Species and Speciation-Wk6-12ASP-Oct2022

​Starter-Wk5-Block1 (Oct3-Oct7, 2022)

Check previous week understanding ​

​*Relative fitness

*Genetic Drift (Founder's effect and Bottle neck effect)

*Sexual Selection (Sexual dimorphism, Intrasexual and Intersexual selection)

*Balancing Selection (Frequency dependent and Heterozygote advantage)​

​Natural selection is the only mechanism that consistently causes adaptive evolution

By Ms.Raji​

Multiple Choice

One population of a species has 25 individuals, all with genotype AA; a second population of this species has 40 individuals, all with genotype aa. Assume that these populations live far apart but in similar environmental conditions. Based on this information, the observed genetic variation most likely resulted from ________.

(Levels 3-4: Applying/Analyzing)

• gene flow

• nonrandom mating

• genetic drift

• directional selection

Multiple Choice

The idea of relative fitness is best exemplified in which of the following statements?

(Levels 3-4: Applying/Analyzing)

• A flowering plant that attracts fewer bees that transfer pollen to other plants has higher relative fitness than a plant that attracts more pollen-transferring bees.

• A deer that teaches her offspring how to avoid predators has a higher relative fitness than a deer that does not teach her offspring to avoid predators.

• A bison that does not digest grasses efficiently has a higher relative fitness than a bison that has more efficient digestion.

• An oak seedling that always dies when infected with a certain virus has higher relative fitness than an oak seedling that always survives the infection

Multiple Choice

In those parts of equatorial Africa where the malaria parasite is most common, the sickle-cell allele constitutes 20% of the β hemoglobin alleles in the human gene pool.

 

In the United States, the parasite that causes malaria is not present, but the sickle cell allele is present in many African-Americans whose ancestors were from equatorial Africa. Which of the following processes are most likely acting on the sickle-cell allele in the United States, and in equatorial Africa?

(Levels 3-4: Applying/Analyzing)

• stabilizing selection in the United States; disruptive selection in equatorial Africa

• disruptive selection in the United States; stabilizing selection in equatorial Africa

• directional selection in the United States; disruptive selection in equatorial Africa

• directional selection in the United States; stabilizing selection in equatorial Africa

Multiple Choice

In a very large population, a measurable trait has the distribution pattern shown in the diagram. Assume the trait is genetically determined. If there is no gene flow and the curve shifts to the left or to the right, which of the following processes is most likely occurring?

(Levels 1-2: Remembering/Understanding)

• immigration or emigration

• directional selection

• disruptive selection

• genetic drift

Multiple Choice

When a species deviates from a 50:50 sex ratio (male to female), the members of the minority sex often receive a greater proportion of care and resources from parents than do the offspring of the majority sex. Which of the following processes most likely causes this pattern?

(Levels 3-4:Applying/Analyzing)

• sexual selection

• balancing selection

• stabilizing selection

• frequency-dependent selection

Multiple Choice

Adult male humans generally have deeper voices than do adult female humans. Which of the following processes was most likely occurring given that the fossil records of apes and humans alike show a trend toward decreasing larynx size in adult females and increasing larynx size in adult males?

(Levels 5-6: Evaluating/Creating)

• intrasexual selection seems to have occurred in these species

• selection was acting more directly upon genotype than upon phenotype

• sexual dimorphism was evolving over time in these species

• stabilizing selection was occurring in these species concerning larynx size

Multiple Choice

Imagine a human population with an extremely low frequency of sickle cell alleles. Which of the following changes is most likely in the human population 15 generations after introducing a mosquito population that carries the malaria parasite?

(Levels 5-6: Evaluating/Creating)

• an increase in red blood cells without nuclei

• a decrease in the number of mosquito bites

• an increase in the mutation rate of the hemoglobin gene

• an increase in the sickle cell allele

​Reference - Heterozygote Advantage

https://study.com/academy/lesson/heterozygote-advantage-example-lesson-quiz.html

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https://www.albert.io/learn/question/ap-biology/hardy-weinberg-and-heterozygote-advantage​

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Everything about Evolution:

https://www.blackwellpublishing.com/ridley/toc.asp​

​How do new species originate from existing species?

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​Focus Question

• •Darwin was fascinated by speciation, the process by which one species splits into two species

  •Speciation produced the tremendous diversity of life, and helps to explain the unity of life

• ​

• •Speciation forms a conceptual bridge between the processes of microevolution and macroevolution

  –Microevolution consists of changes in allele frequency in a population over time on a small scale.

  –Macroevolution refers to broad patterns of evolutionary change above the species level

Slide 7 in the powerpoint​

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​Animation: Macroevolution​

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​CONCEPT 24.1: The biological species concept emphasizes reproductive isolation

• Comparisons of physiology, biochemistry, and DNA sequence generally confirm that morphologically distinct species are discrete groups

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Open Ended

What do you understand by the term "Species"?

In other words define the term "Species"

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​Happy teaching!

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