The Process of Speciation
How Natural Selection CausesEvolution Key factor= environment The environment “selects” which  organisms will survive.
Giraffes Variation is the raw  material for natural  selection. Living things face a  constant struggle for  existence....
Giraffe Notes
Kettlewell & Peppered Moths Step   1 Adaptation- an inherited  characteristic that increases and  organisms ability to s...
Kettlewell & Peppered Moths Found   that 2/3 of the recaptured moths were  dark (released in a polluted area) Moths that...
Kettlewell & Peppered Moths Step 3 Kettlewell set up hidden cameras in  the forest to record the capture of  moths by bi...
Sickle Cell Anemia Homozygous    recessive individuals die at an  early age. Heterozygous individuals will live a normal...
Sickle Cell Anemia Balancing  selection-  two opposite forces  affect the allele in a  population. Sickle cell allele  l...
Sickle Cell Anemia cont Balancing   selection-  – Situation in which natural selection for an allele    is balanced by se...
Seaside Sparrows There  are many different types of seaside  sparrows. They have adapted to better fit  into their enviro...
Selective Breeding aka ArtificialSelection Choosing    an organism with a  desirable trait and breeding it with  another ...
Extinct vs. Endangered       Extinct-               the        population of a        species drops to        zero.      ...
Geographical Isolation Mating does not occur because of a  separation of egg and sperm. Caused by physical barriers  – R...
Speciation The  evolution of a new species. Occurs when a population of  interbreeding individuals is split into  separa...
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Process of speciation

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Process of speciation

  1. 1. The Process of Speciation
  2. 2. How Natural Selection CausesEvolution Key factor= environment The environment “selects” which organisms will survive.
  3. 3. Giraffes Variation is the raw material for natural selection. Living things face a constant struggle for existence. Only some individuals survive and reproduce. Natural selection results in genetic change Species adapt to their environment.
  4. 4. Giraffe Notes
  5. 5. Kettlewell & Peppered Moths Step 1 Adaptation- an inherited characteristic that increases and organisms ability to survive and reproduce in its specific environment. knew- coloration is an inherited trait. Raised moths in lab Marked and released. Set traps to capture live moths
  6. 6. Kettlewell & Peppered Moths Found that 2/3 of the recaptured moths were dark (released in a polluted area) Moths that matched the trees were more likely to survive. Step 2 Using the same procedure Kettlewell released moths in an unpolluted forest. 2/3 of the recaptured moths were white. Moths matched the color of the trees.
  7. 7. Kettlewell & Peppered Moths Step 3 Kettlewell set up hidden cameras in the forest to record the capture of moths by birds. Results: birds are more likely to capture moths that do not match the color of the tree trunk.
  8. 8. Sickle Cell Anemia Homozygous recessive individuals die at an early age. Heterozygous individuals will live a normal life span. Central Africa 1:500 has the sickle cell trait Advantage of having a sickle cell allele– are not likely to contract malaria Person more likely to die of malaria than sickle cell.
  9. 9. Sickle Cell Anemia Balancing selection- two opposite forces affect the allele in a population. Sickle cell allele lethal=decrease Sickle cell allele protects against malaria = increase
  10. 10. Sickle Cell Anemia cont Balancing selection- – Situation in which natural selection for an allele is balanced by selection against it, and remains at the same frequency. • Sickle cell causes anemia • Sickle cells prevents malaria Directional Selection- – Situation in which selection for or against an allele in a population is unopposed • Sickle cell is less likely to occur in the US because it has no advantage.
  11. 11. Seaside Sparrows There are many different types of seaside sparrows. They have adapted to better fit into their environment. The are not different enough to be considered their own species but they have taken the first step. Divergence- an accumulation of differences between species or populations
  12. 12. Selective Breeding aka ArtificialSelection Choosing an organism with a desirable trait and breeding it with another organism with that same trait. Goal to produce offspring with that trait. Example:
  13. 13. Extinct vs. Endangered  Extinct- the population of a species drops to zero.  Endangered- the population is so small reproduction may be difficult. Gene pool is decreased.
  14. 14. Geographical Isolation Mating does not occur because of a separation of egg and sperm. Caused by physical barriers – Rivers, mountains, or other bodies of water. Createsa subspecies. If both species can still interbreed they are the same species.
  15. 15. Speciation The evolution of a new species. Occurs when a population of interbreeding individuals is split into separate populations. Over time these populations become a new species. (can’t interbreed)

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