Unit 8 was all about evolution, how all the species, and the earth itself, have changed over time. We learned about what exactly was the definition of evolution and how it was measured. All the alleles that make up genes in population are called the gene pool. The frequency of an allele in the population is called allele frequency. Evolution is measured as a change in allele frequency in the gene pool, so all species are constantly evolving. One allele becomes more or less frequent due to natural selection. Natural selection ultimately ends up choosing the genes in individuals that are more likely to survive and reproduce, therefore, making the population look like the "winners". In the Hunger Games Lab, which was the main lab this unit, we saw the disappearance of stumpys over time. They had undesirable characteristics, and therefore did not get a chance to survive and reproduce. The pinchers, on the other hand, grew more in the population because they had the most desirable characteristic to pick up food (using their thumb and index finger).
Natural selection also works in different ways. Directional selection is when one extreme phenotype is favored. As we saw in the bird beak lab, the tweezer beaks were favored since they were the most helpful in picking up food and soon the amount of offspring were mostly tweezer beaks. Stabilizing selection is when intermediate phenotypes are favored. Disruptive selection is when two extreme phenotypes are favored. Natural is not the only thing that causes species to evolve. Genetic drifts are random events that suddenly changes the allele frequency. This change may be either good or bad. Gene flow is the movement of alleles from one population to another. Mutations can cause a change in DNA, and if desirable, will become frequent in the population. Sexual selections that improve mating success but not help the organisms survive better.
Speciation is the creation of new species. Species separate when they are reproductively isolated. This means that the two species cannot reproduce and have fertile offspring. Temporal isolation is when they reproduce at different times. Geographic isolation is when they are physically separated. This is a technique often used with dog breeders. Behavioral isolation is when they have different techniques to attract mates.
The theory of evolution is opposed, but there is evidence to support it. When all organisms are an embryo, they all look very similar. This suggests that we all share a common ancestor. We also have features that helped our ancestors or that they had, such as our tailbone which shows that we used to have tails. Some organisms have same structures with different functions (homologous). Others have different structures with the same function.
The earth's history is longer than anyone can comprehend. Species have been evolving on this planet for billions of years. The timeline has been divided up based on major extinctions and emergence of species.
This unit was relatively easy for me. The only difficult thing is wrapping my head around the scale of the timeline. Also I am not sure exactly how unicellular organisms became multicellular organisms and how those grew into plants, animals etc.
I still have many unanswered questions. Is it possible that if even one event from the past had not occurred then we would not be here? How did species evolve if they were mainly asexually reproducing (bacteria, unicellular)? If there have been several mass extinctions, then is it wrong that we are stopping some species form going extinct? How does "natural selection" choose the better genotypes if each organisms' genotype is randomly assigned?
Going back to the New Years Goals, I have been keeping up quite well. I started studying 3-4 days in advance and I utilize my free time to finish homework if I know I will not get time.
To be more assertive I have tried to be more honest, but kind, to people. I am not aggressive, but sometimes passive aggressive and I try to stop myself whenever I feel that I am being more aggressive. I need to stop being passive in situations where I stay passive to avoid trouble to difficulty in solving the problem.
Natural selection also works in different ways. Directional selection is when one extreme phenotype is favored. As we saw in the bird beak lab, the tweezer beaks were favored since they were the most helpful in picking up food and soon the amount of offspring were mostly tweezer beaks. Stabilizing selection is when intermediate phenotypes are favored. Disruptive selection is when two extreme phenotypes are favored. Natural is not the only thing that causes species to evolve. Genetic drifts are random events that suddenly changes the allele frequency. This change may be either good or bad. Gene flow is the movement of alleles from one population to another. Mutations can cause a change in DNA, and if desirable, will become frequent in the population. Sexual selections that improve mating success but not help the organisms survive better.
Speciation is the creation of new species. Species separate when they are reproductively isolated. This means that the two species cannot reproduce and have fertile offspring. Temporal isolation is when they reproduce at different times. Geographic isolation is when they are physically separated. This is a technique often used with dog breeders. Behavioral isolation is when they have different techniques to attract mates.
The theory of evolution is opposed, but there is evidence to support it. When all organisms are an embryo, they all look very similar. This suggests that we all share a common ancestor. We also have features that helped our ancestors or that they had, such as our tailbone which shows that we used to have tails. Some organisms have same structures with different functions (homologous). Others have different structures with the same function.
The earth's history is longer than anyone can comprehend. Species have been evolving on this planet for billions of years. The timeline has been divided up based on major extinctions and emergence of species.
This unit was relatively easy for me. The only difficult thing is wrapping my head around the scale of the timeline. Also I am not sure exactly how unicellular organisms became multicellular organisms and how those grew into plants, animals etc.
I still have many unanswered questions. Is it possible that if even one event from the past had not occurred then we would not be here? How did species evolve if they were mainly asexually reproducing (bacteria, unicellular)? If there have been several mass extinctions, then is it wrong that we are stopping some species form going extinct? How does "natural selection" choose the better genotypes if each organisms' genotype is randomly assigned?
Going back to the New Years Goals, I have been keeping up quite well. I started studying 3-4 days in advance and I utilize my free time to finish homework if I know I will not get time.
To be more assertive I have tried to be more honest, but kind, to people. I am not aggressive, but sometimes passive aggressive and I try to stop myself whenever I feel that I am being more aggressive. I need to stop being passive in situations where I stay passive to avoid trouble to difficulty in solving the problem.
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