KNEC KCSE BIOLOGY TOPICAL QUESTIONS AND ANSWERS - ATIKA SCHOOL

K.C.S.E Biology Q & A - MODEL 2015PP1QN02

29/6/2020

K.C.S.E Biology Q & A - MODEL 2015PP1QN02

During a lesson, students observed the structure of bat, cat and human forelimbs to determine their evolutionary relationship.
(a) State the name given to the structure of the limbs observed by the students.
(b) Name the type of evolution illustrated by the structure of the limbs observed.
(c) What evidence of evolution is illustrated by the limbs?
(d) State the significance of the type of evolution illustrated by the limbs.

answers

(a) The pentadacty/ limb/homologous structures;
(b) Divergent evolution/adaptive radiation;
(c) Comparative anatomy;
(d) It allows the organisms to exploit different habitats to reduce competition;

Why are some bacteria able to resist the effect of antibiotics?

28/6/2020

K.C.S.E Biology Q & A - MODEL 2014PP1QN22

Why are some bacteria able to resist the effect of antibiotics?

ANSWER

They have a gene for resistance/acquire it through mutation;
The gene for resistance is passed to offsprings establishing a population of resistant forms;

Name two vestigial structures in human beings.

28/6/2020

K.C.S.E Biology Q & A - MODEL 2014PP1QN22

Name two vestigial structures in human beings.

ANSWERS

Appendix/nictating membrane;
coecum and ear drum;
Tail/coccyx;

What is meant by the term organic evolution?

26/6/2020

K.C.S.E Biology Q & A - MODEL 2013PP1QN21

What is meant by the term organic evolution?

answers

Emergence of new life/species/organisms from pre-existing simple forms, gradually over a long period of time, to present complex forms;

Explain the role of continental drift in evolution.

26/6/2020

K.C.S.E Biology Q & A - MODEL 2013PP1QN21

Explain the role of continental drift in evolution.

answers

Continents existed as one large Landmass/Pangea/Laurasian and Gondwana Land;
Present continents drifted from it leading to isolation of organisms; organisms in each Continent evolved along different lines hence emergence of new species;

Explain the theory of evolution by natural selection.

26/6/2020

K.C.S.E Biology Q & A - MODEL 2013PP1QN20

Explain the theory of evolution by natural selection.

answers

Genetically acquired bene1cial characteristics which occur spontaneously; are perpetuated through reproduction;

K.C.S.E Biology Q & A - MODEL 2012PP1QN26

26/6/2020

K.C.S.E Biology Q & A - MODEL 2012PP1QN26

(a) State the theories of evolution proposed by the following scientists.

Charles Darvin
Jean-Baptiste de Lamark

(b) State the evidence of evolution based on
(i) cell organelles
(ii) fossils

answers

(a) Theory of natural selection;
Theory of environmental influence on inherited characteristics;
(b) (i) Similar organelles performing similar functions in different organisms suggest a common ancestry/cell biology;
(ii) Fossil records/palaeontology/by comparing fossils to show phyllogenetic relationship between organisms/common ancestry;

State the importance of divergent evolution to organisms.

26/6/2020

K.C.S.E Biology Q & A - MODEL 2012PP1QN22

State the importance of divergent evolution to organisms.

answer

Results in adaptations that enable organisms to exploit different ecological niches; leads to the formation of new species;

Explain how comparative embryology is an evidence for organic evolution.

25/6/2020

K.C.S.E Biology Q & A - MODEL 2011PP2QN02

Explain how comparative embryology is an evidence for organic evolution.

answer

Vertebrate embryos have similar morphological features; which suggest a common ancestry;

State two limitations of fossils as an evidence of evolution.

25/6/2020

K.C.S.E Biology Q & A - MODEL 2011PP1QN21

State two limitations of fossils as an evidence of evolution.

answers

Missing links;
Distortion of parts during sedimentation/earthquakes/putrefìcation;
Destruction of fossils by geological activities/faulting/folding;

What is meant by convergent evolution?

25/6/2020

K.C.S.E Biology Q & A - MODEL 2011PP1QN21

What is meant by convergent evolution?

answer

Where different structures evolve to perform the same function (e.g. wings of insects and birds are different in structure but are used for flying);

Why is Lamark’s theory not acceptable?

24/6/2020

K.C.S.E Biology Q & A - MODEL 2010PP1QN24

Why is Lamark’s theory not acceptable?

answer

Acquired characteristics cannot be inherited;

State two ideas proposed by Lamark in his theory of evolution.

24/6/2020

K.C.S.E Biology Q & A - MODEL 2010PP1QN24

State two ideas proposed by Lamark in his theory of evolution.

answers

Use and disuse;
Acquired traits can be passed on to offspring;

Explain why certain drugs become ineffective in curing a disease after many years of use.

23/6/2020

K.C.S.E Biology Q & A - MODEL 2009PP1QN10

Explain why certain drugs become ineffective in curing a disease after many years of use.

ANSWER

Disease causing organisms mutate; and become resistant

Give an example of a vestigial structure in human

23/6/2020

K.C.S.E Biology Q & A - MODEL 2009PP1QN10

Give an example of a vestigial structure in human

ANSWERS

Appendix/ coccyx/tail ( tail bone)/ semi - lunar folds of cornea of eye/ nictitating membrane caecum/ ear muscles/ body hair/

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