We know that DNA makes us who we are and we know that we can inherit from our parents. But how does that happen? Do all organisms have do the same process we do? No!
Bacteria reproduce asexually, using a process called binary fission.
Humans and other animals use a process called Meiosis which produces sperm and egg cells. Instead of having 46 chromosomes each, these cells only have 23 chromosomes. Why? Because this way when a sperm and egg join during fertilization, the new cell has 46 chromosomes. Believe it or not, you all started as one single cell.
Sometimes there can be unusual events during Meiosis and instead of having 23 chromosomes, a cell has 22 or 24 chromosomes. These are called non-disjunction disorders. Today in class we spent some time discussing the symptoms of these disorders.
Homework:
Tomorrow we will be looking at how traits are passed from one generation to the next. For homework you need to complete the data collection sheet for the four traits. Your 5th grade friends have also been given the data sheet to do for homework, so they will be completing the activity as well.
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