Week of March 3rd
Natural Selection At Work
Consider the following:
Tardigrade in moss
Is this an alien lifeform? Probably not, but of all the living things that inhabit Planet Earth, this might be the best candidate! The Tardigrade is an extremophile. This means that this organism can survive in very hostile conditions...like
- Can live for decades without food and water
- Survive temperatures from above -273 degrees F to 212 degrees F
- Survive pressures from 0 to the bottom of the ocean
- Survive exposure to extreme radiation
- These waterbears are so versatile because they are able to repair their own DNA
Talk about some extreme natural selection!
African Elephants
African elephants have been hunted for the ivory tusks for many years. By 1930, 1% of African elephants began to never develop tusks. Hunters would not kill these elephants without tusks, so the genetic code for "no tusks" was passed along and populations of these elephants with no tusks has grown to about 40 %! Elephants use their tusks for digging and defense, so life for these tusk-less elephants is quite challenging.
How will the process of natural selection continue in this situation?
Links for the week:
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