When the sea floor spreads or collides it creates breakages which would be ocean ridges and deep sea trenches
Answer:
genes for flower color and edge shape are linked. They do not assort independently.
Explanation:
<u>Available data:</u>
- test cross between a purple-flowered pea plant having serrated leaves and a white-flowered pea plant having smooth edges.
- serrated leaves → dominant trait
- smooth edges → recessive trait
- purple color → dominant trait
- white color → recessive trait
- F1: 4 purple-serrated:1 purple-smooth:1 white-serrated:4 white-smooth.
There are two genes involved in the cross. The expected ratios are 1:1:1:1 because we assume genes assort independently. However, we see a different phenotypic distribution. When phenotypic ratios differ from the expected ones, it means that genes are linked.
To know if two genes are linked in the same chromosome, we must observe the progeny distribution. If individuals, whose genes assort independently, are test crossed, they produce a progeny with equal phenotypic frequencies 1:1:1:1. But if instead of this distribution, we observe a different one, that is that phenotypes appear in different proportions, we can assume that genes are linked in the double heterozygote parent
Answer:
It occurs in organisms because an organism with a beneficial trait/mutation have a higher chnace of surviving compared to organisms that do not. So the organsims that do survive pass on their genes to the next generation, and the bext generation will pass on those genes to the generation after and so on. But all the organisms that do not possess a beneficial trait/mutations will not survive, therefore they cannot reproduce and pass on those genes to their offspring. This means that most of the population will posses that trait/mutation.
Example: Spotted moths camouflage with bark so they are seen by predators and eaten. Black moths are easily seen by predators and are eaten. Spotted moths then pass on their genes to the next generation of moths.
