Page 112 - General and Inorganic Chemistry for Advanced Secondary Schools Students Book Form Five and Six

Biology for Secondary Schools

(d) They have jointed and paired Classes of phylum Arthropoda
appendages that may be modified
in various ways to form structures, Task 5.14
such as antennae, mouthparts, Search from the library and reliable
legs and reproductive organs. The internet sources the information on
FOR ONLINE READING ONLY
modified appendages are used for classes of phylum Arthropoda, then
various functions, such as feeding, make short notes.
gaseous exchange, locomotion
and sensation. Based on the presence of antennae,
(e) Their body plan is bilaterally position and numbers of appendages,
symmetrical. This means, their habitats, life histories and habits,
bodies can be divided longitudinally arthropods are classified into five
into two equal parts through a central classes. These are class Crustacea
axis. which includes crabs and lobsters;
(f) They have compound or simple class Arachnida which includes spiders
eyes. and scorpions; class Chilopoda which

(g) They have open circulatory system includes centipedes; class Diplopoda
where blood is not confined to which includes millipedes; and class
the blood vessels and heart only. Insecta which includes cockroaches,
Blood flows into the body cavity to termites, and grasshoppers.
reach various tissues and organs.
Activity 5.15: Observing the external

Distinctive features of arthropods structure of crab, spider, grasshopper,
(a) They have jointed appendages and millipede
which serve different purposes, Materials: Preserved specimens or
such as feeding, locomotion and pictures of crab, spider, grasshopper,
sensation.
and millipede, notebook, pen and hand
(b) They have segmented bodies lens
organised into regions called Procedure
tagmata.
1. Using forceps, pick specimens
(c) They have an exoskeleton made from a preserving container and
up of mostly of chitin. put them in a petri dish.

2. Using a hand lens, observe the
specimens carefully to identify
their external features.

106 Student’s Book Form One Student’s Book Form One

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Biology FORM 1 new.indd 106
Biology FORM 1 new.indd 106 15/10/2024 09:24:35