PCB 4043 Chapter Notes - Chapter 6: Allele Frequency, Evolution, Ais People

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orchidbeaver616

24 May 2016

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Concept 6. 1: evolution can be viewed as genetic change over time or as a process of descent with modification. Biological evolution is change in organisms over time. Genes are made of dna and specify (encode) proteins. Genes can have two or more forms called alleles. As a population accumulates differences over time and a new species forms, it is different from its ancestors. But the new species has many of the same characteristics as its ancestors, and resembles them: charles darwin used the phrase descent with modification. He proposed that populations change over time through natural selection: Individuals with certain heritable traits survive and reproduce more successfully than other individuals. If two populations experience different environmental conditions, different characteristics may be favored: natural selection causes the populations to diverge genetically over time. African elephants are poached for ivory; the proportion of the population that have tusks is decreasing.

Related Questions

1.Did either allele A or a disappear from the population youstudied? Why or why not?
2. Did the effect of natural selection vary with different startingallele frequencies in identical environments? Why or why not?
3. A population in which the frequency of alleles remains the sameover generations is said to be in genetic equilibrium. Describe onemechanism by which a populations' genetic equilibrium can bedisrupted and result in the process of evolution.
4. In which of the simulated environments do individuals of thegenotype Aa survive best?
5. In which of the simulated environments do individuals of thegenotype aa survive best?
6. Which set of data represents a type of natural selection thatstabilizes the allele frequencies of the population?
These are my lab questions & this is the labsite:/www.mhhe.com/biosci/genbio/virtual_labs/BL_12/BL_12.html

blushgnu391

____________________________ create new alleles in a population.

The change in allele frequency in a population over time is ____________________, not macroevolution, which refers to the formation of new ____________________.

Name one assumption (condition) that a population must satisfy to remain in Hardy-Weinberg equilibrium.

___________________________________________________________________

____________________ is the movement of alleles from one population to another due to migration.

_____________________ is a random change in allele frequency and has the greatest effect on ____________________ (small or large) populations.

The _____________________ of a population, resulting from some population crash, will cause the entire loss of some alleles due entirely to chance.

A type of genetic drift, known as ________________________________________, can cause rare alleles to become âcommonâ in the population, such as polydactyly in the Olde Order Amish populations.

Females prefer to mate with males who express certain traits. This is known as ____________________ and requires the two sexes to have different appearances (known as: ____________________ ____________________).

Which of the following is most likely as a population goes through a bottleneck?

Heterozygosity decreases because genetic distance increases.

Genetic diversity increases because mutation rate increases while the population is going through the bottleneck

. Genetic diversity decreases because some alleles can be lost as the number of individuals dwindles

. The proportion of individuals that are heterozygous increases because there are fewer individuals.

2)What is meant when it says that genetic drift produces "non-adaptive" evolution?

Sometimes natural selection can favor a trait that is good for the current conditions, but when conditions change it is no longer helpful.

Evolution is just a genetic change in a population. If genes are lost from a population due to chance (i.e. genetic drift), that may not be adaptive, meaning the remaining organisms are no more fit.

Evolution isn't perfect, and sometimes it makes mistakes.

whitekoala529

PCB 4043 Chapter Notes - Chapter 6: Allele Frequency, Evolution, Ais People

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