Conservation and Biodiversity: An Introduction to natural selection

1
Conservation and Biodiversity An Introduction
to natural selection

• Darlene Oehlke
• ESS
• Nido de Aguilas

2
Species

• Organisms that are able to reproduce to produce
  live, fertile offspring

3
Natural selection

• There are more organisms than the habitat can
  support, thus there is a competition for
  resources.
• Diversity exists within the population, so
  organisms of the same species posses different
  traits.
• If a trait helps the individual survive, it is
  passed onto the offspring.

4
Natural Selection

• Organisms possessing such advantageous
  characteristics increase the proportion of
  beneficial characteristics in the population.
• Pressure from the environment influences the
  proportion of a population displaying a
  characteristic in this way organisms become
  adapted to their environment and way of life.

5
Peppered moths in 19th Century England
6
Speciation Evolution of a new species

• If a small population is isolated on a remote
  island, desert oasis, or mountain peak, a new
  species may evolve quite quickly because
• The gene pool is small
• New genetic material does not come in from
  elsewhere.
• The population adapts to a specialised
  environment and the traits of the population
  change.

7
Isolation can lead to different species

• Isolation of populations can lead to different
  species being produced that are unable to
  interbreed to yield fertile offspring.
• Geographic Isolation
• Reproductive Isolation

8
Geographic Isolation

• The voles on islands off the coast of Scotland
  have been separated from the populations on the
  mainland for just a few thousand years - since
  the rise in sea level following the Ice Age.

9
Isolation of species example

• In Lake Victoria there are 170 species of
  cichlids in Lake Tanganika 126 species, and in
  Lake Malawi 200 species. These lake faunas have,
  probably been isolated from each other for
  millions of years.

10
Behavioural Isolation

• If courtship differences which prevent
  reproduction.

11
Plate tectonics

• Plate activity in generates new and diverse
  habitats, thus promoting biodiversity.
• Gene pools are isolated by moving plates.
  Natural selection over time creates new species

12

• http//www.livescience.com/images/pangea_animation
  _03.gif

13
Bibliography

• State of the Planet http//www.bbc.co.uk/nature/pr
  ogrammes/tv/state_planet/habitat.shtml
• IB Booklet Biodiversity and Conservation
• Course Companion