May 18-22

This week we worked on more about evolution and what causes it.  We talked about mutations which are random occurrences that cause a change in the DNA.  Selective breeding is when people make two things to mate to get a desirable trait.  Natural selection is just when an organism adapts to survive in its environment.  Genetic engineering is when scientists make a mutation forcefully so that the organism can have a desirable trait.  Gene flow is when there is a change in the gene pool in an area because some organisms have come to that area when they are different.  Genetic drift is when a whole trait goes extinct because of a random chance occurrence.  We also learned that there was another person besides Darwin who had some theories about evolution.  This created the Lamarckian theory which states that if work hard enough you can change your genes and pass it on.  Like if a really skinny guy worked out a lot and became muscular then he could pass it on to future generations.  More recently we are learning about hominids which were early humans/apes.  These hominids were the common ancestors of humans and apes.  But only one kind of hominid survived, homo sapiens, which are what we are.