Multiple Choice QuestionsGenetic drift operates only in
island population
smaller population
larger population
none of these
B.
smaller population
Genetic drift is the change in the frequency of an existing gene variant in a population due to random sampling of organisms. It is more likely to occur in a small population.
Assertion : Organochlorine pesticides are organic compounds that have been chlorinated.
Reason : Fenitrothion is one of the organochlorine pesticides.
If both Assertion and Reason are true and the reason is the correct explanation of the assertion
If both Assertion and Reason are true but the reason is not the correct explanation of the assertion
If Assertion is true statement but Reason is false
If both Assertion and Reason are false statements
C.
If Assertion is true statement but Reason is false
Organochlorinc pesticides arc organic compounds or hydrocarbons to which are added several atoms of chlorine through the process called chlorination. Rate of degradation of organochlorines is very low. E.g. DDT, BHC.
Fenitrothion is an organophosphate pesticide which is the organic ester of phosphoric acid and its derivatives. These pesticides arc very toxic but are not persistant. It is an inhibitor used as an insecticide. It is cheap and used worldwide.
Assertion : Bats and whales are classified as mammals.
Reason : Bats and whales have four-chambered heart.
If both Assertion and Reason are true and the reason is the correct explanation of the assertion
If both Assertion and Reason are true but the reason is not the correct explanation of the assertion
If Assertion is true statement but Reason is false
If both Assertion and Reason are false statements
B.
If both Assertion and Reason are true but the reason is not the correct explanation of the assertion
Bats and whales are classified as mammals as they possess the essential mammalian characteristics like presence of milk gland or mammae, presence of pinnae, viviparous nature, hair on body, presence of diaphragm etc.
Though bats and whales have four chambered heart, it cannot be considered as the main characteristic of being mammals because it is also present in some reptiles (e.g. crocodile) and all birds.
Assertion : All birds, except the ones like koel (cuckoo) build nests for retiring and taking rest during night time (day time for nocutrnal).
Reason : Koel lays its eggs in the nests of tailor bird.
If both Assertion and Reason are true and the reason is the correct explanation of the assertion
If both Assertion and Reason are true but the reason is not the correct explanation of the assertion
If Assertion is true statement but Reason is false
If both Assertion and Reason are false statements
C.
If Assertion is true statement but Reason is false
Koel or cuckoo need not build nests because they transfer their responsibilities to build nests, incubate eggs and nurture hatchlings to other birds specifically crows. Thus, they are called as brood parasites ie, they rely on others to raise their young ones. Being the brood parasite of the crow, the koel's breeding cycle synchronizes with that of crow. Both the koel's and crow's eggs are grey-green with rusty brown markings.
Tailor bird is a garden bird which makes its nest by sewing, it has no direct relation with koel and cuckoo. Also it is a songbird found across tropical Asia.
The cranial capacity was largest among the
Peking man
Java ape man
African man
Neanderthal man
D.
Neanderthal man
Neanderthal man was the first human fossil discovered, having a cranial capacity of 1400 cc.
African man (Australopithecus) was discovered, having a cranial capacity of 300-500 cc.
Java ape man (Pithecanthropus erectus) was discovered with cranial capacity 900 cc.
Peking man (Sinanthropus pekinensis) was discovered with cranial capacity was 1100 cc. Therefore, Neanderthal man has the largest cranial capacity.
The first animal domesticated by primitive man was
dog
horse
cat
cow
A.
dog
Dog was the first animal to be domesticated by man.
The correct sequence for the formation of chemicals on the primitive earth is
NH3, protein, carbohydrate and nucleic acid
NH3, water, nucleic acids and proteins
NH3, nucleic acids, protein and carbohydrate
protein, carbohydrate, water and nucleic acids
B.
NH3, water, nucleic acids and proteins
As the earth cooled, free atoms in the atmosphere formed inorganic molecules (including H2O and NH3) which interacted to form sugars and then proteins and nucleic acids.
Which of the following is an egg laying mammal ?
Kangaroo
Platypus
Penguin
Whale
B.
Platypus
Among all the 4 mammals, Platypus is the egg laying mammal.
The early stage human embryo distinctly possesses
gills
gill slits
external ear (pinna)
eye brows
B.
gill slits
Both chick and human embryos go through a stage where they have slits and arches in their necks like the gill slits and gill arches of fish. These structures are not gills and do not develop into gills in chicks and humans, but the fact that they are so similar to gill structures in fish at this point in development supports the idea that chicks and humans share a common ancestor with fish. Thus, developmental characters, along with other lines of evidence, can be used for constructing phylogenies.
Assertion : Holoblastic cleavage with almost equal-sized blastomeres is a characteristic of placental animals.
Reason : Eggs of most mammals, including humans, are of centrolecithal type.
If both Assertion and Reason are true and the reason is the correct explanation of the assertion
If both Assertion and Reason are true but the reason is not the correct explanation of the assertion
If Assertion is true statement but Reason is false
If both Assertion and Reason are false statements
C.
If Assertion is true statement but Reason is false
In holoblastic cleavage, the cleavage furrows bisect the entire egg ie, entire egg divides by each cleavage furrow. Placental mammals have isolecithal or microlecithal egg, the holoblastic cleavage produces blastomeres of equal or approximately equal size.
Centrolecithal eggs are found in insects and in some hydrozoa. In these yolk is concentrated at the centre of egg and the cytoplasm is present surrounding it. Meroblastic cleavage occurs in them.
