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The figure shows the skull of which Homo erectus?
The skull belongs to Homo erectus erectus, also known as Java man. Chin was absent whereas jaw prognathous. They were omnivorous. Cannibalism was also found.
Who among Homo erectus used fire for hunting, protection, and cooking?
Homo erectus erectus, also known as Java man used fire for hunting, protection, and cooking. It had complete erect posture and lived in caves. It used tools of bones and stones.
Who was known as the direct ancestors of homo sapiens?
Homo erectus were known as the direct ancestors of humans. It had many similarities to modern man. Their face, skull structure, and posture were the same.
The cranial capacity of Homo habilis was _____ c.c.
They had a cranial capacity of 650-800 c.c. They were the first human being like and had complete erect posture similar to them. They had the knowledge to create tools of stones to hunt.
Which of the following is not included in natural selection?
Natural selection mainly leads to three selections. They are: Stabilizing selection, directional selection, and disruptive selection. Technical selection does not belong to natural selection. This classification is based on different organism-environmental relationship.
Mortality in babies is an example of ______
Mortality in babies is an example of stabilizing selection. It is all depended on the baby’s birth weight. The optimum birth weight is 7.3 pounds which favor this selection. Newborn infants with less than 5.5 pounds and more than 10 pounds have the highest mortality rate.
Directional selection is also known as ______
Directional selection is also known as progressive selection. This selection always operates in a changing environment. After this natural selection, mean value always changed.
Which is the correct example regarding this diagram?
The graph given belongs to directional selection as the graph shifts to one direction. The resistance of insects to DDT is an example of directional selection. A single mutation which occurred in a specific gene helped them to breakdown the toxin. It shows that it favored one extreme value.
How many peaks are there in the disruptive selection?
In disruptive selection, most of the individuals get the periphery values at both ends of the curve given in the graph. The population gets divided into two different groups. Hence, they have two peaks which resemble a two-humped camel.
How does shell pattern in limpets show disruptive selection?
Limpets shell has a continuous pattern with color ranging from pure white to dark tan. They either attached to white gooseneck barnacles or to tan colored rocks. The light-colored limpets camouflaged with white barnacles while tanned limpets camouflaged on tan-colored rocks. But, the limpets with intermediate shell patterns were conspicuous and were preyed by predatory shorebirds.
Marine mollusca is also known as _____
Marine mollusca is also known as limpets. They are aquatic snails with a conical shaped shell with a muscular foot. They are members of the family Gastropoda. Their shell pattern shows disruptive selection.
What happens during disruptive selection?
In disruptive selection, the members of both extreme are selected. The average gets rejected. Most of the individuals get values other than the mean character value. The naturally selected members are shown by two peaks.
This diagram represents which selection?
This graph indicates stabilizing selection. As we can see, the peak gets higher and narrower. In this selection, most of the individuals acquire mean character value.
Which of the following are properties of stabilizing selection?
Stabilizing selection operates in a constant environment. It favors the average or complex phenotype and eliminates the extreme values. The mean value never changes. Also, the peak gets higher and narrower.
Which of the following is monocistronic?
Cistrons are the segments of the DNA helical structure which code for polypeptide chains. The structural gene in the transcription unit can be either monocistronic or polycistronic. The monocistronic genes are mostly present in eukaryotes.
Which of the following is the key difference between exons and introns?
The sequences of the genes which appear in the mature or processed RNA are called as exons. They are the coding sequences of the gene. These sequences are interrupted by introns. Introns are the intervening sequences which aren’t present in both the mature or the processed RNA.
Which of the following is polycistronic?
The polycistronic organisms can code for more than one polypeptide sequence as individuals inside the RNA molecule. Examples of such are the bacteria and prokaryotes.
What is a cistron?
A cistron is the segment of a DNA. It is responsible for coding polypeptide chains. This is seen during the process of protein synthesis.
Which of the following is an adapter molecule?
The tRNA was known by the name sRNA in its early days. sRNA stands for soluble RNA. This was even before the postulation of the genetic code. But, the role of tRNA as an adapter was assigned much later.
Which of the following is the actual structure of the tRNA?
The actual structure of the tRNA is actually a compact molecule which appears to be like an inverted L shaped molecule. But, the secondary structure of the tRNA appears to look like a clover leaf shaped structure.
What does the anticodon loop of the tRNA contain?
The stop codons are UAA, UAG and UGA. These codons are absent in the tRNA molecules. tRNA possesses an amino acid acceptor end which is the site for binding the amino acids. Finally, the anticodon loop of the tRNA contains bases that are complementary to the codes.
Who came up with the idea of “adapter molecule”?
Amino acids do not have any structural specialties to read a code. Francis Crick came up with an ideology that an adapter molecule will be present. This adapter molecule will be capable of both reading the code and also on binding itself to the specific amino acid.
People suffering from colour blindness fail to distinguish which of the two colours?
