Speciation | Heredity and Evolution | Assessment | English | Grade 10

In the course of evolution, formation of the new species of any organism is called _________.

• Speciation

• Microevolution

• Adaptation

• Macroevolution

Answer explanation

In the course of evolution, formation of the new species of any organism is called speciation.

A group of organisms in which all organisms can reproduce to give birth to a fertile offspring is called _____.

• Hybridization

• Species

• Speciation

• None of these

Answer explanation

A group of organisms in which all organisms can reproduce to give birth to a fertile offspring is called species.

Which of the following group has maximum number of common characters?

• Two genera of a class

• Two genera of a family

• Two members of a species

• Two species of genera

Answer explanation

In the taxonomic hierarchy, the species is at the lowest level. That's why the members of the same species has the maximum number of common characters. Hence option 3 is the right answer.

Which of the following results in the speciation of organism?

• Accumulation of variations in several generations

• Sudden accident in nature

• Natural selection

• All of these

Answer explanation

New species is formed due to the changes in DNA for several generations. Therefore accumulation of variations in several generations can lead to formation of new species of organism. Sudden accident in nature can give rise to new species of any organism. Natural selection, genetic drift and geographical isolation together results in the formation of new species. Therefore option 4 is the right answer.

Which of the following must occur for speciation to happen?

• Geographical isolation

• Reproductive isolation

• Natural selection

• Genetic drift

Answer explanation

Geographical isolation, natural selection and genetic drift are the different factors of speciation. But if all these factors leads to a condition when two different populations cannot reproduce to produce a fertile offspring. Then only the speciation occurs. So the reproductive isolation is the condition when we can say that the two populations are different species. Hence option 2 is the right answer.

Two populations of the same species grow distant from one another over a period of time. At what point these two population will be considered as different species?

• When the population began to eat different food

• When they are geographically isolated

• When they are unable to interbreed

• When the two populations have not been in contact for 100 years

Answer explanation

A group of organisms in which all organisms can reproduce so as to form a fertile offspring is called Species. So when the two populations can not reproduce then they are said to be of different species. Hence option 3 is the right answer.