Question

1.Which is true about sickle-cell anemia? Choose all that are true.

The allele that causes the disease is recessive.

Natural selection favors the heterozygote in areas with malaria.

The mutation that causes it is a SNP.

People homozygous for the sickling allele experience episodes of severe pain that may permanently damage their vital organs.

2.What was probably a selective pressure against dark skin in the our earliest ancestors to leave Africa?

Spina bifida from excessive ultraviolet light.

Rickets from a Vitamin D deficiency.

Lactose intolerance.

A combination of sickle-cell anemia and malaria.

3.What must have been the original cause of lighter skin color in our ancestors?

Skin cancer

Mutation

Natural selection

Rickets

4.The major differences among human populations today are in

anatomy (such as facial structure).

culture (no consistent biological differences).

cephalic index (measurements of the skull).

skin color (measured as reflectance).

5.There are many ways to classify humans. Which of the following is WRONG?

As strepsirhines.

As catarrhines.

As primates.

As apes.

6.The differences between strepsirhines and haplorhines include nose structures.

False

True

7.Which of the following is true about non-human ape material culture?

They use tools, but they don't make them.

They make and use tools, but only in captivity.

They don't use tools.

Chimpanzees make and use tools, but not the other non-human apes.

All the Great Apes make and use tools in the wild.

8.Which of the following is true about non-human primate communication? Choose all that are right.

They don't communicate.

They have languages.

Some monkeys have specific alarm calls for different predators.

Haplorhines communicate with facial expressions.

Lemurs and lorises communicate with scent.

9.Using a relative dating technique, we could determine:

if a fossil qualified as a relative of the primates

the exact age of a given fossil relative

whether one fossil is younger or older than another fossil

10.What can you date with radiocarbon dating?

Fossil bones of Turkana Boy.

Anything that was once alive within the last 50,000 years.

Layers (strata) between 50 and 100 kya.

Volcanic materials older than 100,000 years.

Answer 1

Sickle cell anemia is caused by recessive alleles (SS) where the RBC takes a sickled shape like structure affecting the oxygen transport by RBC. In heterozygotes having (AS) allele there is codominant expression of both normal and sickled RBC. This is favoured in regions that have a high onset of malaria because the heterozygote gives resistance to malaria and so natural selection favors the AS in these conditions. This is also called Heterozygote advantage. The phenotype is due to one change (variation) in the nucleotide sequence in the HBB gene. The variation is a single nucleotide polymorphism (SNP).The most common mutation in sickle cell is a change in an amino acid in the HBB protein from glutamic acid to valine. In this disease the number of RBC decreases from hemolysis and anemia results. The irregular sickled cells blocks blood vessels causing tissue and organ damage and pain.

So all four options are correct.

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