This topic contains a solution. Click here to go to the answer

Author Question: Explain how mutation, migration, genetic drift, and natural selection affect evolutionary processes. ... (Read 119 times)

ETearle

  • Hero Member
  • *****
  • Posts: 580
Explain how mutation, migration, genetic drift, and natural selection affect evolutionary processes. Provide a specific example for each.
 
  What will be an ideal response?

Question 2

Explain what behavioral geneticists mean by the term heritability and why it is frequently misunderstood. Provide one example of low heritability and one example of high heritability.
 
  What will be an ideal response?



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

juicepod

  • Sr. Member
  • ****
  • Posts: 310
Answer to Question 1

ANSWER:
Mutations are errors that occur when DNA is replicated. The average human baby is born with about 130 new mutations, but the vast majority have no effect. Mutant alleles that provide some advantage often spread through the population, but most mutant alleles that result in a disadvantage disappear from future generations. Example: The original appearance of the allele for blonde hair was probably the result of a random mutation that occurred in Northern Europe some 10,000 years ago.

Migration occurs when organisms move from one geographical location to the next. Phenotypical traits that are advantageous in one environment might be less so in another. Example: Migration, or rather the lack of it, might account for the relatively restricted area in Northern Europe populated by blondes until fairly recent times. Geographical barriers of mountain and ocean contained the blonde allele for many centuries.

Genetic drift produces change from one generation to the next through chance or accident. Example: Genetic drift undoubtedly reduced the global frequency of the blonde allele between 1300 and 1700, as waves of Bubonic plague decimated the European population, which at that time contained nearly everyone carrying the blonde allele. If by chance every single person carrying the blonde allele had died from the plague before reproducing, the allele would have disappeared from the human genome.

Natural selection is the process by which survival and reproduction pressures act to change the frequency of alleles in subsequent generations. Example: The continuation of the blonde hair allele may have been influenced by natural selection. When a person has a choice of mates of equal value, he or she will select the one that stands out from the crowd. Individuals with blonde hair color, which was different and more rare, might have enjoyed more reproductive success than those with more common, darker hair colors.

Answer to Question 2

ANSWER:
Heritability is the statistical likelihood that variations observed across individuals in a population are due to genetics. Heritability is usually presented as a ratio of the amount of variation observed in a population due to genetics relative to the total amount of variation due to both genetic and environmental influences. Heritability is a concept that is frequently misunderstood. Heritability always refers to populations, not to individuals. Saying that a trait such as shyness is 40 heritable does not say that 40 of one individuals shyness is produced by genes and the other 60 by the environment. Instead, a 0.40 heritability ratio suggests that the variations in shyness we see across the population (from very high to very low) are influenced moderately by both genetic and environmental factors.

If genes play no part in producing phenotypical differences between individuals, heritability is zero. For example, genes are responsible for us having hearts, but there is no individual variation in the population in terms of the presence of a heartwe all have one. Consequently, the heritability of having a heart is 0.0. If genes are totally responsible for all phenotypical differences between individuals, heritability is 1.0. All variation in the population in terms of having or not having a fatal neurological condition known as Huntingtons disease is entirely due to genetics. If you inherit a Huntingtons gene from one parent, you will develop the condition, so the heritability of Huntingtons is 1.0.




ETearle

  • Member
  • Posts: 580
Reply 2 on: Jun 19, 2018
YES! Correct, THANKS for helping me on my review


miss_1456@hotmail.com

  • Member
  • Posts: 289
Reply 3 on: Yesterday
Thanks for the timely response, appreciate it

 

Did you know?

The average person is easily confused by the terms pharmaceutics and pharmacology, thinking they are one and the same. Whereas pharmaceutics is the science of preparing and dispensing drugs (otherwise known as the science of pharmacy), pharmacology is the study of medications.

Did you know?

About 60% of newborn infants in the United States are jaundiced; that is, they look yellow. Kernicterus is a form of brain damage caused by excessive jaundice. When babies begin to be affected by excessive jaundice and begin to have brain damage, they become excessively lethargic.

Did you know?

Giardia is one of the most common intestinal parasites worldwide, and infects up to 20% of the world population, mostly in poorer countries with inadequate sanitation. Infections are most common in children, though chronic Giardia is more common in adults.

Did you know?

There are more bacteria in your mouth than there are people in the world.

Did you know?

Certain chemicals, after ingestion, can be converted by the body into cyanide. Most of these chemicals have been removed from the market, but some old nail polish remover, solvents, and plastics manufacturing solutions can contain these substances.

For a complete list of videos, visit our video library