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Biology for Advanced Level Secondary Schools
capital letter and separated from specimens and state any three
species name by a dot. For instance, natural morphological features
Panthera lupus can be written as P. justifying the placement in their
lupus or the bacteria Escherichia coli respective genus.
as E. coli. The abbreviation “spp.” is
used to represent several species. In Questions
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this case, the genus, is italicised or 1. Give two features you would use to
underlined and not the abbreviation. justify the placement of each of the
For instance, Hyparrhenia spp. three plants to their respective species?
imply several species of the genus 2. What two characteristics differentiate
Hyparrhenia, such as Hyparrhenia the three species from each other?
rufa, Hyparrhenia collina, and
Hyparrhenia variabilis. On the other
hand, if the actual specific name Task 2.5
cannot be ascertained or specified, an Walk around the school campus or
abbreviation “sp” followed by a dot is visit a nearby botanical garden to
placed after the generic name, but it identify trees by their common and
is not italicised while the generic name scientific names.
is italicised or underlined, for example,
Hyparrhenia sp. 2.4.2 Significance of scientific names
The use of scientific names is very
important for the following reasons:
Activity 2.2: Binomial nomenclature
(a) They simplify communication
Materials worldwide. This is because only one
Solanum incanum (thorn apple or valid name is used for each living
bitter ball or bitter apple), Solanum organism.
nigrum (black nightshade or Hound’s (b) The system maintains uniformity in
berry), Solanum tuberosum (irish naming organisms worldwide. This
potato plant) helps to avoid confusion and ambiguity.
Procedure (c) Unlike common names, scientific
(a) Collect the following specimens names are not influenced by language
from the school surroundings or barrier or region.
nearby environment: Solanum
incanum, Solanum nigrum, and Exercise 2.2
Solanum tuberosum.
1. A secondary school student wanted
(b) Name the genus in which the three to order some plant species from
collected species belong. Tanzania Tree Seeds Agency (TTSA)
(c) Using a hand lens where necessary, for the home garden. The student
observe each of the collected plant named the species to be ordered
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