Biology_2017_STPM term 3_Objectives

Which characteristics is true of the phylum Porifera?

• Triploblastic

• Some of them are sessile

• Body wall comprises ostia

• Possesses gastrovascular cavity

Which phyla correspond correctly to their respective characteristics?

• I : (p)

  II : (q)

  III : (r)

  IV : (S)

• I : (q)

  II : (r)

  III : (s)

  IV : (p)

• I : (r)

  II : (s)

  III : (p)

  IV : (q)

• I : (s)

  II : (p)

  III : (q)

  IV : (r)

If the efficiency of energy transfer from producers to herbivores is 10%, and to the higher level is 20%, while the amount of energy obtained by the secondary consumers is 36 kJ m^-2y^-1, calculate the net primary productivity of the producers.

• 360 kJ m^-2y^-1

• 720 kJ m^-2y^-1

• 1800 kJ m^-2y^-1

• 7200 kJ m^-2y^-1

Which is true about a population which grows exponentially?

• Growth is unlimited.

• Growth starts rapidly.

• Growth is limited by the environment resistance.

• Growth is influenced by a high population density.

What is X?

• Fungi

• Bacteria

• Inorganic materials

• Non-living organic materials

A swampy area was the habitat of a population of wild rats. When an airport was built in the area, the rats lost their habitat and moved to the store within the airport area. After many generations, the rats had adapted to the environment in the store. Their characteristics changed and they became a new species of rats.

What type of selection has occurred?

• Artificial selection

• Disruptive selection

• Stabilising selection

• Directional selection

The example of reproductive isolating mechanism in the formation of new species are given below.

I. The population of lizard live in two different islands.

II. Two different populations of buffaloes mate and their offspring are sterile.

III. Two different populations of fish mate but their offspring fail to develop.

IV. Two different populations of snails live in the same area but do not mate due to different structure of reproductive of organ.

Which statement are the examples of post-zygotic isolating mechanisms?

• I and II

• I and IV

• Ii and III

• III and IV

The progeny of F1 from a cross between a true breed dominant round seed pwa plant with a wrinkled seed pea plant were self pollinated. Predict the result in the F2 generation.

• All seeds are round.

• All seeds are wrinkled.

• 1/4 of the seeds are round.

• 1/4 of the seeds are wrinkled.

After a test-cross is performed, two gene were mapped to be 17.2 cM apart. The result suggested that

I. 82.8% of the offspring are showing the parental phenotypes.

II. a single crossing-over has occurred between the two genes

III. 172 of the offsprings are showing the recombinant phenotypes

IV. the COV can be calculated by diving total number of recombinant phenotypes with total number of parental phenotypes.

• I and II

• I and IV

• II and III

• III and IV

Which type of gametes will be produced if non-disjuction of chromosomes Q occurs during first meiotic division?

• Two daughter cells contain two copies of chromosomes Q respectively and one daughter cell without chromosome Q.

• Two daughter cells contain two copies of chromosomes Q respectively and two daughter cells without chromosome Q.

• Four daughter cells without chromosome Q

• Four daughter cells with one chromosome Q