People who are colour blind fail to distinguish between red and green colours. Colour blindness is a sex-linked recessive trait in which the normal gene and its recessive allele are carried by X-chromosome.
Which of the following type of inheritance is shown by colour blindness?
Colour-blindness is a sex-linked trait which shows criss-cross inheritance which means male transmits his trait to his grandson through his daughter, while a female transmits the traits to her granddaughter through her son.
What percentage of children are colour blind if their father is colour blind and the mother is a carrier for Colour blindness?
The percentage of children which are colour blind if their father is colour blind and the mother is a carrier for colour blindness is 50% because the father will produce Xc and Y chromosome and the mother will produce Xc and X chromosomes. Their children will have the genotypes- XcY, XY, XcXc and XcX. Therefore, 50% of children are colour blind, 25% have normal vision and 25% are the carriers of the disease.
How can a female be haemophilic?
A female can only be haemophilic if her mother is at least a carrier of this disease and her father is haemophilic. But the possibility of a female becoming haemophilic is extremely rare because being haemophilic for the parents at the later stage of life is unviable.
What is the percentage of children being a carrier of haemophilia if their mother is a carrier and their father is a normal man?
The percentage of children being a carrier of haemophilia if their mother is a carrier and their father is a normal man is 25% because the gametes formed by mother are X and Xh while the gametes formed by father are X and Y. The genotype of the offspring obtained would be XY, XX, XXh and XhY. Thus 50% of children are normal, 25% are carriers of haemophilia and 25% are haemophilic (only son).
In which of the following places thalassemia is not common?
Thalassemia is not common in North America. It is common in the Middle East, Indian subcontinent, Mediterranean and South-east Africa. It originated in the Mediterranean region and is caused by the deletion or mutation of the chromosomes.
Which of the following statements is incorrect with respect to alpha-thalassemia?
Alpha-thalassemia is not inherited in a Mendelian dominant fashion. Instead, it is inherited in a Mendelian recessive fashion. It involves the genes HBA1 and HBA2 and it is also connected to the deletion of the 16p chromosome.
Which of the chromosome mutation leads to Beta-thalassemia?
The mutation in the HBB gene on chromosome number 11 leads to the disorder beta-thalassemia. It is inherited as an autosomal recessive trait. The severity of beta-thalassemia depends upon the nature of the mutation.
By which of the following defects, thalassemia is caused?
The defect in the synthesis of globin polypeptide in RBC causes a group of disorders known as thalassemia. Absence or reduced synthesis of one of the globin chains leads to the excess of other chains which accumulate in our body to causes different diseases.
How many genotypes of sickle cell anaemia are possible in a population?
Three types of genotypes of sickle cell anaemia are possible in a population. These are:
i. HbA HbA: Normal individuals
ii. HbA HbS: Normal individuals but act as a carrier in spreading the disease
iii. HbS HbS: Diseased individuals and they die before attaining maturity
What is the full form of AHG?
AHG stands for Anti haemophilic globulin. It is a type of blood protein which is required for normal blood clotting. The person suffering from haemophilia A cannot synthesise this protein and even a small cut may lead to continuous bleeding for a long time.
What will be the percentage of sons having a normal vision if the father has normal vision and their mother is colour blind?
The percentage of sons having normal vision, if the father has normal vision and mother is colour blind is 0% because as colour blindness is a sex-linked trait, it means that the trait only transmits through X-chromosome. As the mother is colour blind, both her gametes will carry the gene for colour blindness, so none of their sons will have a normal vision.
When can a female be colour blind?
A female can be a colour blind only in two conditions:
i. When her father is colour blind and her mother is the carrier of this disease
ii. When both her father and her mother are colour blind
Therefore, for a female to be colour blind, her father must also have colour blindness.
What diagram is used to study the production of zygotes in F1 and F2 generation?
The Punnett square is a mathematical tool used in probability and statistics. Mendel employed it to study the genotypes of F1 and F2 progeny based on the games produced by the previous generation.
Where are the parental genotypes mentioned in a Punnett square?
Punnett square gives a graphical representation for the transfer of genetic information in crosses. The gametes from the parents are represented on the top and the left sides of the Punnett square.
What gametes are produced by a Vv heterozygous plant?
The process of segregation that occurs during meiosis is a random process. Thus the gametes will have 50% of each allele. Hence Vv heterozygous plant would produce 50% V and 50% v containing gametes.
Which of the following is the correct number of offsprings produced by self-fertilization of a heterozygous pea plant for a trait that exhibits Mendelian genetic pattern?
Self-fertilization of heterozygote will lead to 25% homozygous dominants, 25% homozygous recessive, and 50% heterozygous dominants. This is satisfied if the population sampled has 250 homozygous dominant and recessive plant and 500 heterozygous dominant plants.
The ratio of phenotypes observed in progeny after a cross has been performed is called ________
The phenotypes of a progeny can be studied by manually counting the offsprings. The ratio of different phenotypes defines the phenotypic ratio of the cross.