of the most important conservation areas in the world
- Refuge for many endangered species, eg: Sumatran Rhino
Failures:
- Oil palm plantations near protected area could discourage ecotourism
- Presence of people near protected area could encourage poaching or illegal logging activity
- Conflict between aims of commercial industry & aims of conservation project
- Change in leadership may lead to changes in aims