EasyBiologyHigh School (9–10)GeneralHeredity and Evolution › Heredity and InheritanceHeredity and Evolution › EvolutionConceptualBoard Exam
In a species of bacteria that reproduces asexually, trait A is found in 10% of the population and…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
In a species of bacteria that reproduces asexually, trait A is found in of the population and trait B in . Which trait is more likely to have arisen earlier? Explain.
Need a reminder? The key ideaShow
Heredity passes on a common basic design and small changes in it. DNA copying is never perfect, so asexual reproduction makes a little variation. Sexual reproduction mixes the DNA of two parents and makes far more. Variations build up over generations, and one that helps survival is more likely to be passed on.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. How a trait spreads. A new variation appears in one cell, and is passed on to all its descendants.
Step 2. Time. The longer ago it arose, the more generations its owners have had to multiply.
Step 3. Compare. Trait B is in many more bacteria than trait A.
Answer: trait B is more likely to have arisen earlier, because it has had longer to spread through the population.
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