12th Class Biology Chapter 10 Short Questions with Answers Solved

Question: 1

Define evolution.

Answer: 1

1-29

Evolution refers to the processes that have transformed life on earth from its earliest forms to the vast diversity that we observe today.

Question: 2

Differentiate between convergent and divergent evolution.

Answer: 2

2-29

Evolutionary processes that leads to the formation of homologous structures is called convergent evolution.

Question: 3

What are vestigial organs?Give one example.

Answer: 3

3-29

Organs which are rudimentary or non functional in present organisms but were full developed in the ancient organisms are called vestigial organs.
For Example: Appendix in man,ear muscles in man.

Question: 4

What is endosymbiont hypothesis?

Answer: 4

4-29

Hypothesis which explains the origin of organelles by symbiotic association is called endosymbiont hypothesis.

Question: 5

Explain the term homology with a suitable example.

Answer: 5

5-29

Similarity in structure due to common ancestral origin is called homology. Homologous organs are best example of homology like flipper of whale,front leg of horse,arm of man,wing of bird.

Question: 6

What are hydrodermal vents?

Answer: 6

6-29

Origin of life may begin deep in the oceans;in under water hot springs called hydrodermal vents.These vents could have supplied the energy & raw materials for the origin & survival of early life forms.

Question: 7

Define hybridization.

Answer: 7

7-29

It is a process in which two organisms having different genotypes are crossed together to produce a new organism which show the characters of both the parents.

Question: 8

Define Lamarkism and theory of special creation.

Answer: 8

8-29

Lamark gave two important points of his theory of evolution

Question: 9

What is role of geographical barriers in evolution?

Answer: 9

9-29

Due to geographical barrier the members of a population cannot meet with each other nor they can reproduce with each other.After a long time they show morphological as well as genetic differences due to living in different habitats and this leads to evolution of a new species.For Example:Wings of bird and wings of an insect.

Question: 10

Define theory of natural selection.

Answer: 10

10-29

Natural selection occurs through an interaction between the environment and the variability population.

Question: 11

Define theory of special creation.

Answer: 11

11-29

According to this theory all living things came into existence in their present from especially and specifically created by nature.

Question: 12

Differentiate between homologous and analogous organs. Or Define analogous organs.

Answer: 12

12-29

Homologous Organs: Organs which have similar anatomical structure but perform different functions are called homologous organs.
For Example: Arm of man,front leg of horse,wing of bat and bird are homologous organs.

Question: 13

What is Neo-Darwinism?

Answer: 13

13-29

Darwin's theory has been modified from ideas of many different fields including palentology,taxonomy,biogeography and population genetics is called Neo-Darwinism.

Question: 14

How does genetic drift affect the gene frequency?

Answer: 14

14-29

It is a change in frequency of alleles at a locus that occurs by chance.In small populations,such as fluctuations may lead to loss of particular alleles.This may occur in a small population when a few individual fail to reproduce and then genes are lost from population.

Question: 15

What is Hardy-Weinberg theorem.Give its equation.

Answer: 15

15-29

It states that the frequencies of alleles and genotypes in a population remain constant over the generation unless acted upon by agents other than sexual recombination.
(P+q)²= P²+ q²+ 2pq

Question: 16

Define species.

Answer: 16

16-29

Group of organisms which have same morphological characters and can reproduce with each other and can produce fertile offspring similar to the themselves is called species.

Question: 17

Name any four species declared extinct in Pakistan.

Answer: 17

17-29

Cheetha. Crocodile, Tiger and Asian lion.

Question: 18

Define gene pool.

Answer: 18

18-29

The total aggregate of genes present in a population is called gene pool or whole genetic information present in a population is called gene pool.

Question: 19

Define Biodiversity.

Answer: 19

19-29

The variety of organisms present in an area is called biodiversity.

Question: 20

Give the concept of fixed alleles.

Answer: 20

20-29

If the members of a population are homozygous for the same allele,that allele is said to be fixed in the gene pool.

Question: 21

Differentiate between endangered and threatened species.

Answer: 21

21-29

Endangered Species: Species which are near to extinct are called endangered species.

Question: 22

Differentiate between population and gene pool.

Answer: 22

22-29

Population: Member of same species living in an area at the same time at same place is called population.

Question: 23

How artificial selection is different from natural selection?

Answer: 23

23-29

Natural selection: Natural selection occurs through an interaction between the environment and the variability in any population.

Question: 24

Name any four factors affecting gene frequency.

Answer: 24

24-29

Following are the factors which cause change in gene frequency

Question: 25

What are endangered species?Give one component of their conservation plan.

Answer: 25

25-29

The species which are near to extinct in near future are called endangered species.
They can be conserved or protecting in botanical gardens,zoos,and making strict laws,preventing their hunting or cutting of trees.

Question: 26

What is endosymbiont hypothesis?Give example.

Answer: 26

26-29

The enkaryotic cell might have evolved when a large anaerobic amoeboid prokaryote ingested small aerobic bacteria and stabilized them instead of digesting them.This idea is known as the endosymbiont hypothesis,which are the sites of aerobic respiration & most energy conversion in eukaryotic cells.

Question: 27

Differentiate natural and artificial selection.

Answer: 27

27-29

Natural Selection: In natural selection,nature selects the individuals with favourable variations for better survival in an environment.
Selection pressure is exerted by environmental factors.

Question: 28

What are endangered species?Give example.

Answer: 28

28-29

An endangered species is in imminent danger of extinction throughout its range (where it lives)
Example: Cheetah, Tiger, Asian Lion, Indian rhino, cheer pheasant, crocodile and Gavial.

Question: 29

Differentiate between endangered and extinct species.

Answer: 29

29-29

Endangered Species: Endangered species are those which are near to extinct.

Biology Chapters

12th Class Chapter 10 Biology Short Questions

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