(a) Explain the term adaptation in relation to the mode of life of an organism.
(b) Explain how each of the following structures adapt the organisms that possess them to their modes of life:
(i) succulent leaves in Aloe sp
(ii) succulent stems and reduced leaves in cactus plants
(iii) short, strong beaks in fowls
(iv) counter shading in fish
(v) tiny scale leaves on needle-like branches of pine trees.
(c)(i) What is population?
(ii) State five effects of overpopulation on a community.
(a)(i) What is placentation?
(ii) Name two organs associated with the human placenta.
(b) State five functions of the human placenta.
(c) Write short notes on the following:
(i) viviparity
(ii) territoriality
(iii) seasonal migration
(a) List four characteristics which can be genetically transmitted in humans.
(b)(i) Name two sites eac• in plants and animals where meiosis occurs.
(ii) State two differences between meiosis and mitosis
(c) A woman with blood group ‘A’ (heterozygous) claimed that her son who has blood group ‘0’ was fathered by Mr. James who has blood group ‘A’ (homozygous). With the aid of suitable genetic diagrams
(i) prove or disprove the woman’s claim
(ii) give reasons to support your answer.
(a) Write short notes on each of the following:
(i) ecological niche
(ii) population density
(iii) climax continually
(b) Describe briefly the interactions between abiotic and biotic components of an ecosystem.
(a)(i) Name two types of germination of seeds giving one example of each type.
(ii) Describe a simple experiment to demonstrate that oxygen, water and warmth are necessary for germination of seeds.
(b) State two distinguishing features each of
(i) epiphytes
(ii) parasites
(c) Give two examples o parasitic plants.
(a) Write the chemical equation for each of the following processes:
(i) aerobic respiration
(ii) anaerobic respiration in plants
(iii) anaerobic respiration in animals.
(b) State four functions which the liver of a patient suffering from cancer of the liver will not be able to perform.
(c) Make a diagram 8 -10 cm long of a flame cell and label fully.
(d) Name one appropriate hormone each responsible for the following conditions in plants:
(i) ripening of fruits
(ii) breaking dormancy in seeds
(iii) weed control
(iv) leaf fall.
Which of the following animals exhibits territoriality?
- A. Rabbit
- B. Earthworm
- C. Lizard
- D. Toad
Which of the following statements reflects the mechanism of natural selection?
- A. There are variations within every species
- B. Individuals of every species are genetically identical
- C. No organism in a species dies before sexual maturity
- D. Organisms with selective advantages are less likely to survive
In evolution, analogous structures are significant because they show
- A. physiological diversity
- B. functional diversity
- C. genetic diversity
- D. structural diversity
The importance of courtship in animals includes the following except
- A. ensuring that the female chooses the right male species
- B. arousing both male and female partners
- C. protection of territory
- D. to coincide with the ovulation period and ensure fertilization
The percentage probability that a normal male married to a carrier woman would have a haemophilic male child is
- A. 35%.
- B. 50%
- C. 75%
- D. 100%.
What would be the phenotypic ratio of the offspring of a cross between a heterozygous dominant parent and a double recessive parent?
- A. 1 : 2: 1
- B. 1 : 1
- C. 3 :1
- D. 2 : 1
Mr. Andrew, his wife and child belong to blood groups A, B and O respectively. The genotypes of both parents are
- A. IA IO and IB IB
- B. IA IA and IB IB
- C. IA IB and IA IO
- D. IA IO and IB IO.
Which of the following statements is correct about the structure of a chromosome? A chromosome consists of
- A. two chromatids joined at the centromere
- B. Two chromatids joined at the spindle
- C. Two chromatin threads joined at the centrioles
- D. thread-like structures not joined together
In a family of eight (8) all the children are girls Which of the following reasons correctly explains this?
- A. The woman cannot produce male children
- B. The man has a low sperm count
- C. The Y component of the man’s sex chromosome was always involved
- D. The X component of the man’s sex chromosome was always involved.
In artificial selection, individuals without desirable traits may be prevented from mating by
- A. outbreeding
- B. sterilization
- C. inbreeding
- D. genetic engineering
An example of a saprophytic relationship is a / an
- A. vulture feeding on decaying meat
- B. mushroom growing on decaying vegetation
- C. boy eating stale bread
- D. earthworm feeding on decaying vegetation.
Which of the following statements about heredity is not true? In heredity the traits are
- A. carried by genes
- B. contained in the ovum and sperm
- C. always transmitted by one parent
- D. transmitted from parents to offspring
A man heterozygous for albino gene marries a woman who is also heterozygous for the gene. Both have normal skin colour. The probability that they will have an albino child is
- A. 1/3
- B. 1/4
- C. 4/4
- D. 2/4
A person with blood group, O can be given blood from persons who have blood belonging to
- A. group O only
- B. group A only
- C. groups A and O
- D. groups A, B and O
Fingerprints are useful in crime detection because
- A. the police have sophisticated fingerprint machines
- B. thieves may leave their prints at the scene of a crime
- C. no two people have the same fingerprint
- D. fingerprints are easy to make