Evolution is any change in the gene pool over time. Cutting your hair is not evolution because it isn’t happening over time, and it’s not a heritable trait. Evolution happens over multiple generations, and the change is hereditary, meaning that you can pass it on to your offspring.
There are five things that influence evolution, and they can be remembered by the fingers on you hand.
The pinkie finger is population shrinking, also called genetic drift. Genetic drift is the term scientists use to describe shrinking or increasing of a specific gene or trait in a population. If five people were stranded on a desert island, and two of them had red hair, some of the offspring would have red hair, but, since the red hair population wasn’t very large to begin with, the red hair trait might die off in the next few generations.
The ring finger is mating with specific traits. This is an obvious way that genes would be passed on.
The middle finger is mutations. Mutations change the DNA and genes of an organism randomly, and the mutation can be beneficial, negative or neutral to that organism. If a cat was born with floppy ears and neither of its parents had floppy ears, that would be a neutral mutation, meaning that the ears neither benefit nor harm the cat.
Gene flow is the pointer finger. Gene flow is when genes move from one population to another. In that population, those genes that were carried to it didn’t previously exist. If a white dog ran into a population of black dogs, their offspring would be white and black.
The thumb is natural selection. Natural selection is when there are two traits in the gene pool. One of the genes is more beneficial to a certain species than the other. The more common trait is passed on, and the other trait dies off. Natural selection eliminates certain traits in the gene pool to cause change in heritable traits. If green and blue birds lived together in a population, and the blue birds were eaten more often, there would be less blue birds to reproduce. The blue bird gene would soon die off, and only green birds remain in the population.
S&EP: SP3: Planning and Carrying out Investigations
We collected data in a mutations lab simulation. Each group of four received 25 M&M’s in a cup. We first began with counting the number of M&M’s in each color and wrote the numbers down. We had to find out the percentage of the total population that color was. Each person at the table had to pick five out of the cup randomly. The first person went, and then we recounted and recalculated, adding in five red hots so the total population stayed the same. We repeated this, each time dumping out the M&M’s and matching them up in pairs of the corresponding color. If there was an extra red and yellow, we would pair them up and set them to the side. If the pairs had two of the same color, we would add another M&M of that color to the cup. If the pair was of red hots, we would add a red hot. If we had a pair like the red and yellow pair, we chose one of the colors to add. This way, colors could ‘die off’ within the population. In our group, the brown candies dominated and the red ones died off. This lab helped us see the way that evolution worked with mutations.
XCC: Stability and Change
IN NATURE, SOME THINGS STAY THE SAME AND SOME THINGS CHANGE. CHANGES CAN BE FAST OR SLOW.
Evolution is the perfect example of how slow changes occur in nature. Change is only evolution if it occurs over several generations, meaning that the changes are not immediate. The five fingers can cause evolution. Evolution can occur because of a mutation that causes the organism to change, like a puppy with extra furry ears even though its parents did not have extra fluffy ears. The puppy will pass on the fluffy ear trait to its descendants, and the descendents will pass it on, and soon the puppy population will have lots of puppies will fluffy ears. As long as the changes in the organism are hereditary (able to be passed on in genes to offspring) and last several generations, the changes are evolution.
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