Biology_2013_STPM Term 3_Objectives

Polymorphism in life cycle is a unique feature of the phylum

• Cnidaria

• Echinodermata

• Platyheminthes

• Porifera

The dichotomous key below is used to identify arthropods up to the class level.

1.a. Body divided into three parts, three pairs of jointed legs and a pair of antennae...p

1.b. Body divided into two or three parts, more than three pairs of jointed legs and antennae present or absent...refer to 2

2.a. Body divided into three parts, four pairs of jointed legs and antennae absent...q

2.b.b. Body divided into two parts, many pairs of jointed legs and two pairs of antennae...r

Which arthropods correspond correctly to their classes?

p q r

• p: Arachnida

  q: Insecta

  r: Crustacea

• p: Crustacea

  q: Insecta

  r: Arachnida

• p: Insecta

  q: Arachnida

  r: Crustacea

• p: Insecta

  q: Crustacea

  r: Arachnida

What is the average percentage efficiency of the energy conversion in each level of a food chain?

• 10%

• 50%

• 70%

• 90%

Which will not affect population growth?

• Migration

• Mortality

• Mutation

• Natality

Which are true of K strategies?

I. Early sexual maturity

II. High competitive ability

III. Live in a stable environment

IV. Short gestation period

• I and III

• I and IV

• II and III

• II and IV

What is the density of Imperata sp. ?

• 33.3%

• 37.21%

• 53.33%

• 59.26%

A study shows that the average mortality rate among infants who are less heavy and very heavy is high. Which is true of the above type of selection?

• Elimination

• Directional

• Disruptive

• Stabilising

Which evolutionary mechanism causes random variation in an allelic frequency occurring by chance from one generation to another especially in small population?

• Gene flow

• Genetic drift

• Gene mutation

• Genetic isolation

Which is the possible term used to describe phenomenon when a red - flowered snapdragon is crossed with a white - flowered snapdragon plant producing a pink - flowered progeny?

• Epistasis

• Codominance

• Complete dominance

• Incomplete dominance

An allele Y which controls the yellow coat colour of mice is dominant over the allele y which controls the grey coat colour. In a population of 2500 newborn mice, 400 are grey. Assuming that the population is in genetic equilibrium, determine the frequency of allele Y.

• 0.84

• 0.60

• 0.40

• 0.16